oH ‘ i syeet Dabepbeaee ars pebiavene Pep apesesayvapreebent eat et) Ussbeabedborty yt BSA ELI LL aAIEAD (prey PAUSED OES enya sey ESTES IEPA AE ONION} Debeesbuddabbelpaeebr ges HINO a Jaipsebeegerertes TSVPOPT DS ED SHS Beata Deepa ap agen ) ARR Tee a ed a) Feepnrtny H PAPE LPAUDMASVESSNDOESD OND ED DOP UL PAE MSE STON SE rae p at vase ) Ses tberogdy "PUPP ORR obs atee tei etge LN EAIEM ER ERIE ay HHEREY rty8 MALLETS SLES DESI ERLALUVISS ISL SETENT| Hteitate vires ih spate yyy PPUEDTEP PDD DL HO etyet red sebati onde tioat We ; 1 x as asa Brera rs toa or oa en ‘yop Db 4 Leia. yy iteest we VAS) ay eee Hiayas PUD ONTa RPAH AE atts At asain } yess ASTI POIASEESEEEI EL ' Hoag aed SURsaete PPEY POOP ADD CREAR eS ee ad ed DEAPAP Poe eeba obo rdi tee tha : UE MUST gD ABD i WPA Ei tee oepbte bea PT ie Srayrabe DAUPAE TNE RTT Cheer seb eaba NOPSUDO CPOE sv eP ban Tae eerie ject son Heian Atari ad ia PTE Peerisee sae eeR cata X THEO Ue aby: Ridabrestha dt ae Gspyabpareivar Wpaletashe AIPRCAIIASP ESS PLIST SITET SS ah2 Neier we row eer sere fase aan 3 } i } Sa es desetietie Me SSS sSeS iss taye THeeADA iidaats aaa gine oe Pe, AO) hives? weep eaibiabaar aa Peteat hie Thebarateaboareadeel be aaah aon Ea! tH a Meg J PeeesealradeainaT PRPAPEEEOPVESY Gay DAPSUN PANU ER Eel bab eae bis i SUSPUPUEP ENDS Obb si sehateaanl ate Mtbal AVY beat aaah Peeks) fark en ere, ~ i 3 HEEL eee n PUPA TERE be epee SrretUaTy ny Leihaes PADD ARS Va Dab ady ti : POAedESSaedind Dbeab tee bead SeshPeae Ate bigs Pateabetieates PADD be She apo FPMEDSERAREENDD ODL a eRL prob aee OPPETP AD end Fey POPUTRI Serdar tee Piderakbeeysenccgay Vas abee TUPI eeS Pees Tested ire ys AU UUERRR AGERE Dae aeeiey i 4 Has abaiee beesteel ub tihy, UST sha eb ad . ; Ae step bp uRE PY é SEA ate i Bay PRT e REPORT EEE } } ny Hy AUN cu aka Rsteset ated Hes butsbeitib bye i beer ies Satie PUNE abr PUSSTEIN Deter UR ea restay bac sip ed abetereeeyenas hy Shu beatiitrsey hibesbetaotanys asbesteatertoct Ube rage abisasate Diesteate st ebb ate} See EAE et PRATzb yep sh FOR THE PEOPLE FOR EDVCATION FOR §Q\UERN CE ~ CANCELLED LIBRARY OF THE AMERICAN MUSEUM OF NATURAL HISTORY U. 8. DEPARTMENT OF, AGRICULTURE. a 63-06 (7 Department Bulletins Nos. 76-100, mail 2} ww / ~] WITH CONTENTS AND INDEX. Prepared in the Division of Publications. NY "Y ~y MATION OF ies WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1914, vit HAST a neat yy ae whe pam ne Fe ek CONTENTS. 15 66 TOF Work AY DEPARTMENT BULLETIN 76.—LABORATORY AND FIELD ASSAY OF ARSENICAL Dierine Fiuips: REN COM INC EROS Re. < Aecmu un aA NS Ree eal Vk lela oes MA ORALOM MIC EROUS. a aks os 8 eal fale he eee le Ne Rue ne: PetgenrCENOUGIOMASSAY 22 Sema ccs. Oe eres Shai ae ee ele eae aa rela method for actual arsenious oxid ./-°. 42-22 452. -244-24525-54 2 2= Lece Breldemethodsion<; Notalvarseni@ a ots 2 20s seen ent nae a eae ease RE MINLeLOLC ALON ORTeESMI Se cae 2 ae SO Ce eS Ae see See oe DEPARTMENT BULLETIN 77.—Rocky Mountain MINE TIMBERS: Dirength 2.022... Spr =f ia AR ene IEEE te =, RON Bree ee en Deen PUN Consumpivomand durabilttys-: 250.2... S822. sae LCN ACR St spat oy ogee LA DTD CIES Ib G5 oe RRs Wa ee aR te nga see Relation of imported to domestic p Mhel9is potato cropse: osteo... oe A progressive policy needed. ...-. Protection from disease..........-- OLATORS = o's ons 26 oe eee Lack of an outlet for surplus potatoes: .-222-22-2- 252-44.) ee eee eee DEPARTMENT BULLETIN 82.—PowpDERY ScaB (SPONGOSPORA SUBTERRANEA) oF POTATOES: Imtroductione}: eee seco £ Common name of the disease caused by spongospora.......--..----.-.---- Scientific name of powdery scab... Description of the disease........- Geographical distribution of powdery scab..............-.-------------- Presence of powdery scab in Canada-.:.-.)-. 2443 Sees eeeeee see eee Powdery scab in the United States Damage to the potato crop...-.---- Effect on seed potatoes.......-.-- Macroscopic differences between spongospora and oospora scab .........-. Function of the spore balls and methods of infection .......-........--..- Seed ‘treatment. 2.3.5. 2 ees ee Soltreatment=...27s sg es Sacks and barrels as agents in spreading powdery scab...............----- Bamnoorap hy. 22° ..> eerste. = 2 DEPARTMENT BULLETIN 83.—FARMERS’ INSTITUTE AND AGRICULTURAL Ex- TENSION WORK IN THE UNITED STATES IN 1913: Progress of farmers’ institutes in 19 TS te a ee Growth of the institutes during the last decade................---------- Administrative methods........... Extension work by the agricultural colleges...........-..---+---------+-- Section on extension work of the association of American agricultural colleges and experiment stations 10 CONTENTS. DEPARTMENT BULLETIN 83.—FaRmenrs’ INSTITUTE AND AGRICULTURAL Ex- TENSION WORK IN THE UNITED States In 1918—Continued. NIETO OME CLUIRCS att. Neste iA So ace atin on ota Merah at Soe a ca la,b Ie Siel em isichs = ee Saurespoudence Schools. nese sc) so eee ces oe ee eee ans Dette Aid to agriculture by transportation companies...................---..--- Agricultural extension work in foreign countries. ............----------- SUSE) THE] OUOU RST Ne Sa Re pe i eR ere ee oe ea State officials in charge of farmers’ institutes.................-...-------- Sioinienes Onianmers/anstituitess LO ge: 2. eee cence So cls = eee cle nae = = Statistics of aericultural extension, 19130: 2/220... te oe DEPARTMENT BULLETIN 84.—EXPERIMENTS witH Upo, THE NEW JAPANESE VEGETABLE: Sanarterol nen COTA caer cele ene ran ea SS) TU a Ire oth lees a tae ciahe pene eas BEeM ae a DeTMMCTUES With UCOre eye. tle MAR Se et ye eee aa Relatives ol ude. .2...0.% Css cl ENR HARLAN ADE NA al BR Re ital cael RCO NORD TCL Co Bots) 0) Ge SVG UDI ee lle el ape SS ae Ma Lie ua Method of culture........--. Ph oN a RR pee a USE Wee tees Meso lamehinovor Ghershootsss ines. os. os eset oe ce ceiene as oe ipnepararionuor theitable: 2e 4s. 42.5.2 22 aes. 8 ic RS ce RRR ag TESST SE Soa Ie ar) oe gu TYP Shintatesne qmimTements Of dG 15 scons ls ae ole ae wee eas oe eee TD eeoeaysreyel aT MONT MIRAE saa ee ati os a ep ARN NS eV INCASONS Ton MemminodmetlOMkon WG Os e5— ees se hee ae ee ae DEPARTMENT BULLETIN 85.—THE Cost oF PASTEURIZING MILK AND CREAM: imiroduction:: =... +. Ne 8 Bact a eh 8 UD Ne Med UL aR esis oumilk-pasteunizing apparatus... 225..9222.222.9sc¢el se. oe eee Mestsior-cream-pasteurizine apparatus... ..- 2.222. 4-.:..-2he 2.22222 doe Choral SHOE S18 eis NUE NG CS ESTAR Rae eR ee PN ee I DEPARTMENT BULLETIN 86.—TxESTS OF WOODEN BARRELS: OD jeeiottnextestsi ai Mei eee ops elena Re cain eects Se) ee et Waa EVA Tatu Mee ys es os Nt Lt 20. 7 Ce Apa a se UEOe a 2 vege aca iBarmelitestsenc seo. 8 A NUR AIN EEA, SIR ea iS Sr RN LOD Minvortestse ie 32 es SN CA LSE ergs ye 0 ar ECSU LSEMmE PON Ninn RMU CA has LSM Meal aie ure aM acd au teac ate Changes in design as indicated by the character of the failures. . .--. Beye SRE SEAKOMeIMA Ce “UptDATheI Sas ete ote... SoM ne ee et en Ue eh Suggestions regarding tests of shipping containers.................-.----- DEPARTMENT BULLETIN 87.—FLUMES AND FLUMING: imercasin Amportance Ol tumess so 2.5... 2 GES oe ek ee Borms of lumber transported by flumes..../5.o...--+.--5.--2-22522- 2.5. GD syfBes) OST ARTOIS Se NN CSUN RENE oe HR Aey egacee ga agek Nane a oN Cea LMSC LES) 4 che GIES Sang snr mag em neva "0 Re eRe ee ea “ote ne Ws nae RY CN Ra ee ree CRE a EO cyan DU Small holding reservoirs at different points of flume..........----------- esenvoir pondsatiheadioimumes. 25540. gaol cece. ee ee TS HER WAG] ay TOONS aVElS pM Saget asp elmer MIEN NoaemaM ne, SS a oe el The use of ‘‘snubs” in unloading material from a flume........-....----- Reinforcement of flumes at points where extensive loading is to be done. . Telephones a valuable adjunct to flume operation......-...---..--------- Sawed material for stringers, sills, braces, etc., not a. necessity, but usually TOEE TCC OMONUCA eaten ert ia MERA ein ge Cera ce a a Water used in fluming sometimes available for irrigation purposes.....-.- - Brailimne-andaccouterme lumber: 2... .j06-4 4422 1 eee See see eS OD be = i) NIOnntb OnMH HE 6 DEPARTMENT OF AGRICULTURE, BULLS. 76—100. DEPARTMENT BULLETIN 87.—FLUMES, AND FLtuminc—Continued. Planing mills should be located at lower end of flume.............-.....- Size and carrying capacity of flumes for different classes of material. . ...- Cost of transporting different classes of material..................-. ..--- Gost.of construction... 222. ..6:...., + 2h sek. eR ee ee Advisable method:of nailing: ... 222.522... 3. 5 saa ee DEPARTMENT BULLETIN 88.—THE CONTROL OF THE CopLING MorTH IN THE Precos VALLEY IN New MExico: Introduction ck .c Sess soo a ee ee nee ese ee ee Experiments in the Sherman and Johnson orchard...............--------- Places of entrance of fruit by codling moth larvae.................---..-- Recommendations based on the foregoing results. .............---.------ DEPARTMENT BULLETIN 89.—THE DEATH or CHESTNUTS AND Oaks DUE TO ARMILLARIA MELLEA: Introductions. 2225s. oes ce cele ee ee Character.of the -timberexamined: 2722 25 ee Character of data obtained =... 545.50 pe eee ee ee ee ee eee General condition of the chestnutse:2--2- en. eee eee ee eee eee General condition-of the white oak=>. 2240. 225 a2 se eee ae Armillaria mellea on chestnuts, oaks, and poplars.....-..........-.------ General discussion of the diseased chestnuts and oaks.................--.-- Aréa infected by armillaria,.mellea...0 524), (ss See Se eee Armillaria mellea on chestnuts in North Carolina................-------- Conclusions: :;. 022050 aos Soe n oe be ceee Se eee eee ene eee ee DEPARTMENT BULLETIN 90.—THE Eyres APHIS: Improdu Chloe eee Le ae i a eS Recent TeCOr dss xc eecevafo eons bw oe te Deseription. 2s. 22s4255- obs i: eee ge 8 ee ee Distribution: 2.22622... ce os a ee Character of injury... 2. 2.2 2-.5-6..- seme ee eee - eee eee ee ea Halbite 2 .nksc oc = She Rs sia ee Life history and reproduction in Califormia..........22 220-2 eens esse Life history and reproduction in the greenhouse.....-.--....--.:-------- Lite.cycle im Califomia.3::..02- Jas theees- o> - - seen eee eee Natural control. 5% ge )sn:f cca Syn ie Soe eee one += See ee eee Experiments with remedies,.....- 222-2 s6- 2 2s-- - 5 = ae ee DEPARTMENT BULLETIN 91.—Cost AND MrTHODS oF Cinecmee LAND IN THE LAKE STATES: Introduction... 2. 2225.2. 3635 p02. noe oa 2 oe ee Be ee Methods ofclearing: - 25.2... .....:00%52 ee. oo oe ee Cost of clearing land. - 3652... .ag8 a8) 2 os. oe Disposal of. stumps aiter gulling./.22227)2...2. .. yb: eee en ee Summary and suggestions. f.. 2.482 see te 2. ose eee eee ee DePpARTMENT BULLETIN 92.—DeEstTRUCTION OF GERMS OF INFECTIOUS BEE DISEASES IN HEATING: Diseases of adult bees: - 222.22. See on ae nt oo) eee , Summary and general remarks. . 08". 2222072 0 so Se DEPARTMENT BULLETIN 93.—THE TEMPERATURE OF THE HONEY-BEE CLUSTER: Iastroduction:. :.. ccc ee oe SS ee eee tb ei oie bc oe ee The influence of external temperature on heat production........-.-.---- The effect of confinement and the accumulation of feces......-...--.----- Methods of heat production and conservation. ......------------+----+--- Soop ONIPMAKRNH EH ee — w wmnoowoonroark NH FR CONTENTS. DEPARTMENT BULLETIN 94.—DomeEstic BREEDS OF SHEEP IN AMERICA: TENTHRO GIOIA Beene he Be EAD ARAN LEAR BRE Be oe ane an. Je Rata nmemg nea @lissiteatton ol tie PreedSeen == acess = oe ee eo oe Ae ee BIST m ire BINT Oe tee me ase 2 cues cede ALi ee Rar ee Ae RT eT ASS ASS We Weroomva TD OUUle terrace © > teem Zoek rte’ Shp mene Re ete oli 28 Ny Ae pe BRITE GSO WHET CLO Wiican Se ent ey eet te ey Pear SNE RRND nay BE Sate ye ree oe EELS (SUG [GIS COU (Ss She apa sae A Re eA SE rg SirosEEMipshines. set 217 wean eee: Ue ee See TE ek Se eS MheOxiord Down she: . 22 ae! FD oc ts One SEL REE, Se Hite Ge len Spee be RDOrsetelOnMee cates s aacee ee en yee e oot Sone ore Seeman Shey Near is SO Sinttolke Downer 22 --ce asa oe CERT IES Came aaa MEMS Si 2 RS. sae res are ahee Clie vo uannee ne oe st Ieee sins ae ran) SS ies AN roa ee ee Ee “APT Suey TE GEO NSH ae on ne Pe SRS eed Spat Aa ne Ve regi Nee Sh 7) Mie Velsh Mommtain= 2) ares a Ss Se RR oe 8 aes OP a ‘iheyEixanoqorhorn:sireeps:2 2554282 2 25 Wiese ee eae caer ase See eee Piigeebve lamers ss sete ns ee Ro ene alee a cts Ae aa Ae he OETA Mier Wernya rh ee Se fo AOS We nS eae sek UR ER. oS MEE ARNG) SUNS Bawa a epee ss A STN FSIS eee i i oes a ere Pts A ee ere eR Mine wherCeStenss scams mace ee ee es ne Se oe PDinenCOus WO cian sai a a seeee te ee eS Ae OAR re eS as Dace at PTE ares wales trun oo Mra eee a te a 2 ft ah Ee pe IE ice) 7 ey eee hae Wine ivent: ormvommeyeMarsh oS. 2252 eri ae ee ey, Siineaiuensiesialer Yass cake sen ose as ean Sea wesans Oe Pe eel ees BRING SD AT ETO ORSnA = Sesame See ee Re yet arate roe es J ee Se ey Pane Wterblack-taced Hishland=: 235. 222255) Sie es Ee ee eS Rinemiana kinle-OncAna Wie sel «35 :o Okeke yen ee a I ys er ee hegre ersian: Seep-~ cs. ca kaso - sees ee es Jo ee as Se Sareea OeG ee tt ose Se eel aa pes ers eee Se bre La dae eee cian os Partial index of recent publications on the breeds of sheep.......-..----- DEPARTMENT BULLETIN 95.—INSECT DAMAGE TO THE CONES AND SEEDS OF Paciric Coast CONIFERS: SPrreesT eK (CDT OM pae eee ps coe els i Uta eee 2 2'. IS Nees tee Ne eta Cae eee Character and.cause: of damage. 2.22 Scio. eee ee oe 6 fae oie os ne Important groups of seed-infesting insects....-....--...------------------ Adaptation of the insects to the intermittent cone-producing habits of the NASIR ULE CS eons ey ee IS) oR crn 5 2 mem capietn ge Manse Sear InoveshIONs on misect damagers so. 2.2.2: MR eee ee Micthodsor preventine lossessss 6565252... Gee ee DEPARTMENT BULLETIN 96.—THE TEMPERATURE OF THE BEE COLONY: aE RO CUETO eee seep ee oe eee ee ine Same a oN AT cS paelees sit wn Ure ae The arrangement of the thermometers. .................-..:...---2--.--- MOE TUONO! APPALAUUS. eevee Se sky OT Re eS co a Ee Aes WineelaeOlOMy | ween see Se es 5 eG ee nate es TS Methods of observation and recording.......--...---..../2..42--.-----. Theconsuimption Olstores aim winter-.-.2.. ses es. OP ee General phenomena of the cluster in winter....................---.----- Temperature below frames in relation to outside air. .............-..---- - Comparisons of temperatures of the center of the cluster and of the outside Hiectsot manipulation on the cluster-..2..-2-.2 2222-2 Behavior of the cluster in winter; observaticns on the check colony...... bo OS O& o& Or or or Ot HH I DEPARTMENT OF AGRICULTURE, BULLS. 76-100. DEPARTMENT BULLETIN 96.—THE TEMPERATURE OF THE BEE CoLoNy—Con. Temperature accompanying the laying of the first eggs...................-. Transition from winter to summer conditions.....................-------- General phenomena of the summer temperature....................-.-.-- Relation of C to the outside temperature... ..... esse. sen sseseeee asses The maxima and minima of C in relation to O. ......-............---.-- Fluctuations in the hive temperature and the causes. ...............-... The effect of “‘Onentation” or “Play flights”... 2255-5 aes eee Effects of cluster heat on the temperature below the frames. .............. ‘The etiects of stormsso1-.5.....- ine Bw cin os Sate cin ele op The effects of transportation on the temperature of the colony............. DEPARTMENT BULLETIN 97.—IDENTIFICATION OF COMMERCIAL FERTILIZER Ma- TERIALS: Introduction... 23.5222 0.-.-deaee oe. eee). eee Mquipmente. .. oo). ofa es ee gees oe et Oe ele Isotropie substances. 50.22 2c. ae es ee 0. to. Sea Anisotropic substances... 0... 62 sapee ees doe: ae eee Uniaxial substances: -..:..--... -tkgpe ssa 2 a Biaxial substances, '... -s 1.24. --.s See eee SoS eee Optical constants of fertilizer materials. ..........--- 22-525. -- sees ees DEPARTMENT BULLETIN 98.—THE APPLICATION OF REFRIGERATION TO THE HANDLING OF MILE: Changes in milk caused by temperature and time........-........-.----- Methods of utilizing refrigeration... ..--.2.-+5.- ho see nee eee Trnsplation o.oo. 2 20+ njeeeicieiew > sie eelecise +A eee eee Estimating the size of refrigerating plants....-...- septs: Coe eee Approximate cost of producing mechanical refrigeration in small plants... Requirements of refrigerating plants for dairy purposes..........-...----- Cooling milk on the farm.....-.- nargianetanetb lin eid = Gite tie toners Uae Maintaining low temperatures during transportation...........-.-..---..- Cooling milk at receiving ‘stations: 227... -! 22-202) Cooling milk in bottling plants... 2202252. -- ..-2 3 eee ee Refrigeration In creameries:'. .. 205222922. Se DEPARTMENT BULLETIN 99.—TESTS OF SELECTIONS FROM HYBRIDS AND Com- MERCIAL VARIETIES OF OATS: Introduction. ..- 22... 2 oss. 0c apie ee ee ee Parentage of the selections... ...-. 24s¢2%--5- - 4.0 See. Oe The system of numbering...’ ....s522-).22-+ 22 a2 boo ee Making the selections: . 0... ..-- cece - 5 oa a Tests'at MelLiean... 225. 3B 26... 2a ese oe oes eee eee eee Tests at the Iowa Agricultural Experiment Station.................-.---- Tests at the Cornell University Agricultural Experiment Station.......... Tests at various other experiment stations.............-...--.------------ SUIMMATY 222. ~ soaeevee tesa be Lemecanosoces 66 - Oe DEPARTMENT BULLETIN 100.—WaALNUT APHIDES IN CALIFORNIA: Introduction....... wt ewittbever seca s tease hele 6.2. pee The European walnut apbis (Chromaphis juglandicola Kaltenbach). - - -.- The American walnut aphis (Monellia caryae Monelli)......-.-..-..------ The little hicko:y aphis (Monellia caryella Fitch).........---------.--.- Monellia californica Waste... - 22 202 enn ie ene 2 ose + Natural control of waluut-aphides.......--..:--...-~ i=: ees Artificial control of walnut aphides......--.....----- mp ma ph Summary 210% =... oe ee ee eee ULL tire Or! THE sl) USDEDARENT OP ACICLTRE No. 76 Contribution from the Bureau of Animal Industry, A. D. Melvin, Chief. April 29, 1914. (PROFESSIONAL PAPER.) LABORATORY AND FIELD ASSAY OF ARSENICAL DIPPING FLUIDS.’ By Rozserrt M. Cuarin, Senior Biochemist, Biochemic Division. INTRODUCTION. The use of arsenical dipping fluids for the treatment of cattle infested with Texas-fever ticks is ncreasmg. A mixture termed by the Bureau of Animal Industry “‘standard arsenical solution” is pre- pared from white arsenic, sal soda, and pine tar, and is largely used for both official and private dipping operations. Proprietary dipping fluids also have appeared on the market to some extent. Previous publications ? of the bureau contain directions for the preparation of ‘‘standard arsenical solution,” together with general information of importance to users of arsenical dips. During the last few years wide practical experience of the bureau with all kinds of arsenical dips in the field has shown with increasing forcefulness that one of the greatest obstacles to the successful use of these preparations, and consequently to the effective prosecution of the tick-eradication work now progressing so well over considerable areas, lies in the uncertainty attached in many cases to the composi- tion of these dips. There is no doubt that arsenical baths, properly prepared and used, are very effective tickicides and cause little injury to cattle. But the Texas-fever tick is a resistant organism. Destruction only follows its immersion in rather strong solutions of arsenious oxid, so strong in fact that if made only a little stronger the cattle themselves will begin to show effects. That is, the margin of safety within which solutions of this violent poison may be satis- factorily used is rather narrow. ‘Too little fails to kill the ticks; too much injures the cattle. In either case the cause of tick eradication 1A popular account of laboratory tests for actual arsenious oxid and for total arsenic, together with methods of field assay for dips used in tick eradication. Of special application to officials and others con- cerned with the analysis and control of these preparations. 2 Warmers’ Bulletin 498; Bureau Animal Industry Circular 207. 29207°—14——__1 2 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. recelves a setback, not onl} through the wasted lanor of ineffective dippings or the economic loss of injured cattle, but still more through the arousing of distrust or even enmity in those very persons whose willing cooperation in tick-eradication work is most to be desired. The causes which may lead to the use of a bath of the wrong strength are rather numerous. Impure materials may be purchased; mistakes in measurements or computations are sometimes made even by a careful man. But these things can all be checked and guarded against; the greatest difficulties arise in maintaining the bath at the right strength, once it has been prepared. A fresh bath can not be made up every time a few cattle are to be dipped. Practical con- siderations render it necessary to use the bath over and over again, perhaps during a period of several months, sufficient fresh fluid being added from time to time to replace that carried out by the cattle. During such a period of time, especially in the hot summer weather, evaporation of water from the dip naturally tends to con- centrate it. This may be compensated for in a measure by marking the level of the dip on the side of the vat before a period of disuse, and then fillmg up to the mark with water when the dip is used again. But it is difficult to construct a vat holding one to three thousand gallons so as to be entirely free from leaks. Therefore it is uncertain in any case how much of the lowering of the level of the dip is attributable to evaporation and how much to leakage. Leakage may likewise be in as well as out; that is, rain, surface water, or ground water may enter the vat. Even if these difficulties are avoided, there is still another factor which evades all precautions, the fact that used arsenical dipping fluids may in course of time undergo a process of oxidation whereby the arsenious oxid originally present as sodium arsenite is converted. to arsenic acid or sodium arsenate. Various observers have noted such a tendency, but have usually attached little importance thereto, assuming it to be caused by a slow and relatively insignificant chemical reaction. It has remained for Fuller, working in this laboratory, to show that the change is essentially caused by the growth of microorganisms in the fluid—that is, it is a biological process and not a simple chemical action—and furthermore that it may become very extensive, converting nearly all the arsenic into the oxidized form. Tests by the Zoological Division of the bureau indicate that arsenic in the form of arsenate is probably a less effective tickicide than when present as arsenite, while at the same time decidedly poisonous to animals. Laws,? as the result of a certain number of experiments, has concluded that arsenic, existing as arse- 1 Bureau Animal Industry Cireular 182. 2Laws. The Tick-killing Properties of Sodium Arsenate. The Agricultural Journal of the Union of South Africa, 1913, vol. 5, p. 915. ASSAY OF ARSENICAL DIPPING FLUIDS. 3 nate is probably somewhat less than half as powerful as arsenic in the form of arsenite in its effects upon both cattle and ticks. Also it has recently been observed that arsenical baths under certain con- ditions sometimes display the converse phenomenon of reduction— that is, arsenate tends to be reconverted to arsenite. Laws, in the article above mentioned, suggests that the phenomenon of reduction may likewise be attributable to the action of microorganisms, of course of different species from the organisms which cause oxidation. Recent work in this laboratory has substantiated the correctness of Laws’s surmise. Pending the completion of certain researches it may simply be stated here that both phenomena have been observed to occur in baths in actual use in the field, sometimes in the same bath; that is, a single bath may show alternating tendencies in the two directions, first toward oxidation, then toward reduction followed by oxidation again, andsoon. The primary condition which determines in which direction the change shall progress at any given time or in any particular bath is the degree of use which the bath is receiving. Under present ordinary conditions which appear to prevail in the field a gradual oxidation may be looked for. It is only in vats through which cattle are passed in exceptionally large numbers and at very frequent intervals, such as the vats at some of the stockyards centers, that reduction as a separate phenomenon becomes apparent. A consideration of the above facts renders sufficiently obvious the necessity for some analytical control of the baths used for dipping. The assay of arsenical dipping fluids, at least with sufficient accuracy for practical purposes, is not a difficult matter. It is no- where described in chemical literature, however, and the average chemist, when offered the problem, will be somewhat daunted, not knowing how he may best set to work to obtain good results without a considerable expenditure of labor. It is believed that some of the methods herein to be described can be successfully executed by per- sons who possess but a limited chemical training. In almost every section of the country there should besome one, pharmacist, physician, veterinarian, instructor in school or college, or even student, who would find it worth while for a comparatively small fee (provided a sufficient number of samples are sent. in from various sources) to undertake the assay of such preparations. A 4-ounce sample! is sufficient, though a larger quantity is rather more convenient for the analyst. It is also purposed to describe a portable testing outfit that has been devised for the use of bureau inspectors in the field, and that enables them, without the possession of any chemical knowledge whatever, at the side of the vat and in a few minutes, to determine 1 For precautions necessary in sending samples see page 4. 4 BULLETIN 6, U. S. DEPARTMENT OF AGRICULTURE. the strength of arsenical solutions prepared after the ‘standard formula.” It is necessary therefore to describe (1) methods for the determina- tion of actual arsenious oxid, and (2) methods for the determination of ‘‘total arsenic,’ that is, methods which shall include arsenic present in the oxidized form as well as that existing as actual arse- nious oxid. It is necessary also to describe different variations or modifications of processes for these two determinations, respectively appropriate for use by (1) trained chemists with abundant laboratory facilities, (2) persons possessing but slight chemical training and equipment, and (3) persons in the field possessing no chemical knowledge or training whatever, who obtain their results by manipula- tion of an ‘‘outfit”’ prepared by a trained chemist. LABORATORY METHODS. It is to be distinctly understood that the methods here described are not in all cases adapted or intended to reach a high degree of accuracy from a chemist’s viewpoint, though as a matter of fact most of them are very accurate under especially favorable conditions. A certain variation must necessarily be allowed in the composition of baths prepared in the field. Again, experience has shown that the percentage of arsenic in such baths may vary within certain limits without perceptible effect upon either their effectiveness or their safety. Therefore the purpose of assay is not primarily to determine the exact percentage of arsenic—though the nearer this result is ap- proached the better—but to insure that the composition of the baths used shall fall within certain limits. Extreme accuracy, which is not necessary, must be sacrificed to simplicity and convenience, which are necesssary to permit the execution of very frequent tests. METHODS FOR ACTUAL ARSENIOUS OXID. Whatever method may be employed for the determination of actual arsenious oxid, there are certain precautions connected with the tak- ~ ing and the storage of samples which can not be omitted if the results are to be of any value whatever. As already noted, the arsenic in used arsenical baths tends to change its degree of oxidation, mainly through the action of microorganisms. Other things being equal, the rapidity with which this change takes place is greatly influenced by temperature, so much so that a sample contained in an ordinary cork-stoppered bottle and exposed to summer heat may show more change after one day than it would show after a week in the original vat in its comparatively cool location underground. The rate of the change can accordingly be retarded by keeping the sample cold, as by storage in an ice box after receipt; but if the sample has trav- ASSAY OF ARSENICAL DIPPING FLUIDS. 5 eled any considerable distance the mischief probably has already been done before its receipt. The growth of microorganisms, and conse- quently the change in degree of oxidation, can be inhibited by the addition of an appropriate antiseptic, such as formaldehyde, care- fully added from a medicine dropper, in the proportion of 5 drops of the commercial 37 per cent solution to each 100 c. c. of bath. Carbolic acid and mercuric chlorid are wholly inappropriate for the purpose. Also since oxidation obviously can not take place in the absence of air, it is best to fill the bottle nearly full with the sample, leaving only a little air space, cork, and cover the cork and lip of bottle (which must be dry) completely with melted sealing wax, paraffin, rosin, or some similar material. Whatever means are employed to preserve the sample the operations ought to-be executed at the vat side immediately after taking the sample. A few matches will furnish the heat necessary for melting the sealing material. No sample should, of course, be taken from a vat until the contents of the latter have been thoroughly stirred up. Aside from general reasons for this practice in all sampling it is entirely possible that the oxidation of an arsenical bath standing at rest in the vat may proceed from the surface downward. That is, the upper few inches in free contact with air might have become almost entirely oxidized while toward the bottom the bath might be still in its original condition, or might even be undergoing reduction. The first step for the analyst, therefore, is to determine whether the sample has been properly taken and properly preserved during shipment. If the necessary preacutions have not been observed, the analyst is justified in reporting only a “probable” or “ provis- ional’’ figure for ‘‘actual arsenious oxid.”’ The final measurement of arsenic is made in all cases by titration with standard iodin solution and starch indicator, much used by chemists for a variety of purposes. The necessary solutions are the following: (1) Starch solution.—Stir up about a gram of starch, best obtained from the druggist, in about 20 c. c. of water and add the mixture slowly to about 200 c. c. of boiling water. Continue gentle boiling about 5 minutes. The solution should be freshly prepared every day. (2) Diluted sulphuric acid (10 per cent)—Pour 100 grams (or 55 c. c.) of concentrated sulphuric acid slowly, in a small stream and with constant stirring, into 825 c. c. of water. (3) Standard solution of arsenious oxid—Weigh out accurately and exactly 2.5 grams of the purest obtainable white arsenic, and about 10 grams of sodium bicarbonate, bring into a capacious beaker or flask with about 200 c. c. of water, and boil gently until the arsenic is all dissolved. Cool, and cautiously add dilute hydrochloric or 6 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. sulphuric acid until the solution is slightly acid to litmus paper or methyl orange, or, best of all, phenolphthalein. When thoroughly cooled to room temperature, make up the solution to exactly 1,000 c. c. Each cubic centimeter will then contain 0.0025 gram arse- nious oxid. The chemist! will recognize this as approximately a ‘‘twentieth-normal’’ solution. If well stoppered, the solution will keep a year or more. (4) Standard vodin solution.—Weigh out about 6.5 grams of iodin and 20 grams of potassium iodid. Cover with about 100 ec. c. of water and leave, occasionally mixing, until all iodin is dissolved. Then make up to 1 liter. To obtain the exact strength of theiodin solution, measure exactly 25 c. c. of the standard arsenious oxid solution into a 200 ce. c. flask or wide-mouth bottle, add about 25 c. c. of water, about 2 grams of sodium bicarbonate, and a few cubic centimeters of starch solution. Then, while shaking the flask, run in the solution of iodin from a burette? until the blue color of iodized starch just remains permanent. ‘Twenty-five cubic centimeters of the standard arsenious oxid solution contain exactly 0.0625 gram of arsenious oxid. Therefore, the number 0.0625 divided by the number of cubic centi- meters of iodin solution necessary to just produce a permanent blue color, gives a quotient which represents the exact weight of arsenious oxid to which each cubic centimeter of iodin solution is equivalent. For example, suppose 26.2 c. c. of iodin to be required. Then 0.0625 +26.2 =0.00239 gram arsenious oxid per each cubic centime- ter ofiodin. The standard iodin solution should be kept only in glass- stoppered bottles, as it will be weakened by contact with rubber or cork. If preserved in tightly stoppered and well-filled bottles in a cool, dark place, it retains its strength a considerable time, but in practice it should be standardized against the standard olition of arsenious oxid every week or two. For the actual analysis two methods will be described. If the sample is a concentrated preparation, it should always be reduced by dilution with water to the strength at which it is intended for use in actual dipping. METHOD ‘‘A’’ FOR ACTUAL ARSENIOUS OXID. Measure 25 c. c. of bath into a beaker, flask, or bottle of convenient size, add about a gram of sodium bicarbonate and about 10 c. c. of starch solution. Run in standard iodin solution until the blue color appears just as in standardizing the iodin solution, though here it here given are intended, as simply as possible, to meet the needs of those who may be without much chemical knowledge or a highly accurate analytical balance, perhaps lacking even burettes and pipettes. 2A 25¢. c. measuring cylinder may be employed if a burette is lacking. ASSAY OF ARSENICAL DIPPING FLUIDS. i usually fades out in a minute. In the case of very dirty baths the color may appear simply as a violet, reddish, or brownish deepening of the naturally dark color of the bath itself. In such cases it is well to have two flasks at hand, both containing the measured por- tions of bath and starch solution. Then by running iodin solution into one of the flasks and constantly comparing the color with the color of the liquid in the other flask, the point at which the change occurs may be more easily distinguished. Since the color is not at all permanent in the case of old and dirty baths, and since slight changes of tint are impossible to distinguish in such baths, it is good practice to add the iodin solution in quantities of 0.5 c. c. at a time when it is suspected that the end point is close at hand, then to mix . thoroughly and immediately observe the color. This quantity of iodin solution is usually sufficient to produce a very pronounced change of tint if the end point of the titration really has been reached. The final reading should then be corrected by subtracting 0.25 or 0.50 c. c., whichever is judged nearest correct. The number of cubic ‘centimeters of iodin solution needed to produce the blue color, multiplied by the strength of each cubic centimeter in terms of arsenic, and this again by 4, will give the grams of arsenic per 100 c. c. of bath—that is, the percentage. For instance, suppose that each cubic centimeter of iodin solution was found to be equivalent to 0.00239 gram arsenious oxid, and that 18.3 c. c. of iodin solution were employed in the titration of 25 c. c. of a bath under examination. Then the bath contains 0.00239 X18.3X4=0.175 per cent of actual arsenious oxid. Theoretically, method ‘‘A”’ can not be applied with perfect accu- racy to dipping baths, on account of the possibility that substances other than arsenious oxid—such as tar and organic matter derived from the cattle—may absorb some iodin and thus lead to false results. Practically, however, this method has been shown by many tests to give useful results on dipping baths of all ages prepared after the ‘standard formula”? recommended by the Bureau of Animal Indus- try. (See p.1.) That is, the various ingredients of the tar and the organic matter derived from cattle actually do not interfere fatally, but absorb iodin so slowly that the end point with starch is obtainable without difficulty, although it usually fades out in a brief time. Therefore, method ‘‘ A” is suggested for use in the practical testing for ordinary purposes of baths prepared after the ‘standard formula.” It must not, however, be employed on baths prepared from any proprietary dip unless it is certainly known that the particular dip contains no substance which can interfere. Since it is the present policy of the bureau to permit for use in official dipping only such proprietary preparations as may be satisfactorily tested by means of the field outfit later to be described, and since the field test is practi- LL —L——<—<— === 8 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. cally identical with method “A,” the latter method may be safely employed for the examination of samples known to be prepared from proprietary dips which have received such official recognition. METHOD ‘‘B’’ FOR ACTUAL ARSENIOUS OXID. Measure 25 c. c. of bath into a small beaker, add 5 c. c. of 10 per cent sulphuric acid and 0.25 gram of acid-washed blood-charcoal. Stir thoroughly and heat nearly to boiling—best on a steam bath—for five minutes. Then filter and wash with hot water until the filtrate amounts to a little over 100 c. c. If the bath appears to be very heavily loaded with dirt or tar, the addition of about a gram of acid- washed kieselgeuhr (infusorial, siliceous, or diatomaceous earth), followed by thorough stirring before filtration, will greatly hasten the passage of the liquid through the filter. When the filtrate has been thoroughly cooled to room temperature, sodium bicarbonate is added until 1 or 2 grams are present in excess after effervescence ceases. In case the bath was prepared from a proprietary product, dilute to about 200 c. c. before adding sodium bicarbonate, and lastly also add 2 grams potassium iodid.!| Finally, the solution is titrated with standard iodin and the result calculated as under method ‘A.’ If the greatest possible accuracy is desired a correction must be made for loss of arsenic through the use of blood-charcoal. This substance notably adsorbs arsenious oxid, and even after thorough washing a slight amount remains unaccounted for, which presumably still is retained by the charcoal. The amount of arsenic so lost appears—at least within practical limits—to be independent of the concentration of the bath, but is naturally dependent upon the amount of charcoal employed. Hence the charcoal must be rather carefully weighed or measured, and the amount of the correction for each lot of charcoal must be established by running comparative titrations on two portions of a solution of pure arsenious oxid,-one direct, the other after the treatment with charcoal, filtration, and washing, which has been described.2 The power of the charcoal to produce a water-white filtrate in which the blue end point is sharp and permanent far outweighs its disadvantages if accurate results are desired. Method “B,” like method “A,” should not be applied to proprie- tary dips unless they are permitted for use in official dipping or are otherwise known to be free from interfering substances. ! Dilution and the addition of potassium iodid aids in nullifying the interfering effect of cresylic acid and other substances capable of absorbing iodin which may be present in proprietary dips. Phenols rapidly absorb iodin from a solution containing sodium bicarbonate. The presence of free carbonic acid, which of course saturates the liquid during titration, greatly reduces the rate of absorption. Finally, if the solution contains a certain concentration of potassium iodid, and not above a certain concentration of the phenols, the end point comes out perfectly sharp, of good color and permanency, following a titration figure which appears wholly unaffected by the presence of phenols. 2 The sample of blood-charcoal at present in use in this laboratory demands a correction of 0.2 ¢. c. of twentieth-normal iodin for 0.25 gram charcoal. ASSAY OF ARSENICAL DIPPING FLUIDS. 9 METHOD FOR “TOTAL ARSENIC.” Strictly speaking the oxidized form of arsenic no longer contains arsenious oxid as such (As,O,) but only arsenic oxid (As,O;). Never- theless, for the purpose of making simple and convenient compari- sons, it is necessary to refer all quantitative statements regarding arsenic compounds to the common basis of their equivalent in arseni- ous oxid. Therefore, the term ‘‘total arsenic” is employed to signify all arsenic present in any form of combination or degree of oxidation, expressed in terms of arsenious oxid. The method to be described is a standard method based on the well-known fact that the reaction As,O,+41+2H,O—7As,0,+4HI is reversible, going from left to right in neutral or alkaline solutions, and from right to left in solutions which are freely acidified with a strong mineral acid. The reaction from left to right is the basis for the previously described methods for the determination of actual arsenious oxid. To determine total arsenic it is only necessary to allow the reaction to progress to completion from right to left, then to determine the resulting arsenious oxid in a manner similar to that already described. The solutions and reagents necessary, in addition to the same stand- ard iodin solution, starch solution, dilute sulphuric acid, and solid sodium bicarbonate, are anhydrous powdered sodium carbonate, solid potassium iodid, a one-tenth per cent solution of methyl orange, possibly concentrated sulphuric acid, and lastly a solution of sodium thiosulphate containing about 25 grams per liter. | The first step is to clarify and decolorize the solution. Hence proceed exactly as in method ‘‘B”’ for actual arsenious oxid (p. 8) until the filtered solution has been obtained. When both actual and total arsenious oxid are to be determined it is most convenient to double the quantities of both acid and charcoal, and to filter into a 200 c. c. volumetric flask. After thorough washing and cooling, the contents of the flask are made to the mark, mixed, and divided into two equal portions, one for actual arsenious oxid, the other for total arsenic. In either case transfer the solution containing the equiva- lent of 25 c. c. of the original bath to a 200 c. c. beaker, add 4 c. ¢. of concentrated sulphuric acid and about 2 grams of potassium iodid, boil gently until the volume of liquid is reduced to 50 ¢c.c., then cool to room temperature. The next step is to remove free iodin from the solution. This may be done while the solution is still in the beaker, by adding the solution of sodium thiosulphate drop by drop from a burette until the yellow color of free iodin just disappears. Any excess of thiosulphate must be carefully avoided. A safer procedure for one not experienced with the method is to wash the contents of the beaker into a flask of 600 to 800 ¢.c. capacity, dilute 29207°—14——2 r 10 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. to about 200 c. c., nearly discharge the color of iodin by sodium thiosulphate, add a little starch solution, and continue the cautious addition of thiosulphate solution until the blue color disappears. Then add standard iodin solution from a burette until the faintest possible persistent blue remains. Whichever method is used, the solution at this stage should be in a capacious flask, and should be diluted to about 300 c.c. Add a few drops of methyl orange, then render alkaline by the cautious addition with a spatula of anhydrous sodium carbonate. When the solution is clearly alkaline wash down any solid adhering to the neck or sides of the flask and add dilute sulphuric acid until the reaction is clearly acid, taking care that no particles of sodium carbonate remain undissolved. Then add a liberal excess of sodium bicarbonate, 10 ce. ec. more starch solution, and titrate with standard iodin in the usual manner. -The final titration should of course be corrected for the adsorption of arsenious oxid by blood-charcoal. No additional correction for adsorption of arsenic oxid appears necessary. No extra addition of potassium iodid appears to be necessary in case cresylic acid, etc., is present. The above-described methods for actual arsenious oxid and for total arsenic have proved reliable for the examination of all products thus far permitted for use in official dipping, and it is probable that they will be found applicable to any proprietary products which may receive such official recognition in the future, though obviously a positive statement on this point can not be made. The experienced chemist will naturally think of other methods which might be applied. For example, the acidified and filtered bath may be treated in a sepa- rating funnel with ether or some other appropriate organic solvent to extract cresylic acid, fatty acids, etc.; total arsenic may be deter- mined after the destruction of organic matter by appropriate diges- tion or incineration, or it may be separated by distillation; while it is known that some chemists prefer to determine directly arsenic existing as arsenic acid by titration with uranium acetate. FIELD METHODS OF ASSAY. A field method of assay is generally based upon a laboratory method; apparatus, reagents, etc., being simplified to the extreme in the interests of durability and portability, and the operations being reduced to the fewest and simplest, that they may be success- fully executed by persons wholly unacquainted with chemistry as a science. But a skilled chemist in the laboratory to supervise the field tests is even more necessary than if all the work were actually performed in the laboratory itself, for upon his experience and care reliance must be placed to standardize the methods in such a way that useful data may actually result from the manipulation of inade- quate apparatus by unskilled hands. Of course, it is only excep- ASSAY OF ARSENICAL DIPPING FLUIDS. 11 tionally that a laboratory method can be modified so that it is of any practical use whatever in the field, and in any event it 1s almost certain to lose something in accuracy. One thing is absolutely essential, that the field operator shall follow the instructions given him to the minutest detail, no matter how irrelevant or unimportant they may appear to him. FIELD METHOD FOR ACTUAL ARSENIOUS OXID. The field method at present employed by the bureau for actual arsenious oxid is simply an adaptation of laboratory method “A” for the same substance. The outfit is pictured in figure 1, and each part composing it will be described in detail. (1) The case.—The carrying case for the outfit is a rectangular box with a hinged cover, made of five-sixteenths-inch oak, of inside dimen- sions 74 by 5¢ by 14 inches. The interior partitions, of thinner and softer wood, are sufficiently indicated in the diagram. The case must be strongly mortised or nailed together, not simply glued, and should be varnished inside and out. (2) The utensils Bottle A’, fitting into compartment A of the case, is an ordinary 3-ounce wide-mouth bottle of clear glass. Measuring cylinder ©’, fitting in compartment C, is of ordinary type, of 25 c. c. size, graduated to half cubic centimeters. Preferably the figures indicating the graduations read down only. C’’ is a bristle swab for cleaning. It will be noted that the partitions of compart- ment C are cut away at the bottom to admit the foot of the cylinder. At the point p on the back wall of the case is fastened a quarter-inch pad of cork to protect the cylinder from breakage. The swab C’’ is put into compartment C after the cylinder, thus protecting the latter from breakage on that side. (8) The reagents —The iodin solution, or, as it is termed for field use, the “‘test fluid,” is contained in bottle D’, a 4-ounce standard- shaped “‘sample oil” bottle, preferably of amber glass and provided with a ‘‘flat-hood” glass stopper. A half-inch ring of the 13-inch (measured flat) thin rubber tubing, manutactured for use with Gooch crucibles, is drawn over the shoulder of the bottle, cemented in place, and coated with collodion. At the bottom of compartment D is fastened by a screw a conical spiral spring, the upper whorl of which is large enough to inclose the bottom of the bottle. In placing the latter in the case the bottom is inserted in the whorl of the spring and the bottle then pressed down until it slides into place. The partition between C and D is cut away in a semicircle at the point q¢ to allow the fingers easy access to the bottle when it is to be removed. The test fluid is of such strength that in the actual performance of the test each cubic centimeter of it employed represents exactly one 12 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. Fic. 1.—Test outfit for arsenic baths. ASSAY OF ARSENICAL DIPPING FLUIDS. 13 one-hundredth of 1 per cent of arsenious oxid in the bath under test. Therefore its strength should be originally fixed by standardizing it with the field apparatus against an average sample of used bath from the field in which the percentage (adjusted if necessary by the addi- tion of a little concentrated solution of arsenious oxid in sodium ¢ar- bonate) of actual arsenious oxid is close to 0.20 per cent and is accu- rately known through laboratory analysis. The true strength of this empirically standardized iodin solution should then be ascertained by titration against a strictly tenth-normal or twentieth-normal solution of arsenious oxid, and the result obtained may thereafter serve as the basis for the preparation of subsequent lots of test fluid. Obviously the true strength of the 1odin solution will be influenced to some extent by the method of graduation of the e¢ylinder, whether graduated “to contain”’ or ‘‘to deliver,’ and aiso by the depth of the meniscus, which in turn is influenced by the diameter of the cylinder. Hence, all field outfits under the supervision of a single laboratory should be fitted with cylinders of uniform model. Reserve supplies of test fluid should be kept in small, well-filled, tightly closed glass-stoppered bottles, and in a cool, dark place. In addition to the test fluid, starch and sodium bicarbonate, or some equivalent substance, are of course necessary. In fact, the practical preparation of a satisfactory form of starch has been the greatest difficulty attached to the whole process, though at the same time the key to its success. Tt has been known for many years that by the use of alcohol starch may be precipitated in water-soluble form, also that high-percentage, yet mobile, starch solutions may be obtained through proper treat- ment with hydrochloric acid, but the working out of a practical process for the preparation in quantity of a dry starch readily soluble in cold water and appropriate for use as an indicator appears not to be recorded. Into a5-liter round flask with a long neck is brought 400 grams potato starch, 2,300 c. ¢. distilled water, and, lastly, 80 ¢. c. of normal hydro- - chloric acid. The flask is well shaken to thoroughly wet and distrib- ute the starch and is floated in a kettle of water previously brought to vigorous boiling. The neck of the flask conveniently rests on the side of the kettle at an angle of about 45°, and as soon as the flask is brought into the bath it is gently but continuously rotated about its longitudinal axis. As the flask becomes hot the starch forms an evenly distributed, uniform jelly, which in about 7 minutes from the time of starting begins to liquefy and to fall away from the wall of the flask. When this stage is reached the mouth of the flask is loosely closed with an inverted beaker and the flask left in the boil- ing bath with an occasional rotation until the liquid becomes mobile 14 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. and shows no lumps of gelatinized starch remaining, which should take a little over an hour. The flask is quickly cooled in running water until it can be comfortably handled, then a few drops of methyl orange are added, followed by concentrated ammonia to alkaline reac- tion. Next is added 800 ¢. c. of 95 per cent alcohol with thorough mixing, and after a few minutes standing to allow air bubbles to sepa- rate, the liquid is strained through moderately coarse muslin. The addition of this amount of alcohol is insufficient to permanently pre- cipitate any starch, but notably thins out the original aqueous solu- tion. Starch will separate some time after the solution has become cold, but with proper management ample time remains for the subse- quent necessary operations. The solution, still at 40° to 45° C., is run through a number of fine jets into 4,000 ¢. ¢. of 95 per cent alco- hol, under continuous stirring. The whole is left for at least 48 hours with an occasional thorough stirrimg, after which most of the supernatant alcohol is decanted, and the rest used to transfer the starch to a 2-quart narrow percolator provided with a filter plate which is covered with filter paper or cloth. Here it is percolated with 95 per cent alcohol, being stirred up with a stick at intervals to prevent the formation of clumps or fissures, until the alcohol comes through of a specific gravity indicating a strength of 90 per cent. The starch is then transferred to a Biichner funnel, well drained with suction, and then spread out to dry in a moderately warm place.~ The starch so prepared is a fine white powder, more or less compacted to friable lumps, which completely disintegrate under slight pressure. A little of it thrown into cold water in less than a minute dissolves sufficiently to yield a good blue upon the addition of iodin and potas- sium iodid. Moistened with water or diluted alcohol it becomes gummy and dries out to a horny mass, difficultly soluble in cold water. The efficiency of the preparation therefore is dependent upon its fine state of subdivision, and care must be taken during the process not to expose it to air until after thorough digestion with alcohol of 90 per cent strength. It should be passed through a 60 or 80 mesh sieve and protected from moist air. The soluble starch may be thoroughly mixed with 10 times its weight of powdered sodium bicarbonate and the mixture divided into powders of about 0.6 gram, which may be packed in a paste- board box fitting into compartment B of the case. On the large scale, however, it is much better tomake the mixture up into tablets,’ after the following formula: 1 It is something of an art to make good tablets. No one should attempt it until thoroughly conversant with the principles of the process, and then only on a small scale until experience is gained. ASSAY OF ARSENICAL DIPPING FLUIDS. 15 Mallksusanim, cimexpoweer seks 2) oc. VMeReE LS SS22 el ies grams.. 100 Dadiuna bicarbonate, im powder... ..9 Bee... 6... 2.22. do.... 1,000 Mix, moisten with dilute alcohol, granulate, dry thoroughly at only slightly elevated temperature, and grind granules to pass a 20-mesh sieve. Mix granules with— Slludolles SU PRRCIOR eA Ae CMe ae eon a; ee ae a ee ie grams.. 100 USAIN DVO UNTO HUET ARE SSS Shee) cf a A ea ee dotee: 75 ‘TST, MUS Sa ea eR IS 2 = a douse: 25 Compress into tablets of 0.65 gram. The practical tablet maker will be tempted to criticize this formula because it carries so much powder; but since the soluble starch is ruined by wetting it can not be incorporated into the granules, so that there appears to be no escape from this drawback, which at any rate has not prevented the practical preparation of the tablets on a large scale for the use of the bureau.’ The tablets are put up in the 1-ounce wide-mouth bottle B’, fitting into compartment B of the case. On the inside of the cover of the case is glued a printed instruction sheet, which is protected by pyroxylin varnish. The instructions read as follows: UNITED STATES DEPARTMENT OF AGRICULTURE, BUREAU OF ANIMAL INDUSTRY. TEST CASE FOR ARSENICAL BATHS. Not to be used on baths prepared from proprietary preparations except on special instruction. Keep test fluid in acool dark place in glass-stoppered bottles only. DIRECTIONS. 1. Fill clean graduate with bath, setting the top edge of the surface of the bath on the upper gradua- tion (zero or 25 c. €.), pour (draining out drops) into clean wide-mouth bottle, add one white indicator tablet, and gently swirl or shake till tablet is nearly all dissolved. 2. Rinse graduate with clean water, shake out ad- hering drops (or rinse with a little test fluid), and fill to upper graduation (zero) with test fluid, setting the bottom of the curved surface on the mark. 3. While gently swirling bottle, slowly pour in test fluid from the graduate until the blue or violet color remains permanent for a half minute throughout the entire contents of the bottle after thorough mixing. Avoid excess of test fluid, adding only a few drops at a time toward the end. The number of cubic centimeters (reading at the hot- tom of the curved surface) of test fluid added to just pro- duce the color gives the number of hundredths of 1 per cent of arsenious oxid in the bath. If the assay is not performed at the vat directly after taking the sample, the same precautions to prevent changes in degree of oxida- tion must be observed as described under ‘‘Laboratory Methods for Actual Arsenious Oxid” (p. 4). The scope of application of the method is of course subject to exactly the same limits as laboratory ‘method ‘‘A”’ for actual arsenious oxid (p. 6).. 16 BULLETIN 76, U. S. DEPARTMENT OF AGRICULTURE. FIELD METHOD FOR “TOTAL ARSENIC.” Since, pending further investigation, it is not possible to credit arsenic in the higher form of oxidation (arsenic acid or arsenates) with definite value as a tickicide, the efficiency of dipping baths must be judged for the present solely on the results afforded by the test for actual arsenious oxid. On the other hand, studies of changes in the composition of a number of dipping baths in actual service in the field, together with practical experience, have so far failed to show a clearly defined danger that the average bath, in which the strength of actual arsenious oxid is maintained, is likely to reach a degree of oxidation which may render it dangerous to cattle. Nevertheless, in view of obvious possibilities in these two directions, it is desirable to possess a field method for the estimation of total arsenic. The method to be described makes use of a chemical reaction recently discovered by the writer,? namely, the reduction of arsenic acid to arsenious acid by thiosulphuric acid. After reduction and removal of excess thio- sulphuric acid by iodin in acid solution, sodium bicarbonate may be added and the arsenious oxid, now representing the total arsenic, may be titrated in the usual way. The method is necessarily more com- plicated, more tedious, and less accurate than the simple method for actual arsenious oxid. . Nevertheless, rather comprehensive tests by representatives of the bureau in the field indicate that, if conditions demand such a test and no better can be SL Ov are, the one at hand will afford useful results. In addition to the outfit and supplies already described, the pallor: ing supplies are necessary: “* Red tablets” Taleum:powder,; U.S: P.. oo cee 2k. 2S 2 eee oe grams.. 10 Raw potato, stan... jc- 2... = 2 MRE ote aan eps eee dozesn, 30 Mix, and stir in 0.1 gram Sudan Red III dissolved in sufficient ether to distribute the color, and evaporate off ether at a moderate temperature with frequent stirring. Add: Sodium bicarbonate in fine powder....4...-...--.--+.---+---2---+5 erams.. 3 Special soluble starch... . . . . . "RR. =. Ae Aisa se.-lO Mix, andadd potassium pyrosulphate powdered to pass a 40-mesh sieve.do. - 185 Mix well and compress into tablets of such size that 1 tablet will neailivers 9 to 10 c.c. of normal alkali. The mixture, not being granulated, can not be run through the hopper of a power tablet machine, but must be fed by hand into the die from the table of the machine. 2. ‘Blue tablets”: Ultramarine blue... )-..... (Ree = Bee. . ] Utowtl..2 CapSeeneee eee ener { \ 16 Do. 141 1 tojd.-.-.- Douglas fir: LS EL ONLOE. == Partly from yards of Northern Coal & Coke Co. Bouncpraps——----: " : GOVaee 225: \ 15 { partly from Gunnison National Forest. i LOWO==2- i Usguiba soczooesr 14 vee iit 15 Do. ristle-cone pine: Round props....-... { 3 1 ey cae = \ 15 | Pike National Forest, Colo. 13 | 1 to 10.--.--. CAPS. o-2-2eeeenees \ 15 Do. 14 | 1 to5-...... pate ey pine shipment A): 10 tontO.. 2 Pike National Forest, Colo. (Shipped as “Black Round props....... OP ei 0) \ 15 Jack.’’) : 435) Lito tol. .-- Caps ecccseee eee \ 15 Do. 14 | 1 to5.....- nhac ibaaeteh pine ipment B): 11 | 11 to 20....}\ - |fPartly from yards of Northern Coal & Coke Co. Round props... { 12 | 6 to 10.....|f op { partly from Gunnison National Forest. ; , 13 | 11 to 20.... Capss sce nese sce { (As 6 to)10-cee \ 15 Do. The material from the National Forests was received at the labora- tory in a green condition. The timbers from the yards of the coal company were partially air-dried. Upon arrival at the testing sta- tion all green material was barked and some of the specimens were soaked in water, while others were piled to air-season. The object of the water-soaking was to keep the timber in a green condition until tested or, in the case of the dead beams, to increase the moisture content to a point which would enable them to be compared with green material. The material cut green and water-soaked is used as the basis for making the comparisons with air-dry material. ROCKY MOUNTAIN MINE TIMBERS. 3 The water-soaked material was placed in a small pond during the summer months and the first tests were made after 60 days and the last after 125 days of soaking. No means were available to give complete submersion. The caps and props were tied in bundles of five and the beams were rafted, iron rails being used to help submerge a part of the material. At intervals of two or three days the bun- dles and the individual beams were turned to make the soaking as uniform as possible. a Ee nee ee ae! weer SSA oS seo =a | CRUSHING STRENGTH AT MAXIMUM LOAD = POUNDS PER are INCH BRISTLE CONE PINE LODGEPOLE PINE — a ccd ill a SS OGG aa i DOUGLAS FIR — an oe ha —_ ae MG ]) pp 7529 - estan en q yautow rae eal SARS IED LopatroLe. Pine — a0 an NSAIR_ DRY SG aa MQ MW S41228 Parent | EN@ELMANM SPRUCE cr ail HEE See | ALPINE FIR rel (| iE a SK TIE WESTERN YELLOW PINE SHIPMENT WESTERN YELLOW PINE SHIPMENT -B- Sani Lata SEEN feesadict flee aa Hunan ne ere a sul Le NS ETER meine TTT 8 rr i) 1000 2000 ni ia 6000 8000 9000 maa ile KOSS ay Tif ENnE can SAIR DRY ——— we WK MODULUS OF haben = POUNDS PER pe INCH Fic. 2.—Comparison of different species; 6-inch round mine caps—air-dried and green. was practically the same for both the crushing and bending tests, at the maximum load it is much more pronounced in the crushing tests. Stiffness in bending was increased by seasoning to 1.4 times the green value. There appears to be no marked variation in this strength ratio among the various species tested. It is slightly below the average in Douglas fir, due to the consistently high values for the green material in comparison with the other species, ROCKY MOUNTAIN MINE TIMBERS. 5 TABLE 2.—Summary of crushing tests on round mine props (nominal size, 5-inch top by 6 feet long). GREEN (WATER SOAKED). | Diameter. Crushing Rings strength anit Modulus Species, number of tests. Moisture.| per at maxi- at elastic| 01 elas- inch, mum aa ticity. Top. | Butt. load limit. Lbs. per | Lbs. per | 1,000 lbs. Lodgepole pine (shipment A); 10 tests: | Per cent. Inches. | Inches.| sq. in. 8q.in. | per sq.in. 75.7 40 5.73 6.18 1, 865 1, 495 599 102.0 56 6.13 6.92 2,285 1,981 839 48.3 23 4.93 5.33 1, 440 1,049 343 70.8 43 5,90 6. 58 1,605 1,240 496 108. 2 58 7. 00 7. 56 1,890 1,559 621 57.5 31 4.85 6.05 1,169 866 387 91.0 26 4.90 5.65 1,920 1, 490 541 123.6 42 5.37 6.05 2,355 1,944 706 38.6 13 4.62 5.38 1, 573 1, 268 401 62.3 32 4.95 5.80 1,750 1, 347 529 89.1 46 6.20 7.08 2,115 1, 755 686 38.1 19 4.14 5.09 1,511 1,062 358 50.5 39 5.48 6.05 2,580 2, 130 758 91.6 76 6.84 7.16 2,870 2, 438 865 30.0 17 4.93 5.41 2,200 1, 885 596 85.9 35| 4.58] 5.38 1,657 1,310 508 109.0 43 5.33 6. 40 2,026 1,590 638 56.1 31 3.98 4.77 1,364 965 390 Wer yellow pine (shipment A); 10 E | ENGR A See Bee BOERS GO ARE BEE ee 96.1 14 4.44 5.20 1, 475 1,201 443 AUPE ATE OTS ee EE: ea ne eae 116.1 16 4.78 5.60 1,681 1, 412 516 1A GER UUTENS ITT | AS a a | 83.2 13 4.14 4.94 1, 269 1,038 345 Western yellow pine (shipment B); | 10 tests: LS ECG SES oie eee hoe ee eee ae 82.0 18 5.35 6.00 1, 940 1, 450 561 IME ETERS Toby aS) ee ee 113.2 32 5.65 6.17 2,410 1, 883 762 LA GTa Pai Tet SS See a ee ee 54.8 11 5.01 5.73 1, 668 1,132 448 | AIR SEASONED. Lodgepole pine (shipment A); 5 tests: ESIGLE LST Le Maer gt eee ae ee 11.5 46 4.93 5. 43 4,130 3,513 993 JUG GCE STU See OR Bs EN (ol ol 12.3 57 5.17 5.57 4,770 4,190 1,194 i RET eye Pelee eae enck cama ce 11.0 34 4.77 elles 3,340 2,750 875 Lodgepole pine (shipmen* B); 5 tests: Pe SUOEIG aD ae ae he ee re 12.2 45 4.81 5.44 5, 568 4, 438 1, 282 ITPA TT TTA, RY ee 15.9 50 5.25 5.73 6,340 4,980 1, 452 JMB TeGVeT DUTT VP OR al Be 11.0 42 4.01 5.01 4, 980 4,010 1, 135 Alpine fir; 3 tests: A SUG EG AREER Bees ore 11.6 18 4.27 5. 28 4,097 3,530 978 LUG rare rots ey AEE Tey eA, Ae a meee ae 12.4 23 4.46 5.41 4, 260 3,875 1, 043 NERSETHEESII en oo eee | EOIN 10.5 15 4.06 5.09 3,910 3, 165 890 Engelmann spruce; 7 tests: Sveravamie GRIMS 11.8 33] 4.42] 5.29 4,122 3,297 1,042 JU EPSaTEEYS TT a 2 ge Dahlen BS 13.7 50 5.09 5.97 5, 560 4,290 1,321 AERPFEVUYERE 2 ok See ee SE 10.9 16 3.50 4.62 2, 990 2,410 703 Douglas fir; 5 tests: PAV Oar Gee sce sen sol Laman 5 12.3 49 4.85 5.33 4,634 3, 617 1,131 MiGs ari Cee pet eee 13.7 76 5.33 6.05 5, 720 4, 450 1,324 MEISITIEITIE aoe cee ab ee. 11.5 23 4.30 4.62 2,960 2, 340 873 Bristle-cone pine; 5 tests: ITE = See hE Cea 12.4 38 3. 68 4,44 3,501 2, 823 826 AMINE yo ese Nae Seale ae o 12.6 45 3.98 4.85 4,390 3,512 1,023 Wb ver bree iat aU aay | Uo ea 12.2 30 3.18 4.22 2,340 2,013 628 Western yellow pine (shipment A); 5 tests: PAV OTAGO eet a bcicwisewe nse sc - aee 11.7 14 3.93 4.78 3, 764 3,401 887 mtb ee fee ee 13.4 16 4.30 4.85 5, 330 4,730 1, 146 (Li BTie et S011 ya eS ey see aa a 10.5 il 3.50 4.62 3, 050 2,470 626 Western yellow pine (shipment B); 5 tests: IAVCTAGO Ha. 5 ceaseas~--: ae eee 11.7 18 4,82 5.44 4,132 3, 266 956 PEAT 2 oe ae 13.0 31 4.93 5.65 4,790 3,770 1,160 Minima. yt e ae o 10.9 12 4.62 5.25 3,120 2,270 628 ee al 6 BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. TABLE 3.—Summary of bending tests on round mine caps (nominal size, 5-inch top by 8 feet long; span, 7 feet; third-point loading). GREEN (WATER SOAKED). Diameter. i iff Rin MSS | Modulus] streceat | factor Species, number of tests. Moisture.) \Spe0) | a of einai Pp inch. Top Butt. | ™upture limit ( Id. Lodgepole pine (shipment A); 10 Lbs. per | Lbs. per tests: Per cent. Inches. | Inches.} sq. in. 8q. in. BWCIOLS oo = sane a see ae eeee 89.3 43 5.59 6. 20 5,172 3, 104 98.0 Maximum: v.22. aeseoe eet 133.3 61 5.90 6. 68 6, 460 3, 830 119.7 Minimpms - 7. 52. Seo 2- 5 ok eee 56.7 23 5.17 5.60 4,040 2, 635 72.1 Lagrepele pine (shipment B); 10 3 Rita WES. E Lon See aes See eS 60.6 43 5.78 6. 45 4, 768 2, 762 86.0 KIMIUURY 2 2 = bes eee eee cee 89.5 52 6.00 6. 75 6, 180 3,555 126.2 Minimums. , 0: J-us5-.4-55-tasce- 40.1 31 5.25 6.00 3,585 2, 090 ES Alpine fir; 9 tests: Averagero. Joi. 4 fhe ho8 5 hee 99.5 21 4.65 Dede 4,139 2, 450 79.3 Maxims oc. jsSaseeases bias ane 147.2 36 5.63 6.50 5, 260 2,910 108.8 Minimynns of osc 32s S-n0- doe ae 57.6 8 4.13 5.38 1,945 1, 782 57.6 Engelmann spruce; 11 tests LASTS be Saat ns sobs seeneesoese 54.3 30 5.16 6. 40 5, 308 2, 709 95.0 74.6 45 6.00 7.00 J, 280 3, 665 130.5 36.3 17 4.44 5.88 3,500 1,991 68. 2 69. 4 27 4.78 5. 66 6, 568 3, 455 85.2 119.1 38 6. 25 7.00 7,310 4 675 107.9 32.6 16 4.00 5.00 4, 840 2, 505 55.0 74.3 37 4.63 5.62 4,578 2,459 66.6 96.1 62| 5.63} 7.00 5, 480 3, 960 85.7 66.2 25 3.38 4.00 3, 500 1, 666 48.3 Western yellow pine (shipment A); 10 AVETAP OR 5. Soe eee eee ee 88.5 13 4.39 5.60 4, 333 2,170 74.5 SxnuN Balae cm ao sepia ne See fates ia 106.3 15 4.80 6.25 4,960 2,775 86.9 pm oie aaa tia bie ox Rags is's 71.1 12 3.75 4.75 3, 860 1,553 59.1 Western alters pine (shipment B); 10 ests: AVOTAEOS 2-5-5 Beae eco ce sek cee 147.1 26 4.42 5.45 4, 897 2, 890 72.6 Maximum: -¢ 25/3235 seen 6 baer 198.4 42 5.00 6.12 6, 190 3,540 89.8 Minimums 2 (05-55-8202 S256 eee oe 86.5 15 3.62 5.00 3, 320 2,148 35.9 AIR SEASONED Lodgepole pine (shipment A); 5 tests AVGClALCs 5202. oo ape eee hk ieee 11.4 54 4.76 5.21 9, 026 6, 600 133.1 Maximum: 20 22: o8eie. a-cb eee 11.9 72 5.09 5.49 11, 630 8, 640 152.2 Minimpme oo ee eemas + bee ete 10.6 33 4.54 5.09 7,180 4,790 119.5 Lodgepole pine (shipment B); 5 tests verage 11.1 44| 4.84] 5.49 6, 954 5, 962 114.5 Sta ry 47 5.41 5.73 9, 620 7, 290 148.2 Minim 10.6 42 4.54 5.33 4,490 4,230 84.1 Alpine fir; Bt tests: Rverages.d 2 A Seen en he 11.4 26| 4.22] 5.28 7, 340 5, 460 108.5 Maximum: .: 2 - gotseeeec ce rete cc. 12.1 37 4.62 5.57 9,350 6, 600 125.2 Minimim 928. ee 10.4 20| 3.66] 5.09 5,270 4,320 85.2 Engelmann spruce; 5 tests: ANOTALO so 252520 Soto te eee as Ae 10.9 37 4.41 5.35 8, 242 6, 618 118.5 - aaa S nis Sic Be eee ae Eee a's 11.8 45 5.33 6.05 9, 900 7,340 151.2 hols anja so peste oP aera 8.8 27 3.50 4.62 6, 260 5,190 7280 Douglas ib 5 tests: Verages fi. cl: essere es eee 11.8 23] 4.30] 5.20 9, 232 6, 842 126.3 xiMUM,..c- So. ase eee Zee = 12.3 29 4.77 5.57 10, 960 7,660 145.1 Minimum... ..-c5seeeee rome - 11.4 15 3.82 4.77 5, 790 5,100 92.8 Bristle-cone pine; 5 tests: AVOTAPOO Ls Jt. . 2: ie-P ees = 11.5 37 3.82 4.98 8, 408 5, 684 97.7 Maxininm, .¢ ...2-2s5-5/-+- ssa 12.5 52 4.22 5.25 9,550 6, 700 116.1 Minimnm 2... /.css-2-220) ee 10.7 27{ 3.50] 4.54 7, 000 4,120 89.3 10.3 14 3.58 4.85 7, 660 5,770 103.8 10.6 15 3.66 5.09 9,770 7, 730 118.2 9.4 13 3.50 4.62 5, 660 3, 870 87.5 ROCKY MOUNTAIN MINE TIMBERS. 7 TaBLE 4.—Summary of bending tests on round beams, 16 feet long (span, 15 feet; third- point loading). Species, size, number of tests. Lodgepole pine, cut from live timber: 8-inch butt, 10 tests— ‘Average Wepetaelieees eee Maximum......... Lodgepole pine, cut from timber after standing dead for 30 years: 8-inch butt, 5 tests— Lodgepole pine, cut from live timber: 8-inch butt, 5 tests— jedgenae pine, cut from timber after standing dead for 30 years: 8-inch butt, 9 tests— ee LASS TE i GREEN (WATER SOAKED). Moisture. Per cent. 77.3 Res wees Soe) SHER) CONN OTH One tow ow meee Ta uO > a Si BS) bees! “100 CO oor bo 6 00 Bere 13.7 14.6 11.5 12.9 14.4 12.1 13.8 16.6 12.0 Rings per inch. Modulus Fiber stress at Stiffness factor (1a) Diameter. Top. | Butt. Inches. | Inches. 6.77 8. 20 7.32 8.75 6. 29 7.76 8. 26 9.97 9.23 | 10.74 7. 24 9.39 9.82 | 11.62 10.82 | 12.41 9.23 | 10.98 7.00 8.50 7.08 9.06 6.92 7. 80 8.21 | 10.24 9. 23 11.14 7. 56 9.71 10.00 | 12.47 10.98 | 12.97 9.31 | 11.77 AIR SEASONED. { FOGIES — ICI) Caio NOI COUAS WHO S Ars Crer1cd =00 CS ae: CORNICD SCHH moM BOO JIAO BEG ARS 7, 748 9, 310 7, 160 6, 948 9, 060 4, 480 5, 409 6,350 3, 745 5, 625 7, 780 3, 843 5, 166 8,970 2; 690 4,720 7,310 2, 060 Ow StS iS ORE CNM ARR Wow Goa ESCO SG NOW NOR WOR Sabo bh Se Ab MOONE CHRD COME 6 = The average results do not show a consistent difference in the relative strength of the various species tested. Figures 1 and 2 show that, with the exception of the green props and caps of Douglas fir and the dry props of lodgepole pine (Shipment B), there is not a » very large difference in the strength of the various shipments. ; le oe s 8 BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. is apparent from the various positions occupied by the different shipments of lodgepole pine and western yellow pine that species is not in itself a reliable guide to strength in the selection of material of this form and size. With clear material, consistent differences would probably be found between some of the species, but in the props especially the degree of straightness of the piece and the pres- ence of knots seem of greater effect than the species. BEAMS. The results of the tests on the three sizes of 16-foot round beams of lodgepole pine are shown graphically in figures 3 and 4. With the exception of the work to maximum load, all the strength functions decrease in value with increase m the diameter of the beam. The amount of this variation differs im the different kinds of material, being least in the green, greatest in the air-dried, and termediate in the dead timber. The reason for the decrease in the unit strength of the larger beams is not apparent. It is not due to visible defects, such as cause a decrease in the unit stress in large strmgers when compared with small clear pieces cut from them, since the defects in the 8 and 12 inch beams did not differ mn kind or in appearance. The fact that stiffness decreases in the same manner as strength corroborates this statement, since such defects as knots and checks do not generally affect stiffness up to the elastic limit. The differ- ence may, however, be due, at least in part, to rate of growth, which increases in all cases with increase in diameter. The smaller beams were apparently cut from the suppressed growth of a fairly even- aged stand. The unit weight of the beams does not vary consist- ently with the strength. The dry weight per cubic foot of the air- dried beams is lowest in the 12-inch size, but for the dead beams the weight is highest in this size. The relative values of the dead, green, and air-dried timbers are also indicated in figures 3 and 4. In strength the dead material falls between that of the air-dried and green, being close to the air- dried at the elastic limit and close to the green at the maximum load. The air-dried material is the stiffest, the green and dead having practically equal values for this factor. The closeness of the values for green and dead water-soaked material and a comparison of their curves with those of the dry timbers show very clearly the effect of moisture in reducing the stiffness and strength at the elastic limit. In work to maximum load, which is an indication of toughness, the order of the curves is reversed, the green and water-soaked beams ree values about twice as great as the dry material. The posi- tion of the dead water-soaked beams, especially, brings out the fact at the greater brittleness of the dead or air-dried material is due to Nee and not to a deterioration of the wood. Drying the beams \ ‘ POUNDS PER SQUARE INCH POUNDS PER SQUARE INCH STIFFNESS FACTOR ROCKY MOUNTAIN MINE TIMBERS. CE oo ak sa Na A SEES EAS TE Led [2 PS So i Rene Bae ceeereeeeree: seca gGRneR= ~--.--e-e-e- === Foleielae ans 212 2\~ - Meee he sad ere,-\e ane Re Re eee 1, 354, 000 4 Limber pie. = 288 228 Soseee eae teenie n ee sais oo os =) ae ine cic iene ce eee ee 431, 000 1 Bristle-cone pine: ~. .-. Ree eee eek cock oes Ree ce classe ee 183, 000 SPORE see se aoe eat Se ae 149, 000 Alpine fir 109, 000 1 Blue spruce. 75, 000 White fir.... 65, 000 CO pee ea Bred et ts ey lee ae RE 2 RE RS Sree a Sa 1,000 Motaleaep ence eee e Ree eae eek BASHIR RSE 33 4o a edadRBBSseEtasboossse 36, 274, 000 100 TaBLE 8.— Unit costs for various diameters. : - Cost per inch of Dane Cost, per piece 16 | Cost perlinearfoot.| diameter 16 feet 2 B- long. Inches. 3 $0.35 $0. 022 $0. 117 4 - 40 to $0. 50 . 025 to $0. 031 - 100 to $0. 125 6 -45to .65 .028to .041 -075to .108 8 -60to 1.25 -038to .078 -075 to .156 10 1.15 to 1.60 .072to .100 .115to .160 12 1.50 to 2.15 .094 to .135 .125to .180 14 2.00 to 2.25 -125to .141 .143to .161 16 2.50 | . 156 - 156 Table 7 shows that lodgepole pine is the main source of supply for round mine timbers, and, together with Engelmann spruce, makes up 88 per cent of all the props cut. Douglas fir, although a very desir- able wood, formed only 6 per cent of the total. COSTS FOR DIFFERENT SIZES. Table 8, giving costs for props of various diameters, was compiled from such data submitted by the operators as were definite in regard to the size of the material. Several methods of purchasing round material were reported—cost per piece for a given length and diam- eter, cost per linear foot for a given diameter, and cost per inch of diameter at the small end for a given length. A large majority reported the cost per linear foot. LIFE OF TIMBERS. There was a large variation in the reported life of timbers in the different mines, especially in the metal mines. The timbers in the coal mines had an average life of only about one-half that found in the metal mines, but their size was also only about one-half as great. Tables 9 and 10 give the average values obtained from statements of the operators. ROCKY MOUNTAIN MINE TIMBERS. 15 TaBLE 9.—Reported life of untreated round mine timbers in coal mines (mostly 5 to 7 inches diameter). 4 Engel- : Conditions in mine. Pong: Pine.! | mann Alpine Pifion. spruce. Years.| Years.| Years.| Years.| Years. 5 4 4 3 PAY PEACE RE ice tant et ACL tp DER fo HIOOTAV CTEM ATIOU ssa se = si esct o sisin oe c- clas siciereie Hipaareisie aiaieieie = eels 2 1 iG eeerer 1 Goodeuentiianion® 156222250) 08) 2.8 Ee 2s Ba os 10 8 fc NN ee 6 FESXCEDUIONA Seen sac cis se Sole oe teas alaele tsa Teieciele ena a Bee 25 We Wendeeege KP Nee cee ben 1 Includes lodgepole pine and western yellow pine. TaBLeE 10.—Reported life of wntreated round mine timbers in metal mines (mostly 8 to 10 inches diameter). Douglas Western | Lodgepole | Engelmann Conditions in mine. fir. yellow pine. pine. spruce. a Years. Years. Years. Years. 9 9 7 LEHR ED: Ae, 6 LGAs TESS BOS SOME Eo eee et ee a a Meryspoor-ventilation: 2204) (2222222220). 2to 5 iia» 83 1 to 2 lto 2 Constanthyawet. sa2522 23 jase sceelse ns hides ye Rea ahah 20 to 40 OOD |e oe seceose de 15 to 20 The conditions under which the estimates were made vary so much that the relative life of the different species is probably not reliable. For example, several operators reported that under the same condi- tions Douglas fir outlasts lodgepole pine or spruce two to three times; yet the average values show comparatively little variation among the species. The factors that cause variation in the life of the timbers are prin- cipally ventilation, moisture, acid mine water, and the condition of the timbers when placed. The influence of fresh and compara- tively dry air was clearly indicated in several mines which reported a life fully four times as long for the timbers in the intake shaft as for those in the return shaft (8 and 2 years, respectively). Several operators reported that they had increased the life of their timbers from two to three times by peeling and seasoning them before place- ment. Certain mines reported that their timbers were sound after standing from 25 to 35 years under conditions where they were nearly always wet, and in one or two cases the water was stated to contain “sulphuric amd’’ or “copper and arsenic,” which probably acted as an antiseptic. Both constantly wet and constantly dry conditions appear, from the replies, to be favorable to a long life, while damp- ness, due to stagnant air, or alternating dryness and wetness, appears to furnish the best conditions for the growth of wood-destroying fungi. PRESERVATIVE TREATMENT. Preservative treatment to prevent decay was not regularly prac- ticed at any of the mines reporting. Sixteen operators referred to some use of preservatives, though none had had a long enough expe- rience to furnish data on the increased life from such treatment. The methods spoken of were dipping in creosote or crude oil, and brush eee ee ee LL ll 16 BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. treatments with creosote, carbolineum, or crude oil. One operator referred to the disagreeable effect on the miners of the odor from the creosote in the mine. There was great variation in the replies to the question regarding the proportion of timber used for replacements made necessary by decay. Replies from 30 coal mines averaged 11 per cent (14 reporting 0 per cent and none 100 per cent), and from 112 metal mines aver- aged 21 per cent (44 reporting 0 per cent and 11 reporting 100 per cent). Itis apparent that the economy of preservative treatment is a local problem with each mine. In order to decide whether it would be economical in any given case to apply treatment only a few factors concerning the present costs and life of the timbers are essential. The proper method! of treat- ment would depend upon species of wood, capacity of apparatus, and local conditions, but the preliminary steps could be taken on the basis of the lige data: 1. The amount and cost of material that goes annually toward replacing decayed timbers. 2. The cost, in place, of the timbers used. 3. The average life of the timber. The first of these factors will readily show whether the amount concerned is large enough to warrant further consideration of pre- servative treatment. In certain coal mines, where but few timbers are necessary in the permanent entries and where the majority of timbers are used in temporary positions, a brush treatment would probably be all that is warranted, unless impregnated material could be procured in the market. On the other hand, where a large amount ) of material is used to replace decayed timbers the installation of a : small treating plant might be seriously considered. From the cost in place and the average life of the timbers there can be calculated an annual charge, a measure of the relative economy, with which any other combination of cost and life (such as that resulting from a preservative treatment of the timber or perhaps from the use of some other kind of material) can be compared. In figure 5 is presented a series of curves, each for a definite initial cost of a timber or set of timbers, which show the relation between length of life and annual charge when compound interest on the investment is considered and maintenance is assumed for an indefinite time:? 1 Forest Service Bulletin 107, The Precervation/ of Mine timbers) iy ml, a Berens methods of preserving mine timbers from decay. 2 The annual charges are figured on this basis so that a fair comparison can be made between different methods involving various combinations of costs and length ofservice. Ifa material were placed that would last forever its annual charge would be simply the interest on the cost in place. If the material must be replaced every so often, the annual charge represents the interest on a sum of money which, if placed at compound interest, would pay for the initial cost in place and all future replacements and would be itself used up at the end of the period of maintenance under consideration. If this period be of an indefinite length (forever), the annual charge is the interest on a sum of money sufficient to pay the present cost of installation and, by the accumulation of compound interest on the balance, take care of future replace- ments at the assumed intervals of time. ROCKY MOUNTAIN MINE TIMBERS. nf NE dS an I Sa a Baer ne | SE Es a a aay ee FD a A NN wl 2s) EES stall J SSCS SS0R R00 gE anEean ee sla B SRM ae ite | lle a a TENS SE a i | Ge Coro ea 5s Nw a a ee ee oe [ | JNA ba pea ae B Baiiamiense asics Cane lee PN IS ae Pe er ee CT) a a CSE alma LF oe Ca a fea aha Ne aba ae fa CT eect ele CoS tee eee mall! (called = ay COC EET TTT) aseuie canas & r+ 228" 0.05 1 a : (ol a B R=IWITIAL COST IN PLACE-DOLLARS Ge | | W=LIFE CF TIMBER—YEARS eI SOIC) aerenest s percent <1 A et Se eeea = C2530 a 2 (LOM EEC ene eee VY a a ee GOR eeees eee eee BE se STO se a te en cf ne eS LN an 2 aed oa oe eee = SVL a TT 0 a 0 a a CSN ea TAA im De sna ao SE eee fl a [3 SN i a a a ole ale led JO Gea oe PEPE eee COMMON Eee Len ca a) hn S ONE See eee Sane Se ee eae UST CNN 22D ee eee oo eee —-. Oe eee eae Bua FIBER AN i asf sD 1M ANSE SE SS 9 a COD IDES SIRS Sone Sees PEIN NS EE a Tl enon aN at |g IOS SL PS tats Tl PO NIN ON eS RE alae LONI OS Sas SSSA ee ee WOOCC OS DNS RO ERE CREE PSR EEE SE [SUNG SRS S0SS0GaES. (Lens s2 SSE Rees JCS SaaS s ose s. oe REbeEeseeeee Sede | oe eee eee Pith 2225 Bee Ss ; [alee ea es eS | Siete ee LIFE IM YEARS Fic. 5.—Relation between life of timbers and annual charge. 29206°—14-_3 18, BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. The curves will show how much additional initial cost is warranted when a given increase in life due to the treatment under consideration is assumed and the initial cost and life for the existing conditions are known. The diagram also illustrates graphically, by the steepness of the curves, the great economy in prolonging the life of timbers that ordinarily last but a few years. To illustrate the use of the curves, assume that an operator wants to find out approximately what saving he would effect by carrying out some proposed scheme to lengthen the life of his timbers in cer- tain permanent openings. Assume that each timber set costs $6, including the expense of framing and setting. If its life is five years, its annual charge as shown by the curves is approximately $1.40. Let us next assume that the proposed treatment will double the life; that is, give the timbers a service of 10 years. A further inspection of the curves at the line of 10 years’ life shows that the same annual charge of $1.40 results from an initial cost of $10.50. In other words, the economy of a timber that costs $6 in place and lasts five years is the same as one that costs $10.50 and lasts 10 years; and, therefore, the proposed treatment would pay if the final cost of the treated timber was anything less than $10.50. If we assume the cost of the treat- ment to be $1.50 for each timber (making the total cost in place $7.50) the annual charge would be about $1, The cost of using treated tim- bers would increase the total cost of timbering each year until the period of the natural (untreated) life of the timbers (five years in this example) had been passed; after that time, however, there would be a period of very low total costs until it was necessary to replace the treated material. The economy shown in an annual charge of $1 in comparison with $1.40 represents the average conditions due to a continuous maintenance. It means, expressed in another way, that the investment required to maintain the untreated timber perma- nently would be $28, and that the investment for the maintenance of the treated timber would be $20, under the conditions given in this example. APPENDIX. METHODS, . TESTING, The 6-foot props were tested in compression parallel to the grain at a speed of 0.119 inch per minute. A bearing block was used between the prop and the base of the machine. The compression of the prop, as indicated by the movement of the head of the testing machine, was read to thousandths of an inch by means of an Olsen deflectometer. Figure 6 shows a prop in the testing machine after failure. The 8-foot caps were tested on a 7-foot span with third-point load- ing. The tests were made on a 200,000-pound Riehle testing machine at a speed of 0.231 inch per minute. The ends were supported by curved cast-iron bearing blocks and the load apphed at two points (one-third the length of the span from either end) through curved wooden blocks. Deflections were read at the center of the beam to hundredths of an inch by observing on a taut string the movement of a polished metal scale attached to the timber. The method of loading is shown in figure 7, all parts of the testing machine being omitted except the weighing platform. The 16-foot lodgepole pine beams were tested on a 15-foot span with third-point loading. The arrangement was similar to that used for the caps. MOISTURE DETERMINATIONS, A 1-inch section was cut from near the point of failure of each piece tested. This was immediately weighed and later dried to con- stant weight at the temperature of boiling water. The loss in weight divided by the dry weight, expressed in per cent, is the moisture content of the piece. : GENERAL OBSERVATIONS. The length, weight, and diameters of the timbers were obtained just before testing. The rings per inch and the proportion of sapwood and of summerwood were obtained from a section cut near the point of failure. The values for the amount of summerwood are approxi- mate, as the summerwood bands were not distinctly marked in many of the pieces. COMPUTATIONS, The load and deflection at the elastic limit were obtained from the load-deflection curve, and at maximum load by direct observation. : 19 20 BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. The fiber stress at the elastic limit and the modulus of rupture were computed for the diameter and moment of inertia obtaining under the smaller loading point, the section being regarded as a true circle. The stiffness factor a was obtained from ‘the moment of in- ertia (I) and the deflec- tion (d) at the center of the beam. These values for stiffness are compar- able for pieces of the same span only. The true modulus of elasticity, which is difficult to ob- tain accurately for a beam with a varying moment of inertia, depends upon the cube of the span. This relation is not con- sidered in the “‘stiffness NNN HLA AA | i Hi q 1} |): RE ie | | Sui Mm) | Hin! A HY Ati)! i \| H il Wh SS a | Hi WU i a, Hi Ba. ii | He iN ) P i factor’ used, ig and this causes the values for the 7-foot span to be approxi- mately ten times as large as for the 15-foot span. The work to maximum load was calculated from the area under the load- deflection curve, and is given in terms of unit volume. In the calcula- tions involving the unit stresses of the props, the top area of the prop was used. The volume of the test pieces was calculated by multiplying the average of the areas of the top, the butt, and the mean proportional between them, by the length. The weight per cubic foot was obtained from this estimated vol- ume, and is therefore given as “approximate.” | Fic. 6.—Method used in testing mine props in compression. ROCKY MOUNTAIN MINE TIMBERS. 21 TaBLE 11.—Data on individual crushing tests of green round mine props (nominal size, 5-inch top by 6 feet long). mo EE } orm Z BES Species. Q ; poms | si aes 2 8 oS © A2| 22 SD ° ABS ee] a i< Per |Lbs. per cent. | cu. hi. Lod gepole 1 | 63.4] 26.23 pine (ship- 2| 85.6] 22.50 ment A). ! 3 | 64.0] 24.18 4| 99.0] 22.23 5 | 48.3 | 24.72 6 | 65.3] 22.79 7 \102.0} 21.48 8 | 83.7] 23.46 9 | 67.4] 24.22 10 | 78.4} 25.70 Av’ge.|.---- 75.7 | 23.75 Lodgepole| 11] 61.8] 24.57 pine (ship-| 12 | 63.3] 23.08 ment B). 13 | 58.7] 26.40 14 | 81.0] 22.76 15 | 57.5] 19.45 16 | 82.4} 22.86 17 108.2} 24.38 18 | 61.8} 22.21 19 | 69.6 | 20.56 20 | 63.7 | 22.39 Av’ge.|...-.- 70.8 | 22.86 Alpine fir...) 1} 58.5] 19.44 2] 38.6] 24.07 3 |119.9] 20.03 4 |115.3 |........ 5 | 86.3 | 22.41 6 | 78.1] 20.28 7 {123.6 | 21.58 8 | 63.1] 22.82 9 |1385.7 | 20.22 Av’ge.|..... 91.0] 21.36 Engelmann 1 | 52.4 | 23.32 spruce. 2] 68.8) 24.14 3 | 53.1] 24.08 4| 75.4] 22.98 5 | 89.1] 22.82 6 | 73.2 | 24.20 7|72.2| 22.96 8 | 53.8] 25.46 9 | 55.8] 23.79 10 | 53.3] 27.38 11 | 38.1] 23.66 Av’ge.|....- 62.3 | 24.07 Douglas fir..; 1) 89.1] 27.34 2 | 34.9] 25.22 3 | 91.6} 24.29 4| 66.9] 25.33 5 | 37.8] 28.57 6 | 38.2} 27.08 7 | 42.9) 27.52 8 | 34.8] 31.84 9 | 30.0} 30.10 10 | 38.5 | 27.77 Av’ge.|....- 50.5 | 27.50 Rings per inch. Summerwood. : | Diameter. |> Crushing streng at Crushing strength at elastic limit. Modulus of elas- ticity. eS NS a ee a a SS | ee ee SS) SSS | s SE | SS SS SS SS for) 90 > NDAD NAH H nen RGR Cure GO ea mt TOUS GO © Or bo z Remarks. Grain slightly spiral. Slightly crooked. Grain slightly spiral. 5 Imots, in failure plane. Unusually knotty. Grain spiral. Do. Do. Slightly crooked. Do. Grain spiral. Do. Slightly decayed. Grain spiral. Grain slightly spiral. Do. Crooked. Grain spiral. Crooked. Grain slightly spiral. Crooked. 22 BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. TaBLe 11.—Data on individual crushing tests of green round mine props (nominal size, 5-inch top by 6 feet long)—Continued. = 3 & 5 : Diameter. |= 8 Ss 3 x : q aR |e s| |se.lél¢ sq | 88/2 Zz 3h 8/8 $k Bo Ob Species. g $ ge 2 Py E 3 wo 30% 25 Remarks. 2 = eo . = = | 25 | 2 leeels/a/F] .| [2.2] 22 |e 3 oe |ara/8/8) 2] & 5 |pal| Fa 3 maiai< Bla}la]| a A 10 13) = 1,000 Lbs. | Lbs. | lbs. Per |Lbs. per Per | Per per per | per cent. | cu.ft. cent.| cent.| In. | In. | sq. in.| sq. in.} sq. in. Bristle-cone 1] 86.7] 30.78 | 34] 22] 56 | 4.25] 5.13 | 1,474] 1,128] 390] Crooked. pine. 2 {109.0 | 26.83 | 32] 19] 56) 4.65 | 5.50 | 2,026 | 1,590] 638 3 | 74.9] 30.86 33] 18) 39 | 4.80] 5.50] 1,364] 1,050] 453 4 {106.1} 26.17 | 41} 21) 36] 5.33] 6.40 | 1,690 | 1,485] 505 5 | 94.5 | 29.57 | 31} 22) 47 | 4.52] 4.91 | 1,480] 1,185 | 525 6] 56.1] 25.68 | 31} 24/]....- 3.98 | 4.77 | 1,400 965 | 446 | Crooked and unusu- ally knotty. 7 | 60.3} 28.95 38} 16| 51 | 4.46] 5.17 | 1.760 | 1,408] 574 Do. 8| 85.1] 25.83 | 43} 23] 46 | 5.17] 6.05 | 1,828 | 1,480 | 464] Grain slightly spiral. 9 101.0} 25.72 | 32] 16| 43 | 4.38] 5.16 | 1,941 | 1,528] 571 10 | 85.5 | 26.39; 39] 16; 38] 4.30; 5.17] 1,610 | 1,378] 516 Av’ ge.|.-.-: 85.9 | 27.68 | 35} 20] 46 | 4.58] 5.38 | 1,657] 1,310 | 508 Western yel- 1 | 91.8} 22.67) 14! 14]..... 4.25 | 5.25! 1,355 | 1,128! 428 Do. low pine 7 iy ia Cae Ae (iat Le ie i spe La TE ae 4.25 | 5.00 | 1,630 | 1,410} 516 (shipment 3 | 88.9] 22.52] 13] 14}]...-.- 4.35 | 5.10 | 1,443} 1,211 | 345 A.) 4|92.0| 23.55] 14] 14]..... 4.70 | 5.40 | 1,269 | 1,038] 451 | Crooked. 5.) 83.2 | 22348) 430° 152... 4.65 | 5.60 | 1,322 | 1,060] 402 Do. 611045] 22:33) '13)). 12")..... 4.30 | 5.13 | 1,481 | 1,172 | 475 Do. a 1103:2 1225 7a aan lon o- - 4.78 | 5.16 | 1,518 | 1,119] 438 S)} 96.651) 23262) a5 aS yee 22 - 4.38 | 5.41 | 1,522 | 1,262} 448 9 | 89.3] 25.70) 15] 13 ]--... 4.14 | 4.94 | 1,681 | 1,412 | 512 | Grain slightly spiral. WOWWG. 1 Ie. F-. 1314), aos. =: 4.62 | 5.01 | 1,512 | 1,193] 416 Do. Av’ ge-}.-- 22 96.1 | 23.18 | 14] 15 ]...-. 4.44 | 5.20 | 1,475 | 1,201 | 443 Western yel-| 11 | 81.1] 25.6% | 32 low pine| 12} 90.5| 23.22 | 11 (shipment | 13 | 83.0] 24.80 | 24 B.) 14,1143 .2 | 5-2 te 19 2,000 | 1,570} 611 | Unusually knotty. 1,726 | 1,320] 457 on slightly spiral. 0. 1,682 | 1.352 | 478 | Grainspiral, crooked. Crars3 Go ww Or tt lo iS) esi on ao SUD 2. D> GUD CORR AI-F ROCKY MOUNTAIN MINE TIMBERS. 93 * Taste 12.—Data on individual crushing tests of air-seasoned round mine props (nominal size, 5-inch top by 6 feet long). bo . s Bie | Eb a glia Diameter. Se we a S re | Wt 28 | 25 A Cees 8/8 $ H $2 |o5 Species. x Hoa ER 2|§ Fig no 8 ne | ae Remarks. q = Mot a) & 6 | .| 33 SS P| & Pers jo} 8 je ; |e 3| 3° 13 oo ES 8 3 S| 2 (Bea /8|/8)a) & | 8 388) 33/5 eS je. |< Slanal|n |] & a |5 5 = 1,000 | Lbs. | Lbs. | lbs. Per |Lbs. per Per | Per per per | per cent. | cu hh cent.| cent.| In. | In. | sq. in.) sq. in.| 8q.in. Lod gepole 1) 11.5] 24.58] 51 | 21] 55 | 4.85 | 5.17 | 3,910 | 3,465 | 890 | Grain spiral. pine (ship- 2/11.4] 24.46] 43} 22] 58) 4.77 | 5.57 | 3,992 | 3,580 | 875 Do. ment A). 3; 11.2] 27.96; 57] 18] 33 | 5.17 | 5.57 | 4,770 | 4,190 |1,194 Do 4112.3] 24.16] 34] 20] 68) 5.09 | 5.57 | 3,340 | 2,750] 954 Do 5 | 11.0] 25.83 | 47] 19] 35 | 4.77 | 5.25 | 4,640 | 3,580 |1,031 Do Av’ge.|.-.-- 11.5] 25.40] 46] 20] 50] 4.93 | 5.43 | 4,130] 3,513 | 993 Lod gepole 6} 11.0] 28.14] 43 | 26| 42] 4.38 | 5.01 | 5,100 | 4,110 |1, 198 Do. pine (ship- 7) 12.0) 27.72 | 457 26.2... 5.25 | 5.57 | 6,340 | 4,980 1, 450 ment B). 8 | 15.9] 23.42] 50] 26| 61) 5.17 | 5.49 | 4,980 | 4,010 |1, 135 Do. 9/ 11.2] 29.52] 45 | 20) 37] 4.01 | 5.73 | 6.190 | 4,750 |1, 452 Do. 10 | 11.1] 26.58 | 42} 17) 37 | 5.25 | 5.41 | 5,230 | 4,240 {1,175 Do. AVEO. S-in- 2 12.2} 27.08 | 45 | 23] 44] 4.81 | 5.44 | 5,568 | 4, 438 |1, 282 Alpine fir. . 1| 12.4} 20.24 | 15 Gees 4.30 | 5.41 | 4,120} 3,165] 890 M20 ea22.SSiiecoudeule oes 4.46 | 5.33 | 4,260 | 3,875 |1,043 3} 10.5] 20.38 | 16 Ce eee 4.06 | 5.09 | 3,910 | 3,550 |1,002 Do. Av’ge.|...-- PIG ake een ke |eee ce 4.27 | 5.28 | 4,097 | 3,530 | 978 Engelmann | 1/| 11.7| 27.42|41| 23|..... 4.62 | 5.97 | 5,560 | 4,290 |1,321 Do. spruce. Bel 2 woe Olea y a daa ooe 5.09 | 5.49 | 3,280 | 2,555 | 802 Do. 3111.0 | 23993 (904-43 Hoos: 3.50 | 4.62 | 3,742 | 3, 120 |1, 021 Do. 4/ 13.0] 24.00 | 43 | 22 |..... 3.98 | 5.25 | 2,990 | 2,410 | 703 | Crooked. - Dillagi eeseSh | OOM) 12a ieee ee 4.30 | 4.93 | 4,540 | 3,850 |1,196 | Grain spiral. 6] 11.3] 23.86 | 31] 20]..... 4.62 | 5.33 | 4,710 | 3,822 |1, 150 7} 10.9} 21.78 | 16 1 ee 4.85 | 5.49 | 4,030 | 3,030 |1, 098 Av’ge.|....- 11.8 | 24.76 | 33 19t- 352. 4.42 | 5.29 | 4,122 | 3,297 |1,042 Douglas fir..} 111.9] 31.63 | 76 | 25] 311] 4.30 | 4.62 | 2,960 | 2,340 | 873 | Crooked; grain spiral. 2) 11.5] 32.66} 47} 25) 39] 4.54 | 5.39 | 5,250 | 4,450 |1,322 | Crooked; grain un- usually knotty. 3 | 11.6] 28.98 | 65] 28] 39] 4.85 | 5.17 | 4,580 | 3,465 | 986 | Crooked; grain spiral. 4| 13.7] 28.31] 30| 26] 60| 5.25 | 5.41 | 5,720 | 4,240 [1,324 Grain ii tly spiral, otty. 5 | 18.0] 26.06 | 28) 21] 37] 5.33 | 6.05 | 4,660 | 3,590 |1,151 Av’ge.|.---- 12.3} 29.53 | 49 | 25] 41 | 4.85 | 5.33 | 4,634 | 3,617 /1, 131 Bristle-cone 1| 12.5 | 29.38 | 40 | 22) 42 | 3.90 | 4.54 | 4,320 | 3,512 |1,023 pine. 2| 12.6] 32.01 | 45} 19] 49 | 3.66 4.30 | 4,390 | 3,420 | 862 3.| 12.4] 36.46 | 42] 20]..... 3.66 | 4.22 | 3,042 | 2,280 | 837 | Crooked; grain spiral. 4/12.2| 30.34 | 35 19 | 68 | 3.18 | 4.30 | 2,340 | 2,013 | 628 | Crooked. oli 0474 | \eP-aayi a Ue || uo? UN eeeee 3.98 | 4.85 | 3,415 | 2,890 | 779 Av’ge.|.--.-- POA SOs Wes 20) \eeae 3.68 | 4.44 ! 3,501 | 2,823 | 826 Westernyel-| 1|10.5| 21.48|16| 17] 21| 3.66 | 4.80 | 3,050 | 2,470| 742 low pine 2) 11.1] 23.55) 15] 18] 88] 4.30] 4.62 | 3,842 | 3,310] 852 } Grain spiral. (shipment| 3] 11.9] 21.99] 14] 13] 95| 4.06 | 4.85 | 3,230 | 3,625 |1,068 A). 4|11.6] 25.50] 11 19 | 96); 3.50] 4.80 | 5,330 | 4,780 |1, 146 5 | 13.4] 23.69) 15] 12]..... 4.14 | 4.85 | 3,370 | 2,822} 626 Ay’ ge.|.-.-- 11.7] 23.24)14] 16] 75 | 3.93 | 4.78 | 3,764 | 3,401 | 887 Western yel-| 6 | 11.7| 26.30|17| 12|..... 4.93 | 5.57 | 4,070 | 3,250| 976 | Crooked. low pine 7{11.6}] 24.03) 19] 17 ]..... 4.70 | 5.25 | 4,260 | 3,690 | 863 | Grain spiral. (shipment Sets Oe zieidan ots | 20) 1. = 228 4.93 | 5.65 | 4,420 | 3,350 |1, 160 F SEP caster | Poneto) |. oe 4.93 | 5.41 | 4,790 | 3,770 |1,115 Do. 10 | 10.9 | 23.64] 12] 14]..... 4.62 | 5.33 | 3,120 | 2,270 | 628 | Grainspiral, crooked. Av’ge.|..... 11.7 | 25.48 | 18 16: | 4.82 | 5.44 | 4,132 | 3,266 | 956 — a nm BULLETIN 77, U. S. DEPARTMENT OF AGRICULTURE. 24 681 ‘F tL°S oo 99 61 QROGE— JERSE t SSSR SSS ge je es “""""O2B0AY ali ore ‘¢ ge°¢ 88'F $6 LT £6 6 “i 09% ‘+ GL" cL‘ 88 “61 T “LOT 8 fi “iL O91 ‘F 8o°¢ OFF 19-91 I ‘OFT Z I aD S66 'T 0g"s el F 98 81 o LPL 9 li 016 ‘F 0g"¢ 09°F 610 1°06 g ih 020 ‘¢ 08 °¢ 08°F oL 61 8°92 7 10) 088 ‘F 88 °S 00'S $91 8 601 £ ‘og “Li 0£0'¢ 0g 9 £9°S 88 02 1°89 z *yeads Anystys urerp | OD 092 ‘¢ 0g°¢ 08 °F 88 02 9°2¢ Fe 5 Beebe cee econo ee ee Ig oudry 892 ‘F cP °9 8L°S 91 8% DOO; ae | Seas pee ee on eee cee ese10A ¥ WL OTL *€ 0s "9 88 °S 08 2 a"lp 0@ ‘od #0) OLP ‘F 00°9 Go's ZI ‘2 1°38 61 alt ggg 'e €9°9 GL °¢ 68 “02 08h 81 ‘od 20 Ore ‘¢ cL°9 00°9 60 FZ 9°29 LT fo) 09T “¢ o¢'9 88 °¢ 18 °¥ £°6F 91 ‘jeqdsureip | °“O 069 ‘F €9°9 009 90 “8% 8°€9 cI 7) ost‘9 | 00°9 oL°g Ig"c% | 89 a! 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N ‘eZzIS pure Seloedg ° IOUUe yy 0} SSou ¥ ut J I BS emn ‘3 A JOU seqig | -npo MIS 3) SACs) Sep eyeuL 410A “png Qh Pon “IoJOULVIC -1xoiddy "(Buapoo) yurod-p.inyy ssscckec5c Aug. 14. ID Xo} seat AD) BS Vestas eae Aug. 1. DOR See Comise eae oe sere. July 27. BY On as eee INSEE GO Dsse eacecoc July 29 The females die soon after egg laying is finished. There is appar- ently only one generation a year, the eggs hatching in summer and the larve completing their growth during the follow- ing year. The greater number of larve are in the pupal stage during the first half of July. DESCRIPTION. THE EGG. The egg (fig. 2) is creamy white when first deposited, but grad- ually assumes a pinkish shade, which deepens to orange rufous before hatching. The average length is 4 mm. and the diameter 1G. 2.—The to- 0.32 mm. It is regularly oval, with the ends slightly truncate, P2cco Crambus: d 0 Z Kgg. Greatly and has a polished appearance. There are about 18 longitudinal — onjarged. (Once carinze and numerous transverse striz. nal.) THE LARVA. FIRST INSTAR. When first hatched, the body of the larva is semitransparent, and the alimentary canal can be plainly seen. The outline of the body, when seen from above, is almost triangular. The larva is white, or pale yellowish white, and about 1 mm. long, with a few scattered, light-colored hairs on the head and body. The head shield measures 0.15 mm, in width, is yellowish brown, and moderately bilobed, with the clypeus attaining the apical third. The cervical shield is tinged slightly with brownish. Five pairs of prolegs occur on the 7th to 10th segments, inclusive, and on the 13th segment. LAST INSTAR. The full-grown larva (figs. 3, 4) is about 15 mm, long, and yellowish white, with a tinge of pink dorsally. The hairs of the body are slender, brownish, and set on large fuscous tubercles. The head shield measures 1.2 mm. in width, and is pale yellowish 6 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. brown, flecked with darker brown. The cervical shield is distinct, shining, yel- lowish brown, tinged with fuscous, and bears 12 hairs in two transverse equal rows. The anal shield is pale fuscous. About the middle of abdominal seements 3, 4, 5, and 6, and slightly above the spiracles, is a series of distinct, dark fuscous, chitinous areas about the size and shape of spiracles, one to each segment. The arrangement of the tubercles is as follows: Beneath the anterior margin of the cervical shield is a tubercle bearing two hairs, The mesothorax above bears eight setigerous tubercles on the anterlor margin, each, ex- cept the lateral tubercle, with tvvo hairs. Posteriorly itis provided with three bare tubercles, of which the medi- Fic. 3.—The tobacco Crambus: Full-grown larva, or ‘‘wireworm.”’ an is narrow and transverse. Much enlarged. (Original.) The metathorax is armed, as is the mesothorax, Each abdominal segment above the spiracles bears two transverse rows of four tubercles each, The anterior dorsal pair are subquadrate, with the posterior lateral angles strongly rounded. The posterior dorsal pair are oblong, transverse, about half as long as the anterior, with the posterior lateral angles strongly rounded, The-anterior lateral tubercles are supraspiracular, irreeularly quadrate, with the lower margin produced diagonally behind the spiracle, emarginate at the spiracle and before the impressed area on segments 3, 4, 5, and 6. The corresponding tubercle on segment 8 has the pro- duced portion isolated and is placed anterior to the spiracle. The posterior lateral tubercles are trans- verse, elongate, and somewhat oblique. Abdominal segments 1 to 7 each bear a minute spinule anterior to and nearly equidistant from the spiracle and the supraspiracular hair. The legs are pale brown, the maxillary palpi brown, and the mandibles brownish fuscous at apices. The color of larve collected from differ- ent food plants varies considerably, this Fic. 4.—The tobacco Crambus: Head Z /of larva. Greatly enlarged. (Origi- being merely an effect of the color, whether “,,,) light or dark, of the food in the alimentary canal. Larvee collected from corn are considerably lighter than those collected from tobacco. s THE PUPA. The pupa (fig. 5) measures about 8 mm. in length and 2 mm. in greatest width. The general color is dark brown, or pale yellowish brown when newly transformed, with the appendages and segments marked with dark brown. The head is blunt, with a median apical emargination. The tips of the wings are rounding on abdominal segment 5; the margin of the inner wing is visible over segments 2, 3,and4. The spiracles are not prominent, the first three pairs being set on blunt tubercles. The cremaster is transversely rounded oblong, with a lateral bristle near the apex. THE ADULT, OR MOTH. Expanse of wing, 13-25 mm. Head, palpi, and thorax dark fuscous, sprinkled with gray scales. Fore wing dark fuscous, sprinkled with brown or yellowish, and fre- quently with a few gray scales; median line dark brown, often edged with white, aris- lo) { THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. ing a little beyond the middle of the costa, extending outward, forming a very acute angle, thence backward across the end of the cell to the hind margin, a little beyond the middle, and giving off an outward angle on the fold. Subterminal line dark brown, edged outwardly with dark lead-colored scales, and frequently dentate along the first part ofitscourse. It arises from the costa about half way between the median line and the apex, extending down to a point beyond the end of the cell, where it forms an out- ward angle, thence to the hind margin, a little within the anal angle, giving off an inward angle on the fold. This angle is frequently connected along the fold with the outward angle of the median line; terminal line dark brown, rather indistinct. The lines are often obliterated more or less, especially the median. Fringes dark leaden gray. Hind wings dark fuscous; fringes a little lighter. [Fernald, 1896.] (See fig. 1.) The moths vary somewhat in color and distinctness of markings, some specimens being much darker than others when first trans- formed. In the hind wing the frenulum is a single short spine in the male. In the female the frenulum is more slender and is very finely divided at the tip. In the female of a number of other species of this genus the frenulum consists of two dis- tinct spines. LIFE HISTORY. HABITS OF THE MOTHS. The moths fly during late afternoon, on dark days, and during the early part of the night. They are attracted to light, but in comparatively small num- bers considering their great abundance at certain times. The majority of the females collected at trap lights are those which have deposited their eggs. During the day, when disturbed, they make short, Sa ee ‘erratic flights, usually alighting head downward on crambus: Pupa. the stems of weeds and grasses, their tightly closed Re RS Ae wings and grayish color making them very inconspic- uous. As with other members of the genus Crambus, their long palpi, extending parallel to the stem of the plant on which they are at rest, help to make the outlines of the body conform to the appearance of that part of the plant. OVIPOSITION. When the meths were confined in cages, the eges were deposited at random over the surface of the ground. They seemed dry when deposited, rolled about easily, and did not adhere to papers placed over the soil in the rearing cages, or to glass when females were con- fined in large test tubes. Normally the eggs are doubtless placed in the same manner, for on two occasions eggs were found on the upper surface of leaves of sweetbrier lying flat on the ground. Egg laying commences shortly after the moths emerge. Fertile eggs were not obtained from moths reared in the cages. - 8 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. Records obtained from a large number of females, collected in the fields and placed in separate cages for egg deposition, show the average number of eggs laid to be 177... Among the records obtained at Appo- mattox, Va., during 1910, are those in Table IT. TaBLE I1.—Number of eggs laid by the tobacco Crambus, Appomattox, Va., 1910. No ; one me, No : > ay hice cata ; 5 ?eriod of ovipo- er : 5 Atoka eriod of ovipo- | ber atts Moth collected. Stich exes oie Moth collected. |. sition, if eas ale.) aid. alt aid. 1910. 1910. 1910. 1910. US RAS aA ae Seer July 9-13... .-: oe al 2S LO))|| Avie l yeee Atle. D2 wares. 83 BM Ie 2 OSL Ao eae Gost ier te 68 1) SEO ae cee Aug. 12-16. .-.....- 203 oul ee OAR Sone July 9-14......--.. 271 12.) Aug. 14 ee ee Aug. 15-20... - 2.4 218 uly lone euulivatl U4 oe ee 156 13H (ee Ones eees Aug Ta-18. 2. 2 e 194 ay int h ea Pe Se July 13-18. ....--.. 211 14))) Avg, 15 ee eee ATIg 16-2022 2: .- 2 222 OM uly yee ee ese vUUlye S22 ene ee lee T5i eases Q0ke re pees Aug. 16-19. .....-- 91 (ig (Serer dose eed July 18=23_ =... - 287 HIG) sees Vaya eee, Saree Aug. 16-21 « : - 2. 238 Si) Ahulya2osce 22 oe July 26-30. -.....-- 77 if aes 00 seee AUS WG=LB)r0223- = 63 9 evr | See ANS QB ese 2 ae 301 Several individual females laid over 300 eggs, and over 300 were obtained in several instances by dissection. It is probable that the average number of eggs deposited normally is above rather than below the average obtained in the cages, as some of the moths may have laid eggs before capture, although records were not included from moths which deposited eggs within 12 hours after capture.t The period of oviposition lasts from 3 to 5 days, the females dying shortly after egg laying is finished. The records of two females col- lected in the field on August 10, 1910, are given in Table TIT. TaBLe II1.—Rate of oviposition of the tobacco Crambus, Appomattox, Va., 1910. Female No. 1. Female No. 2. Num- | Num- ber of ve ber of Date. eggs de- | Date. eges de- oe | posited. = Sa eee ees | =: as 1910 1910 ANT OSL 2 o.. SAS emer neers yeti (4 7 Ag. 10! oe ne A ee Oe eee ae 93 TET) DA A iy ied de es ee Coen | foe oF ab rere MIL Ss oko ee 87 aS & ergs eget 8 NS Rae ee 7 ATE. 1D... 2. Sa celta = cies eee ae eee ae 23 ANIC AS =. x. 3ins see eee ane. eee 36) |)oAugi ls | odo k eee ee ee ee eee ee 5 PY tS rte eee ek a es cere 19 c : Potal's 4:2) 0 ae Ro ee ee | 221 Total : sus. heckehe a US sep 208 DURATION OF THE EGG STAGE. The period of incubation was found to be from 5 to 9 days, the greater number of eggs hatching about the sixth day at ordinary summer temperatures. 1 The dissection of 17 females of Crambus caliginosellus collected in the field during the third week in July, 1912, showed that 8 of the 17 collected contained more than 100 eggs. The number of eggs (mature or nearly mature) found in the 8 moths containing more than 100 eggs was as follows: 143, 322, 127, 290, 307, 124, 342, 208. Bul. 78, U. S. Dept. of Agriculture. PLATE I. Fic. 2.—INJURY OF THE TCBACCO CRAMBUS, OR “ WIREWORM,” TO CORN. WORK OF THE TOBACCO CRAMBUS. Bul. 78, U.S. Dept. of Agriculture. PLATE II. FiG. 1.—PoOR STAND OF TOBACCO RESULTING FROM PLANTING ON WEEDY LAND. Note heavy growth of oxeye daisy in part of field not in tobacco. Fic. 2.—WILD CARROT AND OTHER WEEDS IN FIELD OF RED CLOVER. Injury from the ‘‘wireworm” occurs when land of this kind is planted in tobacco or corn. RELATION OF WEEDY LAND TO INJURY BY TOBACCO CRAMBUS. THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 9 TaBLE IV.—Duration of egg stage of the tobacco Crambus, Appomattox, Va., 1910. AE | Incuba- of Incuba- N Eggs laid— | Eggs hatching— tion No Eggs laid— | Eggs hatching— tion Ys: period. eee period. | 1910. 1910. Days 1910 | 1910. Days il || divihy TES Reeeaee af AB oadees 5 Sh Ati peal 2h ees | Aug. U7=18—- 2-2 5-6 2 |) dually ikke yeue July 19-20....... 8-9 @) || Avie, RL oo {eae CON eee i 5 34 |) L100 ea Be eee Ap UG ee eee 7 il) | Alib sess Aug. 19-20....:. 5-6 4) July 13.-2. 2... Juty 19-20.....-- 6-7 ill | Arete Gee oe ese Ae 20 eer ene 5 5 | anol PAs ee Dulyacle eee 6 U2 NURSE WG) oe eee Atig, 21-22). 2 5-6 Gis Pony: 26% eo ee ANTE = 28 ne 6-7 eNO Le (pene see | Allg. 23-24 2 a= 6-7 Hig (PAM Oy LYE (Saar: Aug. 16-17...--. 5-6 | | HABITS OF THE LARVA. NATURAL FOOD PLANTS. Larve of the tobacco Crambus have been found feeding on the following wild plants: Buckhorn plantain (Plantago lanceolata). | Wild carrot (Daucus carota). Oxeye daisy (Chrysanthemum leucanthe- | Sheep sorrel (Rumex acetosella). mum). | Senecio (Senecio jacobexa). Wild aster or ‘‘stickweed” (Aster eri- | White-top (Hrigeron annuus and other coides and other species). species). The first two plants named, the buckhorn plantain and the oxeye daisy (Pl. Il, fig. a), were found to be the main food plants of the larvee in the localities studied. The eradication or control of these weed pests, therefore, will result in comparative immunity from loss by this insect. Both species of plants have been found heavily infested in many localities in widely separated sections. During early spring the plantain seems to be the preferred food plant; later a heavy infestation occurs on both plantain and daisy. On July 8, 1910, 23 out of 25 oxeye daisy plants examined in a weedy field were infested, there being a total of 69 larve about the roots. As many as 20 larve have been collected from one plant of the oxeye daisy. In tobacco-growing sections of Tennessee and Kentucky white-top is a frequent food plant. When meadows are plowed up and planted to tobacco there is frequently serious injury from the ‘‘wireworms.”’ (See Pl. IL.) Where such injury has occurred the weeds mentioned above have invariably been found abundant in the sod, which explains the pres- ence of the “‘worms.’”’ Injury has not been observed where there had been previously a clean growth of grass or clover. Attempts to rear adults from larve confined in field cages containing only timothy and clover resulted in failure, although the larve lived for a considerable time without other food. 30183°—Bull. 78—14——2 10 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. INJURY TO TOBACCO. The tobacco is attacked soon after planting, and feeding by the larve continues until the first or second week of July. The larvee usually commence operations just below the surface of the ground, although newly set plants are frequently attacked at the ‘‘bud”’ or whorl of terminal leaves. As feeding continues the larve, especially the smaller ones, frequently enter the stalk and tunnel upward, the burrows often extending to the base of the first leaves and some dis- tance above the surface of the ground. (See PI. I, fig. a.) When not feeding the ‘‘worms”’ are found about the base of the plant, usually in cylindrical, web-lined galleries, which extend from the plant, often for several inches, beneath the surface of the soil. Injured plants may usually be detected by their stunted or wilted appearance, which is more noticeable during hot, dry weather. The stems are in some cases entirely cut off, although this form of injury is rather unusual. . Although plants often partially recover they do not obtain full growth, and it is evident that the presence of many dwarfed or stunted plants must result in very materially lessening the yield. The value of the crop is greatly decreased also, owing to the large proportion of late plants resulting from replanting. Early planted tobacco is usually better in quality than the late planted, it being finer and more elastic, curing better, and consequently bringing higher prices. The attacks of the larvee often make it necessary to reset the crop several times, and a good stand of plants 1s not secured, if at all, until too late to make the crop as profitable as it should be. INJURY TO CORN. Owing to its wide distribution in the Eastern States the tobacco Crambus is a serious pest to the corn crop. ‘Injury has been noted in many localities where little tobacco is grown, and it is probable that damage to corn amounts to even more than that to tobacco. As with tobacco, injury is most severe when corn is planted on land ~ which has been in weedy pasture or meadow previously, or when planted on land which has not been under cultivation for a number of years and on which there has been a rank growth of weeds. On such land it is usually difficult to secure a satisfactory stand of corn, and the yield is greatly reduced. (See Pl. I, fig. 6.) In central Virginia many fields under observation were replanted several times, and owing to the lateness of the season when a stand was secured the value of the crop was decreased fully one-third. Corn or tobacco planted on newly-cleared land seldom suffers injury from theCrambus. Since the species of weeds which are the natural food plants of the insect do not thrive in woodland, the larve are not present when the crop is planted, THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. leh The larve attack the young corn near the surface of the ground and burrow into the base of the stalks, the outer portion of the stalk being frequently girdled. If the stalks are small when attacked, they are _ either killed or so stunted or dwarfed that they never fully outgrow the injury, and produce little or no grain. Much of the corn is attacked just after the seed has sprouted. The larve frequently _ burrow into the folded leaves as the corn is coming through the ground. As the leaves unfold they show transverse rows of holes. When the stalks reach a height of a foot or more comparatively little damage is done. Several larve are frequently found about the roots of a single stalk, and as many as 22 have been collected from a single hill of corn. In wet weather injury is not apt to be so severe} as the plants are then more vigorous and the weeds, which furnish suit- able food for the worms, more plentiful. As with tobacco, corn is attacked when the natural food supply of the “worms” is cut off. GENERAL FEEDING HABITS. The feeding habits of the “wireworm”’ on plants other than corn and tobacco are, in a general way, the same. There is a tendency to girdle soft-rooted plants, such as plantain and the wild carrot (PL. I, fig. b), and the larve are often found embedded in cavities where they have fed. The buckhorn plantain (Plantago lanceolata) is frequently killed where the infestation is heavy. A marked preference is shown for the natural food plants, and farmers, when the larve are especially troublesome, frequently take advantage of this fact by cultivating at first only one round to the row, allowing the weeds to grow in the center of the row until the corn or tobacco has become better estab- lished. In a plowed field the larve, if they have not finished feeding, concentrate about plantain, daisy, and stickweed (Aster spp.) which have not been killed by plowing. The larve do not seem to travel far in search of food, as was ascertained by plowing badly infested land adjoining fields of corn and tobacco. When disturbed they crawl actively in either direc- tion, and they will often spin a slender silken thread by which they may be suspended. They feed most actively at night. THE PUPA. The larve pupate in the soil near the plants on which they feed. Before pupation there often seems to be a rather long period during which the larve remain inactive in their cells. The pupal cells are usually found at a distance of from 1 inch to 6 inches from the base of the food plant and at a depth varying from one-half inch to 4 inches. Table V shows the depths at which pupe were found about various food plants in soils varying from hard stiff clays to loose sandy loams. 12 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. TaBLe V.—Depth at which pupation of the tobacco Crambus takes place, Appomattox, Va., 1910. Date Character of soil. | Food plant. | Depth. Date. Character of soil. | Food plant. | Depth. 1910 Inches. || 1910. Inches. July. .9.| Red.dlayon-- es = Tobacco 2.5 || July 11 | Red clay, ne SERRE Tobacco... . i Do....| Sandy loam......-]....- Trewern 3.5 DO. 22). 5 00. eee OLS A os. 2.5 Doz. atieeas dol Jere Plantain 1 iDosa2s Sandiz loamss sa Daisy .....- 5 Dow.) Red claysccaee see seseee doz :. 5 Do... ..| Red clayce seeeseee Plantain - -. 1 Do: ...:| BlackJoami- _.-2.-| Daisy... << 4 Doz |t meee down: oe ee SD aisyiee ee 1.5 July il Gray sandy loam..| Tobacco... 3.5 Numerous measurements made at different times gave results very similar to those shown above. The average depth at which pupation takes place was found to be about 1.5 inches. The cells averaged about 9.5 mm. in length and 4.5 mm. in width (inside measurements). The lower portion of the cell is usually somewhat larger than the upper portion, the pupa lying in the larger end of the cell in convenient position for its egress. The cells are extremely fragile and are easily broken when removed from the soil. They are constructed of fine particles of earth and grains of sand in- terwoven with a silky weblike material. The walls are thin and the interior surface quite smooth. The pupal period, as shown in Table VI, lasts from 10 to 15 days. TasLe V1.—Pupal period of the tobacco Crambus, Appomattox, Va., 1911. , ] | | Num- Num- Larve Moth Fs Larvee Moth collectea— | Pupated— | emerged— fees | collectea— | Pupated— | omerged— Sete 1911. 1911. 1911. | 1911. 1911. 1911. June 18.......} July 7-10....| July 21....-. 11-14 |) July 1.......-. uly sS=e ee JUL yee E ee 2. 14 DOrAn eee | July 10-11...|..... dornes22 10-11 || July. 12:...... Aug. 1-3....| Aug..15..... } °12-15 Junewoses 2 July 7-9..... -| July D2 Ree 15-17 | Doe. 22Ee dualbye5 see Aug ds ge 5 7 15 DOs sees July open eee eee dO ess 10 | DON nase s July 28-31...| Aug. 10..... 10-13 Dor ces, 5} Afiilreisioeaeae July 26. /..-. | 11 || Dowss2tss Aug..1-2...-| Auged5.2.2! 13-15 TCLVAle owes | July 28-31...) Aug. 10..... | 10-13 ! IDs ospees Ao et eee Aug. 12 sens | 12 Table VII shows the duration of the period during which the insect is in the pupal cell before and after pupation. Taste VI1.—Duration of prepupal and pupal periods of the tobacco Crambus at Appo- mattox, Va., 1911. Num- Num- j Larvz ceased Moth fais Larvee ceased Moth Le feeding— emerged— | DP2YS- eee feeding— emerged— | DAYS. | 1911 1911 1911 1911 Li June 182232. 2 dilly Oe es... 22 TA ly aD eee eee Arie es Bid z 7A Bee (i (cee ae July 1528... . 27 | 8) dil De eee July 28s eee 13 1 Oe 6 [Ee Sear | July d6s22-=--: 28 | OF uly eee eee Juilyi29 feet s 16 Ni lel VCE as 2h algae ea Jtlvaltiene.. .s 15 10°) July Ae Soe Aug. 3 es 20 ie eee GOs. es 3 | July 7 ee 17 ADE eee doves. 22828 July 203s: 3 15 a ° ~ = Sas: _ © . ‘ ' = or) THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 13 NATURAL ENEMIES. In spite of its long larval period the tobacco Crambus does not seem to be largely parasitized, at least during the later stages, this being due presumably to the subterranean habits of the larve and the protection afforded by the loose web in which they usually lie when not feeding. Nevertheless parasitic and predaceous enemies are doubtless factors in keeping the insect in check. The vast num- ber of newly hatched larve as contrasted with the number found later in the season shows that comparatively few survive the earlier larval stages. This reduction is due in part to various natural ene- mies the exact or relative importance of which it is hard to estimate. Various carabid beetles have been observed to feed on the larve. Among them were Calosoma calidum Fab. and Chlenius tomentosus Say. Adults and larve of Harpalus (Harpalus pennsylvanicus De G. and H. faunus Say) were observed to be very abundant about roots of oxeye daisy and plantain which were heavily infested with Crambus larve. As the species of Harpalus are known to be gen- eral feeders, they were thought to feed on the larve of the Crambus. The adults, when confined in tubes with larve, occasionally fed on them. Spiders of several species were observed to feed on the larve, and large numbers of the moths are captured in spider webs in weedy fields. Ants also occasionally attack the larve. An ant found carrying a partly grown larva at Chatham, Va., was examined by Mr. Theo- dore Pergande and found to be a species of Solenopsis. W. G. Johnson, in Maryland, reported the rearing of an undeter- mined hymenopterous parasite from the larve. No _ parasitic Hymenoptera were secured from the rearing cages at Appomattox, although large numbers of larve were confined. Several Diptera were observed in cages containing larve on vari- ous occasions, but actual proof of parasitism was not obtained, although a species of Phoridze was secured from tubes containing larvee under circumstances pointing strongly to parasitism. In the National Museum are specimens of a hymenopterous para- site, Perisemus prolongatus Prov., labeled as reared from larve of Crambus caligynosellus from La Fayette, Ind. The record is doubt- ful, however, as the notes concerning the specimens in the files of the Bureau of Entomology clearly refer to a different species of Crambus as the host. Birds are a factor in keeping the tobacco Crambus in check. Two species, the quail (Colinus virginianus) and the kingbird (Tyrannus tyrannus) were observed by the writer to capture the moths, and others are known to feed freely on moths of this genus. F. M. Web- ster states that the wood pewee (Myiochanes virens) was observed to 14 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. destroy large numbers of Crambus laqueatellus at Haw Patch, Ind., and C. H. Fernald observed barn swallows feeding on different species of Crambus in Maine. Meadowlarks frequent weedy fields which harbor the larve of Crambus, and as these birds are known to feed on various species of cutworms, they doubtless feed also on the larvee of the tobacco Crambus. REPRESSION. CULTURAL METHODS OF CONTROL. Injury from the tobacco Crambus occurs where crops susceptible to injury are grown on weedy land. Tobacco or corn planted on land which has been under clean cultivation the previous year and kept free from weeds which live throughout the winter does not suffer serious injury. The larve can not live over winter in the soil from the previous summer unless plants on which they are able to feed are present. All field experiments and observations so far have shown that the most effective means of control consist of freeing the land from the weeds, such as buckhorn plantain, daisy, stickweed, etc., which have been found to be the natural food plants of the larve. There are many methods by which weeds may be eradicated or controlled, but the most practical and effective is the systematic rotation of crops. Sowing clean seed, preventing weeds from ripen- ing seed, fall or winter plowing, the use of lime or of certain fertil- izers, and doing away with wide fence rows are important preven- tive measures. Mowing and burning over weedy fields destroys many weed seeds and weeds which live over winter, and also destroys many injurious insects. Burning durmg August or September has been found to destroy the eggs and young larvee of the tobacco Crambus, but as this method destroys humus, which is so badly needed in most tobacco soils, it is In most instances not advisable. Many weeds are “‘soil indicators,” their presence showing that the soilis lacking in fertility and in some instances pointing to a deficiency of lime. CLEAN SEED. One of the main factors in the control of weeds is clean seed, and the importance of procuring such seed can hardly be overestimated. Many weed pests are introduced and disseminated in the seed of various crops, such as grass and clover. As tobacco or corn must frequently be grown on land which has previously been in these crops, and as injury from the tobacco Crambus is apt to occur if the meadows have been weedy, it is desirable, for this and other reasons, to have the meadows as free from weeds as possible... Owing to 1 An analysis made by the Massachusetts Experiment Station shows that 1 ton of oxeye daisy (cured) withdraws from the soil approximately 25 pounds of potash, 8.7 pounds of phosphoric acid, 22 pounds of nitrogen, and 26 pounds oflime. ‘To restore the stated amounts of the first three constituents to the soil it would be necessary to apply about 50 pounds of muriate of potash, 65 pounds of superphosphate, and 140 pounds of nitrate of soda. (Farmers’ Bul. 103, U.S. Dept. Agr.) THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 15 careful cultivation of previous crops, the land is frequently fairly free from weeds when seeded to meadow; so that if the clover and grass seed has been sown pure there will be few weeds in the tobacco field or cornfield. | An examination of samples of clover and grass seed procured from farmers and seedsmen in various sections of Virginia shows that seeds of buckhorn plantain and oxeye daisy—both natural food plants of the tobacco Crambus—are common. Of 30 samples ex- amined by the seed expert of the Virginia State department of agriculture during 1910, 28 contained seeds of oxeye daisy, and of these, 5 contained plantain and daisy. Of 70 samples of clover, redtop, and timothy seed examined at the Virginia Experiment Station in 1909, seeds of buckhorn plantain were found in 16.1 The United States Department of Agriculture and those in charge of similar work in many of the States have provided means by which samples of seed may be examined for purity by experts. Some of the States, also, have laws compelling dealers to furnish a stated guaranty as to the purity of the seeds sold. | _ WEEDS TO BE ELIMINATED. The buckhorn plantain (Plantago lanceolata) is one of the numer- ous naturalized weed pests from Europe. It ranks among the worst weeds, particularly upon the lighter soils and on clay uplands. “Ray-bud,” ‘“‘rib-grass,’’ “‘ribwort,” ‘buck plantain,” ‘English plantain,” “ripple,” ‘ripple grass,” and “narrow plantain’ are names applied to the plant in different sections. It is perennial or biennial and is common in meadows. ‘The seeds are widely dis- tributed with clover seed, from which it is difficult to separate them. Rotation of crops, thorough cultivation, and the use of clean farm seed are the usual methods for its control. The oxeye daisy (Chrysanthemum leucanthemum) (P1\. II, fig. a) is also a naturalized species from Europe. It is often abundant on old or poor soil. It spreads from the seeds, which are distributed in various farm seeds, in hay, and in manure; also, by shoots from the perennial root stocks, which must be entirely killed before the plant can be wholly eradicated. It is best controlled by rotation of crops, by smothering out by means of cowpeas or other suitable soiling crops, and by thorough cultivation. It is a bad weed pest in meadowland. The seed can be prevented from ripening by mowing the hay early. White top or fleabane (Hrigeron annuus and other species) is a common pest in meadows. In some localities it has been found to be a cood plant of the tobacco Crambus. Early mowing of infested meadows. before the seeds ripen and pasturing with sheep, which 1 Bul. 184, Va. Agr. Exp. Sta. 16 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. readily eat the weed, are control methods commonly practiced. Chemical sprays are fairly effective, but can not be used in meadows where clover is grown, as clovers are killed by the solution. Sprays have been found most effective while the plant is in bloom. The stickweed or aster (Aster ericoides), known also as frost- weed, steelweed, white heath, etc., and related species, are com- mon and abundant weeds in old fields in tobacco-growing sections of the Atlantic States. They are perennial and thrive on poor soil. It is useless to try to eradicate them completely, but they can be readily controlled by growing cultivated crops and by putting the land in a higher state of fertility by the use of lime and clover. Aster is not a usual food plant of the tobacco Crambus, but as the weed is so frequently associated. with daisy and plantain, which thrive best under similar soil conditions, its control is essential in the preparation of land for tobacco. CROP ROTATION. One of the main reasons for a rotation of crops is that the accumu- lation of weeds in meadowland and pastures may be destroyed during the cultivation of the crop that follows. A rotation found very satisfactory by the Virginia experiment station has been devised by Mr. E. H. Mathewson, Crop Technologist of the Bureau of Plant Industry. This plan is slightly modified to meet condi- tions in different tobacco-growing sections. It calls for a seven- year rotation of crops, as follows: First year, tobacco, fertilized heavily; second year, wheat without fertilizing; therd and fourth years, mixed grasses and clover, seeded alone early in the fall and top dressed early in the spring with 200 to 300 pounds of nitrate of soda; fifth year, corn, with barnyard manure and a small amount of fertilizer; sith year, cowpeas, fertilized with a little acid phosphate and sulphate of potash; seventh year, tobacco. Crops such as cowpeas, soy beans, and crimson clover, which aid so greatly in fitting land for increased and more profitable yields of tobacco and corn, not only add humus to the soil and increase the fertility, but help to eradicate certain weeds by smothering them out. The weeds are also destroyed or prevented from maturing seed when crops are plowed under. Although eggs of the Crambus may have been deposited in such a field, the larve can not survive until the tobacco is planted unless there are weeds which remain alive over winter to supply them with food. The following rotation experiments have been under observation during the present investigation: A test with tobacco following crimson clover was conducted as a cooperative experiment on the J. R. Horsley farm in Appomattox County, Va., in the season of 1910-11. The field selected contained THE SO-CALLED TOBACCO,-WIREWORM IN VIRGINIA. 17 4acres. It wasin corn during the season of 1910. Previous to plow- ing for corn the field was in weedy sod. The corn was badly injured by the Crambus and was replanted twice. At the last cultivation of corn in July, crimson clover was sown. Rains were frequent during the latter part of the summer, and a fairly good stand of clover was secured. There were some weeds, in spots, which cultivation at the time clover was sown had not destroyed. ‘The field was planted to tobacco during the season of 1911. Damage by the Crambus was estimated to be about 6 per cent. A test with tobacco following cowpeas was conducted as a coop- erative experiment on the S. L. Ferguson farm, Appomattox County, Va., in the seasons of 1911 and 1912. A field containing about 6 acres was used in the experiment. The land previous to plowing for cowpeas was in weedy pasture, and numerous Crambus larvee had been observed. A good growth of the cowpeas was secured. The land was deeply plowed during winter and was prepared for planting to tobacco during the third week in May, 1912. Scarcely any injury from the Crambus to the first planting was observed. After the first planting damage from the Crambus and from other causes was esti- mated to be less than 4 percent. In the check field, where conditions were similar to those in the experimental field, except that a crop of cowpeas had not been grown, there was an estimated damage from the Crambus of about 9 per cent. The sod in the check had been wiuter-plowed. In the plats of the Virginia Tobacco Experiment Station, at Appo- mattox, nine experiments were under observation, as detailed below. The first experiment was with tobacco planted on sod in an old weedy pasture. A-large part of the first planting was destroyed. The plat was replanted three times. About 9 per cent of a stand was secured by the second week in July. Owing to injury from “‘ wire- worms”’ and the large percentage of late plants the value of the crop was decreased 25 per cent as compared with plats in which an early stand of plants had been secured. The second experiment was with tobacco following cowpeas on land that had been uncultivated for several years and was very weedy. Almost a perfect stand of plants was secured at the first planting, which was made the last week in May. The injury (decrease in the value of the crop) was less than 1 per cent. The third experiment was on a plat used for fertilizer tests. The condition of the land was similar to that used in the second plat, except that cowpeas had not been grown during the preceding season. The tobacco was replanted three times, The decrease in the value of the crop was 7 per cent. 18 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. The fourth experiment was again with tobacco planted on sod. There were few weeds in the sod. Nearly a perfect stand of plants was secured at the first planting, which was made during the last week in May. The plat was replanted once. The loss was esti- mated at less than 1 per cent. The fifth experiment was again with tobacco following cowpeas. A perfect stand of plants was secured at the first planting, made during the last week in May. Injury from the tobacco Crambus was estimated at less than 1 per cent. The sixth experiment was with tobacco planted on red-clover sod. The stand of clover had been good and there were few weeds. To- bacco was planted during the last week in May. A good stand was secured at the first planting. Loss from the Crambus was estimated at less than 1 per cent. The seventh experiment was on spring-plowed land where stick- weed, daisy, and plantain had been abundant. The tobacco was planted during the second and third weeks in May. The loss was estimated to be about 20 per cent, owing to late plants, the tobacco having been replanted three times. Injury from the Crambus was. worst in the portion of the field where weeds had been most abundant. The eighth experiment was with tobacco followmg rye. The stand of rye had been poor and the stubble was weedy. The first planting was made on June 8, and was almost completely destroyed. Tobacco was replanted three times. A stand of 90 per cent was secured by the second week in July. The estimated decrease in the value of the crop was about 30 per cent. The ninth experiment was with tobacco fo..owmg cowpeas. The first planting was made on June 2. About 20 per cent of plants were injured by ‘‘wireworms.”’ The plat was replanted once, there being only slight damage after the second planting. The estimated loss in value of the crop was about 10 per cent. Most of the injured plants were in the end of the plat where the stand of peas had been poor. . Three experiments were under observation at the Virginia Tobacco Experiment Station at Chatham in 1910 by Mr. R. P. Cocke, super- intendent of the station. In experiment No. 1 tobacco was preceded by corn in which crimson clover was sown at the last cultivation. This clover was fallowed May 2. The corn was kept clean of weeds and: grass. Tobacco was set June 6. The first replanting was made June 14 with 5 per cent of the plants injured; the second replanting was made June 23, with 3 per cent injury; and the third replanting, June 28, with 2 per cent injury. About 97 per cent of a stand was finally secured after the third replanting. THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 19 In experiment No. 2 tobacco followed corn, in a plat used for fertilizer tests. Tobacco was set June 6. The first replanting was made June 14, with 5 per.cent injury; the second replanting, June 23, with 3 per cent injury; and the third replanting, June 28, with 2 per cent injury. About 98 per cent of a stand was secured after the third replanting. In experiment No. 3 tobacco was planted after a cover crop of wheat, in variety test plats. The wheat was fallowed May1. Tobacco was set June 7. The first replanting was made June 17, with 20 per cent injury, and the second replanting, June 28, silt 6 per cent injury. About 95 per cent of a stand was Becnredi In these plats it was estimated that about 5 per cent of the entire loss was due to cutworms and to true wireworms (larve of Elateride). SUMMER PLOWING. The moths are local in habits and do not fly far from the weedy fields, which furnish protection for them and which are suitable places for them in which to deposit eggs. On emerging from plowed or bare land, or from fields in which the vegetation is not suitable for protection or for egg deposition, they fly to surrounding fields where conditions are more favorable. The land from which emer- gence took place will then be left free from worms which, if present would attack the crop the followmg year. The preparation of weedy land for tobacco or corn must, therefore, be commenced the season before the crop is planted. Best results have been obtained by summer piowing, as the land was thus rendered bare of vegetation, and conditions were not suitable for egg laying when the moths emerged. By this means infestation of the land is prevented in the first place. It has been found that it is difficult to prevent injury, or to eradicate the worms, if they have once become established. Summer treatment of land makes conditions unfavorable for the moths to deposit eggs, destroys weeds which furnish food for the young larve, and kills many of the insects while in the pupal stage. The results of an experiment made in 1910 to ascertain the effect of plowing on pup is given in Table VIII. Larve were placed in large field cages. When the greater number had pupated, one of the cages was removed temporarily and the land plowed. TasLeE VIII.—E£ fect of plowing on pupal stage of the tobacco Crambus. | Number) | | = aap Num- Per Cage No. | | oflarve. Collected. Moths emerged. ie aries |- sees EER ae atin Sa | 200 | June: Second and third week. - | July: Third and fourth week.. 84 42 5 (check) - - | BIN) |e eee OS pe a ee ener SIM Det ORS a en en 118 59 20 BULLETIN 78, U. 5. DEPARTMENT OF AGRICULTURE, Pupation takes place at an average depth of 14 inches. The pupal cells are fragile and easily broken up by plowing or disking. Many of the pupe are deeply buried by plowing and the moths are unable to reach the surface. The satisfactory results followmg summer treatment of land, whether or not cowpeas or other similar crops are grown, are mainly due to the fact that conditions are made unfavorable for the deposi- tion of eggs by the moths and for the growth of newly hatched larve. FALL AND WINTER TREATMENT OF LAND. During September, 1909, two cultural experiments were begun in Appomattox, Va., to ascertain the effect of fal! and wincer treatment of land already cuiscied with Crambus larvee The field selected on the J. F. Purdum bom contained five plats of one-half acre each. In this experiment (experiment A) fall and winter preparation of the tobacco land gave decidedly beneficial results. The field had been in pasture previous to plowing, but the erowth of weeds was not so rank as on the land used in experiment B. The following were the results obtained in each of the plats: Plat No. 1.—Ground plowed during second week in December, 1909. Thoroughly disked during first week in January, 1910. Tobacco planted during last week in May. Number of plants, 2,200. Number replanted, 89. Per cent injured, 4+. Plat No. 2.—Land plowed during first week in January, 1910. Disked during second week in February. Tobacco planted during last week in May. Number of plants, 2,350. Number of plants reset, 165. Per cent injured, 7+. Plat No. 3.—Land plowed during last week in February, 1910. Disked during third weekin March. Tobacco planted during last week in May. Number of plants, 2,280. Number of plants reset, 138. Per cent injured, 6+. Plat No. 4.—Land plowed during third week in March, 1910. Disked during third week in April. Tobacco planted during last week in May. Number of plants, 2,214. Number of plants reset, 251. Per cent injured, 11+. Plat No. 5 (check plat) —Land plowed during third week in April. Prepared for planting during last week in May. Tobacco planted during last week in May. Num- ber of plants, 2,225. Number reset, 375. Per cent injured, 17+. Tobacco in all plats was replanted twice. A good stand of plants (about 98 per cent) was secured by July 4. After July 4 there was but slight injury from the worms. The land had been heavily fertilized, and the tobacco made a fine growth. The second tobacco cultural experiment was conducted on the farm of Mr. J. R. Horsley (experiment B), in Appomattox County, Va. Four plats, each containing 1 acre, were included in the experiment. Two check plats, one at each end of the experimental plats, were used. Each of these contained 1 acre. The growth of weeds was heavy, stickweed, daisy, and buckhorn plantain being abundant. In this test beneficial results from fall and winter plowing were not so conclusive as in the experiment on the Purdum farm (experiment ta eee THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 21 A). On plat No. 1 the effect of mowing and burning the weeds after the eggs had hatched was noted. Plat No. 1.—Weeds mowed and burned during third week in September, 1909. The land was not disturbed until the ground was prepared for planting, during the third week in May. Number of plants in plat, 4,400. Number of plants reset, 610. Per cent injured, 13.8+. Tobacco replanted twice. Plat No. 2.—Ground plowed during last week in September, 1909. In March, April, and May it was disked and harrowed at frequent intervals, no vegetation being allowed to grow before the tobacco was planted, in order, if possible, to starve out the hibernating larve. Number of plants, 4,400. Number replanted, 415. Per cent injured, 9.4+. Plat No. 3.—Land plowed during second week in March and not disturbed until just before planting. Number of plants, 4,400. Number of plants reset, 410. Per cent injured, 9.3+. Plat No. 4.—Land plowed during third week in December, 1909. Nothing furthgr done to it until prepared for planting during last week in May, 1910. Number of plants, 4,400. Number replanted, 540. Per cent injured, 12.2+. The results of these experiments are shown also in Table IX. All plats were replanted twice. A good stand of 98 per cent was secured by July 5 TABLE IX.—Effects of fall and winter treatment on injury by the tobacco Crambus in 1909 and 1910. Exper- Dee anon Preliminary treat- | Time of treatment. | Later treatment. Time. Gy ment. bettie, eu. tal IA PlOWwe@ Banc 2eo- oo: Second week of December, 1909........|Thoroughly disked.| First week of January, 1910. J eee AG FEU I SRE got First week of January, 1910........... DISked ss sear ene Second week of February. 18%) ae GOR a er eae ibastsweek of Bepruaryess2seeece-ceesalee ees doses eee Third week of ( : March. IAAL CS 325 GOs 2225 aoe iRhirdaweeksonMarchassseessseaeotcos eee GO Sse ose ccaee Third week of ril. 1\GSal ea Se) G2 2 ee AE HInGyyeekiOL-Apralyes> See me eee ae roe | ewe Cool ee ee AP B1 | Weeds mowed and | Third week of September, 1909.....-.- burned, Disked and har- Mawar, Sal B2'| Plowed....---.-.. Last week of September........-.----- rowed at fre- | Mo ey, Balle. dope eats Second week of March. ...-.-..--:-..-- quent intervals. MAY® AB es: doses: Third week of December.......:.-..-- ; 1B Hap | bits dows eas HITSinweek- OL Aprils). 3-s-te see coe Diskede sss eee First week of May. Exper- : | Number | Number | Per cent ent ; Planted tobacco. ofplants.| reset. injury. . } 2,200 | 89 | 4 2,300 165 7 2,280 | 138 6 2,214 251 11 2,225 | 375 17 4,400 610 13.8 4, 400 415 | 9.4 4, 400 410 | 9.3 4,400 540 | 12.2 8, 800 1,218 | 13.9 In the season of 1910-11 another series of cultural experiments was conducted on the J. F. Purdum farm, in Appomattox County, Va The land previous to preparation for tobacco was in meadow pe BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. (timothy, herd’s grass, and clover) which had been quite weedy. Natural food plants of the tobacco Crambus were abundant. This series was made for the purpose of ascertaining the effect on the tobacco Crambus of preparation of weedy land at different times during the fall and winter as compared with spring preparation of land. The field was divided into 6 plats containing one-half acre each. Tobacco was planted in all plats on the same date. The amount of fertilizer applied to each plat was the same. In plat No. 1 the land was plowed September 6, 1910, and fallowed February 25, 1911. It was harrowed and disked on April 3, April 10, April 20, and May 3. The stand of tobacco was nearly perfect after the first planting except along one end of the plat. The percentage of astand secured was 95.4. In the preparation of this plat it will be ndticed that the land was plowed during the first part of September, a time just after the larve had hatched. Plat No. 2 was plowed December 8, 1910, and fallowed February 28, 1911. It was harrowed and disked on April 3, April 10, April 20, and May 3. Tobacco was replanted once. About 85 per cent of a stand was secured at the first planting. Plat No. 3 was plowed January 8, 1911, and fallowed or replowed February 28,1911. Itwas harrowed and disked on April 3, 10, and 20 and May 3. Tobacco was replanted once. About 85 per cent of a stand was secured at the first planting. In plat No. 4 the land was plowed on April 11. No further treat- ment was given until the third week in May, when the land was prepared and bedded for planting. The tobacco was replanted three times. About 51 per cent of a stand was secured at the first planting. In plat No. 5 the land was plowed on January 18, 1911, and disked May 15. Tobacco was replanted three times. About 70 per cent of a stand was secured at the first planting. Plat No. 6 served as a check plat. The land was plowed during the third week in April, and was prepared for planting on May 15. Tobacco was replanted three times. About 55 per cent of a stand was secured after the first planting. Further cultural experiments were conducted on the 8. L. Ferguson farm, in Appomattox County, Va., in the season of 1911-12. This series was made to ascertain the effect of deep winter plowing and subsoiling of pasture land infested by the Crambus. The field of which the experimental plats were a part had been in sod for a number of years and was used as pasture land, The general conditions for the experiment were ideal. The oxeye daisy, buckhorn plantain, and stickweed were abundant. There was not a rank growth of weeds, however, as the field had been quite closely pastured. The field was deeply plowed in February, a subsoil plow following the turning plow, and the clay subsoil was broken up to a depth of several THE SO-CALLED. TOBACCO WIREWORM IN VIRGINIA. 2D inches. The tobacco in all plats was planted at the same time. The kind and amount of fertilizer applied was the same in all plats, and after the first cultivation all plats received the same treatment. The land was divided into 3 plats of 2 acres each and 1 plat containing one-half acre. Below are given the details of each experiment and the results obtained. Plat No. 1 contained 2 acres. It was deeply plowed and subsoiled in February, 1911. The land was thoroughly disked and harrowed at frequent intervals during March, April, and May and kept almost entirely free from weed growth until tobacco was planted. The stand of tobacco was practically perfect. Only an occasional plat could be found which showed damage from Crambus larve. Plat No. 2 contained 2 acres. The land was deeply plowed and subsoiled in February, 1911, and was not disturbed until prepared for planting in May, when it was deeply disked, harrowed, and bedded just before planting. Ninety-four per cent of a stand was secured at the first planting. The plat was reset once. Plat No. 3 contained one-half acre. The land was plowed and sub- soiled in February, 1911, as in plats Nos. 1 and 2. The land was not disturbed until prepared for planting as in plat No. 2. Weeds and grass were allowed to grow after planting. The middle of the row was not disturbed until after the first cultivation, in order to provide natural food for the Crambus larve, so that they would not be forced to attack the tobacco plants. The infestation of this plat was not heavy enough, so that the effect of this treatment, which is said to be practicable under certain conditions, could be accurately determined. The stand of tobacco secured at the first planting was 96 per cent. A few larvee were found in the weeds left in the middle of the row. Plat No. 4 was used as a check. The land was plowed and pre- pared for planting just before the tobacco was set out. The weed erowth and general conditions were similar to those in plats Nos. 1, 2, and 3. The stand secured at first planting was 86 per cent. ‘The tobacco was replanted twice. In land adjoining this tract which had been under clean cultivation during the previous summer and where there was no weed growth, about 98 per cent of a stand of tobacco was secured at the first planting. This land had been prepared for planting in practically the same manner as in the check plat, No. 4. CHEMICAL SPRAYS FOR WEED DESTRUCTION. Certain chemical sprays, such as iron-sulphate (copperas) solution, copper-sulphate (bluestone) solution, and common-salt solution, are frequently used for eradicating weeds and under certain conditions have been found very effective. The success of this method of erad- icating such weeds as oxeye daisy and wild mustard from grain and pasture fields without injury to the grains or grasses depends largely 24 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. on the fact that cereals and grasses are narrow-leaved plants with a single seed leaf, whereas the weeds injured are broad-leaved plants with two seed leaves. Spraying with a solution of iron sulphate at a strength of 1 pound to one-half gallon of water was found to be fairly effective on the oxeye daisy in a test made at Appomattox, Va. While spraying may be practical where certain weeds in grain fields are to be eradicated, it is hardly a suitable remedy under most con- ditions in tobacco-growing sections, except possibly where small, patches of weeds are to be destroyed. Chemical sprays have been found to be more effective when applied on warm bright days when the plants are dry. Immediately after weeds have been cut off close to the ground an application of salt, kerosene, crude oil, or acid solutions will often be found effective. In eradicating weeds from pastures the salt solution is preferable, as copper-sulphate solution is poisonous to stock. ' LIMING. Aside from improving the mechanical and chemical condition of many soils, liming will be found to aid greatly in the control of several of the weed pests which have been found to be the natural or favorite food plants of the tobaccoCrambus. Control of weed pests may be accomplished by making soil conditions less favorable for the weeds, or by making conditions more favorable to the cultivated crop. Many weed pests, like other plants, require for their best development certain soil conditions; and they are excessively abundant in certain locali- ties because soil conditions are peculiarly favorable to their growth, or because conditions are less suited to more desirable plants which under favorable soil conditions would crowd them out. A change in the condition of the soil, brought about by the use of lime, will often bring about a marked effect in checking or preventing the growth of a weed pest, and at the same time make the soil better adapted to the growth of certain cultivated crops such as clover. The sheep sorrel’ (Rumex acetosella), on which newly hatched Crambus larve frequently feed, thrives in acid soil. Where lime had been applied to certain fields, and to some of the State experiment station plats in Appomattox County, Va., the sheep sorrel was practically eradicated or at least checked by the better growth of the clover. Plantain, daisy, and aster (stickweed), all food plants of the worms, are weeds which flourish in acid or worn-out soils. In all cases where data have been secured, the use of lime has resulted in a marked decrease in the abundance of these weeds. Most soils in the Fiedmont region of the Eastern States are greatly benefited by lime, and its use has in many instances resulted in markedly increased yields of tobacco. In plats of alfalfa at the Appomattox experiment station 1 Attempts to rear larvee in cages containing only sheep sorrel were not successful. THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. PAD there was scarcely any plantain (Plantago lanceolata) after a heavy application of lime had been made, and there was an excellent crop of alfalfa. In the unlimed check plats plantain nearly covered the eround, and there was a very poor growth of alfalfa. Increased fertility of the soil may also aid in the extermination of a weed, as was noticed where heavy applications of acid phosphate had been made to meadow land on which there was a heavy growth of the oxeye daisy. The year following the application of the acid phosphate but few plants of the daisy could be seen. In this manner certain weeds may often be crowded out by grasses or clovers which are enabled to make better growth owing to greater fertility. The experience of the best tobacco growers has shown that intensive culture gives largest profits, and no expense or trouble should be spared in putting the ground in the best possible condition in every respect before the crop is planted. By commencing the preparation of weedy land the year before it comes in corn or tobacco, an excellent opportunity is afforded to apply lime. Such land can often be con- ventently plowed in winter and during spring or early summer, and easily be put in condition for such crops as crimson clover, cowpeas, ete., which may be profitably followed by tobacco or corn the succeed- ing year. FERTILIZERS. From observations of tobacco fields during the seasons of 1910 and 1911 it is evident that where the land receives heavy applications of nitrogenous fertilizers the damage from the worms is not so great as where light applications are made. Just as many plants are attacked by the worms, but vigorous and rapidly growing plants are more apt to recover from injury. This was very noticeable in the fertilizer test plats of the Virginia experiment station at Appomattox in 1910. INSECTICIDES AND REPELLENTS. The following insecticides and repellents were tested: Arsenate of lead, Paris green, tobacco extract, nicotine sulphate, tobacco dust; kerosene, kainit, and calcium cyanamid. In no instance were results secured which would indicate that the substances tested were of much practical value in combating the tobacco Crambus. The following field notes give details of some of the experiments: ARSENATE OF LEAD. In experiment A, with powdered arsenate of lead, 14 ounces of the poison to 24 gallons of water was used. Two hundred plants were treated, the entire plant being dipped into the solution. The plants were set in land which had been prepared a few days before. The field had been weedy and the worms were numerous. Two hundred untreated plants were kept asa check. On examining the plants five days later 22 injured plants were found in the poisoned plat and 36 injured plants in the 26 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. check plat. Three live larve which had tunnelled in the stalks and were apparently uninjured were found in plants in the poisoned plat. All treated plants had lived, but were not as vigorous in appearance as those not treated. In experiment B, with arsenate of lead paste, the poison was used at the rate of 2 ounces to 24 gallons of water. The tops only were dipped. One hundred plants were treated and 100 left untreated. The plants were examined five days after trans- planting. There had apparently been some injury from the poison, as the plants were in best condition in the untreated plat, while those treated were somewhat stunted or dwarfed. Eight injured plants were found in the poisoned plat. Five plants were found injured in the untreated plat. PARIS GREEN. Paris green at the rate of one-fourth ounce to 3 gallons of water was used on 100 tobacco plants, and an adjoining row kept as a check. The entire plant was dipped in each case, and the plants set out at once. The field was weedy. It had been recently plowed and Crambus larvee were numerous. A light rain fell a few hours after the plants were set. After eight days the plants were examined. Twenty-one plants were injured by worms in the poisoned row and 26 in the unpoisoned row. There had been some injury to the plants dipped in the poison solution, as the un- poisoned plants had a more vigorous start. In some instances plants in the poisoned row were only slightly eaten, thus indicating that the poison had acted as a repellent or had poisoned the worm before the plant had been badly eaten. TOBACCO EXTRACT. One row of tobacco plants in a field was sprayed with a 500-to-1 solution of tobacco extract, 320 plants in all being treated. The solution was applied with a compressed- air bucket sprayer. The substance did not prove effective in preventing injury. On June 6, five days after the mixture was applied, the plants were examined. Fourteen plants were found injured by worms in the speed row and 11 injured plants were found in the unsprayed row adjoining. NICOTINE SULPHATE. A 1,000-to-1 solution of nicotine sulphate was sprayed on 300 plants as in the fore- going experiment, and an adjoining row used asa check. The plants were examined four days after spraying. Eight plants had been attacked by worms in the sprayed row and 13 plants in the check row. While the foregoing substances did not prove of much value in preventing injury from the worms, they seemed to repel flea-beetles, as very few could be found on the treated plants whereas they were comparatively abundant on the unsprayed plants. TOBACCO DUST. Tobacco dust was scattered about tobacco plants directly after planting. One row containing 300 plants was used for the test and an adjoining row with the same number asa check. Eighteen plants were found injured by worms in the treated row. Few. plants were found that were injured below the surface of the ground, the worm having entered the plant at the ‘‘bud” or terminal leaf in most cases. Sixteen injured plants were found in the row where the dust had not been applied. More of these plants had been injured below the surface of the soil than where dust had been applied, this indicating that the dust may possibly have some value as a repellent. KEROSENE. In the first experiment with kerosene the plants were dipped in a weak solution of kerosene emulsion and were set out on June 15. Only 30 plants were used in the test. None of these, when examined five days later, was found infested. There was apparently no injury to the plants from the kerosene. Two infested plants were THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. Pat found in the check row of 30 plants. The number of plants treated was not large enough to make this test of much value. In the second experiment kerosene was mixed with sand and a small amount sprinkled around 100 tobacco plants. One hundred plants in an adjoining row were used asa check. A light rain fell a few hours after the sand was applied. On June 18, eight days after treatment, the plants were examined. Sixteen were found injured in the treated row and 22 in the untreated row. KAINIT. In one experiment kainit was mixed with the scil in the hill before planting. Too large a quantity of the kainit was used in the test, as a considerable number of plants failed to grow. One hundred tobacco plants were put out in soil mixed with the kainit, and 100 plants in an adjoining row were left fora check. A number of infested plants were found where the kainit had been used, the substance evidently not being of much value as a preventive, as the worms often enter the plant at the ‘“‘bud” or whorl of terminal leaves. TURPENTINE. Tn certain sections of Tennessee and Kentucky turpentine is said to have been used as a repellent for Crambus larvee and cutworms. Before planting, the roots of the tobacco plants are dipped in water in which a small quantity of turpentine has been stirred. A test on 1 acre of tobacco was made by Mr. Charles Armistead, of Clarksville, Tenn., and the field kept under observation by the writer. Entirely negative results were obtained. The following are details of the experiment: The tobacco was on weedy land containing an abundance of white top (Hrigeron annuus) and plantain. The first planting was entirely destroyed. When the tobacco was replanted turpentine was used at the rate of 1 teaspoonful to | gallon of water, the roots of the plants being dipped in the mixture. On June 27, two weeks atter planting, the tobacco was examined. Worms were still very numerous. Over 80 per cent of the plants had been entirely destroyed, in both treated and check plats. There seemed no apparent difference in infestation and damage between the treated tobacco and that on which no turpentine had been applied. CALCIUM CYANAMID. Calcium cyanamid (lime nitrogen) is said to have a repellent or poisonous effect upon insects, and on the suggestion of Mr. KE. H. Mathewson, Crop Technologist of the Bureau of Plant Industry, Mr. B. G. Anderson, superintendent of the Tobacco Experi- ment Station at Appomattox, Va., and the writer made a test of the material during 1911, using the calcium cyanamid at the rate of 300 pounds peracre. The land selected had not been cultivated for several years. There was a rank growth of buckhorn plantain, oxeye daisy, and stickweed, and Crambus larvee were exceedingly numer- ous, making conditions ideal for the test. The plat, containing one-twentieth ot an acre, was divided into series of two rows each. The calcium cyanamid was used on two rows and the next two rows were kept as a check. On the treated rows com- mercial fertilizer at the following rate per acre was used: Pounds (Cealleniinia enya wake yng V(C Uy Apion yer ee ee etic ne RaW aM Eos Pee 300 PICTOMMINO SAILOR Sacra aie ek alle a2 sick oe amin Og A lege Ua SY NS 2 . 600 Slip Ware: On, POLS sas ess eet ae aati mt apts on So 8 Ia 2 100 On the check rows the fertilizer used (rate per acre) was as follows: Pounds. HGR PCTREE MIEN OG date yeah. Maki 5 dee RMeay ey * St Aeatis (SES do See's 8 300 ANGHIG! WOO OENO eee ca ie eee ga ECS 2 ee Orc aOR ae pe ea z- +600 Sulphate of potash..............- CE A Ae cers Sete Maen ae 100 28 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. The calcium cyanamid analyzed about 17 per cent ammonia, this making the amount of plant food in the treated and check rows practically the same. The fer- tilizer was applied 14 days before the plants were set, as calctum cyanamid has the effect of stunting tobacco plants if applied directly before planting. It was applied to the rows with a drill, and thoroughly mixed with the soil by running a cultivator over the rows. The plants were set on June 8. By June 30 the plants in both treated and check rows had been almost completely destroyed by the Crambus larve, there being no indications of any beneficial effect from the calcium cyanamid in eS injury. The tobacco was not replanted. LEAD ARSENATE AND PARIS GREEN USED WITH COAL TAR ON SEED CORN TO PREVENT INJURY BY CRAMBUS LARV/E. Experiments in the use of arsenate of lead and Paris green with coal tar on seed corn to prevent injury by Crambus larve were conducted in 1910 on the J. F. Pur- * dum farm. In experiment A, arsenate of lead in paste form was used at the rate of 1 ounce to 1 gallon of water. One peck of shelled seed corn was allowed to soak in the solution about 10 minutes and dried by mixing with fertilizer (acid phosphate). A very little coal tar (about a tablespoonful) was then poured on the corn, which was thoroughly stirred until a thin coating of the tar covered each kernel. Fertilizer was then used to dry the tar. With an ordinary planter one-half acre was planted in seed prepared as just described. Fully one-third of the corn failed to germinate, possibly owing to exclusion of moisture from the seed by the tar, as the weather was dry. No benefit in preventing injury by the worms seemed to result. In the check plat the stand of corn was practically perfect. On June 16, four weeks after planting, a count was made in the treated and check plats of hillsof corn showing Crambus injury. Eleven per cent of the hills showed injury in the treated plat and 13 per cent in the check plat. In experiment B, 1 ounce of Paris green was used to 1 peck of shelled seed corn. A small amount of tar (about one tablespoonful) was poured over the corn, which was thoroughly stirred until a thin coating of tar covered each kernel. The corn was then dried by mixing with fertilizer to which Paris green had been added. One- half acre was planted with seed prepared in this manner. About one-fifth of the seed failed to grow. In the check plat the stand was practically perfect. A count of hills of corn showing Crambus injury, made on June 16, four weeks after planting, showed the results of the treatment to be as follows: Injury in treated plat, 11 per cent; injury in check plat, 9.5 per cent. SUMMARY OF ECONOMIC CONTROL. (1) The eggs of the tobacco Crambus are deposited in weedy fields during July and August. They hatch in a few days. The larve remain over winter in the soil and complete their growth during June and July. They are in their most active feeding stage at the time tobacco or corn is planted. (2) Injury to tobacco or corn occurs when these crops are planted on land which was weedy during the previous year. Crops planted on land which has been under clean cultivation are immune from injury. (3) The weeds which have been found to be the more common natural food plants of the worms are the buckhorn plantain, oxeye daisy, stickweed, and whitetop. The presence of these weeds in meadows accounts for injury to tobacco or corn when planted on sod. THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 29 (4) The worms when once established in land where their natural food plants are abundant have been found difficult to control. (5) Various insecticides and repellents have been tested, but without satisfactory results. (6) Fall or winter plowing has been found to reduce injury, but is only partially effective, as some of the weeds remain alive and furnish food for the larvee until the tobacco or corn is planted. (7) Damage is best prevented by crop rotations, or by cultural methods that prevent growth of the weeds which are food plants of the worms, thus making conditions unfavorable for egg deposition by the moths the summer before tobacco or corn is planted. Summer plowing, thorough preparation of weedy land, and the growing of crops of cowpeas or crimson clover, preferably cowpeas, the year before crops subject to injury are planted, have been found to be the most satisfactory and practical means of control. BIBLIOGRAPHY. 1860. CLEMENS, BRACKENRIDGE. Contributions to American lepidopterology. No. 5. Proc. Acad. Nat. Sci. Phila. for 1860, p. 203-221, June, 1860. The original description of Crambus caliginosellus, p. 204. 1880. Grotr,A.R. Preliminary list of North American speciesofCrambus. Canada Ent., v. 12, no. 4, p. 77-80, Apr., 1880. Gives habitat, N. Y., p. 79. 1887. Morrat, J. A. Further additions to the list of Canadian microlepidoptera. Canad. Ent., v. 19, no. 5, p. 88-89, May, 1887. Specimen of Crambus caliginosellus in collection of Mr. Moffat, Hamilton, Ont., deter- mined by Fernald. 1891. Brcxwiru, M. H. Notes on a corn crambid. U.S. Dept. Agr., Div. Ent., Insect Life, v. 4, no. 1-2, p. 42-48, Oct., 1891. Brief mention. Dr. J.B. Smith reports insect as injuring corn in New Jersey. Dr. L.O. Howard reports insect as abundant in Maryland in 1886. : 1891. Becxwirn, M. H. Notes ona corn crambid. Del. Col. Agr. Exp. Sta., Bul. 14, p. 13-15, fig. 1, Dec., 1891. : Mention of species as injurious to corn in Delaware. Account of feeding habit of larvee. 1894. Fert, E. P. On certain grass-eating insects. Cornell Univ. Agr. Exp. Sta., Bul. 64, p. 47-102, 14 pls., Mar., 1894. “The sooty crambus,” p. 61-62. Brief account of moth; description of eggs and newly hatched larve. 1896. FrernNatp, C. H. The Crambidz of North America. Mass. Agr. Rpt. 33 (Pub. Doc. 31), p. 77-165, pls. 6 & A-B, Jan., 1896. Redescription ofsmoth, p. 137-138. Col. Ann. 1897. JoHNson, W.G. Notes on some little-known insects of economic importance. U.S. Dept. Agr., Div. Ent., Bul., n. s., no. 9, p. 83-85, 1897. “Crambus caliginosellus,” p. 84. Account of injury to corn in Maryland. 1898. JoHnson, W.G. Report on the San Jose scale in Maryland and remedies for its suppression and control. Md. Agr. Exp. Sta., Bul. 57, 116 p., 26 figs., Aug., 1898. “ Crambus calignosellus,” p.9. Account of injury and feeding habits of larve. 1898. JoHNson, W. G. Notes from Maryland on the principal injurious insects of the year. U.S. Dept. Agr., Div. Ent., Bul., n.s., no. 17. p. 92-94, 1898. “The corn crambus,” p.93. Brief mention as destructive in various parts of the State. sl 380 1899. 1900. 1902. 1903. 1907. 1909. 1911 1911 1912 ———EE———E BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. Jounson, W. G. The stalk worm: A new enemy to young tobacco. U.S. Dept. Agr., Div. Ent., Bul., n. s., no. 20, p. 99-102, 1899. An account of injury to tobacco by C. caliginosellus. States that tobacco growers in southern Maryland reported injury for last fifteen years, or possibly longer. Recommends system of crop rotation aimed at control. Jounson, W. G. Notes on insects of economic importance for 1900. U. 8. Dept. Agr., Div. Ent., Bul., n. s., no. 26, p. 80-84, 1900. Brief mention of Crambus caliginosellus. Reports insect as destructive to tobacco on sod lands, p. 83. SANDERSON, E. D. Insects injurious to staple crops. New York, 1902. “The corn-root webworm (Crambus caliginosellus Clem.),”? p. 130-134. Account of injury to corn and tobacco. Recommendations concerning control. ; CHITTENDEN, F. H. The principal injurious insects in 1902. U.S. Dept. Agr. Yearbook for 1902, p. 726-733, 1903. Brief mention of Crambus caliginosellus. One of the most destructive insects to corn in Delaware in 1902, p. 729. McNess, G. T., Mathewson, E. H., and Anderson, B. G. The improvement of fire-cured tobacco. Va. Agr. Exp. Sta., Bul. 166, p. 186-234, May, 1907. Account of difficulty of securing a satisfactory stand of tobacco in experimental work; description of injury to plants. MatHewson, E. H. Intensive methods and systematic rotation of crops in tobacco culture. U.S. Dept. Agr. Yearbook for 1908, p. 403-420, pl. 33-37, 1909. Mention of tobacco ‘‘wireworm” or ‘“‘stalkworm” and effect of crop rotation on control, p. 411. . Runner, G. A. Report upon tobacco insect investigations. Va. Polytech. Inst. Agr. Exp. Sta., Ann. Rpt. for 1909 and 1910, p. 40-43, 1911. Amount of economic importance of insect, food plants, feeding habits of larve. Recom- mendations concerning control, p. 41-42. . Morean, A. C. Insect enemies of tobacco in the United States. U.S. Dept. Agr. Yearbook for 1910, p. 281-296. Brief mention of tobacco Crambus, p. 291. . Hunter, W. D. Relation between rotation systems and insect injury in the South. U.S. Dept. Agr. Yearbook for 1911, p. 201-210, 1912. Discussion of importance of systems of crop rotation in relation to control. O WASHINGTON : GOVERNMENT PRINTING OFFICE: 1914 BULLETIN OF THE > USE ORARCTE No.79 Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief, April 23, 1914. (PROFESSIONAL PAPER.) RESEARCH STUDIES ON THE CURING OF LEAF TOBACCO. By W. W. GABNER, Physiologist in Charge, C. W. Bacon, Assistané Physiologist, and C. L. Fousert, Assistant in Tobacco Chemistry, Tobacco and Plant-Nutrition Investigations. INTRODUCTION. The term “‘curing,” as applied to tobacco, is somewhat indefinite in meaning, being used sometimes to include the separate operations of barn curing, fermentation, and aging, or afterfermentation, while the farmer usually restricts the term to the process of drying the ripe leaf in a specially constructed barn and under such conditions as will develop the desired properties or qualities. In the present article the term is used in the last-named more restricted sense, so that we have only to consider curing as far as it proceeds in the curing barn. The methods now in vogue in barn curing are almost entirely _ empirical, being the result of practical experience extending through several generations, and in general are based more or less on rule-of- thumb procedures, without sufficient flexibility to meet changing conditions and requirements. The barn curing of tobacco has not received the attention from investigators that has been given the subsequent process of fermentation, and such investigations as have been made relate mostly to certain special phases of the subject. There are two general methods of harvesting tobacco and arranging it in the barn which materially affect the results obtained in curing. In the one case the leaves are picked from the stalk as they mature or “‘ripen”’ and are arranged on strings or sticks suitable for hanging in the curing shed, this method being popularly spoken of as priming. In the other method the leaves are not removed from the stalks, but the latter are cut off near the ground and suspended in an inverted 1 For details of these methods consult Garner, W. W., Principles and practical methods of curing tobacco, U.S. Department of Agriculture, Bureau of Plant Industry, Bulletin 143, 54 p., 10 fig., 1909. Note.—This bulletin gives the results of a study of the physiological changes occurring in curing tobacco in the barn and is of special interest to those concerned with the improvement of tobacco curing. 29731°—14—__1 2 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. manner in the barn. There is an important modification of the method of harvesting and curing the leaves on the stalk in that, prior to being severed near the base, the stalk is split longitudinally from the top down the greater part of its length and when cut is placed astride a stick for hanging in the barn. NATURE OF THE CURING PROCESS. Observant growers well know that tobacco leaves which have been killed by freezing or by bruising do not cure normally, and a leaf which is quickly dried by heat does not possess the properties of the cured leaf. Moreover, if the fresh leaf is subjected for a few minutes to the action of protoplasmic poisons, such as formaldehyde or chloroform, it will not cure properly. It is quite evident, therefore, that curing is a life process and thus differs fundamentally from the subsequent fermentation, which takes place after the death of the leaf cells. That curing is essentially a life process can also be readily shown by chemical analysis, as is brought out in later paragraphs. Curing materially changes the physical and chemical properties of the tobacco leaf, more particularly such properties or qualities as the capacity to hold fire, the color, the texture, and the elasticity. It does not develop the aroma, however. With respect to the development of some of the above-mentioned properties of the leaf, fermentation may be regarded as supplementary to curing; but, as we hope to show more fully in a later publication, some of the important changes in composition involved in curing are not continued in the fermentation, so that incomplete curing can not be fully corrected in the subsequent fermentation. As will be shown later, curing involves principally the two familiar | physiological processes of respiration and of the translocation of mobile nutrients. Some investigators have preferred to regard the respiration phenomena as essentially pathological in character, and this view seems logically correct. The stalk and its leaves or the leaves alone, as the case may be, after harvesting are deprived of the water solution from the root system and for the most part are de- prived of sunlight. Since respiration continues, the living cells of the leaf are subjected to a process of starvation, and the degree to which the starvation proceeds is largely dependent on the rate of drying. As a matter of fact, however, the general character of the changes in composition during the curing, due to respiration, is very much the same as in normal respiration. As would be expected, the prevailing temperature and humidity play an important réle in the process. The other important phenomenon, translocation, involves the movement of soluble materials from the leaf web, through the veins, into the midrib, and, if the leaf is attached to the stalk, thence into the latter. With one or two exceptions, investigators have over- STUDIES ON THE CURING OF LEAF TOBACCO. 3 looked the importance of translocation when the leaf is cured on the stalk. It is, of course, well known that during the growth and development of the plant there is a movement of the products of photosynthesis, rendered soluble by enzyms when necessary, from the more mature leaf through the stalk to the younger growing parts. Essentially the same thing takes place after the cut plant has been placed in the barn, except that the materials transported are derived wholly from the surplus food supply of theleaf. While the leaf web perishes in a few days, the midrib remains alive for longer periods and the stalk may remain perfectly green for several weeks. Secondary shoots, or suckers, developing in the leaf axils, may be found growing at the end of several weeks, and the necessary food supply for the stalk and the suckers is derived from the leaf surplus. An interesting con- firmation of this phenomenon is found in the case of excessive mois- ture prevailing in the barn during the later stages of curing, a condition which leads to the decay of the leaf known as pole-sweat. The excessive moisture causes the dying leaf cells to retain more water, thus facilitating the more complete translocation of food materials into the stalk. Under these circumstances the so-called absciss- layer is formed at the juncture of the midrib with the stalk, so that the leaf is cast off as a useless appendage. Under normal curing conditions the leaves remain firmly attached to the stalk. LOSS IN WEIGHT OF DRY MATTER IN AIR CURING WHEN THE LEAF IS PRIMED. The first problem met with in a physiological study of curing is the total loss in dry weight which occurs in the process. So far as we know, no accurate determinations have been previously made on this point, at least in this country. Because of the important réle of translocation in curing, the loss in weight depends largely on the method used in harvesting the tobacco. So far asit relates to loss in weight of the whole leaf, translocation can play no part when the leaf is separated from the stalk in harvesting. Our experiments cover the crop years of 1908 to 1911, inclusive, a period of four years, and were confined to the eae anpenlent section of Connecticut, the experimental material all being obtained from the farm of W.S. Pinney, Suffield, Conn. The types of tobacco included in the experiments are the Havana Seed, the Halladay, and a so-called John Williams broadleaf. The Havana seed is one of the old standard types of domestic cigar-wrapper leaf and the Halladay is a new type developed from a cross of Havana seed on Sumatra. The history of the John Williams type of broadleaf is not known, but it differs decidedly from the ordinary broadleaf, and its habits of growth strongly suggest its origin from a cross of the latter on Cuban. 4 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. In gathering the experimental material each year, a sufficient num- ber of representative plants was selected to give about 200 ripe leaves near the bases of the plants, six or eight leaves being taken from each plant. The leaves were taken in pairs, each alternate leaf being placed in one lot and the other leaves in a second lot, the aim being to have each leaf in the one lot represented by a duplicate in the second lot. For the success of the experiment it is essential that the total dry weight and also the average composition of the two lots of leaves be practically the same. The detailed examination of the material gathered in the manner described indicates that these requirements have been satisfactorily met. As promptly as possible after harvest- ing the leaves the midribs were completely removed from the lot which was used to obtain the original dry weight. This was done to prevent any flow of cell sap between the leaf web and the midrib during the drying. The split leaves as well as the midribs were at once placed in a large drying oven and maintained at a temperature of about 80° C. until all were completely dry. The temperature em- ployed rapidly kills the protoplasm, and comparative tests with other methods of killing, such as plunging in boiling absolute alcohol, showed that the respiration changes during the drying were too small _to be of significance for our purposes. (See p.35.) The dry weights of the leaf web and the midribs were obtained and the material preserved for analysis. The second lot of leaves was placed in the barn for curing in the usual way without removing the midribs. When the cured leaves were ready for examination the leaf web was removed from the midrib, the dry weights obtained, and the material preserved for analysis. As has been stated, observations were made for a period of four consecutive years of the loss of dry matter in curing when the leaves are harvested by picking them from the stalk. The detailed results of these experiments are shown in section A of Table I (p.5). In the case of the 1908 material the curing was stopped before the midribs had cured, but the curing of the leaf web was practically complete. In 1910 a special test of partial curing was made (Table I, fourth column) and in this case the curing was stopped while the larger veins and midribs were still uncured. In 1911 a test was made of the effect of artificial heat on the curing. STUDIES ON THE CURING OF LEAF TOBACCO. 5 Tasie I.—Loss in dry weight in air curing tobacco leaves: (A) by the priming method, (B) 4 curing on the stalk. A.—Leaves cured by the priming method. Havana Seed; 1908 Tobacco leaves. (partially cured). Halladay; 1909. Halladay; 1910. Leaf Whole} Leaf Whole| Leaf Whole web. |Stems.| jear | web. | Stems-| jeap | web. | Stems-| jear. Weight of a0 dry leaves: neured......... grams..} 409.5 | 155.1 | 564.6 | 335.2 | 117.2 | 452.4 | 294.8 | 121.4 416.2 Curedees aco. scicce do....| 329.4 | 157.5 | 486.9 | 306 98 404 256. 4 98.6 355 Loss of weight in curing, per CON Gece cisisicisieisisiceis aicledis aac 19.6 |1—1.6 13.8 8.7 16.4 10.9 13 18.8 14.7 Leaves: Uncured....... per cent..} 72.5 27.5 | 100 74.1 25.9 | 100 70.8 29.2 100 Cured acs. cs. do....| 67.6 32.4 | 100 75. 7 24.3 | 100 72.2 27.8 100 Weight of pure ash in 100 leaves: Uncured.........grams..] 44.9 26.9 71.9 §1.2 26.7 77.9 38.4 23.3 61.7 @uredere 5235: do....| 43.9 26.3 70. 2 55.3 25.2 80.5 41.4 22.2 63.6 Apparent gain or loss of ash in curing........ per cent..| —.24] — .38 | —.29 | +1.20 | —1.28| +.57] +1.02 | —.91 +-.45 Loss of organic matter in cur- ToT es ee eran eae per cent..} 19.6 |1—1.6 13.8 9.6 14.3 10.9 13.6 17.3 14.7 A.—Leaves cured by the priming method. John Williams broadleaf. Halladay; 1910 Tobacco leaves. (partially cured). | 4911 (artificial heat | 1911-B (no artificial applied). heat applied). Leaf Whole} Leaf Whole| Leaf Whole web. | Stems.| jear | web. | Ste™MS-| ear | web. | St™S-) dear. Weight of 100 dry leaves: neured........ grams. .| 269.3 | 120.7 | 390 402 114.8 | 516.8 | 402 114 516 Curedeen tec sece - do....} 234.3 | 108.3 | 342.6 | 356.8 87.6 | 444.4 | 356.5 87.8 444.3 Loss of weight in curing, per CONE desiceccene Sale tecidae aes 13 10.3 12.2 11.2 23.7 14 11.3 23 13.9 Leaves: Uncured....... per cent..| 69.1 30.9 | 100 77.8 22.2 | 100 77.9 22.1 100 Cured............- dGo....| 68.4 31.6 |} 100 80.3 19.7 | 100 80. 4 19.6 100 Weight of pure ash in 100 leaves: Uncured......... grams..| 34 22.3 56.4 48.9 23.8 72.7 48.3 24.2 72.5 Cured oe ook 22... do....| 36.3 21.4 57.6 53.4 21 74.4 |. 52.2 20.9 73 Apparent gain or loss of ash in curing........ per cent..| +.85| —.74] +.31 | +1.12 | —2.43] +.33] +.97 | —2.89 +.11 Loss of organic matter in curing........... per cent..| 13.5 9.1 12.2 12.1 19.1 14 12.2 19.9 13.9 1 Represents gain. 2 These figures are arrived at by deducting from the total loss in weight the apparent translocation of ash between leaf tissue and stem. See page 6. 6 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. TaBLE I.—Loss in dry weight in air curing tobacco leaves: (A) by the priming method, (B) by curing on the stalk—Continued. B.—Leaves cured on stalk. : Havana Seed; 1908 "3 : Mahacne leaves (partially cured). Halladay; 1909. Halladay; 1910. Leaf Whole} Leaf Whole} Leaf Whole web Stems eaf. web Stems. leaf. web Stems. leaf. Weight of 100 dry leaves: : Uncured........ grams..| 487.1 | 165.9 | 603 342.9 | 145.4 | 488.3 | 297.6 | 128.1 420.7 Cured 2. fie eas do....| 312.4 | 134 446.4 | 238.1 | 104.6 | 342.7 | 230 86.7 316.7 Loss of weight in curing, per CONG ees csaedoes oneeebons 28.6 19.2 26 30.6 28.1 29.8 PPai 29.6 24.7 Leaves Uncured....... per cent..| 72.5 27.5 | 100 70. 2 29.8 | 100 70.7 29.3 100 ured bus. 5. 2bs3 us 70 30 100 69.5 30.5 | 100 72.6 27.4 100 Weight of pure ash in 100 leaves: Uncured.........grams..| 45.3 28. 4 73.7 42.3 27.9 70. 1 38.6 23.2 61.9 Cured 2) 2255 do....| 41.4 26.4 67.8 40.3 23.1 63.4 37.3 18.6 55.9 Loss of ash in curing, per cent. 89 1,20 -98 59 3.31 1.38 43 3.74 1.42 Loss of organic matter in curingse 25222565 per cent..| 27.7 18 25 30 24.8 28.4 22.3 25.9 23.3 The content of pure ash is of special interest as serving as a check on the original uniformity in size and composition of the uncured and cured leaves of each series, since there could be no actual loss of ash from the whole leaf. ‘The differences found between the uncured and the cured leaves are so small as to be negligible, and they furnish strong evidence of the uniformity in size and composition of the original duplicate samples. We are safe, therefore, within very narrow limits, in regarding the observed differences in weight be- tween the uncured and cured leaves as representing the true loss in weight of dry matter during the curing process. Regarding the total loss in weight of the whole leaf, it will be seen that the values ranged from about 11 to about 14.5 per cent when the curing was completed. In the case of the 1909 sample of Halla- day tobacco the loss is undoubtedly below normal, and the low value for the whole leaf is due mainly to the slight loss in weight of the leaf web. It is not known to what extent unfavorable weather conditions during the curing may have influenced the result, but by reference to Table IV, section A (p. 18), it will be seen that the sam- ple was very low in starch content, and this constituent is the most important of all as regards loss in weight in curing. (See also p. 31.) Disregarding this sample, the loss in weight in the experiments is surprisingly uniform in view of the differences in types of leaf and the varying weather conditions during the curing. In the two cases where the curing was interrupted before it was complete, the loss in weight of the whole leaf was nearly as great as in complete curing, showing that the principal changes in composition to which the loss in weight is due proceed rapidly. In the case of the Havana Seed STUDIES ON THE CURING OF LEAF TOBACCO. i sample (1908) the loss would undoubtedly have been considerably ereater had the stems been permitted to cure, as is to be expected, because of the relatively high starch content in this sample. For the types of leaf considered, the average loss in weight in dry matter during the curing of the picked leaves may be placed at about 12 to 15 per cent. The data presented in Table I, section A, relate only to types of tobacco adapted to and grown under conditions favorable to the production of cigar-wrapper leaf, which is relatively very thin and light. This class of tobacco is harvested in a less ripe condition than are other classes of leaf, so that a lower content of starch is to be expected in the leaves when harvested. For these reasons the loss in dry weight in curing is greater in other classes of tobacco, and in the case of the export types losses in weight as high as 38 to 40 per cent have been observed. The loss in weight in curing varies with the variety or type grown, the conditions under which the tobacco is grown, the degree of ripeness when it is harvested, and also with the conditions under which the curing takes place. The effects of these factors on the loss in weight are due to their influence on the composition of the leaf before or after the curing, particularly on the content of starch. LOSS IN WEIGHT OF DRY MATTER IN AIR CURING WHEN THE LEAF IS CURED ON THE STALK. The experiments relating to the loss in weight when the leaves are cured on the stalk cover the crop years of 1908 to 1910, inclusive, a period of three years, and the experimental material was obtained _ from the same fields as was that used in the preceding experiments. The stalks of the plants used were not split in harvesting, but were hung in the barn in the usual manner for curing cigar tobaccos. Every effort was made to have the experimental material directly comparable with that used in the preceding experiments for the same years. Plants were selected which were as nearly as possible like those used for the experiments in priming. Beginning near the base of the plant each alternate leaf was picked off, taking three or four leaves from each plant and leaving all of the remaining leaves intact. ‘The stalks were then harvested and placed in the barn for curing. The midribs were promptly removed from the picked leaves and both the leaf web and the midribs completely dried, as in the previous experiment. The dry weights of the leaf parts were recorded and the material preserved for analysis. When the leaves attached to the stalks were cured the weights of the leaf web and midribs were likewise obtamed and the material kept for further examination. As in the case of the experiments in priming, the leaves were removed from the stalks in the 1908 experiment before the midribs were fully cured. With the possible exception of the 1909 material, the 8 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE, ash content und the ratio of leaf web to rib in the uncured leaves, as well as the detailed analyses later reported, show conclusively that the original samples used for stalk curing were very similar to the corresponding samples used in curing by priming. The results of the three-year experiment are set forth in detail in section B of Table I. It will be seen at a glance that the loss in weight of the whole leaf in curig on the stalk is far greater than when the leaves are separated from the stalks. The figuresrun from about 25 to 30 per cent, or approximately double those for curing the picked leaves. In the 1908 sample the total loss in weight would have been somewhat ereater had the stems been given sufficient time for complete curing. The loss in weight in stalk curing is greater in both leaf web and rib than when the picked leaves are cured. It will be seen that the apparent loss in pure ash is positive and marked in all cases in both the leaf web and the ribs, showing conclusively that a portion of the ash passes into the stalk during the curing. EFFECT OF SPLITTING THE STALK ON THE LOSS OF WEIGHT IN AIR CURING. In some tobacco districts the stalk is split longitudinally from the top down the greater part of its length at the time the plant is harvested. Under these conditions the stalk can not remain alive in the barn as long as when it is merely severed from the rootstock, and it is to be expected that the phenomenon of translocation would be less important. A special experiment was carried out to secure information on this point. Two similar lots of 10 plants each were selected, and the stalks of one lot were split in the manner followed by growers. Each alternate leaf was picked from the plants in both lots, and the two lots of leaves thus obtained were cured separately. The leaves remaining on the stalks were cured under the same conditions as the primed leaves. When the curing was complete the dry weights were obtained as in the preceding experiments. At that time the unsplit stalks were still green, while the split stalks had largely dried out. Tape II.—Loss of dry weight in air curing as affected by splitting the stalk in harvesting. | Stalks split in harvesting. Stalks not split in harvesting. Air-cured leaves. fan aid Last aa ea ole ole web. Stems leaf. web. Stems. leaf. Weight of 50 leaves: Cured Ob Stalkte 2 h. Pay me ae grams. . 177.9 70.1 248 176.5 68.3 244.8 Cured after picking .....-....... Gos. 219.5 81.1 300.6 227 84.6 311.6 Difference in loss of weight between stalk curing and curing picked leaves, per ORE: me eee ete Se pen meee ane tec cued 18.9 13.6 17.4 22.2 19.3 21.4 Leaves consisted of: Cried Onsialk 3... /c225..see8 per cent... 71.8 DBsD Nee cwetcleteee 72.1 27M scaadec cls Crued by picking.............-- do. =| 73 D7 iil aoe ook al 72.8 DTD oe badas o So STUDIES ON THE CURING OF LEAF TOBACCO. 9 The results of the experiment are shown in Table II. While the actual number of leaves in each lot was 58, the results are calculated on a basis of 50 leaves for convenience in comparing with the other experiments. ‘The experiment, of course, does not show the total loss in weight in curing in any case, but other experiments with similar material from the same field indicate that the loss in weight of the picked leaves must have been more than 20 per cent. The type of tobacco and the stage of ripeness account in all cases for the larger losses in weight than were obtained with the cigar types. Since only a single experiment was made and a rather small number of leaves used, the results can be taken as only approximately correct. These results indicate that when the stalk is split in harvesting, the loss in weight in curing is less than when the stalk is not split, but, nevertheless, the loss is much greater than when the leaves are picked from the stalk. COMPOSITION OF CIGAR-WRAPPER LEAF BEFORE AND AFTER CURING. The material obtained in connection with the data presented in . Table I was subjected to analysis to ascertain the nature of the changes in composition which take place in air curing and to which the losses in dry weight are due. Because of the variations in the composition of the leaf at the time of harvesting, it is obviously essential that the material chosen for study shall be obtained under such conditions as will insure original uniformity in the composition of the uncured and cured samples. That this has been very closely attained in the above-mentioned material is shown in the values ob- tained for those constituents which undergo no change in the curing. ‘LEAF HARVESTED BY PRIMING. The samples: used in these experiments cover the curing seasons of 1908 to 1911, inclusive, and include cases in which the curing was not fully completed. Although the midrib is never removed prior to curing, it has little or no value in manufacturing and, moreover, differs decidedly in composition from the leaf web, so that for present purposes it is necessary to consider the two leaf parts separately. The cured leaf always contains more or less water, depending on the type in question and on atmospheric conditions, but to simplify matters all results have been calculated to a water-free basis. PREPARATION OF MATERIAL AND METHODS OF ANALYSIS EMPLOYED. To pulverize the material for analysis, the leaf web was simply passed through a 60-mesh wire sieve. ‘The stems were prepared by grinding to a fine powder in an iron mortar. The water content of the sample was determined by drying over sulphuric acid, as recommended by 1 For details as to the methods followed in selecting and gathering the samples, the type of leaf used, etc., see p. 3. 29731°—14——-2 10 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE, Kissling. The pure ash, the carbohydrates, including starch, reducing sugars, pentosans, and crude fiber, and the several nitrogenous con- stituents were determined by the following methods: Pure ash.—The tobacco was incinerated in the usual manner in a platinum dish with a cover, care being taken to avoid fusing the ash. The pure ash is obtained by correcting for carbon dioxid, carbon, and sand. Starch.—Rather than attempt to determine starch directly by the diastase method it was preferred to obtain the total of the carbo- hydrates hydrolyzed by hydrochloric acid, using the official method, and to determine also the pentosans. It is thought that for purely comparative results this method is satisfactory, and nearly all pre- vious analyses of tobacco for starch which the writers have seen have been based on this method of the direct hydrolysis with acid, but usually without determining the pentosans. Pentosans.—The determinations were made by the official method, the phloroglucin being calculated to pentosan by Kréber’s tables. Reducing sugars.—Since nicotine, even in a moderately concen- trated solution, exerts a reducing action on Fehling’s solution, it is removed before preparing the solution for the determination of reduc- ing sugars. This is done by moistening 5 grams of the tobacco with 5 c. c. of a 5 per cent solution of caustic potash in absolute alcohol and digesting the mixture in a flask with 100 c. ¢. of absolute ether. The reducing sugar is then extracted with 60 per cent alcohol, the alcohol removed by evaporation, the water solution made up to vol- ume, clarified with normal lead acetate, and the sugar determined as glucose by the Allihn method. Crude fiber.—The official method, as modified by Sweeney and by Kennedy, was employed. Nonvolatile organic acids.—The method of Kissling ! was followed for the determination of oxalic, citric, and malic acids. We have found it necessary, however, to increase by at least 25 per cent the quantity of sulphuric acid recommended by Kissling to be added to the tobacco, to insure the liberation of all the organic acids. This was particularly true of the cured samples, from which only very small portions of the oxalic acid could be extracted when only 10 grams of a 20 per cent sulphuric-acid solution were added to 10 grams of the tobacco. Protein nitrogen.—Tests having shown that the method of Mohr? gives excellent results for the purpose in view, it was followed in preference to the official (Stutzer) method. In this process the tobacco is simply boiled with a dilute acetic-acid solution, filtered 1 Kissling, Richard. Beitrage zur Chemie des Tabaks. Zur Tabakanalyse. Chemiker-Zeitung, Jahrg. 28, No. 66, p. 775-776, 1904. 2Mohr, E. C. J. Gepfliickter und am Stamme getrockneter Tabak. Die Landwirtschaftlichen Ver- suchs-Stationen, Bd. 59, p. 274, 1903. STUDIES ON THE CURING OF LEAF TOBACCO. 11 cold, and, after washing with hot water acidified with acetic acid, the nitrogen in the residue is determined by the Kjeldahl method. Com- parative tests of cured and uncured samples of tobacco show that the Stutzer method regularly gives results about 0.2 per cent higher than the Mohr method. The protein is estimated by multiplying the nitrogen obtained as indicated by the usual factor, 6.25. Nicotine.—This constituent was determined by the method described in Part VII of Bureau of Plant Industry Bulletin No. 102, entitled “ feet | cer | 90's | che. | op | se" ecg. (eos. soos sre. joss | Tee | peep 1 OOP. 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As between the two leaf parts, however, it is to be observed that in every instance the leaf web appears to gain in ash content at the expense of the midrib dur- ing the curing. There is no doubt that this movement of mineral matter from stem to web takes place during the later stages of dry- _ ing, and tobacco growers are familiar with the discoloration fre- quently caused thereby in the leaf in the vicinity of the stem. The movement is doubtless due simply to diffusion and is not to be con- nected with the reverse movement due to physiological translocation. As is well known, the leaf web normally dies and dries long before the stem, and the latter finally collapses rather suddenly. The remain- ing cell sap then oozes out into the leaf web, causing the discoloration referred to. This movement of materials, occurring after the death of the protoplasm, is not large and is localized. In the experiments in stalk curing there is a loss of ash in curing in the leaf as a whole, © which, of course, can not be due to respiration and can only be accounted for by the assumption that a portion of the ash has passed into the stalk. _CHANGES IN THE CARBOHYDRATES. In both methods of curing, nearly all the starch disappears both from the leaf web and from the midrib during the process. We have been unable to obtaim a reaction for starch by the iodin test in the cured samples. This is in accordance with the results of Miiller- Thurgau already referred to. The more or less complete disappear- ance of starch is one of the most characteristic changes involved in curing, and the relative freedom from starch of the cured leaf is a measure of the completeness of the curing process. It will be seen also that in complete curing by either method practically all of the reducing sugars disappear. The incompletely cured samples of 1908 reveal the fact, however, that the disappearance of starch precedes that of the sugars, as is to be expected, and, furthermore, that there is a temporary accumulation of sugars in the midrib, undoubtedly derived from the starch of the leaf web. It has been pointed out that analyses of flue-cured leaf have shown that under that system of rapid curing the leaf contains high percentages of reducing sugars, which are doubtless derived from the splitting up of starch, and the premature killing of the protoplasm prevents the oxidation of the sugars by respiration. Our results as a whole indicate that the pentosans, which, gener- ally speaking, are not physiologically plastic, undergo but little change in the leaf web, but in the stems there is a more decided decrease of these constituents. The crude-fiber content undergoes little or no change, except that in complete curing there appears to be a slight 26 BULLETIN 79, U. 3. DEPARTMENT OF AGRICULTURE. decrease in the stems, no doubt due to loss of pentosans or related hemicelluloses rather than to any change in true cellulose. CHANGES IN THE NONVOLATILE ORGANIC ACIDS. Tobacco leaves contain considerable quantities of oxalic, malic, and citric acids, and the changes which these undergo during the curing are interesting from the physiological point of view. That these acids are of importance in plant metabolism is generally recog- nized, but their réle has not been fully determined. Because of their close relationship to the amido acids, such as aspartic acid and asparagin, it seems reasonable to associate them with protein syn- thesis. Itis generally believed, however, that oxalic, citric, and malic acids have their origin in the incomplete oxidation of sugars when respiration proceeds in the presence of a limited oxygen supply. It appears that under certain conditions these acids may be converted partially into sugars, on the one hand, and partially into carbon dioxid and water, on the other hand. So far as we know, no dis- tinction has been made heretofore as to the metabolic transforma- tions which these three different acids undergo in the plant, but our results with green and cured tobacco leaves show that they behave quite differently during the curing process, which involves essen- tially the phenomena of respiration and of translocation. It is evident that the content of oxalic acid is not changed during the curing, and this is equally true in both methods of curing. There is a decided loss of malic acid during the curing when the leaf is primed, as well as when it is cured on the stalk. Citric acid, on the other hand, undergoes no decrease during the curing by either method, and, in- deed, there is a considerable increase in content of the acid, which is surprising in view of the behavior of the malic acid. It is, of course, conceivable that the malic acid is partially transformed into citric acid, but a simpler view is that the citric acid resists oxidation to lower products more than the malic acid, so that during the process of partial oxidation of the sugars to acids there is a gradual accumu- lation of citric acid, while the malic acid is more completely oxidized to water and carbon dioxid. CHANGES IN THE NITROGENOUS CONSTITUENTS. Referring to Tables IV and V, it will be seen that the loss in protein in curing is very large in all cases, in some instances exceeding 60 per cent of the total. The marked decrease in protein content, like the disappearance of starch, is a characteristic change involved in curing, and the relative decrease is an index of the completeness of the curing. The decrease in starch content and in protein content furnishes a simple and reliable means of determining by chemical analysis the progress and the completeness of barn curing. STUDIES ON THE CURING OF LEAF TOBACCO. Af There is undoubtedly a considerable loss in nicotine content in curing due to simple volatilization, but all this loss is not shown in our experiments, for the reason that the green or uncured, as well as the cured, leaves were dried at about 80° C. and this temperature is sufficient to expel the more readily volatile portion of the nicotine. In the leaf as a whole there appears to be no marked change in the content of nitric acid in either method of curing. The indicated loss of nitrate in the stem is probably only apparent, at least in part, since about the same losses are indicated for curing the primed leaves as for curing on the stalk. The determinations of nitrate were based on the well-known method of reduction with ferrous chlorid in acid solu- tion and measurement of the oxid of nitrogen liberated. In all cases, however, it was found that with the green stems a sharp end reaction could not be obtained, for, after the principal reaction was com- pleted, a slow evolution of gas continued almost indefinitely, appar- ently due to some reaction other than the reduction of the nitrate. The values for nitric acid in the green stems are therefore somewhat too high, which would, of course, have the effect of indicating a loss of nitric acid in curing. That the results for the green stems are too high is further indicated by the fact that the sum of the protein, nicotine, and nitrate nitrogen as obtained somewhat exceeds the total nitrogen in the green stems. | In the primed leaves there is a very marked increase in the amid and amido compounds, corresponding to the large decrease in protein. A considerable portion of these cleavage products of protein pass from the leaf web into the stem, which in the green condition contains practically none of these products. In the case of stalk-cured leaves there is no increase in amid and amido products, but, on the contrary, a con- siderable decrease, although the decrease in protein in this method of curing is even greater than in curing the primed leaves. Hvi- dently the phenomenon of translocation is here an important factor. In the leaves cured by priming there is always a considerable loss of total nitrogen, which can not be due to translocation, and since there is no equivalent loss of nicotine the nitrogen doubtless escapes in the form of ammonia. The odor of ammonia is readily recognized in the cur- ing barns, and there can be no doubt that it is liberated during the curing process. In other words, the cleavage products of protein are further changed, with ammonia as one of the decomposition products. The observed increase in content of ammonia, therefore, represents only a portion of the total quantity formed during the curing, the amount which becomes fixed in the leaf doubtless depending on the quantity of free acid present. 1Garner, W. W. Relation of nicotine to the quality of tobacco. U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 141, p. 5-16, 1909. 28 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. Considering collectively the changes in the various constituents involved in curing, we find in the case of the primed leaves that, where the analyses are complete, the sum of the various losses recorded, less the sum of the gains, gives a total loss amounting to from 70 to 90 per cent of that obtained in TableT; or, in other words, our analyses have accounted for this proportion of the constituents which are of importance from a quantitative standpoint. A very close agreement is not to be expected, since the factors used in cal- culating the protein and the amid and amido constituents are probably only approximately correct. The results of the analyses account for about 75 per cent of the loss in weight indicated in Table I, where the leaves are cured on the stalk. Aside from the observations made by Miller-Thurgau regarding the loss of starch and sugars in the curing, which have already been men- tioned, the only paper bearing directly on the changes in composi- tion during the curing, so far as known, is that of Behrens, who, like nearly all previous investigators, was concerned mainly in a compari- son of the methods of curing on the stalk and of curing the primed leaves. He presents data, however, showing the comparative com- position of green and cured leaves. Since the total loss of weight in curing was not determined, the changes in composition can only be considered qualitatively. His analyses indicate the disappearance of starch and a decrease in sugars and protein nitrogen in curing. They show also a relative loss of total carbon and a relative gain in total nitrogen during the curing process. While little is known as to the identity of the individual com- pounds making up the groups of constituents involved in the curing changes, particularly as regards the protein group and their cleavage products, the general character and course of the transformations concerned can be considered as definitely established. The follow- ing scheme shows the general course of the changes common to both methods of curing which the several groups of constituents undergo during the curing process, the prime factor in effecting these trans- formations being respiration, although the phenomena of transloca- tion play a more or less important rédle, depending on the method of curing followed. Diagram showing the general course of changes during the curing process. Oxalic acid Starch____________—__—_»Sugars——> , Citric acid }------. (?)-- >Carbon dioxid and water. ee ad Sen Pentosans.----------~~""" Malic acid }_-----~ fo a = (ied Ammonia. fot a te Amidjandamido\s wos. Protein >{ derivatives \ > carbon dioxid. 1 Behrens, Johannes. Weitere Beitrige zur Kenntnis der Tabakpflanze. Die Landwirtschaftlichen Versuchs-Stationen, Bd. 43, p. 271-301, 18 STUDIES ON THE CURING OF LEAF TOBACCO. 29 In the above scheme the changes which take place quantitatively are indicated by solid lines, and partial transformations are indicated by broken lines. The transformation of the sugars into nonvolatile organic acids is bracketed, for the reason that, although the sugars are quantitatively removed, it is not known to what extent the acids are formed as intermediate products of oxidation. There is some question as to whether citric acid is further oxidized during the curing process, and it has not been actually proved that nitrogen-free acids are formed by the hydrolysis of the amido derivatives of protein, although this seems highly probable. The scheme merely presents the course of events in the breaking up of the surplus food supply in support of respiration, and does not take into account the move- ments of the soluble products due to physiological translocation. It will be seen that the so-called ether extract, which is usually included in the analysis of agricultural products and which is intended to show the content of fat or oil, has not been considered in connec- tion with our studies on the changes in composition taking place during the curing. It has not been considered that this determina- tion would throw any light on the problems in hand, for the extract obtained from tobacco leaves is a hopelessly complex mixture, con- taining a portion of the nicotine, chlorophyll, and its decomposition products, tobacco resins, etc., and in reality containing at most very small quantities of constituents which could be properly called fat or oil. No methods are at present available for the quantitative sep- aration of the several constituents of the ether extract, and it is obvious that the crude extract would contain several constituents already accounted for in the analyses. : The results which have been presented and discussed in the pre- ceding paragraphs apply more particularly to typical air curing. - Samples A and B of 1911, in Tables IV and V, should bring out any differences in the final result of the curing when air curing is modified by the moderate use of artificial heat. As a matter of fact these duplicate samples, after curing, show almost exactly the same com- position; so that, although the moderate application of heat hastens the rate of curing, as shown by the appearance of the tobacco during the progress of the process, the final result, so far as shown by the analyses, is the same, whether or not the heat be applied. In the case of flue curing, where much higher temperatures are used, no comprehensive investigations have been made; but analyses of the cured leaves which have been reported show that the curing changes are of the same character as in air curing, the only difference being that in flue curing the transformations are less complete. In typical fire curing, in which the tobacco is only partially cured by the use of heat, the relative completeness of the chemical changes involved probably falls between that in air curing and that in flue curing. 30 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. CURING THE LEAVES ON THE STALK COMPARED WITH CURING THE PICKED LEAVES. The relative merits of the two methods of curing have long been a subject of interest to agricultural investigators, both in this and in foreign countries, and the greater portion of the experimental work relating to tobacco curing which has been done has had special reference to this problem. Some of the earlier investigators main- tained that the leaf weighed more when cured on the stalk, because of a flow of soluble material from the stalk into the leaf. Others, how- ever, notably Nessler! and Behrens,? maintained that there was no particular difference in results as between the two methods of har- vesting and curing, either with reference to weight or to quality of the cured leaf. We are indebted to Mohr ? for the first comprehensive and decisive study of the subject. Mohr brought out clearly the errors in the methods of procedure and in the interpretation of results made by previous investigators and proved beyond doubt that for the particular type of tobacco with which he worked (cigar-wrapper leaf) the leaf cured on the stalk loses in weight approximately 11 or 12 per cent more than if cured after being picked from the stalk. This is equivalent to saying that a picked leaf after curing will weigh 11 or 12 per cent more than would the same leaf if cured on the stalk. Mohr proved conclusively by analyses of the ash and other con- stituents that the increased loss in weight which occurs when the leaf is cured on the stalk is due not so much to a more intense respira- tion but rather to a translocation of nutritive material from the leaf into the stalk. Coming to our own experiments, by reference to Table I (p. 5) it is seen that with comparable material harvested and cured by the two methods in question during the years 1908, 1909, and 1910 the losses in dry weight by curing the leaves on the stalk were 12.2, 18.9, and 10 per cent, respectively, greater than the losses in curing the picked leaves. The larger indicated difference in loss of weight between the two methods for 1909 is to a great extent due to. the unusually small loss in weight of the picked leaves, and this in turn is fully explained by the abnormally low content of starch of the picked leaves at the time of harvesting. However, the average dif- ference between the losses in weight for the three years by the two methods of harvesting and curing is 13.7 per cent, taking the figures as they stand; and this value is in close agreement with Mohr’s results for the same general type of tobacco, namely, cigar-wrapper leaf. On the other hand, Table II (p. 8) shows that the difference in loss 1 Nessler, J. Der Tabak, seine Bestandtheile und seine Behandlung, Mannheim, 1867. 2 Behrens, Johannes. Weitere Beitrige zur Kenntnis der Tabakpflanze. Die Landwirtschaftlichen Versuchs-Stationen, Bd. 43, p. 280, 1894. 3 Mohr, E.C. J. Gepfliickterund am Stamme getrockneter Tabak. Die Landwirtschaftlichen Versuchs- Stationen, Bd. 59, Heft 3/4, p. 253-292, 1903. STUDIES ON THE CURING OF LEAF TOBACCO. 81 of weight in curing between leaves harvested on the stalk and those picked from the stalk may be much greater with some of our manu- facturing and export types, which are grown under different con- ditions and harvested in a much riper state than the cigar-wrapper types. It will be seen that in stalk curing there was a loss of about 9 to 10 per cent of the original content of pure ash, which is in close agreement with Mohr’s results. In curing the primed leaves there can, of course, be no loss of ash. Our results show that, although the cured picked leaves contain little or no starch, the removal of insoluble carbohydrates is pushed considerably farther when the leaves are cured on the stalk. There is a more marked decrease of pentosans in stalk curing. There is no essential difference in the results as between the two methods with reference to sugar content, since in both cases there is a practically entire disappearance of sugars when the curing is complete. The compounds of nitrogen are decidedly the most important con- stituents of the leaf in regard to differences in the results of curing on the stalk as compared with curing the picked leaves. For the three years for which direct comparisons are made, the loss in protein nitrogen, in the leaf web, and particularly in the midrib, was decidedly greater in stalk curing than in curing the picked leaves. Since the temperature employed in drying the samples was sufficient to expel the easily volatilized portion of the nicotine, no definite conclusion can be drawn as to the differences in loss of this constituent in the two methods of harvesting. The results regarding nitrate nitrogen are unsatisfactory, doubtless because of the difficulty in obtaining reliable results with the uncured material, as pointed out on page 28. As a whole, the results do not indicate a very marked translocation of nitrates into the stalk. As far as they were carried, our results indicate that ammonia is readily translocated into the stalk. In comparing the results of the two methods of curing with refer- ence to changes of composition, the most striking difference is to be found in the behavior of the nitrogenous cleavage products from the hydrolysis of protein. From 40 to 60 per cent of the protein is broken up during the curing process and, although the loss in total nitrogen in curing the picked leaves shows conclusively that a por- tion of the nitrogen of the decomposition products escapes as ammo- nia, the loss thus involved is but a comparatively small portion of the whole. The result is that there is a marked accumulation of amid and amido compounds in the cured picked leaves, the increase in this form of nitrogen amounting to 0.5 to 1.5 per cent of the leaf weight, or 100 to 400 per cent more than was contained in the uncured leaf. In the stalk-cured leaves, on the other hand, not only are the products resulting from the splitting of the protein completely removed, but a considerable portion of the amid and amido com- 32 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. pounds originally present in the leaf are also removed in the process of curing. Instalk curing, the loss of nitrogen in these forms amounts to 35 to 45 per cent of the total protein and amid and amido nitro- gen, while in curing the picked leaves the direct loss of nitrogen in these forms by the splitting off and escape of ammonia averages less than 10 per cent of the total. In stalk curing, the content of amid and amido nitrogen alone is reduced by about 15 to 60 per cent, depending on the original content of these forms of nitrogen. As regards total nitrogen, the loss in curing the picked leaves is from 4 to 15 per cent of the total, while the loss in stalk curing is from 35 to 42 per cent. As regards the organic acids, there is no denied difference in the behavior of oxalic acid in the two methods of curing, and this is true also as to malic acid. Citric acid seems to accumulate to approximately the same extent whether the leaf is attached to the stalk or is detached during the curing. There is no satisfactory evidence that these acids undergo translocation in stalk curing. Summing up the more important differences in the results of curing the leaves on the stalk as compared with curing the picked leaves which are brought out in our experiments, it is seen that the loss in weight of dry matter is 10 to 15 per cent greater when the leaves are cured on the stalk. This difference is due mainly to the more complete removal of carbohydrates, including the pentosans, and of protein and, more particularly, to the translocation of the cleavage products of protein and of the mineral constituents from the leaf into the stalk. In stalk curing, in addition to the respira- tion activities which constitute the important factor in curing the picked leaves, the translocation of mobile materials from the leaf into the stalk assumes an important réle. This translocation of materials from leaf to stalk in stalk curing constitutes, in fact, the essential difference between this method of curing and that in use after the leaves are removed from the stalk. Our results on this phase of tobacco curing agree closely with the conclusions reached _ by Mohr from his study of the subject. These results find additional support in the work of Johnson? relating to the composition of two lots of tobacco stalks, from one of which the leaves were removed at the time of harvesting, while the second lot was allowed to cure with the leaves attached. The analyses of the two lots of stalks show that those which were allowed to cure with the leaves attached gained approximately 30 per cent of their original content of total nitrogen, 36 per cent of their content of phosphoric acid, and 8 per cent of their content of potash. This gain in nitrogen, phosphoric acid, and potash can only be accounted for on the assumption that 1 Johnson, 8. W. Analyses of tobacco stalks when cut and after curing. Connecticut Agricultural Experiment Station, 16th Annual Report, 1892, p. 31-34. 1893. STUDIES ON THE CURING OF LEAF TOBACCO. 33 these constituents were transported from the leaf into the stalk during the process of curing. It is evident that the phenomena of translocation in the curing of tobacco leaves attached to the stalk follow essentially the same laws as obtain during the growth and development of plants under normal conditions. The movement of reserve nutrients is from the leaf web through the veins and midrib into the stalk and normally thence to the younger growing parts. Only such constituents as are the most essential, physiologically, undergo translocation to a marked degree. ENZYMS IN TOBACCO CURING. It has been pointed out in the preceding pages that tobacco curing consists, primarily, in the hydrolysis of insoluble carbohydrates and proteins, followed by a partial or complete removal of the cleavage products by further hydrolysis and by oxidation and, in stalk curing, by translocation into the stalk. It is quite generally recognized that the immediate agencies effecting transformations of this character in the vital activities of the plant are enzyms. We have shown that starch and pentosans are converted into reducing sugars, which are then oxidized or translocated, and that protein is converted into the simpler amid or amido derivatives, from which, in turn, ammonia is split off. It seems probable, therefore, that diastases, cytases, and proteolytic and deamidizing enzyms take part in the curing of the tobacco leaf. It seems very probable also that the oxidases play an important part, particularly as regards the changes in color which the leaf undergoes in curing. We have not attempted to go into a study of the enzyms concerned in tobacco curing, except simply to bring out the fact that their activities are for the most part intimately associated with and de- pendent upon the presence of the living protoplasm. We have already pointed out that a ripe tobacco leaf will not cure properly, even under the most favorable conditions, if it has been previously subjected to very high or low temperatures or to the action of pro- toplasmic poisons. It has also been stated that the progress of the curing can be readily followed by determining at different stages the relative quantities of unchanged starch and protein contained in the leaf. The following experiments show by chemical methods that the premature killing of the protoplasm prevents the changes in composition which are essential to successful curing. In the first place, an experiment was carried out to determine the effectiveness of rapid drying at high temperatures in preventing these changes in composition. ‘Two lots of leaves, containing 14 leaves in each lot, were selected in the manner described on page 4, and one of these lots was allowed to cure normally. The midribs were re- 34 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. moved from the second lot of leaves and the half of each leaf thus resulting was plunged into boiling absolute alcohol for a few minutes, while the second set of leaf halves was immediately placed in an air bath heated to 90° C. and dried. The results of the experiment are shown in Table VI. In the case of material killed with alcohol the results were corrected, of course, for the matter extracted by the alcohol. To facilitate comparison, the results are presented on a uniform basis of 14 whole leaves, exclusive of the midribs. TaBLe VI.—Effectiveness of killing fresh tobacco leaves at high temperatures, as compared with killing with hot alcohol in arresting changes in composition. (0) a nae web Leaf web (c) 1911 material. : s killed at | Leaf cured fea ae high tem- | normally 7 perature Dry iweight of V4Jleavesso sus. yee ee ee A grams. . 126. 2 124.6 97.5 essiof weiphtinicuring <3) 2.55 te 3 ee ee eos. DEricen ts Aes oe aee eee 1.3 22.8 Starch... 2 Song = ee eh. oi eek LE ed eel oie eR 4 a do.... 26. 64 24. 57 5.17 Protein mitropen esse. 5 eee ns Se Ones SS LS 72 dove 2.04 2.13 1, 22 Redpicing sugars - occ. tee. Sse Nie es ae eS 2 do.... 1.21 1.63 3.86 In the above table the results are calculated on a basis of the original dry weight of the leaves, as represented by a. These results show that, while subjecting the leaf to a temperature of 90° C. does not immediately stop all action upon the carbohydrates, this method, which was employed in all the experiments already described, answers satisfactorily for the purposes in view. Having established this point, the effect on the curing process of chloroforming the leaf was next studied. A lot of five ripe leaves was collected and their midribs removed. ‘The one lot of leaf halves thus obtained was immediately dried at 90° C., as in the preceding experiment, while the second lot was exposed to chloroform vapors in a closed jar for a few minutes and then placed under the proper conditions for normal curing. After four days this material was also dried at 90° C. The results of the experiment are shown in Table VII. TaBLe VII.—Effect of exposure to chloroform on the curing of tobacco leaves. Beat adeal besa asa. af drie roforme 1912 material. at 90° C. and then “oured.’’ el pens ofS halfileavessosss eee ae ee eee. 3 oe ee grams 18.7 19.00 Sie coe recat raws on esh vacshn des be eibin~ cd aus eee: cies ae eae per cent 41.74 43.88 Proteit Riitropens Sse eee. Stee Be eS. See ee eee eee to) 1. It is obvious that exposure to chloroform effectually prevents those changes in composition which are characteristic of normal curing and, indeed, the appearance and properties of leaves so STUDIES ON THE CURING OF LEAF TOBACCO. OD treated clearly show that normal curing does not take place. Since these normal changes in composition are effected by hydrolytic enzyms, and since it is well known that the green leaves of plants normally contain these enzyms, it is not clear why protoplasmic poisons which do not inhibit the action of such enzyms should prevent the progress of the curing along these lines. Brown and Morris ' considered this matter in connection with their investigations on the occurrence of diastase in the leaves of plants, but did not arrive at a satisfactory conclusion. They found that, although the diastatic activity of the leaf increases markedly when it is kept in darkness, even when a leaf has been subjected to this treatment there is no further decrease of starch after treatment with chloroform. Whatever the explanation of this phenomenon, it seems logical, as suggested by Brown and Morris, that partial starvation will lead to an increased formation by the leaf cell of enzyms designed to furnish the needed nourishment. We have found that such is the case as regards diastase in the curing of tobacco leaves. The method used for comparing the diastatic activity of fresh and partially cured leaves was that described by the above-named investigators, and consists essentially in digesting a given weight of the material with a 2 per cent water solution of soluble starch under proper conditions and with suitable controls. The imcrease in reducing sugars is taken as a measure of the relative diastatic activity. In the following experiments, after having obtained the leaf areas, one half of each leaf was chloroformed and dried at 35° C., while the remaining half of each leaf was maintained under normal curing conditions (slow drying in darkness and at moderate temperatures) for a period of 43 hours in experiment 1 and for one week in experi- ment 2. The material chosen for the first experiment was a single mature bottom leaf taken from a Connecticut Broadleaf plant grown in the greenhouse, and in the second experiment one bottom and two top leaves were taken from a mature plant of Yellow Pryor grown under normal field conditions. The cured material was chloroformed and dried in the same manner as the uncured. The diastatic activity was determined for equal areas and not equal weights of the cured and uncured material, and the results as reported are in terms of the weights of maltose formed by digesting 10 grams of the uncured samples chosen as standards and weights corresponding to an equal area of the other samples with 2 per cent soluble starch solu- tion for 48 hours at 30° C. It is necessary to use equal areas of leaf to correct properly for the loss in dry weight in curing. The results of these experiments are shown in Table VIII. 1 Brown, H.T., and Morris, G. H. Contribution to the chemistry and physiology of foliage leaves. Journal, Chemical Society [London], Transactions, v. 63, p. 604-659, 1893. 36 BULLETIN 79, U. S. DEPARTMENT OF AGRICULTURE. TaBLeE VIII.—Diastatic activity of uncured and partially cured tobacco leaves. Material. weight of | Weightper| weientin | Welghtof | Ginctatic material. | 54 ‘| curing. * | activity. Experiment 1 (14 square inches of leaf sur- ’ face used): A se pia Het ee Per cent. Grams, eA Teen Malis ccs one dent hee aceon 4 2 L2AN eS eee ee . 5000 Cored) halo: fern se ae oceodeeie cies sae 5. 67 4, 489 12.4 - 4378 5. 48 Experiment 2 (9.8 square inches of leaf sur- face used): 2 top leaves— Green hhalves-;. =.:52. <2. -2hsh sneeze 7. 634 70354 222 eee ee - 5000 2.04 Cured halves oe i eee eee 4. 836 4. 659 36.7 - 3167 7.02 A bottom leaf— Green half! (ego ios 2 osek cee oe 8. 536 7.940 |leveskese. Ge - 5398 2. 48 Cured Nalini -oacccuseccoeeoaser acs 5. 004 4. 655 41.4 -3164 6.50 The above results show very clearly that there is a marked increase in the diastatic activity of tobacco leaves during the curing process. It seems probable that there is a similar increase in the proteolytic en- zyms during the curing, but no attempt was made to determine this point. TOBACCO CURING AS AFFECTED BY EXTERNAL CONDITIONS. Since respiration plays a fundamental réle in tobacco curing, it is to be expected that the external conditions, notably the temperature, will have a decided influence on the curing process. The factors of importance in this connection are the temperature and relative con- tent of moisture, oxygen, and carbon dioxid of the surrounding atmosphere and the presence or absence of light. We have made some experiments on the relation of the first two of these factors to the rate of curing, using the quantities of starch and protein hydro- lyzed as a measure of the progress of the curing. EFFECT OF TEMPERATURE ON RATE OF CURING. In 1911 three lots of six leaves each were collected, using the pre- cautions already described in detail, to have the three lots strictly comparable. The stems were removed from the first lot of leaves (a) and the leaf web killed by plunging into boiling absolute alcohol, after which the leaf web and stems were dried at 80°C. The second lot of leaves (b) was placed in a bell jar and maintained at a temper- ature of approximately 10° C. (50° F.) for 24 hours, after which they were treated exactly like the first lot. The third lot (c) was similarly maintained at a temperature of approximately 24° C. (75° F.) for 24 hours and then treated like the other two lots. In 1912 the experi- ment was repeated with two lots of five leaves each. The stems were removed from the first lot (a), one half of each leaf being quickly dried at 90° C., while the remaining leaf halves were chloroformed and placed under favorable conditions for curing for a period of four STUDIES ON THE CURING OF LEAF TOBACCO. 37 days before being dried in'the oven. (This material served also for the data presented in Table VII.) Thestems were also removed from the second lot of leaves (6) and one half of each leaf maintained in a bell jar at an average temperature of 12° C. (54° F.) for 48 hours, while the second half of each leaf was ‘similarly treated, but at an average temperature of 27° C. (80° F.). These leaf halves were then quickly dried at 90°C. The results of these experiments are given in Table IX. TaBLeE 1X.—LH fect of temperature in hastening rate of curing. (a) (0) (c) pees Leaf par- | Leaf par- Material. hol (1911) tially cured] tially cured ap awitin at 10° to at 24° to heat (1912).| 12° C- 24 1911 samples: Tota! ary. weight of 6 leaves, including stems............. grams... 61.1 61.5 57.6 Starch (leaf web).................. Eee Oe ese per cent... 28.47 25.17 21. 33 Protein nitrogen (leaf web)............---.------ ecco enone do.... 1.90 1.94 1.59 1912 samples: Total dry weight of 5 halfleaves, without stems.......... grams... 18.7 18.3 17.4 EURO OL Ee a 8 9 Ee ae Se el ea per cent 41.74 37 26. 46 PPrOocemmonitrog OMe. =< <<)! 5 ELE LELeELTeetisg! 0 ee i ee COLE 18 HT (a a a ae Za oe o | [ Y 18 im rE FERHEEEH : COR RECC CCE bea NOW ase a Oo ACCEL LL LL PATE EE SESS SeeY\eESSEE SaSae FREE ECEEE EEE CREE ERECT Fie. 3.—Typical graphic log of cook. (Cook 24.) 14 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. “opened up’ in a swing-hammer shredder running at low speed and without a cage, so that the largest lumps after shredding were about hazelnut size. This was done to facilitate sampling and increase the accuracy of the dry-weight determinations. The shredded pulp was weighed and sampled (sample D) for determin- ing the dry weight. It was then mixed with water and further opened up in a 25-pound Hollander-style beater, with the roll well off the bedplate so that no real beating could take place, and was pumped from the beater to a 200-gallon stock tank at the head of the screening system, where it was diluted with water to a known volume. This mixture was then screened by means of a 6-plate diaphragm screen with slots 0.009 inch wide. The screenings which went over the plates were then collected, weighed, and sampled (sample E), as described for the crude pulp. The screened, unbleached pulp which went through the screen slots, mixed with a large amount of water, was run to a water extractor and concentrated. Afterwards it was pumped to the paper machine stuff chest, made up to a known volume with water, pumped to the machine screen (diaphragm type, 0.012 inch slots), and run out on a 15-inch Fourdrinier paper machine (see Pl. J), into a sheet 10 inches wide by about 0.010-0.011 inch thick. The rolls of the screened, unbleached pulp thus secured were stored await- ing the tests to determine its properties for which samples G to R were taken. Where the screenings were so large in amount as to preclude accuracy of sampling the crude unscreened pulp, such pulp was screened without the preliminary pressing, shredding, etc., and the screened pulp was collected on a 70-mesh sieve, pressed, shredded, weighed, and sampled for the yield determinations. The pulp was then screened again and made up into a sheet as described. The methods used for determining dry weights, yields, quality of pulps, and composition of liquors are given in the appendix. TEST MATERIALS USED. WOOD. The test material consisted of 31 logs of aspen (Populus tremuloides, Michx.) cut from representative trees growing intermixed with white birch near Rhinelander, Wis. The trees were of seed growth and had attained an average height of 44 feet, with straight, clear lengths of about 22 feet from which the logs were cut. The ages of the logs varied from 28 to 42 years, as determined by counting the annual rings. The logs were fairly free from knots, considering the size of the trees and the species. Volume-weight determinations on 36 samples, representative of the whole shipment, showed the average bone-dry weight per cubic foot of green or PRODUCING SODA PULP FROM ASPEN. 15 unseasoned wood free from knots to be 26.68 pounds. The samples ranged from 23.6 to 31.4 pounds per cubic foot. As a rule the test material was sound, but some of the logs had decayed hearts. The material was peeled by means of a carpenter’s drawknife; all decayed portions on the outside of the pieces and all protruding knots were chopped off. This cleaned wood was then sawed into disks five-eighths inch thick in the direction of the grain. Butts, tops, and all disks containing decay or other defects were culled. The remaining sound disks were split with the grain into chips 1 inch to 6 inches by one-fourth inch by means of a special guillo- tine chipping machine. All knots were culled. The chips were then seasoned to constant air-dry weight, thoroughly mixed and screened to remove sawdust and dirt, and finally stored in cans to await the cooking tests. COOKING CHEMICALS AND SOLUTIONS. In ordinary mill practice the soda cooking liquors are made as described on page 4. The freshly causticized solution contains caustic soda (NaOH) for the most part, but a small amount of soda ash (sodium carbonate, Na,CO,) still remains uncausticized. Various impurities are also present, but these are considered to have no effect in cooking. In the experiments the cooking solutions were made by dissolving fused caustic soda, 76 per cent‘ sodium oxide (Na,O), in water. The resulting solution was similar to the solutions used in commer- cial practice so far as caustic soda and soda ash are concerned, and there is no reason to believe that the results should be different in any way from those which would have been obtained by the use of commercial liquors of the same concentration and causticity. EFFECTS OF VARIATIONS IN THE COOKING CONDITIONS. The influence of the variable cooking condition in each group of tests on resultant yields and properties of pulps and consumption of cooking chemicals is shown graphically in figures 4 to 15.2 The same results in greater detail are given in Tables 10 to 14 of the appendix. While, in general, the tests were carried out in accord- ance with the plan which has been described, minor departures could not be avoided, and the location of certain points on the diagrams are more or less affected by such variations. For this reason the tabulated data should be consulted for the exact conditions of each cook. 1 Manufacturer’s analysis. 2The numerals opposite each platted point on the curves are the serial numbers of the cooks. (See Tables 10 to 14.) ai 16 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. YIELDS. The effects on yields of pulp and screenings are expressed by the curves in figure 4, in which the yields are plotted against the amount of caustic soda, the duration of cooking, the pressure of cooking, and the initial concentration of caustic soda. AMOUNT OF CAUSTIC SODA. With increases in the amount of caustic soda per pound of wood the yield of total crude pulp decreased at the rate of about 1 per cent for each 2 per cent of caustic (0.02 pound NaOH per pound of S Sa 2 |_| a z | iS zi B a ° fens o [- 4 Pe is) # 10 -20 -30 40 0 2 4 6 8 10 =«12 POUNDS NaOH PER POUND OF WOOD 3 20 SUR kM 3 ul ul 5 alah 2 Ne) sale fc Esk cas al a LES RRR eRe. = ae SS 8 SM fd Elif adeeb dob sdis| ld leh 10 20 30 40 0 2 4 6 8 10 «12 DURATION AT MAX. PRESSURE—HOURS 3 2 60 SeeeP Ih sac e se z SRE eM OUIG0 i soa ea : fi PTT F ap Pa esieeeae 7 a a } a 60 76 80 90 100 110 120 40 50 60 70 80 390 100 110 MAX. PRESSURE—PDS. PER SQ. IN. CONCENTRATION NaQH—GRAMS PER LITER: ©=TOTAL CRUDE PULP © = SCREEKED UMBLEACHED PULP ‘= SCREENINGS Fic. 4.—Effects of cooking conditions on yields of total crude pulp, screened unbleached pulp, and screenings. wood). The yield at zero caustic soda would probably fall between 80 and 90 per cent, being influenced only by the cooking effect * of the water condensed from the steam used in cooking. For high amounts of caustic soda the curve tends to approach parallelism with the horizontal axis. The yield would not be expected to become zero unless exceedingly large amounts of caustic were used.? For amounts of caustic soda above what may be considered the minimum for successful cooking under the conditions used, the yield 1 See Tauss’s experiments, Table 1. 2 Tauss used for a single boiling as high as 7 pounds of caustic soda per pound of wood, and the yield or undissolved material after three hours at 58.8 pounds per square inch steam pressure amounted to 8.52 per cent for beech and 2.87 per cent for pine. With 4 pounds caustic soda per pound of wood in each of three successive three-hour treatments under a steam pressure of 132.3 pounds per square inch, the yields for the two woods were 20.61 per cent and 18.20 per cent, respectively. This latter proportion of caustic soda was ten or more times as great as is ordinarily employed in commercial practice. Aiso the other cooking conditions wero proportionately more severe. & Bul. 80, U. S. Dept. of Agriculture. PLATE I. PAPER MACHINE, FOREST PRODUCTS LABORATORY, MADISON, WIS. PRODUCING SODA PULP FROM ASPEN. Luvs of screened unbleached pulp was identical with that of crude pulp, but for smaller amounts of chemical it rapidly approached zero, while under the same conditions the screenings curve naturally approaches and becomes coincident with the curve for the total crude pulp. In this group of tests the minimum amount of caustic soda for successful cooking, so far as yields alone are concerned, is somewhere between 15 and 20 per cent. DURATION OF COOKING. The duration of cooking at maximum pressure influenced the yields in very much the same manner as did the amount of chemical. The yield of total crude pulp decreased about 1 per cent for each additional hour of cooking at maximum pressure. However, the curve (fig. 4) seems to approach parallelism with the horizontal axis, thus signifying that beyond a certain point cooking would have had no further effect.1_ The time allowed for these cooks to reach the maximum pressure was one hour, and the extended curve indicates a yield of about 60 per cent for zero hours duration at maximum pressure. This shows that the greater part of the cooking was accomplished during the first hour, or before the maximum pressure was attained, since during that hour about 40 per cent of the wood substance had been dissolved and the dissolving effect during the next 12 hours was only one-fourth as great. As determined by the yield curves, the minimum duration for successful cooking under the conditions employed was between one and three hours at maximum pressure. No tests were made between these two points. PRESSURE OF COOKING. The curve showing the influence of maximum cooking pressure or temperature on yields indicates that all of the tests were made at pressures above the minimum required for successful cooking, under the conditions employed for these tests; hence, no screenings were obtained from any of the cooks, and the curve for screened unbleached pulp coincides with that for total crude pulp. Increases of pressure from 70 to 120 pounds per square inch resulted in decreasing the yields of pulp about 1 per cent for each five pounds, which indicates that the higher pressures increase the thoroughness of cooking, other conditions being constant. CONCENTRATION OF CAUSTIC SODA. The tests varying the initial concentration of caustic soda in the digester liquors were also made within limits that resulted in thorough cooking for all of the tests. Increasing the concentration under the 1 Figures 12 and 13 show that the active cooking chemical was consumed at the end of 7 hours at maxi- mum pressure; it is therefore not apparent from these tests what would be the effect of continued cooking in the presence of available caustic ‘soda. 31091°—Bull. :80—14——2 18 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. conditions employed resulted in decreasing the yields of pulp about 1 per cent for each 13 grams per liter increase in concentration. It is thus evident that with a given amount of chemical the greater cooking effect is secured by means of the more concentrated solutions. A practical limit of course exists at the point where the volume of the digester liquor becomes too small to afford favorable cooking conditions.! PROPERTIES OF UNBLEACHED PULPS. NATURAL COLOR. Curves indicating the effects of the conditions of cooking on the natural color of the unbleached pulps are shown in figure 5. The larger the amount of caustic soda used per pound of wood the lighter in color was the pulp, as indicated by x o 66 ) 5 POUNDS NAOH PER POUND OF ® wooD ee Sag anak 3 ing, but the curve approaches 0 parallelism with the horizontal a 100 i ea is fa al axis as the amounts of caustic < rac uit = increase. White pulps or those z DURATION AT MAX. PRESSURE—HOURS with zero “‘ parts black’’ would = not be obtained even if exceed- <= 0 . . & QS a Gey ee eer ingly large amounts of chemi- ea LT TT | | cat wore used. = 46 ° MAX. PRESSURE-PDS UPER s0.1N. Longer 2 sagt 3 eon ene e produced lighter-colored pulps up to the poimt where the foal ao clad maximum yield of screened S060 70 80 90 100 10 pulp was obtained. Beyond CONCENTRATION easel tit PER LITER this point there was a tendency Fic. at SR Sa on the color fo r th e pulp to b ecome sli ghtly darker as the duration of cook- ing was increased. This was probably due to the pulp fibers absorbing and retaining coloring matters from the ‘“‘black liquors.’”’ It is gen- erally believed that as the cooking becomes more thorough the cellulose of the fibers gradually becomes more gelatinous or hydrated, and would therefore tend to retain coloring matter during the subse- quent leaching and washing treatments. The pressure (temperature) of cooking seems to have had compar- atively little effect on the color of the pulp within the range investi- gated. 1 As the initial concentrations increased, the volumes of digester liquors at the start of cook decreased (see fig. 17), since the amount of caustic soda was held constant. Hence, increasing concentrations would eventually result in a volume of digester liquor so small that the whole charge of chips would not be covered until late in the cooking period after the liquor had been sufficiently diluted by the condensed steam used in cooking. In this case part of the chips would receive very severe treatment, while the remainder would more or less escape the COOKING effect. The resulting pulp would represent a composite of the two con- ditions. PRODUCING SODA PULP FROM ASPEN. 19 The more thorough cooking resulting from the higher initial con- centrations of caustic soda produced lighter-colored pulps, although the lower limit of fhe cooking condition in these tests was considerably above the minimum for successful cooking. While the several curves shown in figure 5 indicate for each group of tests more or less change in the “‘parts black”’ color ratings or the depth of color, the hues of the pulps were not materially affected. OCCURRENCE OF SHIVES. Shives are most numerous in pulps from the less severe cooks and are entirely absent from those thoroughly cooked. The shives curves (fig. 6) bear some resemblance to those for the yields of screenings, but shives disappear from the pulps only under somewhat more severe cooking conditions than those which reduced the yield of screenings to zero. At the point of maximum yield of screened pulp the cooking has progressed far enough for the fibers to become more or less separated from each other, but 9 Sie not completely so, since some 60 70 80 80 100 110 -20 -30 40 POUNDS NaOH PER POUND OF WOOD Ona e ee rar ene ee 10n,. 42 DURATION AT MAX. PRESSURE—HOURS SHIVES PER GRAM OF BONE DRY PULP of them still remain in groups (shives) small enough to pass the screen slots. But as the cooking becomes more severe the fibers are entirely sepa- rated, and the resulting pulp «MAX. PRESSURE—PDS. PER SQ. IN. 200 SL] eee Ae 40 50 60 70 80 90 100 10 CONCENTRATION NaQH—GRAMS PER LITER Fic. 6.—Effects of cooking conditions on the occur- rence of shivesin pulp. is free from shives. In gen- eral, increasing the amount of caustic soda, the duration or the temperature of cooking, or the initial concentration of the digester liquor decreases the “shiviness”’ of the pulp. ASH CONTENT. The curves in figure 7 indicate that increasing the thoroughness of cooking within certain limits decreases the ash content of the pulp; outside of these limits the ash content may be increased. Since the normal amount of ash in aspen wood is not over three- quarters of 1 per cent, the high amounts in the pulps produced 20 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. from this wood in some of the tests is probably due to the presence of cooking chemicals 1 which were not completely removed during the washing treatments. Increasing amounts of ash as the cooking conditions become more severe may be due to a difference in the physical character of the cellulose produced under such conditions and the resultant increased difficulty of leaching out and washing away any residual and absorbed mineral matters. No tests were made to determine the char- acter of the ash from any of the pulps. STRENGTH. The strength of a pulp de- pends chiefly upon three fac- tors—(1) the strength of the individual fibers; (2) the felting or matting quality of the fibers; and (3) the presence of gelatin- ized fibers and other matters which act as cementing ma- “(a ag Soe pay ad (8) eae 2 ma] DURATION AT MAX. PRESSURE~HOURS terials. Severity of cooking is at- AP Seas =a tended by a weakening of the = ae | cell walls and may result in a 6 0 90 100 10 120 decrease in the strength of the : ; a pulp. Thisdecrease of strength was strongly marked in the tests ad 3, se a in which the more severe cook- fe ae a ing conditions were produced 40 50 60 70 80 90 100 10 : : CONCENTRATION NaOH—GRAMS PER LITER by increasing the amount of Fic. 7.—Effects of cooking conditions on the ash caustic soda. It was most rapid CORI Ee: up to the point where the fibers were completely separated (indicated by the absence of shives), be- yond which it was less pronounced. For increasing durations of cooking the general trend? of the effect was the same as for increasing amounts of chemical, but the total decrease in strength was not quite so great in amount for the range of cooking conditions investigated. PER CENT ASH PER GRAM OF BONE DRY PULP 1 Special precautions were taken. to eliminate the influence of dirt. Further it does not seem reason- able that the cooking action which removed the lignin and other organic matters should have produced in the fibrous residue or pulp a concentration of the mineral constituents which go to form the wood ash. 2 The data are not sufficient for expressing the effect in detail. The true curve would be expected to have a bend coinciding with the point of maximum yield of screened pulp or the point where the shives are reduced to zero. PRODUCING SODA PULP FROM ASPEN. yal Increasing the pressure and increasing the initial concentration beyond a certain point both increased the strength of the pulp. This effect is apparently contradictory to that found for the other two groups of tests and may possibly be due to the high tempera- tures and high concentrations which would tend to cause a physical change in the cellulose with in- crease of the cementing effect mentioned previously. Curves showing the influence of cooking conditions on the strength of pulp are given in figure 8. PDS.PER 0.001 IN. 7) .20 .30 .40 POUNDS NaH PER POUND OF WOOD EASE OF BLEACHING. The chief purposes of bleach- ing are (1) to produce a white pulp and (2) to destroy any non- cellulose materials which tend to make the pulp less durable. PDS. PER 0.001 IN. t=) = oe io i) 4. 6 The more nearly the original (BEC Pacaclitie Wins puRatio pulp approaches to pure cellu- lose the less is bleaching re- quired. However, difficulty of bleachingis occasioned not only by the presence of igneous mat- ters, but also by coloring mat- ters absorbed in the cell walls OF “io mranrateoieiog Tol 1z0 from the “black liquors” and MAX. PRESSURE—PDS. PER SA. Ii. by the residual cooking chem- icals which the leaching and PDS. PER 0.001 IN. z washing treatments have failed § to remove. In the latter case id a certain amount of bleach is & neutralized by reactions with Fd 0 the other chemicals. fs CONCENTRATION NsOH— GRAMS PER LITER Curves expressing the effects Fie. 8.—Effects of cooking conditions on the strength of varying the cooking condi- of pulp. tions on the ease of bleaching, as measured by the amount of bleach required to bring the pulps to a standard white color, are shown in figure 9. These curves show that under the conditions of cooking the residual ligneous matters are the most important factor in determin- ing the amount of bleach required, since the more thorough cooking pro- duces pulps that are more easily bleached. The decrease in amount of 22 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. bleach required was very rapid up to the point where shives were eliminated; beyond this point the effect was less marked. It must not be assumed, however, that the shives alone necessitated the larger amounts of bleach. The presence of shives indicates an incomplete cooking reaction and implies that considerable ligneous matter may remain in the other (completely separated) fibers. The effect of severity of the cooking conditions is especially noticeable in the curves for the tests varying the amount of caustic soda and the duration n) of cooking, since certain of the 10 20 .30 AO : POUNDS NaOH PER POUND OF WOOD pulps produced in these tests were less thoroughly cooked than any of those from the other groups. LOSS ON BLEACHING. The curves showing the losses on bleaching as affected by the varying cooking condi- tions are given in figure 10. As would be expected, the loss decreased with thoroughness 5 of cooking. In the tests vary- O07 MAX. PRESSURE™PDS. PER S0.(N. ing the amounts of chemical and the durations of cooking the rate of decrease in bleach- ing loss with greater severity of cooking was fairly constant, 0 but it is probable that if the bog oe ee pemrgeepiy Sane ie ee cooking conditions were ex- Fig. 9.—Effects of cooking conditions on the ease of tended for higher values than se those used the curves would approach parallelism with the horizontal axis. Such an effect was obtained for the tests in which the cooking pressures were varied. It is not reasonable to believe that more severe cooking would result in pulps which would suffer no loss whatever on bleaching. The platted points for the tests in which the initial concentrations were varied are so few in number and so irregular in location that they give little indication of the influence of this factor. However, additional information is obtained from some earlier tests of the Forest Service, summarized in Table 4. PEAR CENT OF BLEACH REQUIRED PRODUCING SODA PULP FROM ASPEN, 93 TABLE 4.—E fect of concentration on bleaching losses (autoclave tests). Concentra-| Yield of F Cook : Yield of Bleach Loss on No. Hee ae screenings. | required. | bleaching. Grams per liter. Per cent. Per cent. Per cent. Per cent. 1 80 41.10 0.10 15.4 3. 92 2 50 44, 23 -03 14.7 4.08 4 30 46.97 .07 15.8 4. 68 1 Hach cook employed seven hours’ duration at 110 pounds pressure per square inch. The caustic soda charged amounted to 0.25 pound per pound of wood. For complete information see appendix, Table 15. These data indicate that increasing the concentration reduces the loss cn bleaching, hence the curve in figure 10 has been drawn to show such an effect. This is sub- stantiated by the fact that varying the amount of chemi- cal and the duration and _ pres- 4 sure of cooking in each case ac 20 =O eae showed a reduction in the bleaching losses as the severity of cooking increased, and that most of the other curves for the effect of concentration (especially the yield, shives, and bleach-required curves) show more severe cooking with the higher concentrations. The relatively large amount of loss in the case of cook 23 does not seem to be warranted in view of the well-cooked con- dition of the pulp. However, the comparatively high strength of the pulp indicates an abnor- eee mal condition. The loss in weight of a pulp during bleaching is due prima- rily to the removal of the col- ored ligneous matters and to PER CENT LOSS ON BLEACHING 80 90 i600 10 120 MAX. PRESSURE—PDS. PER SQ.1N. 0 40 50 60 70 80 90 100 to the partial destruction of the CONCENTRATION NaOH—GRAMS PER LITER cellulose itself. The latter is Fic. 10—2féects of ooking conditions on the bleach- especially liable to occur if the ing loss. bleaching treatments are severe, or if the cooking treatments have left the cellulose in an easily oxidized condition, so that it is either dis- | 24 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. solved during bleaching or broken up into small particles, which are removed in the washing operations. The partial removal of the min- eral or ash-forming constituents from the pulp may also occasion some loss. On the other hand, the ash in bleached pulp sometimes tends to increase over that for the unbleached pulp (due to an accumulation of lime compounds and other residues from the bleaching solution), and hence may offset the loss due to other causes. RELATION BETWEEN PROPERTIES AND YIELDS. Many of the curves expressing the effects of the varying cooking conditions on the properties of the unbleached pulps have bends or TEST VARYING ©AMOUNT OF CAUSTIC SODA ODURATION OF COOKING @PRESSURE OF COOKING @CONCENTRATION OF CAUSTIC SODA PRELIMINARY TEST BLEACH REQUIRED —PER CENT PEPER EH ane eee erek oe Cerca CRUDE iokee A Fig. 11.—Relation between yields and ease of bleaching. “breaks”? at or near the values for the cooking conditions which resulted in the highest yields of screened pulp. So general is this that, with decreasing severity of cooking, the occurrence of sudden changes of direction for curves expressing properties affords a reliable indication that the yield of screened unbleached pulp is near its maxi- mum. ‘This is especially evident in the curves for ease of bleaching. That properties of pulps are directly dependent upon yields is well illustrated when amounts of bleach required are platted against yields of total crude pulp, as in figure 11. Values for all of the cooks made in these experiments have been platted, irrespective of the testing PRODUCING SODA PULP FROM ASPEN. 25 conditions under which they were secured: It is evident that cooks which resulted in decreased yields produced easier bleaching pulps. For the higher values slight differences in yields are accompanied by marked differences in the ease of bleaching, but the effect rapidly diminishes until a large decrease in the yields affords little difference in the amounts of bleach required. This would be expected in view of the nature of the cooking reactions. The effect is first to remove the intercellular substances and part of the ligneous matters from the wood, then the cellulose itself begins to be attacked, and finally, after the greater part of igneous matters has been removed, the cellulose alone is affected. The ease of bleaching is a measure of the amount of noncellulose matters present in the pulp. Other properties of the pulps when similarly platted against yields show more or less definite relationships, but are apt to be modified according to the cooking condition varied. For instance, when vary- ing the amount of caustic soda or the duration of cooking, decreased yields were attended by decreased strength of pulp; when initial con- centrations or pressures were varied, the strength increased as the © yields decreased. Natural color, shives, and screenings, however, were little affected for yields below 54 per cent, no matter how pro- duced; for higher yields the color, shives, and screenings increased rapidly with increasing yields. The losses on bleaching followed fairly closely the amounts of bleach required, and hence decreased as the yields decreased. SIGNIFICANCE OF PROPERTIES. There are at present no accepted standards of quality or market grades of soda pulps. What may be sufficiently good quality for one purpose or one mill may be poor or medium quality for another. Aside from bulkiness and opacity, which depend mainly on condi- tions not studied in these experiments, the desirable properties of a pulp are, in general, as follows: (1) Low percentage of bleach required. (2) Low loss on bleaching. (3) High strength. (4) Durability (resistance to wear and decomposition). (5) Low ash content. (6) Few shives. (7) Absence of dirt. (8) Light color for the unbleached pulp. (9) Whiteness of the bleached pulp with freedom from certain undesirable tints. It is not often that any one pulp has the advantage over another in all of these properties, and for many uses some of them are of no importance. For aspen (poplar) or other short-fibered pulps used in the manufacture of book papers the properties which are given most 26 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. consideration are freedom from dirt and shives and low percentage of bleach required, with the attendant low loss on bleaching. Both undercooked and overcooked pulps are to be avoided. CONSUMPTION OF CAUSTIC SODA. By consumption of caustic soda is meant the neutralization of the free or active caustic soda (NaOH) existing as such in the digesting liquors. Theneutralization re- sults from the combination of the sodium (Na) of the alkali with the acid products derived from. the hydrolysis of the lignified fibers during cooking. The black liquors at the end of the cooking treatments con- tain in dissolved form these nonalkaline, sodium com- pounds, together with the re- maining free caustic soda. The effects of varying the cooking conditions on the con- sumption of caustic soda, ex- pressed in per cent of the amount charged or the effi- ciency in its use, are shown in figure 12. The actual con- sumption in pounds per 100 pounds of wood is shown in figure 13. As would naturally be ex- pected, the greatest compara- tive efficiency for the cooks made with varying quantities ry 50 60 70 80 90 100 Tio of caustic soda resulted from teeta neal cies ge bd AN the use of the smaller amounts. Pia. 12.—Eflects of cooking conditions on the effi- However, when very small ciency in the use of caustic soda. amounts were employed, the cooking reactions were not sufficiently complete,’ as indicated by the curves for yields and properties of the pulps. In this group of tests well-cooked pulps were first obtained with about 0.2 pound of NaOH per pound of wood. The efficiency in the use of the caustic at this point was about 85 per cent. IN THE USE OF NaOH — PER CENT EFFICIENCY 1See De Cew’s discussion, p. 6. 2Tt is a well-known chemical law that in order to carry a reaction to a given degree of completion for one of the reacting substances it isnecessary to have available a certain excess of the other chemical or chemicals which take part in the reaction. This means that the efficiency in the use of the chemical can not be 100 per cent. The speed of the reaction is proportional to the amount of the excess. PRODUCING SODA PULP FROM ASPEN. ail With increasing durations of cooking the efficiency in the use of caustic soda increased until it reached a constant maximum value. An efficiency of 95 per cent was obtained by seven hours’ cooking at maximum pressure, and, since no greater efficiency was secured by continuing the cooking four additional hours, it is apparent that this represents the maximum efficiency attainable. That the cooking reactions are not due entirely to the presence of active caustic soda is indicated by the fact that after the 95 per cent efficiency had been attained increased durations resulted in some further cooking effect (see curves for yields and prop- erties of pulps) with no increase in the amount of chemical con- sumed. Increasing the pres- sure also resulted in greater efficiency in the use of caustic soda until a maximum of 95 per cent was obtained. In all groups of tests in which a constant amount of caustic soda was charged into the di- gester for each cook, greater percentage efficiency in its use could mean only a greater actual consumption of the chemical. In the group of tests varying the amounts of caustic soda, the decrease in percentage efficiency was ac- companied also by increase in the actual consumption. It is thus apparent that the more thorough cooking, whether 40 20 30 40 POUNDS NaOH PER POUND OF WOOD ‘S070 80 90. 00 110” 20 MAX. PRESSURE—PDS. PER SQ.IN. NaOH CONSUMED PER 100 PDS. OF BONE DRY WOOD—PDS. 3 40°50 60 70 80 90 100 fio produced by increasing the CONCENTRATION NAOH—GRAMS PER LITER amount of chemical in the [fie. 13.—Eftects of cooking conditions on the amount c of caustic soda consumed. charge or the duration or the pressure of cooking, is, in large part at least, due to the greater com- pleteness of the reaction between the chemical and the wood. The tests employing various initial concentrations of caustic soda in the digester liquors (the amount of caustic soda charged remaining the same) seemingly do not bear out this conclusion. In most respects the determinations of yields and properties of the pulps in these tests indicated that the more concentrated solutions resulted in more thorough cooking, but no increase in the consumption of chemical occurred; in fact, with increase of concentration, a decrease 1 For the effect of water alone, see Tauss’s experiments, Table 1. 28 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. of consumption and subsequently decrease of percentage efficiency are indicated. While the possibility of error is not eliminated,’ this result indicates the need for further investigation. RELATION BETWEEN CAUSTIC SODA CONSUMED AND YIELDS. For the purpose of further studying the cooking effects of the various conditions employed, yields of total crude pulps from all of the cooks were platted against amounts of caustic soda consumed per 100 pounds of wood charged (fig. 14). The average curve drawn through these points indicates a definite relation between yields and TEST VARYING GCONCENTRATION OF CAUSTIC SODA CAMOUNT OF CAUSTIC SODA ODURATION OF COOKING ©PRESSURE OF COOKING PRELIMINARY TEST YIELD — TOTAL CRUDE PULP— PER CENT 10 2 4 6 20 22 24 (126 28 ae NaOH CONSUMED PER 100 PDS.OF BONE DRY WOOD—PDS. Fic. 14.—Relation between yields and amount of caustic soda consumed. amounts of caustic soda consumed, regardless of the cooking condi- tions. However, even if it is assumed that the location of some of the points is due to experimental errors, the relation, as regards individual cooks, can be only an approximate one, since it has already been pointed out that in some of the tests increased cooking effects were obtained without any increase in the consumption of caustic soda. If the curve were produced for lower amounts of caustic soda, the yields would probably be somewhere between 80 and 100 per cent at zero consumption, since under these conditions cooking could still be effected by water alone.’ 1 The test data show a loss of digester liquor overflowing through the “‘top relief” for cooks 25 and 26 (that for cook 26 showing the greatest loss), and it is due to the platted points for these two cooks that the curves indicate greater consumption of caustic soda at the lower concentrations. 2 See Tauss’s experiments, Table 1. PRODUCING SODA PULP FROM ASPEN, 29 Since the completion of these experiments Mr. E. Sutermeister has published ! the results of some tests in which a small rotary autoclave and copper flasks were used as cooking vessels. Yields varying from 93 to 24 per cent and consumptions of caustic soda varying from 0 to 29 pounds per 100 pounds of wood were obtained,? giving a relation similar to that indicated by the curve in figure 14. However, in his experiments a greater reduction of yields was obtained per unit decrease in the caustic soda consumed, which is probably due to differences in test material, method of experimentation, and appa- ratus employed. The actual consumption of caustic soda during cooking is a factor which is not given sufficient consideration in commercial practice, although it is one of considerable importance for an intelligent control of the cooking operations. By a careful study of the consumption, together with the other effects of the various cooking conditions, it is possible to determine the best operating conditions. That pulp mills do not ordinarily determine the consumption of caustic soda and the efficiency of its use is due to the length of time necessary for the analysis of the black liquors. While the method used in these experi- ments requires some time for carrying out the analysis, its occasional use in commercial operations would be of benefit in determining the conditions to be used in future cooks.’ If there were a rapid and accurate method of analysis such as is used in sulphite mill operations, it would assist in determining when the cooking had progressed far enough, at which time the digester could be blown. Production of undercooked or overcooked pulps would thus be avoided. SEVERITY OF COOKING AS INDICATED BY MICROSCOPIC APPEARANCE OF FIBERS. A good indication of the thoroughness or severity of cooking may be obtaimed by microscopic examinations of the pulp fibers.* The effects of varying the cooking conditions are shown in figure 15; curve A represents the relative abundance of vessels in the pulps; curve B, the ray cells; curve C, the fiber bundles or shives; curve D, the prominence of the vessel markings; and curve E, the apparent strength of fiber walls. Since there are no absolute units for measur- ing these effects, the ordinates as shown for each curve represent arbitrary units ranging from 0 to 10. The photomicrographs in Plates II to VII, inclusive, present some of the more pronounced 1 Paper, p. 15, No. 2, vol. 9, Sept. 25, 1912. 2 Tn obtaining yields higher than 75 per cent the test material was treated at atmospheric pressure. Under this condition the cooking effect of water alone would have but little influence unless long durations of treatment were used. 3 The boiling of rags with caustic-soda solutions for the production of rag pulps is controlled in this manner. 4 For the normal appearance of fibers in the uncooked wood see Plates VIII and LX, as well as the discus- sion on p. 42. 30 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. effects.'_ While various gradations resulted,’ the experimental pulps may be classified in the following three groups: Overcooked pulps.—Severe digestion treatments resulted in ‘‘over- cooked” pulps, examples of which are seen in Plates II and III. The walls of the fibers show a considerable degree of weakness, as indicated by their thin transparent appearance and by their much twisted and fractured condition. The relative number of vessels present in the pulp is low as compared with the normal number present in the wood, and the pits and other markings on them are only dimly visible. Many of the vessels remaining are $$ > 7 FRR oe 40 60 70 90 100 80 110 Oe 4 6 8 10F J l2 50 DURATION AT MAX. PRESSURE—HOURS CONCENTRATION NaOH--GRAMS PER LITER Fic. 15.—Effects of cooking conditions on pulp fibers. A, abundance of wood vessels; B, ray cells; C, fiber bundles, or shives; D, prominence of vessel markings; and E, apparent strength of fiber walls. ragged and partly disintegrated; and the pulp, for the most part, is also characterized by an absence of the comparatively thin-walled, delicate ray cells. Fiber bundles also are absent, since these are made up of fibers bound together by groups of the brick-shaped ray or parenchyma cell. The indistinctness of the vessels and fibers is due chiefly to the removal of the ligneous infiltrations of the cell walls, in consequence of which the elements developed very little color from the particular stain used in making the microscopic mounts. Well-cooked pulps.—Pulps produced under less severe conditions are made up of stronger fibers, such as shown in Plates IV and V. shown in the photomicrographs alone. 2 The photomicrographs, in the order of their sequence, show gradations of severity of cooking. PRODUCING SODA PULP FROM ASPEN. 31 The milder treatments are apparent in the increasing number of ray cells and vessels, the latter being well preserved and showing their markings quite clearly. The fibers are twisted or broken to only asmall extent, and yet are so well separated that there are no fiber bundles. Undercooked pulps.—Plates VI and VII illustrate the character- istics of undercooked pulps, and show plainly the mildness of the digestion treatments employed in their production. Well-preserved vessels with sharply defined markings are clearly visible, ray cells are numerous, and the walls of the fibers are less dissolved away than in the more thoroughly cooked pulps. Coincident with these characteristics there are also present many fiber bundles or shives; noticeable even when the microscopic slides are examined with the naked eye. Undercooked fibers develop a deep color from the particu- lar stain used in mounting, and on this account appear very distinct. Of the several groups of tests, the one varying the amounts of caustic soda per pound of wood resulted in the greatest range of severity of cooking as determined by the microscopic appearance of the pulp fibers. A small amount of chemical resulted in an under- cooked pulp. With increases in the amount the strength of cell walls gradually decreased, the wood vessels suffered gradual destruc- tion, and their markings were dimmed. The ray cells and fiber bundles disappeared soon after the poimt was reached where the maximum yield was attained. The higher amounts of caustic gave the overcooked effects. For varying durations of cooking the effect was practically the same, and undercooked pulps were obtained at the shortest duration used. However, the highest durations employed did not give as severely cooked pulps as were obtained with large amounts of chem- ical. While all of the tests varying the cooking pressures resulted in fairly well cooked pulps, there was a tendency toward undercooking at the lowest pressure used. ‘The tests varying the initial concentra- tions also resulted in well-cooked pulps, except for the highest con- centration, where a slight overcooking effect was observed. INFLUENCE OF COOKING CONDITIONS ON COST. While it is not feasible from the data’at hand to discuss all cost factors affecting the commercial production of pulps, the more direct effects of the cooking conditions employed can be shown. The actual effects on the cost of production, of course, depend upon various other operating conditions at any particular mill, but the general trend of the effects is the same, irrespective of local conditions. TIME. Shorter durations of cooking result in more efficient use of the digesting apparatus; more cooks can be made per day or per week, 32 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. and, as has been shown, yields of pulp per unit of wood are also increased, and consequently more pulp is secured per cook. The greater plant capacity thus obtained would result in a proportionate decrease of operating costs per ton of pulp. Figure 16 shows the production of pulp per 24 hours continuous operation for each 100 pounds of wood capacity of digester as influ- enced by various durations of cooking. The curve was derived from the experimental data, assuming a one-hour period for blowing the digester after completing a cook and for charging the next cook, and a similar period for BRSS Eee Peeves REDRESS LER ERR 250 oe attaining maximum cooking pressure. Fathead Nex [etal Cie ee) .Thussfora tireesh th VaR eesaeioes See eee : CCCONCEECELEELEELELEEELELe|) period at maximum e CPE NT TTT TTT rrr rrr rt pressure, the total ee eee a), = , = CLLCERLELELEELEL ELLE) 6time between the ¢ COOPON EE charging of two con- Ita aac sana sceenes SO EEEEEEE RCE SCE eel oa eee 2 CCC NECEECEELEEELLLE] Bours. Computation » LLTTITTTTTENITTT TTT tt) shows that decreas- g HH ing the duration at 3 wot maximum pressure Ei ep from eight to five ~- hours increases the WEE daily output 48 per 25 By HE iS 8 9 10 HW 2 B cent, while a decrease peat : MAX. PRESSURE—HOURS from ten to three hours increases the output 156 per cent. If the time allowed for blowing and charging the digesters and for raising the digester pressure is decreased, the increase in the daily output will be even more pronounced as the duration of cooking is shortened. Fig. 16.—Effect of duration of cooking on production in 24 hours. STEAM CONSUMPTION. While the consumption of steam varies with the duration of cook- ing, it is influenced also by the pressure maintained in the digester and more by the relative volumes of the liquor charge. Under the testing conditions employed, the volume of liquor varied both with the amount of caustic soda charged (the concentration being constant) and with the concentration (the amount of chemical being constant). Since the heating was accomplished by steam blown directly into the digester, a measure of the amount of steam used is afforded by the increase in the volume of liquor during cooking.’ The effects of the 1 The steam used was not perfectly dry, containing a small amount ot moisture or ‘‘priming.’”? How- ever, as the steam was of approximately the same moisture content for all tests, the “condensation”’ was proportional to the amount of steam used. Bul. 80, U. S. Dept. of Agriculture. Si || Y si a) Me cm mo ne uf AN! ee sae se a Roe ‘Yi hi fe x a i FIBERS OF AN OVER-COOKED PULP PRODUCED WITH A LARGE AMOUNT OF CAUSTIC Sopa. (Cook 4.) MAGNIFIED 65 DIAMETERS. Partial disintegration has taken place. The fibers are fragmentary and contorted with rather weak cell walls. The vessels with barely visible markings are on the point of being eliminated. ETO NWSE PX re a aR. 7. SZ meee aS Be “= gown bel Ns PLATE III. Bul. 80, U. S. Dept. of Agriculture. ee aN (Cook 23.) MAGNIFIED 65 DIAMETERS. FIBERS OF AN OVER-COOKED PULP PRODUCED WITH A HIGH CONCENTRATION OF CAUSTIC SODA. The fibers are somewhat fragmentary. Bul. 80, U. S. Dept. of Agriculture. : PLATE IV. : ae NL LAT& iw i j Xf SS‘ SASS 3 FIBERS OF A WELL-COOKED PULP PRODUCED WITH A MEDIUM AMOUNT OF CAUSTIC SopA. (Cook 7.) MAGNIFIED 65 DIAMETERS. ; This isa pulp of average good quality. Vessels are well defined. Bul. 80, U. S. Dept. of Agriculture. PLATE V i, Te AN j y LEN Wl? be ng a) i Bs fi 4 ‘Ze iz = .* . Os / pS aA K ee 5 See NALA \ - Re EO RY, a ae rs Ww ys a on FIBERS OF A WELL-COOKED PULP PRODUCED WITH A HIGH PRESSURE OF COOKING. (Cook 17.) MAGNIFIED 65 DIAMETERS. This is a strong, well-separated pulp. Bul. 80, U. S. Dept. of Agriculture. PLATE VI. FIBERS OF AN UNDER-COOKED PULP PRODUCED WITH A SHORT DURATION OF COOKING. (Cook 16.) MAGNIFIED 65 DIAMETERS. Many shives, consisting of two or more unseparated fibers which parallel each other, are present. Bul. 80, U. S. Dept. of Agriculture. PLATE VII. \ ‘ , 4 wa N\ —e A's ws SS i /) FIBERS OF AN UNDER-COOKED PULP PRODUCED WITH A SMALL AMOUNT OF CAUSTIC SODA. (Cook 9.) MAGNIFIED 65 DIAMETERS. Note the vessels with well-defined markings and the ray cells holding together a group of fibers constituting a shive. ~ PRODUCING SODA PULP FROM ASPEN. 83 cooking conditions on the resultant condensations are shown in figure 17. Curves showing the initial volumes of digester liquors for two of the groups of tests are also included in the same figure. In the tests employing various proportions of caustic soda, the amount of liquor at the start of cook varied directly with the amount of chemical, as shown by the straight-line curve. The condensation also increased rapidly as the amounts were increased. The down- ward turn in the heavy-line curve for the higher proportions of caustic is caused by the digester becoming filled and overflowing through the top relief during the final stages of cooking. However, the dotted GALS. OF LIQUOR PER PD. OF CHIPS GALS. OF LIQUOR) PER PD. OF CHIPS = ry 40 50 -60 70 80 90 100 110 CONCENTRATION NaQH—GRAMS PER LITER —_ ry —_ . GALS. OF CONDENSED STEAM PER PD. OF CHIPS (GALS. OF CONDENSED STEAM PER PD. OF CHIPS ae ce 2 4 6 8 0 DURATION AT MAX. PRESSURE= HOURS AX, PRESSURE —PDS. PER SQ. IH, Fic. 17.—Effects of cooking conditions on initial volume of digester liquors and on condensation of steam. line shows the corrected curve, taking the overflow into consideration. The rapid increase in the condensation is a natural consequence of increasing the amount of cooking liquor, which has a high specific heat. ; ' In the tests employing various cooking periods the main influence on steam consumption was the heat lost by radiation, since the initial volumes of digester liquors were constant. The curve in figure 17 representing this effect has been drawn as a straight line to show only the general trend. It will be observed, however, that the platted points occur in two distinct groups. That the reaction between wood and caustic soda is of an exothermic or heat-generating nature may partly explain this arrangement. In the one group, representing the cooks of longer duration, the cooking reaction was 31091°—Bull. 80—14——3 34 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. practically completed before the end of the cooking period (see analogous curves in figs. 12 and 13). This would result in relatively higher amounts of condensation, since no heat of reaction would be generated during the later stages of cooking.1 The same explanation could apply to the cooks made at the higher pressures. The influence of higher cooking pressures on steam consumption results from the greater amount of steam required to heat the digester and its contents to the higher temperatures and the greater loss of heat by radiation at such temperatures. The initial volumes of cooking liquor did not vary. The condensation curve indicates that this effect was comparatively small.in the tests. Like the tests varying the amount of caustic soda, those varying the initial concentration influence the steam consumption principally by the amount of liquor in the charge, which varies as shown by the true hyperbolic curve in figure 17. Hence, increasing the initial concentration decreased the condensation, as shown by the corrected curve in figure 17, which takes into account the overflow of the digester in cooks 25 and 26. In considering these results from a commercial standpoint it should be kept in mind that the experimental apparatus was comparatively small. On this account the heat or steam required for raising the temperature of the digester and for replacing heat lost by radiation per unit of digester capacity was far greater than would be experienced in mill operation. Hence, much less.steam per pound of chips would be required in commercial operations than is shown by these curves. The effects of increased duration of cooking and increased pressures especially would be much less pronounced, since with these radiation is the more important factor. Aside from the direct cost of steam, the condensation is of impor- tance in another way. The tests have shown that decreased initial concentrations, other cooking conditions being constant, result in less severe cooking. It is to be expected that the decrease of concentra- tion throughout the cooking period, due to condensation, also tends to minimize the cooking effects in a similar manner.’ The use of superheated steam in cooking, the installation of larger digesters, the insulation or lagging of digesters, and the use of the minimum volume of cooking liquors at the start of cook are means frequently employed by pulp mills to reduce the condensation. 1 The condensation curve (liquor in digester—gallons) in fig. 3, which is typical for most of the individ- ual cooks in these experiments, also shows a greater rate of condensation at the end of the cook than at earlier periods except during the first hour when the pressure was being increased. Thiscan be accounted for only by the fact that heat, other than from the steam alone, was supplied to the digester during the earlier stages of cooking. As the cooking reaction is most vigorous at the beginning, it seems probable that the heat supplied was heat of reaction. 2 It is evident that the effects obtained in the tests varying the initial concentrations are much less pro- nounced than would have been the case if the diluting effect of condensation had been absent. The auto- clave tests, for which data are given in Table 15, afford fairly conclusive proof of this. PRODUCING SODA PULP FROM ASPEN, aD) CHEMICALS PER TON OF PULP. The chemicals directly employed in the manufacture of soda pulp affect cost of production, in that the full amount of alkali charged to the digester can not be recovered, while the bleaching powder after being used is of no further value. The curves in figures 18 and 19, expressing the effects of the cooking conditions on the amounts of chemicals em- ployed per ton of air-dry, bleached pulp, were derived from the experimental data as explained on page 48, ap- pendix. The amounts shown are less than those generally employed incommercial prac- tice, for several reasons: (1) The yields of pulp are higher; (2) the losses on bleaching are less; (3) the amounts of chemical charged per pound of wood are less; and (4) the amounts of bleach required are less. Whether or not pulp mills can duplicate or approach these results, the general trend of the curves would not be affected. SODA ASH. The amounts of caustic soda and sodium carbonate charged to the digester in the several groups of tests have been calculated to show the equivalent amounts of com- mercial soda ash (58 per cent Na,O) per ton of bleached pulp produced. (Fig. 18.) Increasing the amounts of 2200 2000 1800 10 -20 30 4 POUNDS NaOH PER POUND OF 0 2 4 6 8 10 12 DURATION AT MAX. PRESSURE—HOURS SODA ASH—POUNDS PER TON OF BLEACHED PULP 40 50 60 70 8&0 90 .00 110 CONCENTRATION NaOH—GRAMS PER LITER Fig. 18.—Effects of cooking conditions on amount of soda ash employed per ton of pulp. caustic soda charged per pound of wood obviously results in increas- ing amounts of soda ash per ton of pulp, and the decreased yields of pulp resulting from the more thorough cooking make the effect more pronounced. A bend is found in the curve at the point of maximum yield, since for amounts of caustic below this point the yields decrease rapidly and their influence on the amount of soda ash employed per ton of pulp becomes more apparent. 86 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. When varying the durations and the pressures of cooking and the initial concentrations, the amounts of soda ash per ton of pulp were affected by yields alone, and the mmimum amount is employed under conditions which give the maximum yields. Increased durations, pressures, and concentrations afford decreased yields, and SEE SeeeR ee. 8 =i A ay FE (Pe i increased. The platted point i for cook 10 is not on, the curve, ae Fass. fala RRP due to the initial digester = Fae oe a a liquors for this cook havin ° 4 q s w 100, a aa SS had about 3 per cent lower a POUNDS NaOH PER POUND OF WOOD causticity than the other cooks us in this group of tests. Lower 130 causticities involve the use of 25 a greater amount of soda ash cS for the same amount of caustic ws 300 soda. = 200 BLEACHING POWDER. > Oe a ee The curves in figure 19 show ; that increasing the amounts * and concentrations of caustic 2 soda and the durations and ° pressures of cooking result in zs all cases in decreasing the = amounts of bleaching powder > oo consumed. | = bilen dene Oe Ma Sa. IN. Yields do not influence the a calculations, since the con- om sumption per ton of bleached anes TSS] me tee onthe pe 100 ; 1 Ve eC eT of bleach required and the CONCENTRATION NaOH—GRAMS PER LITER bleaching losses. The ordi- Fic. 19.—Effects of cooking conditions on amount of jpates for the curves represent bleaching powder employed per ton of pulp. 5 - bleaching powder of 35 per cent available chlorine, and losses in making the bleaching solutions are disregarded. COMBINED COST OF WOOD AND CHEMICALS PER TON OF PULP. The curves in figure 20 show costs for certain items in producing a ton of bleached pulp (2,000 pounds air-dry basis) as influenced by variations in the cooking conditions. Curves marked A represent cost of wood alone; curves B, cost of wood and soda ash; and curves C, PRODUCING SODA PULP FROM ASPEN, ot cost of wood, soda ash,and bleaching powder. The vertical distances between curves A and B represent cost of soda ash alone, and those between curves B and C represent cost of bleaching powder alone. The cost values were obtaimed by calculations from the amounts of wood, soda ash, and bleaching powder consumed, based on the experimental results.t A 90 per cent recovery of the cooking chem- icals charged to the digester was assumed in determining the amounts COSTS PER TON OF PULP —— DOLLARS COSTS PER TON OF PULP — DOLLARS "60 7 8680690 6100 10 120 "40 50 66 70 80 90 100 110 MAX. PRESSURE—PDS. PER SQ IN. CONCENTRATION NaOH—GRAMS PER LITER Fig. 20.—Effects of cooking conditions on cost items per ton of pulp. A, wood; B, wood and soda ash; and C, wood, soda ash, and bleaching powder. of soda ash consumed or Jost per ton of pulp. The basic units for costs are assumed average values as follows: Wood, $9 per solid cord (100 cu. ft.); soda ash (58 per cent Na,O), $1 per 100 pounds; bleaching powder (35 per cent available chlorine), $1.55 per 100 pounds.” The bone-dry weight of aspen wood is taken as 26.68 pounds per cubic foot of clear wood, green volume. 1 These amounts were calculated by interpolating from the yield curves (fig. 4), the loss on bleaching curves (fig. 10), and thecurves for soda ash and bleaching powder employed per ton of pulp (figs. 18 and 19), and not from actual test data. On this account platted points have been omitted. 2 Reasonable maximum, average, and minimum values for a “‘solid cord”’ of aspen f. o. b. mill are $11, $9, and $6, as determined from statistical reports received from a number of mills. Correspondence with pulp manufacturers brought the information that reasonable maximum, average, and minimum unit costs as defined above may be assumed with a fair degree of accuracy as follows: For soda ash, $1.20, $1, and $0.85; for bleaching powder, $2.05, $1.55, and $1.10. ‘These values do not depend upon market fluctua- tions alone, but vary through the range given, due largely to differences in freight charges ior mills in different localities. The actual selling price of ‘‘58 per cent” soda ash is 10/48 greater than the manufac- turer’s or market quotations, since the latter are based on the old standard of ‘48 per cent” soda ash. 38 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTUPE. With increasing amounts of caustic soda in the digester charges the cost due to all three factors is decreased until the point of maxi- mum yield of good pulp is attained, after which the total costs increase, due to the increasing amounts of wood and of soda ash consumed. The decreasing cost of bleaching powder only partially offsets the increase due to the other two factors. With increasing durations the effect is practically the same, so far as wood alone is concerned, except that the increase in its cost for higher durations is not so pronounced as with increasing the amounts of caustic soda. The soda-ash costs alone are practically constant, and hence increase the wood costs by a constant amount. However, as the durations increase, the bleaching-powder costs decreased suffi- ciently to overcome the effect of increasing wood costs. After the minimum duration for successful cooking (as determined by yields) has been exceeded, the decrease in total cost is very small, and would not be sufficient to offset increased costs incident to the time element discussed previously. For variations in the pressures of cooking, the influence of bleaching- powder costs is especially marked. The minimum costs due to wood and soda ash result from the use of the lower pressures. When bleaching is considered, the minimum cost is obtained by using medium pressures, although the increases for the higher pressures are very small. : Combined costs for the three factors are practically unaffected by variations in the initial concentrations, but if bleaching is omitted the costs of wood and soda ash are larger with the higher concentrations. All of the diagrams show that of the three cost factors considered, wood is of the most importance and that bleaching powder is more influential than soda ash in determining total costs. Increases in costs of wood and soda ash with increasing severity of cooking are, in allcases, offset, to a greater or less extent, by decreases in, bleaching- powder costs. If maximum or mmimum values‘ had been used for either wood, soda ash, or bleaching powder, instead of the average value, or if a different percentage recovery for the soda ash had been assumed, the general effects would not be changed, although they might become more or less pronounced. SUMMARY. ? (1) The amount of caustic soda per pound of wood, the duration of cooking, the pressure or temperature of cooking, and the concen- tration of the cooking chemicals employed in the production of soda 1 See footnote, p. 37. 2 The more general statements in the summary will be found to coincide in a greater or less degree with previously existing opinions, a fact not surprising when it is remembered that the soda process has been carried on for half a century. On the other hand, satisfactory evidence and data substantiating these opinions have not been available. The present investigation affords such information, as well as a basis for more specific conclusions. PRODUCING SODA PULP FROM ASPEN. 39 pulp influence the yield and properties of the pulp by influencing the severity of the cooking reactions. (2) Severity of cooking is an effect mainly of the amount of caustic soda consumed per unit of wood. Increasing the amount or concen- tration of the chemical or the pressure of cooking produces a quicker reaction and hence one more complete in a given length of time. Increasing the duration results in a more complete reaction because of the longer time allowed for the available caustic soda to be con- sumed. (3) Greater severity of cooking is accompanied by a decrease in the yield of crude pulp, and usually of screened pulp. If screenings are present in considerable quantity (due to incomplete cooking), more thorough cooking increases the yield of screened pulp. (4) The properties of the pulp are influenced by greater severity of cooking as follows: (a) Shives are decreased in number or eliminated. (6) Bleaching is rendered more easy and the loss on bleaching becomes less. (c) The strength may either decrease or increase, depending upon which cooking condition is varied and the degree of variation. (d) The color of the unbleached pulp becomes lighter within certain limits, beyond which it may, under certain conditions, become darker. (5) A good indication of the severity of cooking is the appearance of the individual fibers when examined under the microscope. (6) The decreased yields resultmg from more severe cooking result in a greater cost of wood and soda ash per ton of pulp. As a rule, the smaller cost of bleaching powder incident to the more easily bleached pulp produced by thorough cooking only partially offsets the greater cost of wood and soda ash. (7) While the amount of bleach required decreases with increasing severity of cooking, a point is soon reached where the decrease in bleach required is not commensurate with the decrease in yields. (8) Increasing the initial amount of digester liquor increases the condensation and steam consumption (and hence the cost) because of the greater volume to be heated; increasing either the duration or pressure has a similar effect because of the greater losses of heat by radiation. (9) Yields (bone-dry basis) of well-separated unbleached pulps as high as 56 or 58 pounds per 100 pounds of wood can be obtamed from aspen if the wood is of the best quality. Yields of from 54 to 55 per cent were obtained which required only from 10 to 11 per cent of bleach. The variation in yields obtained by changing the cooking conditions was from 46 to 58 pounds per 100 pounds of wood charged, or about 26 per cent based on the lowest yield. (10) Minimum total durations of from 3 to 4 hours may be success- fully applied to the cooking of aspen for bleaching pulps, provided the other cooking conditions are properly maintained. 40 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. (11) Aspen may be successfully cooked with a minimum of from 20 to 25 pounds of caustic soda charged per 100 pounds of wood. The amount of this chemical actually consumed in the production of well-cooked bleaching pulps varies from 18 to 24 pounds per 100 pounds of wood. PRACTICAL VALUE OF RESULTS. The experiments discussed in this bulletin have shown in detail the effects of certain cooking conditions on the yields and properties of the resultant pulp, on the efficiency of the cooking chemicals, and on various items affecting costs of production. From a study of these results it should be possible for a mill operator so to regulate the cooking process as to secure the largest possible yield of pulp of the desired quality at a minimum cost for chemicals, fuel, labor, and overhead charges in so far as the operation is affected by the cooking conditions considered. The clear, sound wood used in the experiments afforded yields of good pulp from 10 to 25 per cent higher than the better run of the yields reported by pulp mills. Moreover, some of these experimental yields were obtained with shorter cooking periods and less chemicals than are employed commercially. Although the laboratory results may not be equaled in mill practice, the possibility of greatly increased efficiency in the process of converting wood into soda pulp is indicated. APPENDIX. ASPEN AS A RAW MATERIAL FOR PAPER PULP. DISTRIBUTION AND CHARACTERISTICS OF THE TREE.! Aspen (Populus tremuloides Michx.), or quaking aspen, as it is sometimes called, is one of the most widely distributed and best-known American trees. Together with the closely related European species, Populus tremula Linn., from which paper pulp of excellent quality is also prepared, it encircles almost the entire globe. In America aspen extends from Labrador to Alaska and southward to Tennessee and Arizona. Yet it occurs scatteringly, and pure stands of any extent are comparatively rare. For this reason it is not possible to give even approximately the present total stand. In the western forests, notably those of Utah and western Colorado, there are vast quantities which will doubtless be an important source of future supply. In the past New Eng- land furnished most of the aspen pulpwood, and although the supply there is badly depleted, considerable quantities yet remain in certain regions, notably in northern Maine.? Aspen is a very rapid grower and quickly covers burned or logged-over lands. How- ever, it is comparatively short-lived, and the larger trees suffer severely from fire, windshake, insects, and fungi. In fact, aspen is defective from decay to a greater extent than any other commonly used pulpwood, except perhaps balsam fir. The trees ordinarily used for pulpwood are from 5 to 14 inches in diameter. If grown in close stands, the trunks are fairly free from knots and limbs. Logging is compara- tively easy. Aspen wood after cutting is also susceptible to fungous attack unless kept very dry. It is particularly perishable in contact with the soil. The ability of the wood to season rapidly, especially after being barked, is of much advantage. Nevertheless, mills which store a year’s supply or more in open yards undoubtedly have a large proportion of their older wood affected. The general opinion is that ‘‘old wood” produces infe- rior pulp and lower yields. PROPERTIES AND STRUCTURE OF THE WOOD. The wood of aspen is soft, light in weight, not strong, and close grained, but with numerous minute, open ducts. The medullary rays are very thin and hardly distin- guishable with thenaked eye. The color is light brown, the sapwood almost white and very thick, often representing 25 to 30 layers of annual growth. In the green or freshly seasoned material, however, the difference between heartwood and sapwood is in most cases scarcely appreciable. A cubic foot of air-dried wood usually weighs from 25 to 30 pounds. 1 A more complete discussion of the silvical characteristics of aspen is given in Forest Service Bulletin 93, The Aspens; Their Growth and Management, by W. G. Weigle and E. H. Frothingham, 1911. 2 Forest Service Bulletin 93, pp. 13 and 17, 1911. 41 42 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. Determinations ! made on sound sticks of aspen varying from 8 to 10 inches in diame- ter showed about 62.8 per cent of cellulose. Miller, quoted by Clapperton,? gives the following analysis * for the poplars: Per cent. Gellttlosets o-oo. 8s ole ds. See eee eee 62. 77 RESIS east eases eet nde cs soe ig ey) AQUEOUS OXUTACEe Ae oe cis nism cit Wane ga ce os ee 2. 88 Waiber or sot Ue ee Spay etn apy cage 12. 10 hiewin <6 soe Shag ene AS ee ae 20. 88 100. 00 Since bleached pulp is very nearly pure cellulose, the maximum yield obtainable could not be appreciably higher than 63 per cent. Aspen wood is made up of three types of structural elements—fibers, vessels, and parenchymatous tissue. The latter comprises the medullary ray cells and the rather scantily developed parenchyma cells at the end of the year’s growth. The structure is shown in Plates VIII and IX. In Plate VIII, figure 1, the long tubes running the length of the picture are the vessels; cross sections of the medullary rays can be seen scattered among the fibers as dark vertical ‘‘plates,’’ one cell in width and several in height. The ray cells are characterized by exceedingly thin walls, and when the wood is cooked for pulp these cells readily dissolve. The vessels are more resistant to chemical attack than the parenchymatous tissue, and the fibers, because of their relatively thick walls, are least affected by the cooking process. It is also possible that the cellulose constituting the fiber walls is more resistant than the cellulose of the other elements. In Plate IX, figure 2, the middle lamella or intercellular sub- stance appears as a black line between the adjacent walls of the elements. This is dissolved in the process of cooking for paper pulp. Aspen fibers are comparatively short. Examples of long-fibered woods used in paper making are spruce, hemlock, and balsam fir, and of medium-length ones tulip tree, sweet gum, and cottonwood. The actual dimensions of aspen fibers vary a great deal with the tree and the part of the tree from which secured. Forest Service measurements * of a large number of fibers of aspen wood showed a range of from about 0.5 to 1.6 mm. in length and an average length of 1.0 mm.°® PULPWOOD CONSUMED. At the present time soda, sulphite, sulphate, and mechanical pulps are made from aspen and other poplars, but the soda process has always used these woods in by far the greater amounts, and they continue to form the chief pulpwood supply for this process. The other processes of pulp making have been applied to the poplars within recent years only, although it was known 20 or 30 years ago that they could be ground for mechanical pulp and could be reduced without difficulty by the sulphite process to an easy-bleaching pulp. The properties of the wood and the yields and qualities of the pulp made from it, combined with the proximity of an adequate supply and its relatively low cost, made this the best wood obtainable for the manufacture of soft, easy-bleaching soda pulp. 1 Forest Service Bulletin 93, p. 7, 1911. 2 Practical Papermaking, p. 43, 1907. 3 This analysis makes no mention of the ash. According to Sargent (Tenth U.S. Census Rept., Vol. IX) the ash in aspen varies from 0.31 to 0.76 per cent, with an average of 0.55 per cent, of the air-dry wood. See this report also for further data on the chemical composition and properties of aspen. 4 Forest Service Bulletin 93, p. 7, 1911. 5 One millimeter is equivalent to approximately one twenty-fifth of an inch. PRODUCING SODA PULP FROM ASPEN. 43 TaBLE 5.—Consumption of poplar pulpwood and of all pulpwoods in the United States for years 1899 and 1905 to 1910, inclusive. Ratio Ratio Domestic|Imported| Total | All pulp- | domestic ee Year and process. poplar. | poplar. | poplar. | woods, poelat to all “il pulp- poy at. woods. 1910. Cords. Cords. Cords. Cords. Per cent. | Per cent. Mech amicaleer tte eos oe aceite 11, 613 1, 834 13,447 | 1,180,598 86.4 1.1 Sellar. ck GUS en a a tha 2703) eeeeaenes 2703 | 8 2,257, 881 100.0 .03 SEB a ye al he Le ee at 303,401 | 43,525 | 346,926 655, 827 87.5 53.0 A 315,717 | 45,359 | 361,076 | 4,094,306 87.4 8.8 1909.1 | INTEC HMIAT CAR eI La) sek See elcle ce Scte's 2158 17, 905 3, 025 20,930 | 1,246, 121 85.6 1.7 (ipUIAUTMIID = le yy oe Sele a a aa PORNO Non eae 2,930 | 42, 183, 984 100.0 oi SCE. w cone Leese Na epee 282,041 | 22,597 | 304,638 571, 502 92.6 53.3 302,876 | 25,622! 328,448 | 4,001,607 | 92.2 8.2 1908.1 | ie IMecharicalenes. Mea Wav eto. Sota ly 16, 734 2,168 | 18,902} 1,117,428 88.0 1.7 Sul nate meet soe eR ee Ea sr a 3, 734 3, 023 6,757 | 1, 739, 282 55.3 4 rh ASO RD: ic ates COLD aa Ie a a 259,096 | 17,462) 276,558 490, 243 93.6 56.4 ’ 279,564 | 22,653 | 302,217] 3,346,953 92.5 0 16, 903 2, 620 19,523 | 1,361,302 86.5 1.4 GRO We odsecocac 1,536 | 2,059, 496 100.0 | odl 333, 703 17,178 | 350,881 541, 862 95.0 64.7 352, 142 19,798 | 371,940 | 3,962,660 94.7 9.4 2,129} 12,604 | 1,197,780 82.8 et Sra debond inet icin alana a: 1,958,619 |.......... .0 15,421 | 315,866 504, 777 95.1 56.5 310, 920 17,550 | 328,470 | 3,661,176 94.6 9.0 1905.6 i beg Mechanicalee a ieees secs. see Ost aca 8,592 2, 800 11,392 | 1,096, 794 75.4 1.0 STATON UG pate et Sie oye ae ees eres Diep Sere CEN an iS 1,630, 393 |...-..---- 0 SS CCL Camere SL lee LO SN iii reeneeveiel 290, 583 20,083 | 310, 666 464, 936 93.5 66.8 299,175 22,883 | 322,058 | 3,192,123 92.9 10.1 1899.7 . ; Ota emia ses hee cine re cents cee Seas 8 236, 820 | § 20,133 | 8 256, 953 1, 986, 310 92.3 12.9 1 Bureau of the Census Circulars, Forest Products No. 1, Pulpwood Consumption (for respective years). 2 Includes 78 cords reduced by the sulphate process. 3 Includes 10,188 cords reduced by the sulphate process. 4 Includes 38,000 cords reduced by the sulphate process. 5 Forest Service Circular 120, Consumption of Pulpwood in 1906. 6 Forest Service Circular 44, Wood used for Pulp in 1905. 7 Twelfth Census Bulletin 99, Manufactures: Paper and Pulp, Sept. 30, 1901. 8 Used exclusively by the soda process. 44 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. TABLE 6.—Cost of poplar pulpwood and of all pulpwoods at United States mills in 1907, 1908, and 1909.3 " Average Quantity. | Total cost. | cost per cord. 1909. Rough wood: Cords. Dollars. | Dollars. OMeSbIC POPAar lee rece eee Wa halnihe cane ction Rte oe ee eee 13, 953 72,555 5.20 Imported poplar ses ses oe ei ek 5 Sol ayia ai ee 2, 984 24, 469 8. 20 Total poplar 2 -cpesee Sock aise sh ss so ee es ek ee 16, 937 97,024 5.72 All pulp woods! 5. soccese- cers Set he ate Sees ee ee eee 2,219,083 | 17,608, 736 7.94 Peeled wood: : Domestic Poplars. coe mane ne ae nes ade RE oR OE eee eee 288,923 | 2,337, 461 8.09 Imported poplar z-: . 26st 565 sig soca Sao ee 22, 638 179, 019 7.91 Totall poplar aoe eedinc ccc beninac tee ee eee A ee 311,561 | 2,516, 480 8.07 All pulpwoods 323.52 2 A | SOE | OAT | 8e8 | OOT [OL |Z |O-% | 09's | eet) oe |Get |o26 Joe Jo JOR 166 | ELE | se 390 | T |edsoatumpord o S109 qT | Do o | SQT | SHH | “SLA | ‘SL 8qT SQT | “sqT | “SDD | 79 lad | ~£0}1) “aq “taj | “yuan | “SQT “OT6T = 2 Jad “Up \lad “wm p|lad “wWH| Lag Z ed noe ; (e) > we KS id > >| ie Z 5 fo) & 2. lan (=p lat a ® 2 p, LEN = na Se Q cs aah I é Bae acl agd> ees SH oe Peete eee Hogs | oe) | onset icmle cis Z aS A e 2 209 2 = Si ; | 3 a Ge" | we] BS | 86/28 | Ee 2 Bae eee 5 | as real SYIeUIE yy cee |] 8a 2 Qo | o8 | * 28 : Bes £ = Fe s1OG8 . geo] 88 |BE/ 8] gue gf 2B) [ocd ie m @ i B2e| & alee oR e ° “(siseq | gS S *SUOT} 21} Wed) [BIITH z 2 E E| 3 Tay YB | op ro) 5 ag f Arp-euoq) —- sq EE 2s Op Qt Oo is aq oe Enea | is o SS “2u1y009 jo spunod opt sed hae ae ge| fel § [7 | sonoma [Peer semen | Eg | asew sonbyr i ["s}so} Jo dno13 yove UI po} eSISOAUI UOTIPUOD SULYOOD o[qLIIVA Of} O}VOIPUT SOT[e}T UI SonsIq] psuoyipuos buryooo ppjuamrwadxy— OT ATA, 31091°—Bull. 80—14——-4 BULLETIN 80, U. S. DEPARTMENT QF AGRICULTURE. 50 “SUTYOOO JO Sosejs [eUy SULIMp oAyeA Jorjor do} YSnorq} Jonbry 194S9SIP JO MOBIOAO ¢ ; ; ‘sdjnd peyovetqun pue peyovetq oy} Jo Sueumtoeds Surejmod osTe mayen STL *ZI6T ‘sovjng *“q ATUeH Aq ‘spoo MA 4SeI10,q SnolmeA wo sding 1sdeg “( pereqtanuun ) UlJOTIN PIAJeg 4Seloq UI A[snorAeid peysqnd | teeq sey yoo sty} Joy B1Vp 04} JO Weg z : “as8YV9] 10}SeZIp Jo esnvoeq JONDT] 104SeStp Jo ssoy VOSS 1 \ (Caja 5) Xa a) ea FIO Ts} OIL OLT | SEE | OOL | O02 | F 08 | §86L | Fz 00°SG | 669° 8°16 L°6& GT T°0g &'8 | 0°68 | 82-udy | 92 spunod 08 48 UMOTA | SST aD ¢ | 9IT OLT | SEE | OOT | O 4 ye 0 8 | S8"6E | 92 60°S6 GGF * 8°16 ¢c¢ 1G 0°04 8 | e0°6e | eZ -idy | ozs OPT | SIE | OLE | Ste | OO |O'2 | F° | OB | esr | o2- | oO | ees: | sue |e |2e |r06 |2s | go-ce | F-ady | $e eho | PIT | OT | see | OOL | 0°2 | 7 OME | tae WS 4) Meera | exe 82 Calg ee OOIr |%'8 | c0-6s | Teadw | ez |-----aT dno G8" | AIT | Sot |} 91 | ol | 0% |F: | O'S | H66I | 6: | OO'Gs | cue |e26 |ze9 |oe |0:08 |¢°6 | 00-07 | + -ady | 2g 026 ‘ CII GOT | FEE | 08 0 ‘2 if : 0 38 6661 | 06 00°S6 | GLE 16 4°69 6% 0°08 £6 | 00°0F | ¢ “ady | tz 006 ‘1 PIL |¢°99T | TEE | 06 0 2 ¥ : 0 ‘8 | G6 ‘61 16" | 00°SG | SLE £726 69 6% 0°08 6°8 | 00°0F | 9 “idy | 0z G98" | PIT | OLE | 888] OOr |O'2 |%° | 08 | Z6Er | 16° | 00'GZ | ue: | eve [29 |6% 008 |06 | 00-oF | 2 dy | er G26" | LE |¢°€LT | HE | OFF | 69 | F° | 62 | GEE | 6° | 00's | ce: |eu6 |se9 [0 |008 | 0-6 | oo-oF | Ir-ady | gt 086 zel_| 241 | Ose | off | 0% | > 08 | €4'6r | 2¢° |o00'Ge | eze S586. Teo) | SAT 0°08 |¢6 | 00°0F | et-udy | zr |----r dnory ‘SMD | “89T | 0 o | Ho | SOT | ST | sr | sur | “saT | ‘sq7 | “saT | “symp | 79 40g | -uaq | “san | 4am? |-qua0| “sqrr | “THOT wad “wip|iad “up|wad uy) sag ta mn > ia ie be = Q i ost |p se E ao ee ae g Fy s ere | & g e s 5 2 5 uo) 4 = A 5 o © (e) foun © oO = ep e485 Er @gice| 8| = es S fH ieee] =. f= S e | $3 e B airs 5 B/E | 6 Z & ; Bot a Z & Bieta ge Zz ASS) oul 26 BE 22/88 Seales o43| = | B : ite a= 2 5 | i rem lence fe) = A le) ° { Fe : a = o 3 a = oe ek "ooo Gogh) cee (ee a = 2 | 2 /oSa| | eve mm Bom eae. 2 eo. ow | £| ¢g “(sIseq Bs S. "SUOTJeA}UEOUOD [eyTUy | 5 ceed tall Ses ia ey 5 Arp-ouoq) sda | 5 & mS 8 Ea 2 ot Ps | Bs Fa Pee jo sbunod 00T 10d Ba9 = 5 sg 5 = 5 ieee Jo wong pesteyo — S[BOTWLEY Be S ‘asreyo 1oNbrT iF } \ 1 ‘ponur}u09—suoyypuos buryooo joyuauawdxy— Oy AIAV J, PRODUCING SODA PULP FROM ASPEN, 51 TABLE 11.— Yields of experimental pulps. Yields (bone-dry basis). elds of | yields of bleached eae Kind of test. Cook Sereened pulp (air-dry No. Total Serene ae (bone- basi crude | SC" pleated (ary basis)| Basis) | ulp. gs. bleaches per solid per soli 3 pulp. | Per solid | © cord. Per cent. | Per cent. | Per cent. | Pounds. | Pounds. RG RINE TTEATy eee eee otc coe oes mecca 1 48. 01. 0. 05 47. 96 1,279 1, 406 2 50. 34 . 03 50. 31 1,342 1,475 3 49.31 - 02 49.29 1,314 1,444 ROMP Me Seek Socks anicecoaccmmcitine aes cies aol 4 46. 48 - 01 46. 47 1, 240 1,372 5 50. 01 O01 50. 00 1,334 1, 467 6 44.67 - 01 44. 66 1,191 1, 308 7 52. 63 03 52. 60 1, 402 1,533 8 55. 57 01 55. 56 1, 482 1,625 9 58. 30 13. 02 45. 28 1, 208 1,315 GTOMpPplle is cao csesks anne cso h sees cess cet ; 10 50. 36 - 08 50. 28 1,341 1, 487 UE ee eee eromcneate oes oe ert is ise |i Sistem sel a sis | parte eee 12 51. 72 04 51. 68 1,378 1,524 13 52. 49 05 52. 44 1,400 1,524 14 53. 70 09 53. 61 1, 429 1, 558 15 55. 58 44 55. 14 1,471 1,586 16 58. 12 19. 00 39. 12 1,043 1,109 Cini LL a ee a 2 17 48. 67 01 48. 66 1, 298 1, 422 18 50. 02 02 50. 00 1,335 1, 461 19 52. 55 04 52.51 1, 400 1,530 20 54. 97 02 54. 95 1, 465 1,612 21 54. 85 09 54. 76 1, 460 1,595 22 57. 88 13 57. 75 1,541 1,666 GON, LAY 222 el wen ee eee ee 23 49.18 .02 49.16 1,311 1, 432 24 51. 61 01 51. 60 1,376 1,521 25 50. 78 01 50. 77 1,354 1, 483 26 53. 58 03 53.55 1,429 1,573 | 1 Cook spoiled, due to defect in apparatus. BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. 52 ‘snyeredde ul 100Jep 0} onp ‘poTtods Yoog g “pg oded ‘0700400] 809 “FET SI OSVO YORI UI SZUTYeI HOV[q-sjied pure ‘onjq ‘aee13 ‘pei oy} JO WANS EN, z “ITA 0} I] S07] q Ul WAOYs ov sieqy ey} Jo sydviso1orMojoYd 6% pue cP sesed oes sdind ey} Jo suoreArosqo o1doosoiOIM pus SJUSMIEIMSeeM JEqY 10g 1 re 5 ont oe oe! 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NaOH N20 consumed | consumed Goo Causticity | Efficiency per 100 per 100 Kind of test. No of black | in the use | pounds of | pounds of ‘ liquors. of NaOH. wood unbleached (bone-dry | pulp (bone- basis). dry basis). Per cent. Per cent. Pounds. Pounds. reliminianye case sase. Sts 2M ATO MEEEDI West oécrosmon|ecoskeeenacescopocagecse|sancecccsuce 2 13.4 86. 2 23.1 45.9 ‘ 3 P42) 97.8 26.2 53.2 Rerrourrgelnebmereneace hii teiel'! Nl hoped atic: La: 4 22.3 77.0 30.6 65.9 5 21.4 77.9 27.3 54.6 6 14.3 85.3 25.6 57.4 7 15.3 84.2 18.9 36.0 8 17.2 82.1 16.4 29.5 9 2.8 97.1 14.6 32.3 Ginaryey We Seda Be eae eee iy eee a tn og mn ae 4.7 95.0 230i 47.1 12 4.6 95. 4 23.9 46.2 13 3.4 96.5 24.1 46.0 14 10.2 89.6 22.3 41.6 15 18.0 80.7 20.3 36.8 16 25.5 74.0 18.5 47.3 Group IIT.....-. Rds AE ROU eEe eas ea ae ge EER 17 5.7 94.2 23.6 48.4 18 4.7 95.2 23.8 47.6 19 14.4 85. 2 PLB 40.6 20 20.1 79.3 19.8 36.1 21 27.1 724, i 18.0 32.9 22 26.0 18.2) 18.3 31.7 Groupee a n% 52k Pes hele te oe see ss ale IE 23 19.4 80. 2 20.1 40.9 3 24 18.1 81.5 20.4 39.5 25 17.8 81.8 20.5 40.4 26 10.3 89.5 22.4 41.9 1 Cook spoiled, due to defect in apparatus. TaBLE 14.—Wood, soda ash, and bleach employed per 2,000-pound ton of air-dry pulp (10 per cent moisture) based on experimental results. Unbleached pulp. Bleached pulp. 2 Bleaching Kind oftest. — coe Soda ash Soda ash | powder 3 (58 per (58 per (35 per Wood. acai Wood. ean eati NazO). NazO). |available chlorine). Solid Solid cords. Pounds cords. | Pounds. | Pounds. Pe releMIN anys s)=\5 Sa a2 ccs 5c aise veces ao ees 1 1. 41 1,853 1.42 1,872 145.5 2 1.34 1, 308 1.36 1,322 145.6 3 1.37 1,367 1.38 1,384 136.5 Grolier ee res ee Bae AL TR, RAE eS 4 1.45 2,117 1.46 2,126 108. 4 1 5 1.35 1,738 1.36 1,757 127.4 6 1.51 1, 661 1.52 1,681 136.5 7 1.28 1,057 1.30 1,074 164.6 8 1.22 901 1, 23 912 255.6 9 1.49 828 1.52 844 532.5 GROepy Tere tees Seles Shey Pea PE eS 10 1.34 1, 259 1.34 1, 259 144.3 PIRI EN eres ex8 cell yaaa Hepes Eh eR LS A | i 12 1.31 1,191 1.31 1,196 181.2 13 1.28 1,172 1.31 1,196 174.7 14 1.26 1,145 1.28 1,167 192.7 15 1.22 1,177 1.26 1,211 278.1 16 1.72 1,571 1. 80 1,642 432.3 (Ciro) 00 0 ee ee Pe es agate 17 1.38 1, 258 1.41 1,276 127.8 18 1.35 1, 235 1.37 1, 254 146.2 19 1. 28 1,178 1.31 1,196 164.7 20 1. 22 1, 126 1.24 1,137 182.1 21 1.23 1,128 1.25 1,148 201.2 22 1.17 1,071 1.20 1,101 351.2 _ GROUP RUVE eee ees vo anes aye smeciine ous 23 1.38 1, 254 1.39 1, 276 155.7 24 1.31 1,191 1.32 1,199 162.9 25 1.33 1, 214 1.35 1, 232 173.5 26 1. 26 1,149 1.28 1,160 200. 0 a 1 Cook spoiled, due to defect in apparatus. 54 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. METHODS FOR AUXILIARY TESTS. In determining bone-dry weights, properties of pulps, and concentrations of soda liquors, the following methods were employed: BONE-DRY WEIGHTS. In practically all determinations involving exact quantities of wood, pulp, or screenings, either actual or calculated bone-dry weights were used. The actual bone-dry weight is the weight of the material after having been dried to constant weight in an oven with good circulation of pure air at a temperature of 104-106° C.1 Usually instead of drying the entire quantity of material, its ‘“‘bone-dry factor,”’ the ratio of the bone-dry weight to the weight before drying, was determined by means of a small sample. The calculated bone-dry weight is the weight obtained by use of this factor. The errors in calculated bone-dry weights were found by actual test to be less than 0.3 per cent. PROPERTIES OF UNBLEACHED PULP. Color.—The color of a pulp was determined by visual observation and also by means of an Ives new construction tint photometer. The standard for comparison was a block of magnesium carbonate, which affords photometer readings of 100 each for the red, green, and blue color screens used. The sum of the three readings for a pulp measures its ‘‘whiteness,’’ and this sum subtracted from 300 ? (the sum of the three readings for a surface as white as the standard) measures the ‘‘parts black” rat- ing of the pulp. The higher the ‘“‘parts black” value the darker is the pulp. This method of expressing relative ‘‘darkness” of different pulps is reliable only when the pulps are of approximately the same hue, as in the case of these experiments. Shives.—Shives in pulp are the small bundles of wood fibers which were not reduced by the cooking and subsequent operations, and which were not removed by the pulp screens. For the determination, a three-tenths-gram portion of pulp, the bone-dry factor of which was known, was thoroughly broken up in a small Erlenmeyer flask and deposited on a 70-mesh sieve in an even deposit or sheet covering 9.66 square inches. This sheet was ‘‘couched” on a silk cloth and then transferred to a glass plate and dried in an oven. When the plate with the deposit was placed in front of an incandescent lamp the shives could easily be counted with the eye. In cases where the number was large, a glass plate divided into quarter-inch squares was placed on top of the pulp and a small area was examined instead of the whole. Know- ing the area examined and the bone-dry weight of the pulp sheet, the number of shives per gram of bone-dry pulp could be calculated. Ash.—The ash was determined by burning a bone-dry sample of unbleached pulp of known weight in a platinum or porcelain dish over a Bunsen flame until the ash produced was free from carbon and of a white or grayish-white color. The percentage of ash is based on the bone-dry weight of the pulp. Strength.—The strength of the pulp sheets made on the paper machine was deter- mined by a Mullen paper tester and by a Schopper breaking-length testing instrument. The pulp was tested in the ordinary air-dry state for the conditions that prevailed in the laboratory. The Mullen test, or ‘‘pop test” as it is sometimes called, was made by clamping a single sheet, accurately measured for thickness, between a rubber diaphragm and a polished metal ring, and then, by means of liquid under pressure, forcing the diaphragm against the pulp sheet until it burst through the aperture, The ee on the liquid in ees per square inch, or ‘‘points,’’ is read from a 1T he weight was considered constant foie the decrease was not more than 0.1 per cent during an addi- tional hour’s drying at this temperature. 2 At the time of these experiments the shutter of the instrument used had been injured and could not be opened more than 64.7 points. The other aperture was then reduced to this size and the value 64.7 was used in place of 100 for a wide-open aperture, and 194 (3 tgmes 64.7) was used in place of 300. The results obtained for the various pulps were sufficiently accurate for comparison with each other, PRODUCING SODA PULP FROM ASPEN, 55 gauge. For each pulp 20 sheets whose thickness varied between 0.010 and 0.011 inch were tested. The average strength in pounds per square inch per 0.001 inch thickness is the quotient of the average test value divided by the average thickness in thou- sandths of an inch. A quantity one-tenth of this value is sometimes used in express- ing results, and is called the ‘‘strength ratio.’’ 1 The Schopper tester measures in kilograms weight the tensile stress required to break a strip of pulp 15 mm. wide. At the same time the instrument registers the ‘‘per cent stretch,’’ which is the strain or elongation of the strip just before breaking, and is expressed as a percentage of the original length. The ‘‘breaking length” is the length of sheet which, if suspended, would break of its own weight, and when expressed in meters is determined by multi- plying the weight in kilograms required to break the strip by its testing length in milli- meters (180 mm.), and dividing the product by the weight in grams of the portion of the strip subjected to test. Five strips of pulp were tested in the ‘‘machine direction” of the sheet and five across the machine direction, and the average values for the two directions determined. Bleach required—The bleaching solution was made by mixing bleaching powder (calcium oxy-chloride or chloride of lime) with water and allowing the mixture to settle so that a clear solution was obtained. The strength of this solution was deter- mined by titrating 5.00 cc. against fifth normal arsenious acid solution, using a solu- tion of starch paste and potassium iodide as indicator. The number of cubic centi- meters of arsenious acid used, multiplied by 4.0514, gave the strength of the bleaching solution in grams per liter of ‘‘35 per cent bleach,’’ or bleaching powder, in which 35 per cent of its weight is chlorine available for bleaching purposes. The bone-dry weight (about 50 grams) of the pulp sample used for the bleaching determination was first calculated by means of its bone-dry factor. The sample was then thoroughly broken up in water ? to form a uniform pulp mixture. A quantity of the bleaching solution containing a known weight of ‘‘35 per cent bleach” was added and the mix- ture diluted with water ? to approximately 2,500 cc. This mixture was kept at a temperature of 40° C. until the bleach was exhausted, as determined by starch-iodide indicator. The bleached fiber was then thoroughly washed free from bleach residues and made up into sheets on a small hand mold. These sheets, when air-dry, were compared with air-dry standard color sheets made in a similar manner from five or six commercially bleached soda pulps mixed in equal proportions. If the first determ1- nation on the experimental pulp did not give as white a color as the standard, the process was repeated on other samples until the standard color was attained as nearly as possible. The weight of 35 per cent bleach required to produce the standard color is expressed as a percentage of the bone-dry weight of the pulp. The bleaching operations were performed in enameled jars provided with agitators and placed in a tank of water whose temperature could be regulated by an electric heater. It was found best to start the bleaching in the late afternoon or evening, so that the bleach was exhausted sometime the next morning. The comparisons with the standard color sheets should be made at about the same time each day, using light from a north window. Loss on bleaching.—For determining the loss on bleaching, a sample of about 2 grams of pulp was thoroughly broken up in water and bleached in a 250 cc. Erlen- meyer flask, using as near as possible the conditions which produced the standard 1 “Strength factor” or ‘“‘points per pound”’ is distinguished from “strength ratio” by the former being obtained by dividing the “pop test”’ by the weight in pounds of aream of paper. The size of a ream varies, but for a standard of comparison a ream of 500 sheets, 24 by 36 inches, is usually preferred for determining the strength factor. 2 The water should be neutral so far as its action on pulp and on bleaching powder solution is concerned. The use of distilled water is preferable. 3 Actual tests have shown that this method gives results almost identical to those secured in pulp-mill operations. The method of determining the amount of bleach required by adding an excess of bleaching powder and titrating the unconsumed excess after the pulp is bleached sufficiently white, gives much lower results. , 56 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. color in the samples tested for the determination of the amount of bleach required. The bleached sample was thoroughly washed, first with hot distilled water and after- wards with ethyl alcohol. Its bone-dry weight was then determined. The per- centage loss on bleaching is based on the bone-dry weight of the unbleached pulp, which had been calculated from its bone-dry factor. Microscopic examinations.—Representative portions from the pulp sheets were soaked in water, teased apart with aneedle, stained with Bismarck brown, dehydrated with absolute ethyl alcohol, cleared in xylol, and made into permanent mounts with Canada balsam. Photomicrographs of these mounts magnified 65 diameters were used in studying the individual fiber characteristics. Further microscopic study of each of the individual mounts was also made, using different magnifications, and such features were observed as the apparent strength of cell walls, the prominence of cell markings and the presence of vessels, fiber bundles (shives), and ray cells. The general shape and condition of the fibers and the distinguishing characteristics for the species were noted. By means of a micrometer eyepiece about 50 unbroken fibers irom the various mounts were measured for length and breadth at the middle of the fibers, and the average thickness of the cell walls was roughly estimated. The fibers were selected at random, no effort being made to select extremely long or short pave ANALYSES OF SODA LIQUORS. The caustic-soda solutions charged and the black liquors from the leached pulps were examined for their contents of cooking chemicals, in the first case to calculate sizes of charges, and in the second to determine the consumption of caustic soda during cooking. Caustic soda liquor.—The examination of the caustic soda liquor was conducted as follows: A 10 cc. portion was titrated against normal sulphuric acid, using phe- nolphthalein as first indicator and methyl orange indicator to finish the titration. Letting Y=the number of cubic centimeters of normal acid solution required for the first end point and X=the number of cubic centimeters required for the final end point, the following equations were used for calculating the concentration of caustic soda (NaOH) and the causticity: 4 (Y—(X—Y))=grams per liter of NaOH. ee cent causticity. Black liquor.—The examination of black liquor was conducted as follows: (1) A 50 ce. portion of black liquor was evaporated to dryness in a platinum dish. The residue was ashed over a Bunsen burner and the soluble salts were leached out with hot distilled water. The entire solution obtained was titrated with normal sul- phuric acid, using methyl orange as indicator. The number of cubic centimeters of acid required to produce the end point multiplied by 0.62 gives the grams Be liter of total sodium oxide (Na,O) in the black liquor. (2) A 100 cc. portion of the same black liquor was mixed with 50 cc. of 10 per cent barium chloride solution in a 500 cc. calibrated flask. The mixture was then diluted to 500 cc. with neutralized or freshly distilled water free from carbon dioxide and thoroughly agitated. After settling, 50 cc. of the clear supernatant liquor were titrated with tenth normal hydrochloric acid, using phenolphthalein as indicator. The num- ber of cubic centimeters of acid required for the end point multiplied by 0.401 gives the number of grams per liter of free caustic soda (NaOH) in the black liquor. (3) The causticity of the black liquor was calculated from the following equation: A071) 100 per cent causticity. In which: A=the number of grams per liter concentration of caustic soda (NaOH). B=the number of grams per liter concentration of total sodium oxide (Na,Q). PRODUCING SODA PULP FROM ASPEN, 57 AUTOCLAVE TESTS ON ASPEN. A few autoclave tests on aspen (Populus tremuloides Michx.) were made in 1909.! The ordinary soda process was employed, but the digester used was a horizontal, rotary autoclave, made of 6-inch steel pipe, with a capacity of about 2 gallons. As the heat was furnished by Bunsen burners, there was no condensation or loss of liquid through overflow to modify the cooking conditions. Cooks were not blown, but the digester was quickly cooled to room temperature and then dumped. The pulps were thor- oughly washed with cold water and screened on a small diaphragm screen through slots of 0.006 inch width. The test material was cut from fairly young growth near Ridgeway, Colo. Portions of the logs tested, especially the centers and around knots, were discolored a dull reddish-brown, probably due to incipient fungous attack; other- wise the wood seemed to be sound. Chips were prepared in the manner described on page 15. Their sizes were five-eighths inch (with the grain) by three-sixteenths to one-fourth inch by one-half inth to 6 inches (both across the grain). The data resulting from the tests are shown in Table 15. The column headings have the same significance as those in Tables 10 to 14, except as otherwise indicated. However, in the bleaching tests the standard color matched was that of bleached sulphite pulp, and, as soda poplar pulp in commercial operations is never bleached to so white a color, the test data should be reduced somewhat in estimating the com- mercial value for bleach required. The values for loss on bleaching also are probably a little greater on this account. The tests fall naturally into two groups. One of these consists of cooks 1, 2, and 4, in which the concentration of caustic soda in the cooking liquors was varied. The other consists of cooks 3 and 5, in which the duration at maximum pressure was the chief variable. Increases either of concentration or of duration resulted in decreases in the yield of pulp, loss on bleaching, and bleach required, except possibly in the case of one cook. All of the pulps produced were thoroughly cooked. The yields, as compared with those secured in the more recent tests (see Table 11), were uniformly very low and the losses on bleaching very high. The difference may be due to the methods and apparatus used or to deterioration of the wood from fungous attack, or to both. If the wood had been perfectly sound, it does not seem probable that the lower yields would have been accompanied by the higher amounts of bleach required and the larger losses on bleaching, even though these effects were slightly augmented by the higher standard of bleaching. TaBLE 15.—Cooking conditions and results of autoclave tests on aspene Li hi : iti ne Gees pale of Chemicals charged per Weight : digester 100 pounds of chips Cook |Dateot| of ane Wiis Initial concentrations.2 liquors2 | (Pone-dry basis). No. eagle charged per = oer lies aia. "Sled eee 7 =| Caus: pound of asis, ticity. | _ Cops - a Total bone-dr Total NaOH.|NasCOs.| 7300, Coney ¥| NaOH.|NasCOs.| 7300, Grams | Grams | Grams 1909. dis. P. ct. |\perliter.| perliter.\per liter.) P. ct. Gal Lbs. Lbs. Lbs. 1 | May 25 652 33.5 80 7.4 66.3 93.5 375 25.0 2.3 20.7 2 | May 27 i 652 33.5 50 1.8 39.8 97.5 509 25.0 9 19.9 3 |June 2 1,652 33.5 90 4.3 72.3 96.5 - 386 29.0 1.4 23.3 4 |June 8 1.304 18.3 50 1.4 24.1 96.5 1.000 25.0 1.2 20-1 5 |July 3 1.920 15.0 90 4.3 72.3 96.5 390 29.3 1.4 23.5 1 These tests were made by Mr. Edwin Sutermeister, formerly in charge of the pulp-testing laboratory of the Forest Service at Washington, D. C. 2 The water in the chips when charged is not taken into consideration. 58 BULLETIN 80, U. $8. DEPARTMENT OF AGRICULTURE. TaBLe 15.—Cooking conditions and results of autoclave tests on aspen—Continued. Duration of cooking. Yields (bone-dry basis). Properties us uubinebed Maxi- DEES: mum Cook At gauge No At zero} maxi ares P Total | g s 4 1 Loss on r gauge | mum ereen- | Screene Bleach . Total pres- gauge oe aus ings. pulp. Ash. | required. Se sure. | Hrs. Ars. Ars. | Lbs. PC P. Ch. P. ct. P. ct. Pct Pec 1 8.2 0.3 7.0 110 | 41.10 0.10 41.00 1.40 15.4 3.92 2 | 8.5 .3 7.0 110 | 44.23 - 03 44,20 1.27 14.7 4.08 3 4.6 -3 3.0 110 | 40.50 .10 40. 40 1.35 14.3 4.39 4 8.0 2 7.0 110 | 46.97 .07 46.90 1.25 15.8 4.68 5 8.0 .o 7.0 110 | 36.00 . 00 36. 00 1.42 10.0 2.56 (P. L.—66—1, S. 683.) 1 The pulps produced were of good strength and of a fair degree of hardness; the color was very light ~ reddish-brown. Shives were very few in number or almost absent. p manufacture. ee ml iquors at start of cook. | Concentration of NaOH. ecific gravity. a eee a el FE 11.09 | 6 per cent!.------- od (By WN RARE i lata aiaes 11.03 | 2 percent! (Pyeceaiies 11.09 | 7 per cent!..------ A 11.08 | 7 percent?..------ ae 8 iI, Oeil, 1H) |lsonece qed oops soos 171. OS legcecansoes el PPIolos 11. 09-1. 11 | 6-9 per Centeeeere (3) 1 |bsecteeps eee oes aca | Beret 6-8 per cent. .----- 11,07-1.12 | 5-10 per cent !...-- () i Neeceeotedeseassaaas =| USO ESE Sel aetal | 1 1.07-1.11 | 5-7percent Na20- | Mt O7 l;econeeoocas=pe2oRbe 1 7 OO)lsosocesoeeedRoocodlS al 11.09-1. 11 | 7-9 per cent }....-- 5 14. 07-1. 11 | 5-7 per eemttaee == “aa PRU ok sek soa ure and blowing, 45-60 minutes; ee Taste 16.—Cooking conditions employed in the soda process of wood-pulp manufacture. Quantity of cooking Digester. Quantity of chemicals charged. liquor charged. Cooking liquors at start of cook. ' Durations of cooking. Cooking pressure | Cooking Practice followed. Density. 1S tempera; From start Kind Size Wood | yranner of heatin, Actual caustic puolsodey Pereook.|| Percord Concentration of | Caus- ee me Total, | tillcooking moths anes * | capacity. & | soda (NaOH). Beate sllPosese aa NaOH. ticity. | pressure is | vrecsure : Baumé. Twaddle. Specific gravity. reached. |? nO Per cent. | Pounds. oF. Hours. Hours. Fours, o 11.09 | 6 percent}... Es = 60 Sabo @) ae Sinclair’s process. Houghton’s process Huropean practice (1870) .| Cylindrical, vertical. American practico (1870)............... Cylindrical, vertical. American practice (1880-1890)... -do. Modern practice Modern practice (American)... Modern practico. . Modern practice (American). Modern practice Modern practice (Swedish) Cylindrical, Rotaries- vertical. .| Cylindrical, vertical. -do- Stationary. . -. stationary, stationary, Stationary, stationary, Direct fire...... 16 by 5 | lecord...| Direct fire orsteam jacket. 4.3cords.| Live steam....-__- Jacket, direct fire. -| Live steam......-. Leesbodvenlbsoeseee so coils, or 4.5 cords-_ Live steam. = oil). 336 lbs. per ton green wood. 450(?)-920 Ibs. per cord.t 12-20 per cent of weight of wood. 16-20 per cent 637 kilos (=1,400 lbs.)1 NasO for charge. “635(?) to 1,320 Ibs. per cord.! Hf 8-15° at 60° B_. 11° for poplar... 12-14° at 60° F_ 1]. 07-1. 11 11.07 11.09-1. 11 G(s shit | | 6-8 per cent- 5-10 per cent ! Hat (18) oe 31091°— Bull, 80—14, (To face page 58.) 1 Calculated from other data given. 2 Strong solution of caustic soda. 3 Tn addition to the total time of cooking Congdon reports: Time required for charging digester, 30-15 minutes; 4 Not specifically known whether time is total duration or duration at maximum pressure. » Stronger liquors than Ref. No. 9. 6 Less than 10-12 hours. 7See Bibliography at end of appendix, for more detailed references. 180 150-180 65 or more. 110 90-110 90-110 100-120 130-160 132-147 88-118 73-147 |. 73-176 70-80 100-130 100-150 125 1-2 Blowing pressure per square inch. Auttority.7 Griffin and Little, 1894. .| Clapperton, 1907. Watt, 1907. Houghton; Griffin and Little, 1894. .| Sileox, 1875. Tofmann, 1873; Watt, 1907. Congdon, 1889; Watt, 1907. Griffin and Little, 1894. Cross and Bevan, 1900. International Library of Technology, 1902. Clapperton, 1907, Do Cow, 1907. Stevens, 1908, Schubert; Stevens, 1908. Ernst Miiller; Stevens, 1908. Klemm; Stevens, 1908, Sindall, 1908. Beveridge, 1911. Cross, Bevan, and Sindall, 1911. TMennefeld; Beveridge, 1911. for relieving pressure and blowing, 45-60 minutes; total period for a cook, 11-11} hours. 59 PRODUCING SODA PULP FROM ASPEN, "Ud g PUB YIOX MON 91 jo stim Aq pefojduis suonmtpuog -EN6I ‘’Sses pz “30D W109 ‘ZOST ‘00M sSeATIeIUeSeIdey Jo esnoy Se1e1g poltag ut ‘al ‘oureg “9 ‘v Aq Jue “oD BTueA AS T19}21S ¢ WAATS G1BP JoYIO ULOIF Poyeno[eo z “p00 008 iad spunod 0g¢9 *pi09 OF8 Jed spunod 979 zos1eyo Smee pais sate Jad spunod z62‘z 006 a *p.10o 00L ‘g | tad spunod ocg= QOGROS ices BOG Greil as ieaone eas oem ee (ees quad Jad ¢z% - “p09 O18 OUOS GT a tastes See a lod spunod ¢z9 0&8 z OU Catee |S oases OCOSTS sags ea hSeee ese -{ : 00s“ ee @p109 OST T-S262| “00R'8 | 2 00€'T-0g0'T | ed spunod 098-0z2 000‘ (DOO Oey} SONY — [Pees O0OST= mae sSese = Seas “SUOTIDD | “suoj]D) | “p102 ad spunog TWO) EVs aD Est aye naa assaid. ‘(HO®N) ae epos re OL Bpos o14snvo [enjoy *pesieyo ionbiy] sur =yooo jo Aqymuent Wertge iso op*----| 0% ese WK Catan esate srieee taal er Oe Pr Op Sadia eater rea) Or geen Fetes cere OD ers Gg DENCH GCeNe sie a= cies rave tee eae 5 aeee at an ape EE OD aes fee oe ODE eee sommes G (6G ‘jeotrpurpA9 OD emma liz Ji INO ess Patina sy siemens pars tees Or COS SERRA IS IOS O2 Op =a: OD Feat Ge AO Ge CG) 2 7 STOR RSE US es eae eo ee LO ee OP aay ¢¢ (Sos LI Sete lee eee en ean ie ee aoe TC Soke aS Ops THOS OAT, |= 77757 [Rick ANG T(0) pee SRE Sie SEIS PIR BE DOR ERO ROCA GOP A GIO BOOS ODuesae Deck cage Sateen aar es OG) 3 4q 08 [BoTqI8A ‘Arem0rye4s “;eolIpulTAD er ee aro 229) Ge L 4q 02 po gt css s esses sase-="> = -Teatoztdoy ‘A1e,01 ‘eolIpulpAD poe UIB94S BATT | GT OIA GIG pl Sass eo eee ee rns es oe ae ak aes CeO aa Pista me04s GATT \| , tuceaBgsddc| Soa anaague ae ase ame Sade a Spas spose ee caL SaaS aasaa Eb ae Se yexoel mie9849f| ° © Se STG MeajS aArT | G*E-E Tes SNe (eh fasta Reet AE Oe Sa CRS ORGS OR Aare a Src Ss) AI 0) pate “yexovl u1e84S CO} LEDC RS Re Se YE [eal | Cree gti een na Ge een ea [eorqy se ‘Arem0rye4s ‘TeotIpurpADg ey 09) “pad “3UT} Rey JO 1ouUe YL Ee 9219 *puryy *pasieyo speormeyo jo Aywend *194SesI psy djnd-ppos unniwup oifads yp pahojdwa suoyrpuos buryoojg—'L AIAV, “IL “ON 90U01eje1 10} peytoeds sv ydeoxe [ [Iu e[3uIs B SyUeseIdel yI0der YOR 1 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. 60 ‘aINSSoId TANUIIXVUL 4S WOl}VINp 10 WOT}VINP [240} SI SUIT} JOY JOYA UMOUY AT[eoyoeds ON 5 “op erueapcs -uueg pues 10 X MIN oy} JO Si[tur Aq peAo[dume suonipuo0p “G06T “SSeS pz “30D 4409 ‘OST “90q SeATVe}UeSeIdeyY Jo ssnoy seyeig poyiuy ut “ul ‘sureg “H *y Aq JUeMIAIBIS z “UAAIS BVP JoY4O WO] PoyVlNI[VO + “GL ‘OIT “UMOT JON "gL “spunod “yout sienbs aed einsseid SUT MOTE, 8° I 8°¢ 6-o°2 o-1 OI-S'6 ¢01-2'8 8°T-3'T oI-0T “(rey or-¢ &-Z -dod 10} 8) 21-8 *sLNOET "SNOT *SLNOET *payovel ainsseid | st einssoid "1290.1, BuIy009 Vy | Suryx009 TI} 421248 WHOL, *BULYO0d JO SuOT}VING OGT-O1T OZT-OTT “spunod ri) quad Lag ~---" "97190 Jed 6 ~-->*-4t190 Jed 8 BS ness 1 jue0 Jed g O%8N JuUe0 Jed 9 “que0 Ied 0T-¢°g “uoT[e3 qed 1[ex]e [e103 punod 9670 Jo JueTeAInD| --uoT[e3 Jed yse epos punod “yout eienbs red einsseid SuIy00,) “AYE -O1]SnBO --; 9900 Jed QT-¢ ----7, 4m100 Jed 6 T Jo Juajeamnby “HOBN JO WOr}e1} M9000 160 °T 160 °T 60°T rt T80°T *ATARIZ oytoads *3000 JO 4.1B4S 7B SIoNbIT Suryooy *ponuryu09j—s7j7u djynd-ppos unoiwwy ofwads yw pakojrdwua suorppuos bu_yoog—' 1 AIAV], o8I ol ta oSI oGL GL o8I Tt oGL-S TT IT oF OL oll Or o9L Tt of OL 6 oSI-LZT oGI-IL I 8 o9-ZE I o9I-FL Z 096-66 I o9I-FI 9 066-06 I of I-E1 ¢ oT t of 'h F ofG-PT ofI-0L § 066 I ofl z oSI-IT t oGI-L T *TOPPBAL ouneg ‘ON “Aqsuaqy sae I PRODUCING SODA PULP FROM ASPEN. 61 BIBLIOGRAPHY. (January, 1913.) PROPERTIES OF ASPEN AND ITS USE AS A PULPWOOD. JOURNAL OF THE SociETY oF CHEMICAL INDUSTRY. Poplar wood pulp. In: Jr. Soc. Chem. Ind., 24 (1905), 148. L’INDUSTRIA DELLA Carta. Poplar and the paper industry. Extract in: Paper Ve@911),.(5), 13. LircHavEeR, ViKTor. Die ‘‘amerikanische Aspenzellulose.’”’ 3 pp., illus. In: Zentrallblatt fiir die éster.-ungar. Papierindustrie. XX III (1905), (26), 822-5. Macmittan, H. R. Forest products of Canada: pulpwood. Bulletins 12 (1908); 26 (1910); 30 (1911), Forestry Branch, Department of Interior, Canada. 9; 14; 17 pp., tables, 8°. Ottawa; Government Printing Bureau, 1909; 1911; 1912. Papier FaBRIKANT. Die Pappel (Populus canadensis) als Papierholz. In: Papier Fabrikant, 9 (1911), 199-201. SARGENT, CHARLES SPRAGUE. Report on the forests of North America. Vol. IX, Reports of the Tenth Census, United States Department of the Interior, Census Office. 612 pp., maps, tables, 4°. Washington: Government Printing Office, 1884. Svensk Pappers-Tipnine. Poplar asa pulpwood in Italy. Swedish translation of an Italian letter. In: Svensk Pappers-Tidning, 12:te arg. (1909), (22), 225-6. UniteD STATES—AGRICULTURE, DEPARTMENT OF—ForEST SERVICE—BULLETINS 74 AND 77. Forests products of the United States, 1905; 1906. Wood used for pulp; pulpwood consumption. 6; 8 pp., tables, 8°. Washington: Government Printing Office, 1907; 1908. UNITED STATES—COMMERCE AND Lazsor, DEPARTMENT OF—CENSUS, BUREAU OF— Forest Propucts No. 1. Pulpwood consumption: 1907; 1908; 1909; 1910. 14; 12; 15; 10 pp., tables, 8°. Washington: Government Printing Office, 1908; 1909; 1911; 1912. Unirep Stares—CoMMERCE AND Lasor, DEPARTMENT OF—CENSUS, BUREAU OF. Paper and wood pulp statistics; preliminary report for 1909. 6pp.,tables,8°. Wash- ington, April 26, 1911. WEIGLE (W. G.) and Frorsainenam (EH. H.). The aspens: their growth and man- agement. United States Department of Agriculture, Forest Service, Bulletin 93. 35 pp., tables, 8°. Washington: Government Printing Office, 1911. THE SODA PROCESS OF PULP MAKING. Berscx, JosperH. Cellulose, Cellulose-produkte und Kautschuksurrogate. Berlin, 1903. English translation, ‘Cellulose, cellulose products and artificial rubber’’ by Wm. T. Braunt. 336 pp., illus., 8°. Philadelphia: H. C. Baird and Co., 1904. BEVERIDGE, JAMES. Papermaker’s pocketbook. 2d ed., 225 pp., illus., tables, 8°. London: McCorquodale and Co., Ltd., 1911. CLAPPERTON, GEORGE. Practical papermaking. 2d ed., 226 pp., illus., 8°. London: Croxby, Lockwood and Son, 1907. Conepon, E. A. The manufacture of chemical fiber. In: School of Mines Quar- terly, X (1889), 163-172. Cross (C. F.) and Bevan (E. J.). Textbook of papermaking. 2d ed., 330 pp., illus., tables, 8°. London: E. & F..N. Spon, Ltd., 1900. Cross (C. F.), Bevan (E. J.), and Srypatt (R. W.). Woodpulp and its uses. 270 pp., illus., 8°. New York: D. Van Nostrand Co., 1911. 62 BULLETIN 80, U. S. DEPARTMENT OF AGRICULTURE. De Crew, Jupson A. The function of the caustic soda process in the production of cellulose from woods. In: Jr. Soc. Chem. Ind., 26 (1907), 561-3; Chemical Abstracts, 1908, 319. GrirFin (R. B.) and Lirrtze (A. D.). The chemistry of papermaking. 515 pp., illus., 8°. New York: Howard Lockwood and Co., 1894. Horman, Karu. Praktisches Handbuch der Papier fabrikation. 2d ed., 2 vols., 1800 pp., 4°. Berlin: Papier Zeitung, 1897. INTERNATIONAL LIBRARY OF TECHNOLOGY, VoL. 20, Part2. Manufacture of paper. 58 pp., illus., tables, 8°. Scranton, Pa.: International Textbook Co., 1902. Kur, Artour. The process of manufacturing chemical wood ptilp. Proceed- ings, Verein der Zellstoff- und Papier- Chemiker, Berlin, 1909. Also in: Papier Zei- tung, 34, 227, 267: Chemical Abstracts, 1909, 1341. Lerenton, MarsHatt Ora. Preliminary report on the pollution of Lake Cham- plain. United States Department of the Interior, Geological Survey, Water Supply and Irrigation Paper No. 121. 119 pp.,illus.,8°. Washington: Government Printing Office, 1905. Paring, Jr., A. G. Description of the soda process as practiced at the mills of the New York and Pennsylvania Company, 1908. In: Vol. IV (pp. 2628-2633) of Pulp and Paper Investigation Hearings. United States House of Representatives, 60th Congress, 2d sess., Doc. 1502. Washington: Government Printing Office, 1909. Rep, T. ANDERSON. Wood as a papermaking material. Tables. In: Jour. Soc. Chem. Ind., 5 (1886), 273-276. Srncox, GrorcE W. Report on the art of printing and on manufactures of paper. With appendix, 30 pp., index, 8°. In: Vol. II, Reports of the Commissioners of the United States to the International Exhibition held at Vienna, 1873. United States Department of State. Washington: Government Printing Office, 1875. Sinpatt, R. W. The manufacture of paper. 275 pp., illus., bibl., 8°. New York: D. Van Nostrand Co., 1908. SinDatt, R. W. Paper technology. 2d ed., 270 pp., illus., tables, 8°. London: Chas. Griffin and Co., 1910. Stevens, Henry P. Paper mill chemist, 280 pp., 67 illus., 82 tables, 8°. Lon- don: Scott, Greenwood and Son, 1908. SUTERMEISTER, Epwin. The soda process for cellulose manufacture; the consump- tion of caustic soda and its influence on yield and bleaching properties. (Presented at the Eighth International Congress of Applied Chemistry in New York, Sept. 11, 1912.) In: Paper, LX (1912), (12), 15-16. Watt, ALEXANDER. The art of papermaking. 3d ed., 260 pp., illus., 8°. Lon- don: Crosby, Lockwood and Son, 1907. EFFECTS OF CAUSTIC SODA AND WATER ON CELLULOSE. Cross (C. F.) and Bevan (E.J.). Cellulose. 3d ed., 328 pp., plates, diag., tables, 8°. New York: Longmans, Green and Co., 1903. Cross (C. F.) and Bevan (E.J.). Researches on cellulose, 1895-1900, 2d ed., 180 pp., tables, 8°; Researches on cellulose, 1900-1905, 184 pp., 8°; Researches on cellu- lose, 1905-1910, 8°. London: Longmans, Green and Co., 1907; 1906; 1912. Miter, O. Constitution of soda cellulose. In: Berichte, 41, 4297-4304; Chemi- cal Abstracts, 1909, 650. PRODUCING SODA PULP FROM ASPEN, 63 MinuteR-Moskan. The reaction of cellulose with sodium hydroxide. In: Be- richte, 40, 4903-05; Chemical Abstracts, 1908, 1186. ScHwaLBeE, Cart G. Die Chemie der Cellulose. Bibliographie. 2 Bde., 8°. Berlin, 1910-1912. ScHWALBE, CarLG. The cellulose problem. In: Paper, 2 (1911), (4), 9. ScHWALBE, Cart G., and Rosinorr(MicwaAe.). Action of water and alkali upon cotton cellulose. In: Zeitschrift fiir angew. Chemie, 24, 256-8; Chemical Abstracts, 1911, 1838. Tauss, H. Verhalten von Holz und Cellulose gegen erhéhte Temperatur und erhéhten Druck bei Gegenwart von Wasser. In: Dingl. polyt. J., 273 (1889), 276- 285. Abbreviated translation, ‘‘The behavior of wood and cellulose at high temper- atures in presence of water,’’ in: Jour. Soc. Chem. Ind., 8 (1889), 913. Tauss, H. Verhalten von Holz und Cellulose gegen erhohte Temperatur und erhéhten Druck bei Gegenwart von Natronlauge. In: Dingl. polyt. J., 276 (1890), 411-428. Abbreviated translation, “‘The behavior of wood and cellulose at high tem- peratures and pressures in presence of caustic soda,”’ in: Jour. Soc. Chem. Ind., 9 (1890), 883. Viewic, W. The nature of alkali-cellulose, in: Papier Zeitung, 32 (1907), 130-131, 174-175; Chemical Abstracts, 1907, 1320. Viewia, W. The action of cold caustic soda solutions on cellulose. In: Berichte, 40, 3876-83; Jr. Soc. Chem. Ind., 26 (1907), 1157; Chemical Abstracts, 1908, 178. Viewic, W. Action of cold caustic soda on cellulose. In: Berichte, 41, 3269-75; Chemical Abstracts, 1908, 3403. O semaine ie “ori " es : <2 ie hee a ree ee Bens! mab ne ae ae hy bratty SISs rae a Ca puis a } ffi ‘bieiget? eee Ne pda Ene ee on : Ait en i he eer} 152 ft; oO! Ty Bios ee ber eae heats ‘ =. ect As Be tins 1 : wort, ae At ‘ee SMAERCN is he ne td oa) Darke ts its ‘ «3 fits ot # tava ara ira) hci lee. ay ‘ 4p i ee! ia), Ca AIEEA Tait aes mee ‘ = - + a, et bent a ses ade Vale Peek eerie “4 ete : a : t: ‘4 ) ie Te y - 5 ‘ J y , : i . i - ’ . z + , . as - ‘ R i ¥ ¢ i ~§ A ee lc ec Da ¥ Li bd He . i + it ‘ : i , i ane i ae BULLETIN OF THE > USDEPARTHENT OP ACRCULTURE No. 81 Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief, and the Federal Horticultural Board, C. L. Marlatt, Chairman. Maich 31, 1914. . THE POTATO QUARANTINE AND THE AMERICAN POTATO INDUSTRY. By W. A. Orton, Pathologist in Charge of Cotton and Truck Disease and Sugar-Plant Investigations, Bureau of Plant Industry, and Vice Chairman of the Federal Horticultural Board. INTRODUCTION. In September, 1912, a quarantine order was issued by the Seere- tary of Agriculture prohibiting the importation of potatoes into the ~ United States from the British Isles, Germany, Austria-Hungary, and from Newfoundland, St. Pierre, and Miquelon, on account of the potato wart. In December, 1913, an additional temporary quar- antine was laid against Canada and all the countries of Kurope, pending further investigations of the occurrence of powdery scab and the establishment of a system of inspection on the part of for- eign governments that will provide for the certification of potatoes offered for export to the United States, to the effect that they are free from disease, that they were grown in a disease-free locality from which the American quarantine has been lifted, and that in other re- spects they conform to the regulations established by this Government. The discussion of these quarantines has focused public attention on the potato question to an unusual degree and has emphasized the need for available information concerning the reasons fer the quarantines, the nature of the new regulations, and the general status of the potato industry. This bulletin is intended as a contribu- tion to this end. It is sougnt also to outline a constructive policy for future development that will lessen losses from disease and other wastes and place potato culture on a basis more profitable to the producer, while at the same time permanently reducing the cost to the consumer of this staple food. Notr.—This bulletin tells of the necessity for establishing a quarantine against potatoes from certain countries, gives brief descriptions of the potato diseases that have been imported, indicates some of the agencies by which these diseases have been spread over this country, and gives information that potate growers should have in advance of the planting season. Ji is intended for general distribution. 30952°— Bull. 81—14——1 bo BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. REVI=W OF THE POTATO-DISEASE SITUATION. When seeking protection from new plant diseases we must be guided by past experience and by our knowledge of the general principles controlling the occurrence and spread of plant parasites. It is evident that agriculture in general bears a burden that increases from year to year as new diseases or insect enemies appear. In colonial times and up to 1840 the potato seems to have been free from many serious pests that have come in since. We now list 18 or 20 diseases, not including insects, that attack potatoes in some part of the United States. The yearly loss from them is difficult to estimate, but the injury from tuber rots and related troubles was recently placed by the Department of Agriculture at over $30,000,006 annually, and diseases which attack the erop in the field probably reduce the vaiue of the harvest by another $30,000,000 per annum. Not only do new parasites appear at frequent intervals, but they can rarely, if ever, be exterminated. A plant disease, once estab- lished here, is likely to be with us forever. Under these circumstances it is to the credit of American farmers that they have, during the last generatien, by the adoption of sctentifie methods of fertilization and culture and by spraying and seed treatment for diseases, main- tained the average yield per acre of the country and im the more progressive sections eonsiderably inereased it. On the other hand, the average yield is still only about half what it might be, as judged by European standards, and the eost of spraying, increased ferti- lizers, ete., constitutes a heavy annual tax on the grower. INTRODUCED PARASITES THE MORE DANGEROUJS. Plant parasites may be divided into two classes, those endemic or native to the country and those mtroduced from other eountries. It is a general principle, fully estabhshed by experience, that parasites introduced from other continents or distant parts of the same continent are more injurious than the native parasites of the same crop and, more virulent and destructive in their new habitat than they had been at home. The United States has had many costly examples of this fact, among which may be cited the gipsy moth, the brown-tail moth, the codling moth, the asparagus rust, the hollyhock rust, and that recent immigrant from the Orient, the chestnut bark disease, which is threatening to destroy our chestnut forests. Several potato diseases are of foreign origin. The examples men- tioned below are of special interest. LATE-BLIGHT. In the period from 1830 to 1842 there was introduced into both Europe and America a new potato disease which causes a blighting of the foliage, followed by decay of the tubers. This disease, called ~ THE POTATO QUARANTINE. 3 late-blight, is worst im moist, not too hot, weather, when it may spread with incredible rapidity, ruining the most vigorous field in three or four days. The same fungus spreads to the tubers, pro- ducing a typical dry rot in dry storage, which may become a wet rot in damp soil through bacterial action. ‘The cause of this disease is the late-blight fungus (Phytophthora infestans), and its original habitat is believed to be South America. It gained headway secon after its introduction, and in 1845 nearly destroyed the potato crop of Europe, especially in Ireland, and did much injury in America. It has been present every year since to a greater or less extent, and serious outbreaks have recurred periodically when weather conditions favored its development. In North America it is most serious in the northeastern, part of the United States and the adjacent provinces of Canada. Thorough spraying with Bordeaux mixture will control it, but the losses are nevertheless still large. ‘There is no hope of the extermination of this disease. Potato growers will always have it to reekon with. BLACK-LEG. A disease marked by the blackening and shriveling or softening of the base of the stalk, a typical curling and yellowing of the foliage, and in late cases by an infection and partial decay of the tuber has been introduced from Europe comparatively recently, probably having come first to Canada and thence to Maine. It is a bacterial trouble,? transmitted m the seed potatoes. Two points are of special interest: (1) The widespread distribution it has secured within a few years, because seed potatoes are shipped from the district which was the original center of infection to nearly every State in the Union; (2) black-leg takes on a more virulent form under southern conditions and may destroy 10 to 75 per cent of a crop in Virginia when, the seed farm in the North had much less of it. Rigid methods of seed selection and seed treatment will control the disease, and these must be insisted upon? SILVER SCURPE. An example of the rapid spread of an imported fungus is afforded by the silver scurf (Spondylocladium atrovirens}. This is a superficial parasite of the potato tuber, begmning as a brown mold on the surface. Later the infected areas take on a glistening silvery gray color, and finally the tubers shrivel more or less, due to loss of 1 A complete description of the late-blight has been given by Jones, Giddings, and Lutman, in “ Investiga- tions of the potato fungus Phytophthora infestans,” U. S. Department of Agriculture, Bureau of Plant Industry, Bulletia 245, i912. Obtaimable from the Superintendent of Documents, Government Printing Office, for 30 cents. 2 Bacillus phytophihorws Appel and related forms. 3The reader desiring more information on black-leg is advised to procure Bulletin 174 of the Maine Agricultural Experiment Station, Orono, Me. i + BULLETIN 81, U. 5. DEPARTMENT OF AGRICULTURE. moisture. Silver scurf has been known in Europe for many years, but it was not noticed in America, except In one instance (by Dr. Clinton in Connecticut in 1907), until 1912, when it appeared on potatoes from nearly every State from Maine to Florida and westward to Wisconsin. It is now thoroughly established here and, though a minor trouble, adds another to the agencies which disfigure potatoes. There is evidence to justify the fear that silver scurf may become more injurious in the United States than it has been in Europe.t Other potato parasites have come from the far West or from the South. The migration of the Colorado potato beetle from the Rocky Mountain region is well known. ‘Two diseases, the southern bacterial brown-rot and the Fusarium wilt, appear to be of southern, possibly tropical, origin, though this is not fully established. THE WART DISEASE. Potato wart, black scab, or canker is a disease which transforms the tubers into irregular, warty excrescences, at first greenish or white, then black and decaying. It is a fungous disease (Synchi- trium endobioticum) of comparatively recent discovery, first described from Hungary in 1896 and found in England about 1902 and in Westphalia in Germany in 1908. It has spread considerably during the past decade until it seems firmly established in England and Scotland, has gained a foothold on the coast of Ireland, and has crossed the Atlantic to Newfoundland, where Dr. H. T. Gissow, Dominion botanist, discovered it in 1909. Fortunately, it has not yet been found on potatoes grown in the United States. Most authorities consider it one of the very serious diseases of the potato, as it converts the tuber into an ugly, regular, and utterly worthless article, and when established in the soil will attack the succeeding crops and prevent the growing of potatoes in such in- fected soil for many years. The countries where the wart occurs have for the most part taken vigorous measures to suppress it, and other nations have endeavored to prevent its introduction. It was primarily on account of this trouble that the Secretary of Agriculture issued Quarantine Order No. 3, September 20, 1912, prohibiting the entry of potatoes into the United States from Newfoundland, the islands of St. Pierre and Miquelon, the United Kingdom (including England, Scotland, Wales, and Jreland), Germany, and Austria-Hungary, although powdery scab was also taken into consideration at that time.? 1 For further details, see the paper in Circular 127, Bureau of Plant Industry, U. 8. Department of Agriculture, by I. E. Melhus, entitled ‘Silver scurf, a disease of the potato.’? Obtainable from the Super- intendent of Documents, Government Printing Office, for 5 cents. 2 ¥cr further information on the wart disease, see Farmers’ Bulletin 489. THE POTATO QUARANTINE, 5 POWDERY SCAB. Powdery scab is a tuber trouble, differing from the common scab mainly in the following particulars:t The scab spots, or sori, are more often circular and not usually as great in diameter as those of the common (Oospora) scab. They first appear as discolored, slightly raised spots covered by the epidermis, which later breaks away, leav- ing a pit, filled at maturity with a brownish dust, the spore balls of the parasite. With powdery scab there is less of a corky layer formed under the spot than is the case with common scab. For this reason there is a loss of moisture in storage and the eventual formation of a depressed spot. In severe attacks of powdery scab there is a can- kerous stage or eating away of the ¢uber, which nearly or quite de- stroys its value. Finally, there is a great difference between the organisms which cause the two kinds of scab. Common scab is due to a parasite (Oospora scabies) of very minute, threadlike form, now considered to be more related to the bacteria than to the filamentous fungi. Powdery scab is due to a slime mold (Spongospora subter- ranea), a relative of the cabbage clubroot organism: Its spore balls appear under the microscope as large balls characteristically marked and easily recognized. Osborn holds that the soil moisture determines to a great extent the damage done by the disease. Under dry conditions of the soil the external appearance is limited to small circular patches about 5 mm. across. Under wet conditions the damage is more serious and the scabs may be as large as 3 to 4 cm. m diameter and as much as 2 cm. in depth. , Powdery scab is common in northern Kurope, where it has been known for many years. In Canada it occurs in the provinces of New Brunswick, Prince Edward Island, Nova Scotia, and Quebec, not universally but rather generally distributed m many sections. The disease appears not to be established in the United States except in isolated cases, mostly near the Canadian border, where further sur- veys are now being made. There is need for the continuance of careful surveys in all States where any imported potatoes may have been planted, to insure the stamping out of any infection that may be present. POWDERY SCAB IN IMPORTED POTATOES. Very little is known of the extent to which powdery scab was pres- ent in potatoes brought from Europe prior to 1912. In October, 1913, in response to market demands, large shipments of potatoes began to come in from the Netherlands, Belgium, and Denmark, as well as from Canada. Examinations of these potatoes at the ports of New 1 Cf. Melhus, I. H., Powdery scab (Spongospora subterranea) of petatoes, U.S. Department of Agriculture, Bulletin 82,1914. This publication contains a full description of the disease and the causal parasite. 6 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. York and Boston by departmental inspectors showed the presence of powdery scab in most of the arrivals from the Netherlands and in many of those from Belgium and Canada. The percentage of pow- dery scab varied from a trace up to 20 per cent or more. The scab was usually of the superficial type, though some advanced cases were found. Common scab was also present. Jt has been suggested since by the representatives of the Govern- ments of the Netherlands and Belgium that these infected potatoes may have originated in Germany rather than in their countries, and an examination of the situation has indicated that the original quar- antine order may not have provided sufficient safeguards against the transshipment of potatoes from Germany and other quarantined countries through Antwerp, Rotterdam, and other nonquarantined ports. In the situation thus presented, the Department of Agriculture had to determine promptly two points: (1) Is there danger that diseases present on imported potatoes will become established in American fields? (2) Is the powdery scab a new and dangerous disease requiring exclusion by quarantine ? POSSIBLE INFECTION FROM IMPORTED POTATOES. The greater portion of the foreign potatoes imported are intended for table purposes and are consumed in New York, Boston, and Phila- delphia, where it has been urged that by no possibility could infection reach potato fields. The facts, as determined by the Department of Agriculture, are that hundreds of thousands of bushels have been shipped from New York to interior points and that foreign potatoes have been sold as far west as St. Louis and as far south as New Orleans. This was particularly the case in 1911. There are abun- dant opportunities for disease germs on potatoes used for food to reach the land. Partially decayed or scabby tubers are sorted out by the retailers and disposed of for feeding to live stock, and manure thus infected is hauled to surrounding farms. Parings from the potatoes go into the family garbage can and find their way directly or indirectly to cultivated fields. A second avenue of infection is through the use of foreign potatoes for seed. It is now fairly well known that European varieties do not succeed in the United States and that the use of foreign seed is not profitable, yet the number of actual instances traced by the Depart- ment of Agriculture where EKuropean seed potatoes were purposely planted as an experiment or through ignorance of their lack of value, or where unscrupulous dealers had sold foreign stock as domestic, is large enough to show that the danger from this source is a real one. Canadian potatoes are valued for seed purposes and were being bought in large quantities when the quarantine was laid. THE POTATO QUARANTINE. v§ The use of foreign sacks which had contained infected potatoes is a third means of spreading disease to American potatoes. Great numbers of these sacks are gathered up through secondhand dealers and sold in New York, Maine, and other producing centers for use in shipping domestic potatoes. It has not been the practice to sterilize these sacks, though a treatment with steam would render them safe. The conclusion reached after consideration of the possibility of the spread of disease through garbage, seed potatoes, and reused sacks was that 1t will be impossible to prevent the permanent establishment in the United States of any parasitic disease common on imported potatoes. IS THE POWDERY SCAB DANGEROUS? The Federal Horticultural Board was compelled to decide promptly whether the best policy for the country would be to treat powdery scab as a disease of minor importance and make no restrictions on importations from infected countries, recognizing as inevitable that the disease would soon become common and widely distributed in the United States, or whether it should be considered sufficiently danger- ous to warrant exclusion measures. In deciding this important point ail available information was secured. Advice was sought from the plant pathologists in the several State experiment stations, all foreign publications on the subject were consulted, and the advice of representatives of foreign governments was taken through corre- spondence and at a public hearing held in conformity with the plant quarantime act on December 18, 1913. This hearing was attended by a large number of plant pathologists and other State officials, by representatives of farmers’ organizations and commercial bodies, and by interested individuals. The thousands of letters, petitions, and tele- grams received by the board showed that the potato growers of the country are no longer apathetic on the question of potato diseases. The advice of the foreign representatives was to the general effect that European potatoes had been imported in large quantities for many years; consequently, that if powdery scab were communicable ij must be common in the United States, but overlooked, in which event a quarantine would not be lawful under the plant quarantine act. Further, that if powdery scab had not already become estab- lished, this fact should be considered as evidence that no danger exists. It was also represented that powdery seab is a disease of such minor importance that the interruption of trade by a quarantine was not justified, and that, if introduced, it could be controlled by using no infected tubers for planting and by discontinuing the use of infected land for growing potatoes. The evidence on each of these points and on other phases considered is summarized later. 8 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. OCCURRENCE IN THE UNITED STATES. During the past two years the pathologists of the Department of Agriculture have visited every important potato section to look for powdery scab and other diseases. Potatoes in the large markets have been examined, the Plant-Disease Survey collaborators in the several States have been asked to be on the watch for powdery scab, and the State of Maine has been given special attention by both the department and the State experiment station. Outside of the State of Maine no definite cases have been traced to farms, but some evidence of powdery-scab infection was found by Dr. Morse, of the Maine experiment station, in two sendings of pota- toes from western Nebraska and Massachusetts. Considerable powdery scab has been found in Maine very recently. This infection is most abundant on the northern border of Aroostook County, but scattered cases occur elsewhere, many of which have been traced directly to seed potatoes brought over from the infected districts of Canada. Thus far only a very small percentage of Maine farms has been found infected. The State authorities have taken prompt and vigorous action to survey the State in order to locate all infections. An inspection service has been organized, which will issue certificates of freedom from powdery scab, and no potatoes known to be diseased will be allowed to leave the State. Seed stock will be examined with special care. It is believed that these measures will provide an adequate safe- guard against the future spread of powdery scab to other States. The State of Maine expects to quarantine all infected fields and will endeavor to stamp out the disease. A more thorough survey of other States is now under way. The evidence is very strong that at the present time powdery scab is not ‘‘widely distributed in the United States.”’ LIKELIHOOD OF SPREAD. That the disease has not already gained a greater foothold in spite of numerous importations is perhaps the strongest argument advanced by the opponents of a quarantine. This is probably a matter of good fortune rather than proof of noncommunicability. The con- trary evidence includes its apparent general occurrence in certain foreign districts, the fact reported by Dr. Melhus that in Canada those sections which use European varieties and which often import seed are more infected than those using seed from American sources, and the experimental evidence secured by Dr. Morse in Maine and by Irish workers that the disease is readily communicable by planting infected seed potatoes. THE POTATO QUARANTINE. 9 RELATIVE IMPORTANCE IN EUROPE AND THE UNITED STATES. Powdery scab has been in the past a minor potato disease in Europe; that is to say, it has not been recognized by the public as a serious trouble, nor has it engaged the time and attention of scientific investigators to the extent that other potato diseases, such as leaf- roll, have. Recent publications by Johnson and by Pethybridge, the leading plant pathologists of Ireland, lead to the conclusion that the disease is more serious there than has previously been realized, par- ticularly in gardens and fields continucusly cropped im potatees, where it tends to assume the cankerous stage and reduces the market value of the potatoes for eating purposes. It may well be that powdery scab is becoming more serious in Europe. Johnsen states: I have no doubt myself that Spongospora scab has a good deal to do with the miser- able average yield per acre of potatoes in the west of Ireland. * * * Itisinsome districts of Ireland as injurious to potatoes as finger-and-toe is to turnips. DIFFERENCES IN MARKET STANDARDS. An important consideration in this connection is that any scab or other disfigurement of the tuber reduces its market value much more in the United States than in Europe. The consumer abroad does not object seriously to a scabby potato. In fact, we are assured by our English visitors that it is a general belief in Great Britain that scab is an indication of good quality for eating purposes. In the United States, however, scabby potatoes are rejected for market pur- poses. In Maine they were sorted out and sold to the starch factory for 50 cents per barrel as compared with $1.50 which they would have brought if clean. In communities where there are no starch factories the scabby potatoes are fed to stock or left lying in the field. As a consequence, scab-infected fields are worthless for potato growing and their market value is greatly impaired. SCAB DISEASES WCRSE IN THE UNITED STATES THAN IN EUROPE. Powdery scab has not occurred in the United States to an extent that permits any comparison of its virulence here with its behavior in Hurope. It is, however, a well-known fact that introduced troubles as a class are more destructive than in the country of origin, owing to differences in climate or other conditions. The several im- portant potato districts of the United States—Maine, New York, the trucking districts of the Atlantic seaboard, the northern Great Lake district, the Red River Valley, Colorado, Idaho, Oregon, California, ete.—difier exceedingly in soil and climate, and there is reason to fear that powdery scab might find in one or several of these districts con- ditions much more favorable than exist in Europe and that it would assume a more virulent forss 36952°—Bull. 81—14-__2 10 BULLETIN 81, U. § DEPARTMENT OF AGRICULTURE. It is certain that our common scab is much more common and disfiguring throughout the United States than it is in Europe, and the injuries caused by the fungus Rhizoctonia to potatoes in the West are greater than any reported from Europe. COMPARISON OF POWDERY-SCAB INJURIES. Common scab produces a roughened spot or pockmark on the tuber, which in its worst stage may cover the whole potato. Under- neath the scab spots, however, a cork layer is formed and the potato remains sound. It is not more subject to decay than other potatoes, and the actual injury from a food standpoint is due to the greater loss in peeling before cooking. Powdery scab in its milder form causes no greater outward disfigu- ration than common scab, but there is less of a cork layer formed and a progressive decay frequently follows.. The cankerous stage of powdery scab is more objectionable than any phase of common scab and is as bad as the wart disease. Finally, no means of controlling powdery scab through the disinfection of seed potatoes, as practiced for common scab, has proved wholly satisfactory. All these considerations led the Department of Agriculture to the conclusion that measures for preventing the introduction of powdery scab into the United States were not only fully justified, but were demanded by every rule of prudence and precaution. Most foreign countries have long since wisely adopted a similar procedure with reference to American potatoes, mainly on account of the Colorado potato beetle. Canada maintains a complete em- bargo against all European countries, and most of the English colonies restrict the importation of potatoes to a greater or less extent on account of the wart disease and other troubles. GCTHER REASONS FOR POTATO REGULATIONS. Experience gained in the enforcement of the potato quarantine order of September 20, 1912, and further investigations of potato diseases and insect enemies have shown that more efficient and log- ical means are required for the adequate protection of this country against the potato parasites of the world. Where a quarantine is laid against a whole country on account of an infection limited to a small portion of that country, the justice of the act is questioned by residents of the disease-free districts, yet there has been no means of limiting quarantines by other than national boundaries except through the active cooperation of the foreign government. Where a quarantine is laid against one country and not against another concerning a commodity like potatoes, which is a staple ar- THE POTATO QUARANTINE. Il ticle of trade between the two nations, it is very difficult to prevent transshipments from the quarantined country through the ports of the nonquarantined country unless special measures are taken by the governments concerned to regulate such trade. Winally, it is impossible to foresee all the conditions that will arise in the course of international commerce. Shipments come from new sources and may bring parasites hitherto unknown to which existing regulations may not apply. An example is afforded by some small importations of potatoes from South America in 1913, which were found infested with new species of weevils, more dangerous than any previously known, which tunnel through the tuber and destroy its value without greatly impairing its appearance. This finding em- phasizes the necessity of maintaining a careful watch over all pota- toes coming from South or Central American sources. Effective regulations are therefore to be preferred to quarantines, in order to permit the most complete protection against the introduction of parasites without hampering trade more than is necessary. A step in this direction has been taken by the issuance of the fol- lowing order applying to potatoes the provisions of the nursery stock regulations, under the plant quarantine act: Unitep States DEPARTMENT or AGRICULTURE, Orricze OF THE SECRETARY, FEDERAL HorticuLTuRAL Boarp. ORDER COVERING ADMISSION OF FOREIGN POTATOES UNDER RESTRICTION. The Secretary of Agriculture has determined that the unrestricted importation from any foreign country of the common or Irish potato grown in the Dominion of Canada, Newfoundland, Great Britain, Ireland, Continental Europe, and other foreign countries may result in the entry into the United States, its Territories and Districts, of injurious potato diseases, including the powdery scab (Spongospora subterranea), and injurious insect pests. Now, therefore, I, Davin F. Houston, Secretary of Agriculture, under authority conferred by section 5 of the act of Congress approved August 20, 1912, known as “The Plant Quarantine Act” (37 United States Statutes at Large, page 315), do hereby determine and declare that on and after January 15, 1914, common or Irish potatoes imported or offered for import into the United States or any of its Territories or Districts shail be subject to all the provisions of sections 1, 2, 3, and 4 of said act of Congress. Done at Washington this 22d day of December, 1913. Witness my hand and the seal of the United States Department of Agriculture. _[sEat.] Davip F. Houston, Secretary of Agriculture. -i Pierce, W. Dwight. Journal of Agricultural Research, vol. 1, no. 4, p. 347-352, pl. 3, 1914. 12 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. Pending the completion of arrangements with foreign governments for the survey and delimitation of disease-free districts and for the inauguration of a system of inspection and certification of potatoes, a temporary quarantine was laid, as follows: Unirep States DEPARTMENT OF AGRICULTURE, OFFICE OF THE SECRETARY, FrepErAL HorticutturaL Boarp. Notice or QUARANTINE No, 11 (Forerey). POTATO QUARANTINE. The fact has been determined by the Secretary of Agriculture that injurious potato diseases, including the powdery scab (Spongospora subterranea), new to and not heretofore widely prevalent or distributed within and throughout the United States, exist in the Dominion of Canada, Newfoundland, the islands of St. Pierre and Mique- lon, Great Britain, Ireland, and Continental Europe, and are coming to the United States with imported potatoes. Now, therefore, I, Davin F. Houston, Secretary of Agriculture, under the authority conferred by section 7 of the act of Congress approved August 20, 1912, known as “The Plant Quarantine Act” (37 United States Statutes at Large, page 315), do hereby declare that it is necessary, in order to prevent the introduction into the United States of such potato diseases, to forbid the importation into the United States, from the countries hereinbefore named, of the common or Irish potato (Solanum tuberosum) until such time as it shali have been ascertained, to the satisfaction of the Secretary of Agriculture, that the country or locality from which potatoes are offered for import is free from such potato diseases. On and after December 24, 1913, and until further notice, by virtue of said section 7 of the act of Congress approved August 20, 1912, the importation, from the countries hereinbefore named, of the common or Irish potato, except for experimental or scien- tific purposes by the Department of Agriculture, is prohibited: Provided, That ship- ments of such potatoes loaded prior to December 24, 1913, as shown by consular in- voices, will be permitted entry up to and including January 15, 1914. Done at Washington this 22d day of December, 1913. Witness my hand and the seal of the United States Department of Agriculture. [SEAL. ] Davin F. Houston, Seerctary of Agriculture. A GENERAL QUARANTINE NOW IN EFFECT. The order quoted above has resulted in the stoppage of potato importations from Canada and all the countries of Europe for an indefinite period. It is not known at present how many of these countries will ultimately qualify for the lifting of the quarantine, but the apparent general distribution of powdery scab in many of them makes it improbable that they will resume shipments to the United States in the near future. Certain portions of Canada are reported to be nearly free from powdery scab, and the vigorous campaign now being waged there against the disease offers hope that the restriction may be modified with respect to specified districts at an early date. The initiative in lifting the quarantine rests with the foreign government, which must notify the United States that specified dis- THE POTATO QUARANTINE. 13 tricts have been surveyed and found to be free from wart and powdery scab and that they are ready to inspect and certify potatoes intended for export, in conformity with our regulations. Such action has now been taken by the Kingdoms of Belgium and Denmark, and on February 20, 1914, the quarantine was lifted from these countries by an order of the Secretary of Agriculture, and hereafter their potatoes may be imported into the United States subject to and in accordance with the general regulations referred to. These regulations have been issued in printed form, and all persons . desiring full details, especially as to the procedure to be followed in making importations, should procure an official copy.t GENERAL EXPLANATION OF REGULATIONS. Control of importations is secured through a system of permits, as already in force for nursery stock. The importer makes his applica- tion to the Federal Horticultural Board at Washington, on forms provided, and receives a permit authorizing him to import potatoes from a specified firm and district from the time of issuance until June 30 following. A permit for each shipment is not required. Notice must be given to the board when each shipment arrives. For details, the regulations should be consulted. IMPORTATIONS ALLOWED FROM DISHASE-FREE DISTRICTS ONLY. The regulations provide that before the quarantine is lifted or permits are granted for importations from any country the officials of that country shall determine by a field survey, or in the case of the present crop by a cellar or pit inspection, that the country or district is entirely free from wart and powdery scab. It is not intended that there shall be any attempt made to sepa- rate by sorting the clean from the infected potatoes. The warning has been emphatic from all pathologists consulted that such an inspection would be utterly impracticable; that if any disease was present in a lot of potatoes it would be out of the question to sort them under commercial conditions without overlooking some disease. Infection might also be carried on healthy potatoes that had been in contact with diseased tubers. Tt is believed by the Federal Horticultural Board that the freedom of a district from disease can be determined with sufficient accuracy to afford a reasonable safeguard when checked by the foreign inspec- tion and by inspection on arrival at the port of entry. Prevention of transshipments from quarantined districts is accom- plished through the cooperation of the foreign government, which must provide an ‘‘effective quarantine” against districts quarantined 1 Regulations governing the importation of potatoes into the United States under the provisions of the order of the Secretary of Agriculture issued December 22, 1913. 14 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. by the United States. This may be done by a decree prohibiting the exportation to the United States of potatoes not grown in the country taking the action. CERTIFICATE OF INSPECTION. No potatoes are to be admitted to the United States under the new regulations unless they are accompanied by a certificate issued by an official authorized of the country of origin, stating that they were grown in a specified disease-free district or locality, that they have been inspected by him and found free from dangerous insects and plant diseases, and that they are packed in containers that have never been used for potatoes. An original certificate of this nature must accompany the invoice when presented at the customs office, and a copy of the certificate must be attached to each sack, barrel, or other container. Provision is made for bulk carload shipments, but not as yet for wagonloads hauled across the border. INSPECTION ON ARRIVAL. Shipments will not be released from customs until inspected by a representative of the Federal Horticultural Board and found free from dangerous diseases. If powdery scab or wart is discovered the ship- ment must be exported or destroyed. The most important safeguard provided is the limitation of imports to potatoes grown in disease-free districts or countries and the foreign inspection and certification. The port of entry inspection in the United States serves as a check on these, but is not a sufficient means in itself, for the reasons already stated and because only a portion of each shipment can be carefully looked over without maintaining an army of inspectors. LIMITATION OF PORTS OF ENTRY. The right is reserved under the new regulations to restrict importa- tions of potatoes to ports of entry named by the Federal Horticultural Board when the permit is granted. It is manifestly impossible to maintaim an inspection service at each customs office, and at the out- set 1t is probable that entries will be allowed regularly only at New York and Boston, with the exception of special cases where it proves feasible to have inspections made elsewhere. Bry far the greater part of the potatoes imported in past years have come to the port of New York. Permits must be secured in advance of importation in ali cases. ADDITIONAL SAFEGUARDS. If inspection at the port of entryshows that potatoes are infected with the wart disease or with powdery scab or other injurious plant diseases, or with injurious insect pests, the shipments will be refused THE POTATO QUARANTINE. 45) -entry. Permits for the entry of potatoes may be refused and existing permits may be canceled on proof that the certificate of inspection does not correctly give the locality where the potatoes were grown, the character of the shipment as to freedom from disease or insect infestation, or falsely states that the containers have not been previ- ously used for the shipment of potatoes. ; Permits may be canceled and further permits refused for the impor- tation of potatoes from any country whenever such potatoes, in the judgment of the Federal Horticultural Board, are found to be so in- fected as to indicate plainly that the foreign inspection is merely perfunctory, or if the permittee falls to give to the Secretary of Agri- culture and to the duly-authorized inspector of the department at the port of entry designated in the permit notices of the arrival cf potatoes or gives a false notice. IMPORTATIGCNS FROM NONQUARANTINED COUNTRIES. Potatoes will be allowed to enter from sources other than Canada and the countries of Kurope when properly inspected and certified by the authorized officials of the country of origin. The importers must comply with the permit requirements already mentioned. Bermuda has complied fully with the regulations by prohibiting the importation of potatoes from Canada and Europe and by inaug- urating a rigid imspection service. The importation of potatoes from these islands has therefore contmued without check. The total quantity of potatoes brought from Bermuda during the year ended June 30, 1913, was 141,422 bushels. These are all en- tered at New York and find a special market at a high price. None are used for planting in the United States. The importation of potatoes from the State of Chihuahua, in Mexico, having been determined by an inspector of the Department of Agriculture to be attended by no risk from insects or diseases, the requirement of foreign certification has been waived temporarily in consideration of existing conditions in Mexico, and permits are being granted for such importations, from Chihuahua only, subject to in- spection at Hl Paso, Tex., the port of entry. Last year’s importations from Mexico amounted to 8,301 bushels. RELATION OF IMPORTED TO DOMESTIC POTATOES. The total imports cf potatoes into the United States make up a very small proportion of the total consumption, as may be computed from Table I. For the five years, 1907-1911, preceding the quaran- tine, the imports minus the exports were 1.03 per cent of the esti- mated production. 16 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. TaBLe I.—Acreage, production, value, prices, exports, and imports of potatoes in the United States, 1900 to 1912, inclusive. For fiscal year beginning A Average one . vee Acreage Avi , Year. planted and | yield per| Production. | price per Pacuus aug, harvested. acre. bushel, tak Tamestic Dec. 1. exports. Imports Bushels. Bushels. Cents. Bushels. Bushels. TON eee toes. 2,611, 000 80.8 | 210,927, 000 43.1 | $90,811,000 741, 483 371, 911 TO ilies 5 bogies Sa 2, 864, 000 65.5 | 187,598,000 76.7 | 143,979,000 528,484 | 7,656, 162 IG eras oe 2,966, 000 96 284, 633, 000 7.1 134, 111, 000 843,075 358, 505 SOUS eee ee 2 2,917, 000 84.7 | 247,128, 000 61.4 | 151, 638, 000 484, 042 3, 166, 581 (ee eee 3, 016, 000 110.4 | 332,830,000 45.3 | 150,673,000 | 1,163,270 181, 199 iL Uae Se ee 2,997, 000 87 260, 741, 000 61.7 | 160,821,000} 1,000,326 | 1,984,160 TSOBS* oo se sens 3,013, 000 102.2 | 308, 038, 000 51.1 157, 547,000 | 1,530, 461 176, 917 ASOT A Sores Ace 3, 128, 000 95.4 | 298, 262, 000 61.8 | 184,184,000 | 1,203,894 403,952 N90S ee as rere 3, 257, 000 85.7 | 278,985, 000 70.6 | 197,039, 000 763, 651 8, 383, 966 AQ0O Fe aan ies 3,525, 000 106.8 | 376,537,000 54.9 | 206,545, 000 999, 476 353, 208 1910 TF. Eee 3,720, 000 93.8 | 349,032, 000 55.7 | 194,566,000 | 2,383,887 216, 984 GUE as Shee e noe 3, 619, 000 80.9 | 292,737,000 79.9 | 288,778,000 | 1,237,276 | 13,734, 695 AOU ee Re oe 2 3, 711, 000 113.3 420, 647,000 | © 50. 5 212,000; QOOR i ces cance eres ois me ~ THE 1913 POTATO CROP. The potato crop of the United States for 1913 is estimated to be 238,946,000 bushels. The principal shortage is in the Central States, which are not the leading potato States. Comparisons to determine the actual needs of the country can not fairly be made with the 1912 crop, which was so large that hundreds of thousands of bushels went to waste for lack of a market and millions of bushels were sold for. less than the cost of production. . The following is quoted from the department’s Weekly News Letter to Crop Correspondents, January 28, 1914: FirmMer HouLpING or POTATOES BY THE FARMERS. SUPPLY IS NEARLY NORMAL, BUT DISTRIBUTION IS UNUSUALLY UNEVEN—PRINCIPAL POTATO-PRODUCING STATES HOLD SUPPLIES, WITH SHORTAGE IN A NUMBER OF CONSUMING STATES. The yearly estimates of the amount of potatoes remaining in growers’ hands and the stocks in dealers’ hands on January 1 in the important potato States, just com-. pleted by the Bureau of Statistics (Agricultural Forecasts), United States Depart- ment of Agriculture, indicate that a larger proportion of the marketable crop of potatoes was still in the hands of farmers on January 1 than had been the case for four years past. The proportion estimated to be in dealers’ hands was smaller than for any year of the four except January 1, 1912. The figures showed that the total estimated potato production was below normal, but, owing to the slow movement of the crop up to January 1, the supply for the remainder of the year will be almost normal. Distribution, however, seems to be unusually uneven. The holdings of potatoes are relatively large in the important producing States of Maine, Michigan, Wisconsin, and Minnesota; and relatively small in New York, Ohio, Indiana, I]li- nois, lowa, and Kansas, which are important both as potato-producing and potato- consuming States. In consequence of the firm holding by farmers the price early in the season has been unusually high, being on December 1 about 17} cents per bushel higher than THE POTATO QUARANTINE. 17 a year ago and 164 cents higher than three years ago, but 114 cents lower than two years ago, when potatoes on January 1 were selling for 77} cents per bushel and the supply was unusually short, owing to the drought of the previous year. Present conditions do not seem to forecast material, if any, advance in prices in the important producing States this year. In 1911, when supplies were but mod- erately larger than now, and in 1913 the price movement after January 1 was down- ward instead of upward. The only other factor which may enter to change the experience of 1911 and 1913 is the somewhat different distribution of the crop which exists this year. Southern growers who plant in the spring for the early market would seem to be justified, from present conditions, in putting out a normal acreage, but should not expect the big advance in prices which prevailed two years ago. The estimates indicate that about 42.1 per cent of the marketable supply of pota- toes of the 1913 crop remained in the bands of farmers and 9.5 per cent in the hands of dealers on January 1 in the important potato-growing States. These figures com- pare with 39.8 and 9.8 per cent similarly estimated a year ago, 33.1 and 8.6 per cent two years ago, 40.2 and 10.9 per cent three years ago, and 41.2 and 9.9 per cent four years ago. If, for the purpose of comparison, these percentages were applied to the - estimates of total production, it would show total stocks of 123,000,000 bushels on Jan- uary 1, 1914 (in the 19 States analyzed below), compared with 150,000,000 a year ago, 91,000,000 two years ago, 133,000,000 three years ago, and 142,000,000 four years ago. These figures would indicate that the quantity to be carried toward the close of the season will not be sufficient to cause depressed prices, as was the case particularly four years ago (in some States last year, also), nor, on the other hand, will they be so scant as to cause such high prices as prevailed in the spring of 1912. To show the relation between supplics and prices, the following tabulation is given, showing for the past five years the production, stock on hand January 1, and the prices paid to producers on December 1 and the following March 1 in 19 impor- tant potato-growing States: Stocks on Jan. 1. Warm prices. ; Total pro- In growers’ hands. | In dealers’ hands. Years. pata (bushels). Total Tap a Per Per (bushels). | *?°C: 1. | Mar. 1. cent Bushels. cent Bushels. of crop. of crop. 1913-14,... 22... 238, 946, 000 42.1 | 100,495,000 9.5 | 22,797,000 } 123,292,000 CA ese cee OU S Siapeueeece 304, 126, 000 39.8 | 119,678,000 9.8 | 30,167,000 | 149,845,000 48.6 AT. TOME Dea a 217,532,000} 33.1 | 72,072,000 8.6 | 18,706,000 | 90,778,000] 77.6] 101.4 TOTO ee ose 261,141,000 40.2 | 104,954, 0C0 10.9 } 28,463,000 | 133,417,000 49.5 46.9 IGA cea seees 238, 308, 000 41.2 | 122 997,000 9.9 | 29,384,000 | 142,381,000 50.0 47.3 A PROGRESSIVE POLICY N®#EDED. The present situation emphasizes the fact that potato production in the United States is not on a sound economic basis. We have an almost regular alternation of seasons when more potatoes are pro- duced than can be consumed and prices fall below production costs im many instances and of seasons of short crops when prices are unrea- sonably high to the consumer. This condition is reflected in the imports and exports, as shown in figure 1. 18 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. It will be noted that during seven years of the twelve, more pota- toes were exported than were imported, while during five years the imports exceeded the exports. The possibilities of potato production in the United States are almost unlimited. All of the States could increase their acreage and their average yield, and there exist in many northern districts, par- ticularly in Maine, Michigan, Wisconsin, and Minnesota, large areas of cut-over lands, recently in forest but now being brought under cultivation, which could produce many times more potatoes than at present. The same is true of the irrigated West. Under present economic conditions, however, no material increases in acreage could be made without risk of overproduction. Among the most striking features of potato culture m the United States are the low average yield per acre, the relatively high cost of production per bushel, the distance from markets of many important EXPORTS | SIPOR TS FHELLIG? BLSAIELS AAILLSION EUSAHELS esti TZ Sy BO, ME TY EF po FANE SS WQWNS a Fig. 1.—Exportsand imports of potatoes for the United States during the years 1900 to 1911, inclu- sive, showing graphically the alternating seasons of overproduction and scarcity. potato districts, and the fluctuations in the market price, which make potato growing rather a speculative enterprise. To insure permanent prosperity there is a real need for the adoption of a constructive policy that will strike at the roots of the present difficulties, a policy of which quarantines or the regulation of imports are only minor phases, for foreign potatoes must of necessity in the future play a still smaller réle than now in supplying food to the people of the United States as our population increases and as the European crop will be more and more needed for home consumption. PROTECTION FROM DISEASE. In view of the already excessive losses from diseases and insects, it is apparent that it is of national importance to prevent the intro- duction of more pests of this nature from other countries, a pro- tection which is afforded through the plant quarantine act. THE POTATO QUARANTINE. 19 The quarantine law is, however, not the best means of controlling diseases already existent within our borders, for it does not provide authority for quarantining a single farm or a limited district in one of the States except as to interstate shipments. It is, therefore, of the highest importance that each State enact legislation authorizing the proper State officials to search for suspected cases of new or dangerous diseases and empowering them in the event of their dis- covery within the State to destroy infected stock or material, to put under quarantine the areas involved, and to take other measures needed to prevent the spread of the troubie. In some States such laws exist for nursery stock, but they do not always cover potatoes. It is particularly in States doing a large business in seed potatoes that such legisiation is needed. : The fact that many diseases, like the black-leg, dry-rot, scab, and eelworm, are scattered far and wide on infected seed also makes necessary some community or State action to control these troubles at the source by stimulating the growing of seed potatoes as a special business and by establishing a system of inspection and certification that will provide a means by which distant purchasers can be guar- anteed the freedom from disease of potatoe seed stock purchased, as well as its varietal purity and vigor. At present, the consumer sie the loss ee potato diseases, whether in the field, in storage, or en route to market. Much of the loss can be prevented by better spraying or better methods of grading, handling, and shipping, which have not yet been worked out and adopted on account of a lack of concerted action and community of interest on the part of buyers, shippers, jobbers, and retailers. These men can assist the grower in lowering the present excessive retail prices of potatoes. LACK OF AN GUTLET FOR SURPLUS POTATOES. Under present conditions the production of potatoes is limited by the requirements of the market for table stock. A few culls are made into starch and a few fed to stock, but there is no extensive use of potatoes for industrial purposes such as one finds in Europe.! Furthermore, the production in the United States is greatly influenced ay weather conditions, especially by the occasional periods of heat or drought to which we are more subject than Europe and to which the potato is more sensitive than some other crops. The result is that when we add to these two factors the natural tendency of farmers to reduce their acreage after a year of low prices and to increase it after a year of high prices, we have the oxcessive fluctuation in supply and market prices already described. 1Cf. Department of Agriculture, Bulletin 47. 20 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. Some means of disposing of surplus potatoes is an economic neces- sity. If this can be done at a price reasonably above the cost of production, the potato crop will increase and a reserve supply of potatoes grown for industrial uses will be established that will meet the needs of all short years. | Diversification or the introduction of better farming systems wil] be a step in this direction. Means should be worked out for keeping more live stock, especially swine, on potato farms, and a better understanding of the feeding value of potatoes and of the best rations combining potatoes with other feeds should be secured. The industrial uses of potatoes for starch, dextrin, alcohol, etc., require investigation in the United States. Perhaps the most press- ing need along this line is the adaptation of a method of drying pota- toes, as practiced in Germany, to American conditions, to the end that surplus quantities and culls of this perishable product may be preserved and by removal of its water rendered transportable to market. This problem is closely connected with that of varieties, for the starch content of most American potatoes is low, often too low for profitable drying. Breeding for higher starch content needs to be promoted, as well as breeding for table quality, productivity, and disease resistance. A nation-wide cooperation for the solution of these different phases of the potato question should not leave out of consideration the problem of values from a national viewpoint: That the cost of pro- ducing and distributing potatoes should be kept down to such a point that the market price of this staple food shall be comparable with other staples. Marketing investigations and related problems of distribution demand active support. O BULLETIN OF THE PUSDEDARIMENT OFAGRICULTURE No. 82 Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. April 6, 1914. (PROFESSIONAL PAPER.) POWDERY SCAB (SPONGOSPORA SUBTERRANEA) OF POTATOES.* By I. E. Metxuus, Pathologist, Cotton and Truck Disease and Sugar-Plant Investigations. INTRODUCTION. The comparatively recent discovery of Spongospora subterranea in the United States makes it necessary to introduce to the potato grower, importer, and pathologist a new potato disease. This disease is commonly known as powdery scab, and mild attacks of it resemble superficially the common Oospora scab. Its prevalence in many Kuropean countries and the Dominion of Canada has prompted the Secretary of Agriculture to extend, for a time at least, the present quarantine on foreign potatoes. Although powdery scab has probably been known to exist in Kurope since 1841, it was not until within the last decade that it assumed an important réle in pathological literature. It has been most extensively studied by pathologists in the British Isles, where powdery scab is said to be very common. In February, 1913, Spongospora was reported for the first time in North America. It was collected in several provinces of Canada by the Dominion Botanist, Dr. H. T. Giissow (1913),? who has expressed the opinion that the first introduction into Canada must have been at least seven years previous. Dr. W. J. Morse (1913), of the Maine Agricultural Experiment Station, and the writer (1913) obtained evidence during the summer of 1913 showing that this disease exists in the United States. It seems probable that it was introduced with the heavy shipments of foreign potatoes in 1911 before the quarantine law against the wart disease went into effect. Sufficient evidence is at hand to show that powdery scab will make inroads on the potato industry unless proper precautions are taken, and it is the 1 This paper will be of interest to plant pathologists and to potato growers in the northern and southern potato-growing sections. 2 The dates in parentheses refer to the bibliography printed at the end of this bulletin. 30951°—14 2 BULLETIN 82, U. S. DEPARTMENT, OF AGRICULTURE. object of this bulletin to call attention to this fact and ask the con- certed effort of all interested in the potato industry to prevent the spread of this malady. COMMON NAME OF THE DISEASE CAUSED BY SPONGOSPORA. Spongospora, like many other fungi, has been given a variety of common names. In Germany it was early known as “ Kartoffel- raude” (Wallroth, 18426) among the farmers. By Wallroth (1842a), who first recorded its occurrence and who considered it a smut, it was given the common name “Knollenbrand.” According to Brunchorst it is called ‘‘Skorv” in Norway, and is identical with the disease known as ‘‘Schorf” or ‘‘Grind”’ in Germany. In the British Isles, where it has been most intensively studied, it has been called corky end, corky scab (Johnson, 1908), powdery scab, Spongospora scab, and potato canker. The name powdery scab, which was first applied to it by Johnson, of Ireland, is in most common use at the present time. This name has reference to a characteristic symptom of the mature spot, or sorus, as it appears when the infected tuber is dug from the ground. SCIENTIFIC NAME OF POWDERY SCAB. The scientific name of Spongospora has been changed even more often than its common name. This has probably been due (1) to the imperfect understanding of the life history of the fungus and (2) to the superficial resemblance of the spore balls of Spongospora to those of the smuts. Wallroth (1842b), who first collected Spongospora in 1841, named it Erysibe subterranea. It was described and figured by Martius (1842) as Protomyces tuberum solani. In 1844 Rabenhorst concluded it was not a species of Erysibe and described it in a new genus, Rhyzosporium solani. That Berkeley (1846) was familiar with the fungus and knew that it had been reported previously is apparent from a short note in one of his articles on the potato murrain published in 1846. He mentions Martius’s Protomyces and figures the spore balls, choosing, however, to callit Tuburcinia scabies (Berkeley, 1850). The name of the organism was again changed in 1877 by Fischer von . Waldheim, who placed it in another genus and called it Sorosporvwm scabies Berk. It was not until 1886, when Brunchorst found Spongospora on potatoes in Norway, that it was shifted into the correct group, namely the Myxomycetes. Why Brunchorst failed to recognize or mention any of the earlier descriptions of Spongospora is not explained in his paper. That he was aware of the fact that the same disease existed in Germany and perhaps in England is evident from the following sentence: Was das Vorkommen des Spongospora betrifft, ist derselbe hier in Norwegen dusserst verbreitet; wenn es sich bestitigen sollte, was ich sicher glaube, dass der POWDERY SCAB OF POTATOES. 3 Pilz die Ursache der in Deutschland ‘‘Schorf” genannten Krankheit ist, und viel- leicht auch der “Scab” der Englander, wiirde auch sonst die Verbreitung eine ganz _ ansehnliche sein. Nevertheless he described it anew as Spongospora solani, and this name was in general use until 1908, when Massee (1908 and 1910) described it as Spongospora scabies, combining Brunchorst’s generic name and Berkeley’s specific name, a combination which is re- ferred to by Pethybridge (1913a) as not necessary and untenable. Johnson, of Ireland, used the name applied by Brunchorst until 1909, when he found evidence to show that Brunchorst’s Spongospora solani was identical with Wallroth’s Erysibe subterranea. In an article published in 1911, Horne is unable to confirm Johnson and questions whether the organism described and figured by Wall- roth, Martius, and Berkeley really is the same fungus described by Brunchorst. In view of this fact he adheres to Brunchorst’s Spon- gospora solant. In a very recent article Pethybridge (1913q@) brings forth still more evidence to establish the identity of Wallroth’s Hrysibe subterranea and the organism now known as Spongospora. He also emphasizes the fact ‘‘that the question of identity does not rest merely upon the degree of accuracy with which the spore balls are figured, but some regard must also be paid to the very full description given by Wall- roth of the development and fate of the warts, which agrees fully with what we know of the behavior of Spongospora and which does not apply to any other organism known at present.” Judging from the evidence now available as to the specific name of Spongospora, it seems clear to the writer that it should be that first used by John- son, namely, Spongospora subterranea (Wallr.) Johnson. DESCRIPTION OF THE DISEASE. This disease, so far as is known, never attacks the aboveground portions of the potato plant. It is primarily a disease of the young tubers, which develops as they mature in the ground. The earliest stages of infection, according to Osborn (1911), ‘‘are visible on young tubers not larger than hazelnuts. The disease is apparent by small shghtly raised pimples and a slight discoloration of the surface. When cut open, the infected areas appear faintly purplish and extend from approximately the outermost cells of the tuber toward the deeper layers. Actual infection of the potato tuber by Spongo- spora has not been seen, nor have infection experiments been success- ful. The earliest stage in the life history that has been observed is that of a single uninucleate amceba in a young potato eell near the eye.’ Once in the tissues these naked masses of cytoplasm consume the cell content and multiply rapidly, as shown in Plate I, A, and at the same time stimulate the host cells to further growth and division. ae BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. It seems established that the amcebe pass from one cell to another when cell division takes place, although it is claimed by Massee (1908) that the ameebe invade new cells by boring through the cell walls. On the other hand, Osborn (1911), who has made an extensive cytolog- ical study of this organism, holds that ‘‘on the division of the host cell * * * it is a purely fortuitous circumstance whether each resulting cell shall contain an ameba, and so be infected or not. * * JT have never seen any signs of the migration of an ameba to a neighboring cell nor any continuity of protoplasm, such as Massee has described.’’ Osborn’s contention as to the method of migration of the amebe has been confirmed by Horne (1911). The abnormal local increase of cells causes a swelling and a faint discolor- ation of the skin, which latter becomes a wartlike outgrowth. The fungus present in this tissue consumes largely the contents of the cells (Pl. I, C, D), after which the ameebe coalesce (Pl. I, C, D) and form one or more large spongy masses in each cell, known as plasmodia ‘(PL I, D). These latter divide into many small spores, each of which takes on a heavy yellowish brown wall (Pl. I, #). Instead of these spores separating, they remain attached, forming a ‘‘spongelike body,” according to Johnson (1908), and not a hollow sphere, as reported by Berkeley(1846) and Massee (1910). Since the contents of the attacked host cells are used up in form- ing spore balls, the infected area becomes a pit filled with a yellow- ish brown dust consisting chiefly of spore balls (Pl. II, C). These pits, or sori, at maturity are bordered by the torn skin of the tuber. The torn skin standing up on the periphery of the sorus is one of the characteristics of powdery scab, which often enables one to dis- tinguish it from the Oospora scab macroscopically. The powdery con- tents of the sori in this stage of the disease doubtless suggested to Johnson the name ‘‘powdery scab,” as has already been noted. It has been observed that in storage shriveling and shrinkage take place about these pits, or sori. How generally this shriveling occurs and its significance are not known up to the present writing, nor have these matters been emphasized in the literature, to the writer’s knowledge. The cause of this shrinkage is not known, but it may possibly be due to insufficient cork deposition in the bottom of the sori which afford an avenue for storage rots to attack the infected tuber. When conditions are highly favorable for the fungus, it may eat large cavities in the immature tubers. Besides consuming part of the tubers, it stunts their further growth and produces malformed tubers, such as are shown in Plate III. The nature and extent of the depressions caused are shown in Plate III, C. This stage of the dis- ease has been called the cankerous stage (Horne, 1911) and is the one that causes the greatest loss. Bul. 82, U.S. Dept. of Agriculture. PLATE I. - OVI ne Beaten age YS VARIOUS STAGES IN THE LIFE HISTORY OF THE FUNGUS WHICH CAUSES POWDERY SCAB. A, A large host cell in which there are three amcebe of Spongospora. B, A young host cell in the early stages of infection. The amceba lies just below the nucleus. (C, The amcebe are coalescing to form the plasmodium. JD, The plasmodial stage. EH, Mature spore balls in an enlarged host cell. (A to #, after Osborn.) /, The isoiated spore balls photographed. Note the variation. (Original. Bul. 82, U.S. Dept. of Agriculture. PLATE II. Four TUBERS (A, BL, UC, AND D) INFECTED WiTH SPONGOSPORA SUBTERRANEA COL- LECTED IN NEW BRUNSWICK, DOMINION OF CANADA, ON OCTOBER 1, 1918. They represent the scabby stage of the disease. The sorimay he either isolated or grouped, as shown in 4A and B, The variation in size and general appearance of the sori is brought outin Caud D. In the tuber marked D the sori are only about half as large and more superficial than in C. Two tubers infected with Oospora scab are shown as E and F. Bul. 82, U. S. Dept. of Agriculture. PLATE III. THE CANKEROUS STAGE OF SPONGOSPORA. It is this stage that is most destructive to the potato tuber. The cavities and large pustules combine to cause malformation of the tubers. In @ is shown a section through a tuber badly infected with Spongospora. (A, B, D, and E are after Horne, (after Giissow.) POWDERY SCAB OF POTATOES. 5 GEOGRAPHICAL DISTRIBUTION OF POWDERY SCAB. Spongospora seems to be quite generally distributed in northern Europe. As early as 1841 it was recorded as existing in Germany, and that it had existed for some time before this is suggested by the fact that among farmers the disease had come to be known by a com- mon name (Kartoffelraude). Frank more recently (1897) has men- tioned its existence in Germany, but he does not think it is generally distributed. That it does exist to some extent, and possibly more than Frank’s report indicates, is suggested by the following facts: In the spring of 1913 the Bureau of Plant Industry purchased 22 different varieties of seed potatoes from two dealers in Germany. When these were received and examined by the inspecting patholo- gist, four of the lots were condemned, being infected with Spongo- spora. In 1846 powdery scab was discovered in England by Berkeley in connection with his studies of the potato murrain, the disease which is now known as Phytophthora infestans. The little careful study that was given to Spongospora by the pathologists of Berkeley’s day may well have been due to the intensive study given to the Phytophthora disease, which at that time threatened to destroy the potato industry of northern Europe. The general distribution of Spongospora in England and Scotland at the present time can readily be seen from the following statement of the Board of Insect and Fungous Pests for 1909: It has been reported to the board from many parts of Great Britain, chiefly, how- ever, from those parts where wart disease is also present, or where it has been sus- pected. Cases have been reported from Peebles, Stornoway, Forfar, Fife, Lanark, Aberdeenshire, Stirlingshire, Lancashire, Cumberland, Shropshire, Rorks, W. W., Staffordshire, Wales, Hereford, Somerset, and Worcester. In Scotland, therefore, the disease seems fairly widely distributed, but in England, as might be expected, it appears to be confined to the west, where the rainfall is higher. It is not, however, to be supposed for a moment that anything like all affected localities are here recorded. In the spring of the current year the United States Department of Agriculture imported 18 different varieties of potatoes from Scotland for seed purposes, all of which were found to be infected with Spongo- spora and were condemned by the inspecting pathologist. Nine dii- ferent varieties were imported from England for similar purposes and were not allowed to pass, owing to Spongospora infection. On October 31, 1913, Mr. W. W. Gilbert, of the Bureau of Plant Industry, collected specimens cf powdery scab on potatoes imported into this country from the Netherlands. On November 20 the writer likewise collected Spongospora at New York City on two different shipments from the Netherlands. The following day specimens were taken by Mr. O. A. Pratt and the writer from a shipment coming from Belgium. More recently the disease has been found several times 6 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. in considerable quantity on potatoes coming from the Netherlands and Belgium. As already stated, the disease has been in Norway since 1886 and has since been found in Sweden. t is also interesting in this connection to note that Spongospora occurs in South America, probably the native habitat of the potato. Tt was collected in 1891 at Quito, Ecuador, by Lagerheim, who reports that the disease is well known to the natives. This suggests two possibilities: (1) That the disease has always existed there or (2) that it was introduced into South America on European varieties. PRESENCE OF POWDERY SCAB IN CANADA. More recently powdery scab has gained a foothold in North America, and early in the spring of 1913 it was reported in several Provinces of Canada by Giissow. The writer has been able to confirm Giissow’s reports by personally visiting the potato-growing sections in three of the Provinces of Canada, namely, New Brunswick, Prince Edward Island, and Nova Scotia. It was found that powdery scab was quite generally distributed in the lower St. John River valley, New Brunswick, and on Prince Edward Island. POWDERY SCAB IN THE UNITED STATES. That Spongospora exists also in the United States has been defi- nitely established. In the spring of 1913 Morse, of the Mame Agri- cultural Experiment Station, obtamed some evidence that the disease exists in Nebraska and Massachusetts. No further cases have been reported from these States. In June, 1913, the writer collected 84 tubers infected with Spongospora from four barrels of the Green Mountain variety purchased for experimental purposes at Presque Isle, Me. These had been grown in the vicinity of the village during the season of 1912. Spongospora was collected at Washburn, Me., on February 9, 1914, and at Frenchville on the following day. Later it was found at stations farther south in Aroostook County. A thorough survey of northern Maine is now being made by the State department of agriculture, with the cooperation of this depart- ment. The survey to date indicates that powdery scab is more common in the northern half of Aroostook County. Several cases were found where the growers at some time during the last three or four years had secured seed from the neighboring infested sections of New Brunswick, which may well account for the introduction of the disease. The results secured up to the time this bulletin goes to press indicate that there is considerable powdery-scab infection in Aroostook County. The active measures that are now being taken to discover and delimit the infected areas and to prevent the ship- ment of diseased potatoes for seed purposes should result in checking the spread of powdery scab. POWDERY SCAB OF POTATOHRS. 7 DAMAGE TO THE POTATO CROP. The scabby stage of Spongospora, like the common Oospora scab, is a skin disease confined to the tubers, marring their appearance and thereby decreasing their market value. The cankerous stage, as shown in Plate III, completely destroys the tubers for both food and seed purposes. This observation is confirmed by the following quotation irom Pethybridge (1911, p. 442): As was pointed out last year, Spongespora scab presents two forms of attack, in the one ease that of small spots on the surface of the tubers, and in the other the form of a ‘‘canker”’ or eating away of the tuber. This latter is, of course, the most serious one, but there are all degrees of transition between it and the spot form. Pethybridge is inclined to classify the effect on the potato as producing “‘scab spots” and “‘cankers,” the former doing little harm: to the tuber, while the latter, as shown by his illustrations, com- pletely deform and dwarf its growth, so as to make the tubers worthless. Osborn, (1911) holds that the soil moisture determines to a great extent the damage done by the disease and says— Under dry conditions of the soil the external appearance is limited to small circular patches about 5 mm. across. Under wet conditions the damage is more serious and the scabs may be as large as 3-4 cm. in diameter and as much as 2 em.indepth. This is the only external appearance; there is no sign of hypertrophy or any distortion other than that caused by the pitting. The presence of the fungus in the cells stimulates the host to lay down a new layer of cork ceils surrounding the sorus, if the soil is not too wet, which checks its growth. By Giissow (1913), who has, as already stated, found powdery scab in Canada, the disease is not considered trifling. He says— The disease should by no means be regarded lightly. Severe attacks occur when potatoes are planted year after year on infected land. Where this is practiced the result will be potatoes hardly superior in quality te those badly affected with canker. This fact is worthy of notice, especially since, as in the case of canker, no preventive measures have proved of much value. In a very recent publication, Pethybridge (1913), p. 459) refers to the damage done by Spongospora in his experimental plats, as follows: They were particularly disastrous on those portions of the land which for special purposes have now been cropped for four successive seasons with potatoes, the cankerous form of the disease being extremely common. In one or two plats nearly two-thirds of the total crop were practically ruined by it, while the general average loss in the plats on the old land due to it would be about one-third of the crop. EFFECT ON SEED POTATOES. Besides injuring the potato for market purposes and decreasing the yield, as already. noted, powdery scab also depreciates the value 8 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. of the potato for seed purposes. Its harmful effect on the seed has been emphasized by Johnson (1908, p. 453), as follows: Such tubers are not only much reduced in market value for eating purposes, but must provide also poor seed for the next year’s crop. Yet I was constantly told that this was the kind of seed regularly planted from year to year; and that the people used this seed because they had, and could get, no other. * * * Thave no doubt myself that this Spongospora scab has a good deal to do with the miserable average yield per acre of potatoes in the west of Ireland. * * * It is in some districts of Treland as injurious to potatoes as finger-and-toe is to turnips. The following sentence from Pethybridge’s report in 1911 (p. 442) shows more strikingly the relation of the disease to the seed potato: Tt was found during the past season that the crop resulting from the planting of the “canker”? form of disease in clean land gaye 67.1 per cent of affected tubers, while the spot form produced only 54.1 per cent. That other countries are not considering Spongospora scab lightly is apparent from a farmers’ bulletin, No. 110, of the Transvaal Department of Agriculture, issued by Evans in 1910, warning the grower against the use of infected seed potatoes. Evans says— Corky scab has caused a considerable amount of damage to the potato crop in Great Britain, Ireland, and Norway. It also occurs in Germany, and is particularly preva- lent in the west of Ireland. * * * Diseased tubers should on no account be used for seed purposes, for not only will the resulting crop be scabbed, but the ground will also be infected with the germs of the parasites. Tt must also be remembered that not only does powdery scab injure the crop, but the soil becomes contaminated and clean seed planted on this land for several years afterwards becomes infested. Just how long the organism can remain alive in the soil is not known, but that it is resistant and may live for several years is suggested by the structure of the spores and experiments by Pethybridge (1911) showing that the spore balls can pass through an animal without losing their capacity for renewing the disease. Contamination of clean seed may take place, it is claimed, by simply being in contact with diseased potatoes. If such is the case, and there is good reason to believe it possible, clean seed may become infected through the use of old bags and machinery. Indeed, it is even possible for one field to become infested from another by the spore balls being carried by the wind, water, and other agencies. IS POWDERY SCAB A DANGEROUS MALADY? In considering whether powdery scab is or is not a dangerous disease it is well to keep in mind that any inciting agent, regardless of its origin or nature, that mars or defaces the tuber depreciates its value and ultimately its productiveness. The degree of danger pre- sented by this intruder is problematical, but all American plant pathologists who have expressed an opinion upon this point are agreed that powdery scab is a disease possessing characteristics that POWDERY SCAB OF POTATOES. 9 might make it a serious enemy of the potato in the United States, at least as bad as the common scab caused by Oospora scabies, and prob- ably worse. The effect of the milder form of Spongospora upon the tuber resem- bles that of the common scab in that it disfigures the potato and thereby reduces the market price, even though the food value may not be materially impaired. it differs from Oospora scab in that the advanced or cankerous stage ruins the tuber for both table and seed purposes. In this connection it should be remembered that any kind of scab or other injury that mars or defaces the potato tuber is a more serious handicap in the American markets than in those of some European countries, due to the fact that consumers abroad offer fewer objec- tions to scabby potatoes than consumers in the United States. There ig even a belief prevalent abroad that scabbiness is an indication of superior quality. In the United States, when potatoes are put on the market, scabby potatoes must be sorted out, and therefore are of no use except for stock feed or the manufacture of starch. In Maine the price of scabby potatoes in the autumn of 1913 was 50 cents per barrel, while clean stock brought $1.50 per barrel. In the country as a whole, hundreds of thousands of bushels of potatoes are left in the fields because they are too scabby to market. There are frequent instances in the New York markets, according to potato dealers, where carload consignments are rejected because of the presence of numerous scabby potatoes. When the soil becomes in- fested with scab its value as potato land materially depreciates. This is especially true in sections where potatoes constitute the chief crop. The character and relationship of the parasite should also be taken into consideration in judging the danger which powdery scab presents. This is a case of dealing with a slime mold, a relative of the serious disease of cabbage, turnips, and related plants, known as clubroot. If powdery scab should prove no more troublesome in the United States than it has been up to the present in Europe, it would be rated as a disease of secondary importance as compared with late-blight or with Fusarium wilt. But there are reasons for fearing that it may become more prevalent here. It seems to be a fact that common scab is less troublesome in Europe than in America, and the same condition might be the case with powdery scab. It quite often occurs that introduced parasites are more destructive in a new habitat than in their native environment. Likewise, it is not impossible that Spon- gospora may find the American varieties of potatoes more sus- ceptible than the European sorts. There is also no means of pre- dicting the behavior of Spongospora under the varied climatic and soil conditions of the several States. The parasite has only recently 10 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. been found on the American Continent, and the brief experience with it in eastern Canada gives no hint of what its behavior would be in the southern trucking districts, the central West, or the irrigated sections. The common scab is much worse in many parts of the West than in the East. Another reason for grave concern in the United States is that the disease exists in that portion of Canada adjoining the State of Maine, which is the chief source of seed potatoes for the Central Atlantic and Southern States. If powdery scab becomes generally distributed in Maine, only the most extraordinary efforts can check its spread to nearly every State in the Union. MACROSCOPIC DIFFERENCES BETWEEN SPONGOSPORA AND OOSPORA SCAB. . It should be made clear in discussing the similarity of and differ- ences between Spongospora and Oospora scab that the symptoms and ultimate effect on the tuber vary markedly in the case of both dis- eases, depending upon external influences. In spite of the wide variation of powdery scab, two characteristic stages of the disease may be recognized, namely, the scabby and the cankerous stages, shown in Plates II and III, respectively. It is only the former of these that can be easily confused with the Oospora scab, and there- fore the latter stage needs no further consideration in this connection. As pointed out by Horne, the early stages of Spongospora resemble markedly the beginning stages of the wart disease caused by Chryso- phlyctis endobiotica, in that wartlike excrescences appear on the tuber. Such symptoms are in no way like those of the early stages of Oospora scab, and this naturally leaves for comparison only the characteristics of the two diseases as found on the mature tuber at harvest time and shortly thereafter. The scabby stage of Spongospora on the mature tuber, as illus- trated in Plate II, usually differs essentially from Oospora scab in three ways: (1) The sori are more often circular and not usually as great in diameter as those of Oospora scab. (2) The periphery of each sorus is bordered by the upraised outer epidermal layer of the tuber, so that virtually small cups or pits are formed, as shown in Plate I, B and @. (3) These pits are usually deeper than those of common scab and are always filled at maturity with a brownish colored semicompacted dust or sediment, as shown in Plate II, C. The sori of Oospora are usually shallow and composed of corky material of a compact and interwoven nature. It should be remembered that it is extremely difficult, if not impossible, to define the difference between two diseases varying so POWDERY SCAB OF POTATOES. 11 markedly under diverse environmental conditions. In fact, many cases have come to the attention of the writer where the macroscopic characteristics mentioned were not in evidence, and yet the typical spore balls were found in the sorus upon making microscopic exami- nation. It should be especially emphasized that the three differen- tial characteristics pointed out may be totally absent after the infected tuber has been harvested and roughly handled through ship- ment. In Plate II are illustrated what may be called common cases of Spongospora and Oospora scab. The upper four potatoes are infected with powdery scab and the lower two with common, or Oospora, scab. FUNCTION OF THE SPORE BALLS AND METHODS OF INFECTION. The potato crop probably becomes infected by the spore balls present in the soil or on the sets when planted. Just how infection takes place is not known. Infection studies are made difficult because no one has been able to germinate the spore balls in abundance at will. Massee (1908) claims that the content of each spore is liberated as a whole in the form of irregularly globose bodies with a few small projections. These bodies show a slow, sluggish move- ment for some time and then come to rest. Hach amceboid body is about 3 « in diameter and uninucleate. Johnson (1908) saw motile bodies resembling swarm spores in his cultures which he believed were the swarm spores of Spongospora, but he states that he never saw them escape from the spore. Instead of being uninucleate, he found them to have from one to eight nuciei, like the swarm spores of Ceratiomyx. Both Osborn (1911) and Horne (1911) have attempted to germinate the spore balls without being able to confirm either Massee or Johnson. It may be that their germination is sea- sonal, like the spores of a goodly number of other fungi, or that some special stimulus in the soil is necessary to cause them to become active. That they function can not be doubted, because clean seed planted in soil infested with Spongospora spore balls becomes infected with the disease, as shown by Horne’s experiments. It has also been proposed by Massee (1910) that the plasmodia may become encysted during the winter and resume their activity when the tubers begin to sprout, and Johnson (1909) holds that the plas- modium may migrate from the diseased parent tuber into the stem and stolons of the young plant and ultimately infect the young tubers. As suggested by Horne, neither of these investigators has proved experimentally that the plasmodium ever assumes such a réle. It can not help but become obvious that more information as to the method of functioning of the spore balls and the method of infesting oo e 12 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. the soil under field conditions is much needed in order to understand clearly this disease. Such studies are also necessary before control measures can be intelligently worked out. SEED TREATMENT. Powdery scab has received little attention from the standpoint of control measures except in Ireland, and the results obtained are not fully convincing. Johnson (1908) states that soaking infected tubers 18 to 24 hours in 2 per cent Bordeaux mixture, or 1 per cent corrosive sublimate for 14 hours, or 4 per cent formaldehyde solution for 2 hours, is effective in killing the spore balls. It has already been emphasized that very little is known regarding the germination of the spores. Pethybridge (1911, p. 443) has also studied to some extent the control of Spongospora. His results are shown in Table I. Taste I.— Yield of diseased potatoes when seed was untreated and following various treatments for powdery scab. Savon “ Yield of =e lat Treatment of seed potatoes, if any. diseased plat. tubers. Per cent No treatment; seed only slightly affected. 2 ss. bn son sere Se eieetete ate slo co aye er nee 4. No treatment; seed badly affected..-...........- a 67.1 Soaked in formalin solution (1: 600) for 3 hours 2.6 Soaked in copper-sulphate solution (1 per cent) for 3 hours 0 Soaked in copper-sulphate solution followed by rolling in slaked lime 4.4 Soaked in and covered with precipitate of Burgundy mixture for 3 hours........ 2.9 Surface svetted and rolled!in'flowers’of sulphure- sos cee pores onto eee eee 1.03 Regarding these experiments, Pethybridge says— From the table it will be seen that in all cases the treatment of the seed tubers resulted in a most satisfactory checking of the disease. With regard to plats 8, 9, and 10, where copper salts were used, the total yield of tubers was, however, quite considerably reduced. The best yield was given with the formalin treatment, and the next best with sulphur. Of these two, perhaps, the sulphur treatment would be the easier to put in practice. The results obtained by Johnson and Pethybridge are very inter- esting, but are of a preliminary nature, requiring further study before they can be recommended for practice. SOIL TREATMENT. Soil treatment with fungicides for Spongospora scab, as would naturally be expected, has given experimenters but little encourage- ment. This matter has been most extensively studied for the past three years in Ireland by Pethybridge (19130, p. 460), whose most recent results follow. POWDERY SCAB OF POTATOES. 13 Taste Il.— Yield of diseased potatoes when soil was untreated and following various treatments for powdery scab. Total | vicid ield : ANogot Treatment of land, if any. ote of oe [Rec square hae perch, ubers. Pounds. | Per cent. 99 0.3 5 | Extra superphosphate added, 4 hundredweight to statute acre............. 6 | Each tuber planted in a handful of wet sawdust.......-.--.............--- 74 34 7 | Extra sulphate of potash added, 1 hundredweight to statute acre.......... 102.5 38 © |} IN@ TER WHMNGO 6556 see esemeeeer cof eocsccoorocesesosddesepedcenaneHeonessane 100 51 Ohi) eee 60) ce sdeiobesacdovpaoeeeoocests cooolk Codpece pon oe eee SEH eNeHS eee Amenn 97 52.5 10 | Extra muriate of potash added, 1 hundredweight to statute acre........... 94 52.1 11 | Flowers of sulphur applied, 63 hundredweight to statute acre.............. 106 23. 6 Pethybridge writes as follows regarding these experiments: With the exception of the muriate of potash, it will be seen that considerable diminu- tion in the weight of diseased tubers produced has been effected by the methods of treatment used, although the use of sawdust has reduced the total yield. The yields given in the above table are pounds per square perch. The best results were obtained with sulphur, where not only was the amount of disease reduced to less than one-half of that in the untreated plats, but the total yield was higher than in any othercase. This result confirms previous experiments carried out at Clifden, which have always shown that sulphur added to the soil increases the yield of potatoes and diminishes the attack of scab. * * * Substantial as are the reductions in the amount of scab due to the methods of soil treatment above indicated, they can not be looked upon from the practical standpoint as sufficient, and a suitable, cheap soil disinfectant is still a great desideratum for this, as well as for other purposes. Liming the soil, as is practiced for clubroot of cabbage, a parasite related to Spongospora, has proved an aid to the fungus rather than a check to its development. This makes it clear that it does not behave like clubroot of cabbage, as suggésted by Massee. The effect of lime on the development of Spongospora has been pointed out by Horne (1911) and Pethybridge (1911). It is, of course, obvious, as Pethybridge suggests, that there is as yet no method of controlling this disease when it once gets into the soil. In view of this fact, it is plain that potatoes should not be grown for some years on a piece of land that has produced a crop infected with Spongospora scab. Just how many years the fungus is able to remain alive in the soil is not known and is a question that merits investigation. The nature of the spore balls suggests that the disease may well be able to live in the soil for several years. It should be said also in this connection that if more was known as to the germination of the spore balls, it might be possible to predict their longevity. ‘ 14 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. SACKS AND BARRELS AS AGENTS IN SPREADING POWDERY SCAB. Tt is well known that secondhand sacks, barrels, and boxes are often used in marketing potatoes. Seed potatoes shipped from the Northern States to be grown in the South are put up either in sacks or barrels. European potatoes com- ing to this country are shipped in 168-pound gunny sacks. In some of the Western States similar sacks, but holding oaly 120 to 150 pounds, are used. These sacks cost from 12 to 16 cents each, depend- ing upon their quality and whether they are new or secondhand. Sacks of good quality can be used many times, and this has come to be common practice. In both New York and Boston there are firms that act as clearing houses for potato sacks, buying secondhand sacks from anyone who may wish to sell them and shipping them to potato dealers either north or south. It may happen, therefore, that sacks that have previously contained diseased tubers coming from Europe or elsewhere will be used for shipping select seed from the North to the South. It is not improbable, and, indeed, very possible, that spores of Spongospora, Spondylocladium, Fusarium, Phytophthora, etc., may be communicated to healthy potatoes through secondhand sacks. The same thing may take place through using secondhand barrels, but this is not so often done. There is, however, considerable chance of potato diseases being spread by means of old sacks. The question arises as to how this spreading of disease can be pre- vented and, of course, the solution is a simple one—by using only new sacks. But this would increase to some extent the cost of pota- toes and bring about the accumulation of large quantities of old sacks. It seems very likely that some means of sterilizing old sacks could be put into practice which would make them fully as harmless as agents in disseminating diseases as new sacks. This could probably best be carried out by firms dealing in sacks. It seems probable that sub- jecting the sacks to steam sterilization for several hours at a pressure of 15 to 20 pounds would render them free from noxious diseases with- out increasing their cost to any appreciable extent. BIBLIOGRAPHY. BerKkuey, M. J. 1846. Observations, botanical and physiological, on the potato murrain. Jour- nal, Horticultural Society, London, v. 1, p. 9-34, 2 fig. and Broome, C. H. - 1850. Notices of British fungi. Annals and Magazine of Natural History, s. 2, v. 0, no. 30, p. 464. BruncHorst, J. 1887. Ueber eine sehr verbreitete Krankheit der Kartoffelknollen. Bergens Mu- seums Aarsberetning, 1886, p. 219-226, pl. 1. Evans, I. B. Pox. 1910. Corky scab of the potato (Spongespora scabies Mass.). ‘Transvaal Depart- ment of Agriculture, Farmers’ Bulletin 110,2 p.,1pl. Also in Transvaal Agri- cultural Journal, v. 8, no. 31, p. 462-463. FiscHeR Von WALDHEI™, A. A. 1877. Apercu Systématique des Ustilaginées. ... Paris. 51 p. Frank, A. B. 1897. Kampfbuch gegen die Schadlinge unserer Feldfriichte. Berlin, p. 177. Gtssow, H. T. 1913. Powdery scab of potatoes, Spongospora subterranea (Wallr.) Johnson, Phytopathology, v. 3, no. I, p. 18-19, I pl., 1 fig. Horne, A. 8. 1911. On tumour and canker in potato. Journal, Royal Horticultural Society [London], v. 37, pt. 2, p. 362-389, fig. 96-106. JOHNSON, T. 1907. Der Kartoffelschorf Spongospora solani Brunch. Jahresbericht, Vereini- sung fir Angewandte Botanik, Jahre. 4, 1906, p. 112-115, pl. 3. 1907. Some injurious fungi found in Ireland. Economic Proceedings, Royal Dublin Society, v. 1, pt. 9, p. 345-370, pi. 32-35. 1908. Spongospora solani, Brunch. (Corky scab). Economic Proceedings, Royal Dublin Society, v. 1, pt. 12, p. 453-464, pl. 45. 1909. Further observations on powdery potato-scab, Spongospora subterranea (Wallr.). Scientific Proceedings, Royal Dublin Society, n.s., v. 12, no. 16, p. 165-174, pl. 12-14. LAGERHEIM, G. DE. 1892. Remarks on the fungus of a potato scab (Spongospora solani Brunch), Journal of Mycology, v. 7, no. 2, p. 103-104. Martius, K. F. P. von. 1842. Die Kartoffel-Epidemie der letzten Jahre oder die Stockfaule und Raude der Kartoffeln... Muiinchen, 70 p., 3 pl. [MassEE, GEORGE. | 1908. “‘Corky scab” of potatoes. (Spongospora scabies, Mass.). Journal, Board of Agriculture [Great Britain], v. 15, no. 8, p. 592-599, 1 pl. 1910. Diseases of Cultivated Plants and Trees. London, p. 98, 528, 573. 15 16 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. Me tuvs, I. E. 1913. The powdery scab of potato (Spongospora solani) in Maine. Science, n.s., v. 38, no. 969, p. 133. Morsz, W. J. \ 1913. Powdery scab of potatoes in the United States. Science, n. s., v. 38, no. 967, p. 61-62. Ossporn, T.G. B. 1911. Spongospora subterranea, (Wallroth) Johnson. Annals of Botany, v. 25, no. 98, p. 327-341, pl. 27. PETHYBRIDGE, G. H. 1910. Potato diseases in Ireland. Department of Agriculture and Technical Tnstructien, Ireland, Journal, v. 10, no. 2, p. 241-256, 8 fig. 1911. Investigations on potato diseases. Department of Agriculture and Tech- nical Instruction, Ireland, Journal, vy. 11, no. 3, p. 417-449, 14 fig. 1912. Investigations on potato diseases. Department of Agriculture and Tech- nical Instruction, Ireland, Journal, v. 12, no. 2, p. 334-360, 5 fig. 1913a. On the nomenclature of the organism causing ‘‘corky-” or ‘“‘powdery-scab ” in the potato tuber, Spongospora subterranea (Wallroth) Johnson. Journal, Royal Horticultural Society [London], v. 38, pt. 3, p. 524-530. 19136. Investigations on potato diseases. Department of Agriculture and Tech- nical Instruction, Ireland, Journal, v. 13, no. 3, p. 460-461. Watirotai, F. W. 1842a. Der Knollenbrand der Kartoffel. Linnza, Bd. 16, Heft 3, p. 332. 1842b. Die Naturgeschichte der Erysibe subterranea Wallr. Jn his Beitrage zur Botanik, Bd. 1, Leipzig, p. 118-123, pl. 2, fig. 12-15. 1842c. [Uber die bekannte Krankheit an der Schale der Kartoffelknollen.] Flora, Jahrg. 25, Bd. 1, No. 8, p. 119; No. 9, p. 133. O BULLETIN OF THE eb USDEDARMENT rac No. 83 Contribution from the Office of Experiment Stations, A. C. True, Director. 6, April 22, 1914. FARMERS’ INSTITUTE AND AGRICULTURAL EXTEN- SION WORK IN THE UNITED STATES IN 1913. By Jonn Hamitton, Farmers’ Institute Specialist. Reports on farmers’ institute work for the year ended June 30, 1913, were received from all the States except Virginia and Washington, the Territory of Hawaii, and the island of Porto Rico. Institutes were held in all the States and Territories except Louisi- ana, Nevada, Alaska, and Porto Rico. In Louisiana, although a small appropriation is made to the department of agriculture for institute purposes, yet no institutes were held because of the insuffi- ciency of the funds available. Meetings, however, of institute char- acter were conducted by the agricultural college and experiment station. Detailed data regarding institutes are given in the table at the end of this report (pp. 26-33). The more important facts are summarized below. PROGRESS OF FARMERS’ INSTITUTES IN 1913. The total number of regular institutes held in 41 States during the year was 7,926, of which 6,747 were general, 1,098 women’s, and 81 young people’s institutes. The total time devoted to insti- tutes was 10,578 days, an increase of 387 days over that reported for the previous year. There was a total attendance at these insti- tutes of 2,897,391, an increase of 7.6 per cent over that of the pre- vious year. Young people’s institutes were held in four States and covered 89 days, with an attendance of 22,100. Women’s institutes were held in 12 States covering 1,323 days, with an attend- ance of 84,039—a marked advance over the previous year. In addition to the regular institutes, there were various activities classed as special institutes, which included 187 movable schools, held in 13 States, occupying 949 days, with an attendance of 85,637; 25 educational trains in 15 States, covering 24,725 miles, carrying 422 lecturers, making 993 stops for meetings and reaching 501,523 persons; 768 so-called independent institutes in 10 States, attended Notr.—This publication is of interest to farmers’ institute workers in the United States and Canada. 31542°—14——_1 2 BULLETIN 88, U. 8. DEPARTMENT OF AGRICULTURE. by 197,848 persons; 66 ‘‘round-up” institutes in 16 States, with an attendance of 122,400 persons; and 346 farmers’ picnics, fairs, conventions, etc., visited and addressed by farmers’ institute lec- turers, with an attendance of 95,209 persons. Of the movable schools, 50 were for women and covered 362 days, with an attend- ance of 11,502; 14 were for young people, covering 70 days and having an attendance of 1,344. The total reported attendance at regular and special farmers’ institutes in 41 States was 3,900,008 as compared with an attendance of 4,029,546 in 45 States reported the previous year. There was a falling off in the attendance upon special institutes in 1913 of 447,730, due to the fact that fewer educational trains were run than during the previous year. The average attendance per train, however, was larger than in 1912. In a number of States the educational train seems to have served its purpose as an advertising agency and is being replaced by the more localized and systematic forms of itinerant work. The total fund reported as available for farmers’ institutes, $510,784, was somewhat less in 1913 than during the previous year. The amount reported as expended for institute purposes was $474,384, or an average of about $23 per institute session as compared with $25 the previous year. During the year 33 agricultural colleges and experiment stations furnished 415 lecturers at farmers’ institutes, and 28 of these insti- tutions report 2,950 days of time given to institute work by their representatives. This shows a falling off of 59 lecturers in the num- ber furnished by the colleges and a reduction of 5.7 days of time for each lecturer during 1913 as compared with the previous year. This is no doubt due to the rapid expansion of the extension feature in the colleges which is now taking the time of college mstructors and diverting their efforts from the institutes to the other forms of exten- sion work. This withdrawal, however, does not seem to have dimin- ished the total number of lecturers on the institute force in the several States, the reports showing 1,036 persons listed in 1913 as regularly employed by the State directors as lecturers. Institute directors in 13 States report that 63 of their instructors gave 385 days of time to teachers’ institutes, meeting at these insti- tutes a total of 36,819 persons. Eighty-one persons gave 347 days of time to high-school instruction, meeting 43,191 persons. Twenty- five men gave 41 days to instruction in the normal schools, meeting 16,258 persons. Forty men devoted an aggregate of 387 days to lecturing in the rural public schools, meeting 64,420 children. One hundred and twenty-five men gave 18,439 days to itinerant work among the farmers, giving advice and conducting demonstrations, and 97 men gave 1,824 days to other forms of extension work. | FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 3 GROWTH OF THE INSTITUTES DURING THE LAST DECADE. The growth of the farmers’ institute movement in the United States during the last 10 years is noteworthy. In the season of 1902-3 there were held 9,570 sessions of institutes in 41 States. In 1912-13 there were held 20,640 sessions, an increase of 115 per cent. The attend- ance in 1902-3 was 904,654; in 1912-13 it was 2,897,391 at the regular institutes, and at the special institutes 1,002,617; an increase at the regular institutes of 220 per cent and in all forms of institutes 331 per cent. The average attendance at each session increased 49 per cent, or from 94.53 to 141. The appropriations increased from $187,226 to $510,784, or 172 percent. During this period there have developed also the extension departments of the agricultural colleges, which last year reached directly about three millions of people with agricultural information. The following table shows details of the progress of farmers’ insti- tute work from 1903 to 1913: Progress of the farmers’ institute work from 1903 to 1918. Regular institutes. Reais Aggregate Special in- Year. Number Numbey Average stitutes, at- eee te 0 nd 'Ter.| Attend- | attend- | Appropri- | tendance. instit ei half-da; Sitoricsll ance. |anceper| ation. eS sessions. reporting. session. OOS eevee eae cis oe 2 Ls 9,570 41 904, 654 94. 53 SIL STE 226M crete meres | epeiacts semis cs TOO Bese ape TD habs Tt 10, 622 44 841, 698 76. 41 PAPA GS ial hee ees ued, Leal he elie Ken SaeR OOD ee aerate Scie sea aie 10, 555 46 995, 192 94, 28 PPT lor Mae oO He cae oe eee eee pe ee el ; 46 | 1,299,1 114,00} 269,671 | 326,250 | 1,625,492 OO Tease eres ois 11,514 45 1,596, 877 138. 80 284, 450 149, 449 1, 746, 326 POO SAE MIN NS CRN ee 14, 934 2, 098, 268 140. 00 25, 569 340, 414 2, 438, 682 (GG: ak ae e 47 25| 144.00) 345,666 | 617,954 | 2,858,879 OTORE See eee es 16,586 46 | 2,395,508 144. 00 432,374 537, 336 2,932, 844 iii ee 16,741 45 | 2291/8357 | 138.00| 432/693 | 1,323,693 | 3,615,550 PWG Uo .5 i 19, 430 45 | 2/549/199 | 131.00| 533,972 | 1,480,347 | 4/ 0207546 rei eo. 20, 640 41 | 2)897/391 | 141.00| 510,784 | 1.002617] 3,900,008 i This table indicates a steady advance in all directions during the period named. The farmers’ institute has shown this steady growth year by year, notwithstanding the rise of many other agencies for rural betterment that have appeared in the last decade. The inherent quality that has enabled the institute not only to hold the interest but to increase the number of its constituency until now it reaches annually about four millions of rural people in the United States is that it meets a need of rural men and women that no other agency has yet been able to supply, viz, a public forum where the scientist and the common man can meet on equal footing and discuss their problems face to face. It should be noted also that this entire movement has been initiated and conducted without national appropriation for its support and with a minimum amount of departmental aid, thus exhibiting an +t BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. initiative vitality and capacity for service to the great body of farm- ers that no other institution for agricultural improvement in this country can boast. ADMINISTRATIVE METHODS. During the past year a request was sent out to the State farmers’ institute directors for complete sets of their forms in use in conduct- ing their work—for copies of their instructions to their lecturers and local representatives, advertising posters, postal-card notices, etc., as well as forms of reports by the local managers and institute lecturers on the progress of the work. There was a very general response to the request. As was to be expected, the methods in use in conducting the work varied in the several States. Where the States were small and all localities easily reached the methods were extremely simple. Where, on the other hand, the States were large and the work correspondingly extended the administrative methods were more elaborate. An examination of these reports would seem to show that the fol- lowing facts underlying all institute work should be recognized in planning for conducting it: (1) That all local people should be fully informed as to the places, dates, and character of the institutes to be held in their community, and that this information should be given widely enough and far enough in advance to enable proper preparations to be made for holding the meeting successfully. (2) That it is due those furnishing the funds for institute support, whether derived from private or public sources, that the general public, in whose interest the money is given, should have opportu- nity to enjoy the advantages of the institute. In order to do this, the institute must be thoroughly and effectively advertised. (3) That this advertising can not be left to chance, but must be systematically undertaken and be prosecuted by individuals directly interested if the meetings are to be a success from the point of view of attendance. (4) That in order that the State institute director may be informed as to the progress of the work, reports upon the following items are necessary: On attendance, interest manifested, officers selected, ex- pense of conducting the work, plans for the ensuing year, the capa- bility and acceptability of the lecturers, the capability of the pre- siding officer, the names of influential local people in attendance, subjects discussed, results obtained, amounts contributed by local people, as well as amounts received from other sources. (5) Detailed information is also needed respecting instruction trains run, movable schools held, round-up institutes, independent institutes, schools aided, local assistance rendered, demonstrations conducted, special institutes, ete. - FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 5 (6) That the information needed at headquarters for a proper understanding of the institute work is the same as if the director had been present in person at each meeting to observe for himself, or information the same as is needed by the head of a department store or other great enterprise in order to direct it intelligently and to secure its efficiency and success. (7) Whatever letters of instruction, reports, and advertising methods, therefore, are necessary for securing this information satis- factorily and fully should be adopted and used if the director is to supervise his institute operations intelligently or is to be able to render proper account of his administration of his office and of the funds intrusted to his disposal for institute support. (8) The reports showed that several States have worked out sys- tems of administration and reporting that are quite complete and in many respects are worthy of imitation. Indiana, Michigan, Penn- sylvania, Kansas, Nebraska, New York, and Ohio are among the number. ; That there is great need of a careful study of administrative meth- ods, with a view to securing greater efficiency and economy in the use of funds available for institute purposes, is indicated by figures giving the cost of institutes in the United States as a whole and in the different States, as shown in the following table: Number of days and cost of institutes held in the United States in 1912. Days of institutes in 1912 and Days of institutes in 1912 and their cost. their cost. State. State. Average Average Days. | Total cost. cost Days. | Total cost. cost per day. per day. Alabama. ... 33 | $1.600.00 $48.48 || Nebraska.........-- 332 | $18,300.00 $55. 12 Arizona..... 65 1,650.00 25.38 || New Hampshire... - 19 1,600.00 84.21 Arkansas... =|| 283 4,000. 00 18.77 || New Jersey......... 51 2,500. 00 49,02 California. .......... 129} 15,000.00 116.28 || New York.......... 437 | 27,009.00 61.80 Colorado.........--- 150 5,159.00 34.39 || North Carolina. ..... 491 9,530.00 19.40 Connecticut........- 23 819.15 35.61 || North Dakota....... 61} 11,000.00 180.32 Delaware........-.. 23 950.00 nL SOW Oat). | see eononeepde 682] 27,400.00 40.16 HNOGIGaA ees ese) 37 8,000.00 216.21 ||) Oklahoma.......... 614] 10,500.00 17.10 Georgia. 2s. .3.5..- 103 7,500.00 (ZENG OLeg Omer sae eee 77 6, 100. 00 79.22 MASHOR a ee es csc 48 4,900.00 102.08 || Pennsylvania....... 429 | 25,500.00 59. 44 MUIMOIS. 2 os 3- 22-5. 421 | 35,950.00 85.39 || Rhode Island....... 28 485.21 17.33 Ndiiama) 5. 2525S... 532 | 18,750.00 35.24 || South Carolina.....- 191 3.400. 00 17.80 WOW AE rete cee css 240 | 37,245.22 155.19 || South Dakota....... 302 | 13,000.00 43.04 PRSATISAS Ht see aes = = 451 | 18,000.00 39.91 || Tennessee........... 93 5,.000. 00 53.76 Kentucky.........- 119; 14,200.00 GES 27 || ROXAS sere aware a 744} 17,500.00 23.52 Wig nye) at 3 ee ee 119 3,000. 00 Zoazll|; Witaheeeys vse sos eee 297 | 11,000.00 37.03 Maryland........... 63 6,000. 00 95.23 || Vermont...........- 38 3,000. 00 78.94 Massachusetts. ...... 138 2,751.28 19.94 || Washington......... 104 | 10,000.00 96.15 Michigan..........- 590 9,000.00 15.25 || West Virginia. ...... 204 8. 203.20 40.21 Minnesota... . Asia 2peo91s22 79.48 || Wisconsin.......... 353 | 19,688.89 55.77 Mississippi. . ..| 258} 17,900.00 69.38 |. Missouri... . Er 314 8,750.00 27.86 Mota. way ses 10,089 | 487,832.17 48.35 Montana............ 146 | 10,000.00 68.49 This table indicates in brief that the cost per institute day varied widely, the average for the United States as a whole being $48.35. | While it is true that the expenditures credited to some of the States 6 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. in this table were not wholly for institutes proper, a considerable amount going for instruction trains and similar activities, this appar- ently does not fully explain the great diversity shown. If the Michi- gan rate of $15.25 had prevailed throughout the country the number of institute days could have been 31,989 instead of 10,089. A much lower rate than that of Michigan is reported for the women’s institutes of Ontario, namely, $3.16 per meeting, of which only $2.40 was supplied by the provincial government, the rest being raised locally. The low cost of these institutes seems to be due in large measure to efficient organization and local initiative. District organi- zations coextensive with the electoral districts are supplemented by branch societies, each consisting of small local women’s clubs through- out the district holding monthly meetings. The members pay annual dues, and other funds for club purposes and for local public improve- ments are raised in various ways. The strength of the organization is in the fact that the members live in the community, meet fre- quently, and are active throughout the year. They are not depend- ent on outsiders who come and go, as are the institutes in most of the States, but they are largely self-sustaining and self-reliant. The fact that 85 per cent of the women’s institutes held in Ontario in 1912 were conducted with comparatively little outside aid is proof of the fact that independence, the result of self-support, is possible in the farmers’ institute work if proper organization is had for the pro- motion of this spirit. The need for multiplying the number of institutes in the United States is such at present that most careful attention to the whole matter of proper organization to supply this need is a paramount duty on the part of those who have control of the institutes in the several States, and the example of Canada in the conduct of its women’s institutes and of Michigan in the conduct of its general institute operations are worthy of careful study. The county insti- tute with local branches in every community meeting monthly is the ideal organization both for economy and efficiency for which the institute directors should strive. The farmers’ institute can no longer content itself with the simple discussion of agricultural topics. It is not sufficient that it be merely a debating society or agricultural lyceum. Moreover, it can no longer be an occasional visitor. It must live in the community. If it is to develop local forces, and that is its mission, it must be in daily and hourly contact with those forces. It must take up its abode with those whom it is to benefit, and teach, demonstrate, and guide in the things that it recommends. This means that permanent organizations must be formed in every community. The institute must identify itself with local people and get to work at once in the community if it is to survive as an educational force. f FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 7 The statement made before the Country Life Commission of Wis- consin in 1911 by Mr. E. L. Morgan is unquestionably true that ‘after all the only forces that can deal constructively with rural life are the local forces developed.’”’ When this comes to be generally realized and appreciated by extension directors as a fundamental truth, efforts will be made to organize and foster societies for rural betterment in every community in every State. ASSOCIATION OF FARMERS’ INSTITUTE WORKERS. The eighteenth annual meeting of the American Association of Farmers’ Institute Workers was held at Washington, D. C., Novem- ber 10-12, 1913. Representatives were present from 32 States, 3 of the Provinces of Canada, the District of Columbia, and the islands of Porto Rico and Hawaii. Reports upon the progress of the work were received from 39 States and Provinces. These showed increased attendance during the year and general interest in the work. Reports from the various standing committees were presented upon the following topics: Institute organization and methods, institute lecturers, cooperation with other educational agencies, movable schools of agriculture, young people’s institutes, and women’s institutes. Hach year the reports of the standing committees become more helpful in solving the difficulties that institute directors and lecturers encounter in the prosecution of their work. This year the committee on organization and methods called attention specially to the extreme importance of having in each unit or district a strong local organization. This was regarded as essential if the institute movement was to become most highly beneficial to the great body of agricultural people. The value of demonstration as a method of conveying information was also emphasized. In an extended investigation by the committee on institute lec- turers it was found that the average number of lecturers present at each institute throughout the country was 3. Fifteen States re- ported laboratory exercises in stock judging and household art. Movable schools averaged 5 days in duration with from 4 to 12 teachers for each, the average number of teachers being 5.7. From 20 to 25 per cent of the lecturers are employed by the year. The average age of greatest usefulness in an institute lecturer is between 40 and 50 years, and it was held by all of those reporting that he should have had farm experience. The committee on cooperation with other agencies recommended that a local or district agricultural council should be organized to direct extension activities in each district, so as to coordinate the work and prevent overlapping. 8 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. The committee on institutes for women reported general expan- sion of institutes of this character, until now most of the State directors report some attention being given to home conditions and woman’s life and work. Others report ‘‘we are just ready to start.’’ Among the suggestions for the improvement of the work are trained neighborhood visitors, the organization of home-makers’ clubs, and the making available of literature giving information respecting home improvement. One of the significant features of women’s work is the enlarging of its scope to include the interests of young girls. In some States girls’ canning clubs, bread-making clubs, athletic clubs, and literary clubs are being organized, all designed to arouse and hold the interest and activities of young girls in rural life and its pursuits. The committee on boys’ and girls’ institutes summed up its report as follows: States holding special junior institutes, 8; those holding special sessions at regular institutes, 12; those having junior aux- iliary institutes, 5; those holding special junior short courses, 8; those having junior sessions at summer short courses, 12; those having regular boys’ and girls’ club organizations, 36; those conducting junior correspondence courses, 8. The committee reported also that junior encampments seem to be growing in popularity. A criticism was made of the practice sometimes followed of enrolling large numbers in these clubs and requiring no service. It was rec- ommended that members of these clubs not regularly reporting at least once in two months should have their names dropped from the roll. The ‘‘program’? of the meeting of the association was divided into four distinct groups—a general session, a special session, a women’s session, and a round-table discussion. Highteen papers in all were presented at these several meetings and discussed. The president, in his address, spoke particularly of the need for enlisting the cooperation in this institute movement of all classes of citizens, the town resident as well as the people of the rural districts, bankers and business men as well as farmers. He asserted that all were affected directly by the condition of agriculture, and all should, therefore, aid in its improvement. The officers elected for the coming year were: President, Edward Van Alstyne, Albany, N. Y.; vice president, W. J. Black, Winnipeg, Canada; secretary-treasurer, L. R. Taft, East Lansing, Mich.; execu- tive Saami: A. L. Martin, Harrisburg, Pa.; T. B. Parker, Raleigh, N. C., and Mrs. F. L. evens, Mayaguez, P. R. EXTENSION WORK BY THE AGRICULTURAL COLLEGES. Data regarding extension work by the agricultural colleges in all of the States and Territories except Alaska, Arkansas, Colorado, Hawaii, Maryland, Nevada, South Carolina, South Dakota, Vermont, FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 9 Virginia, and Washington are summarized in the table at the end of this report (pp. 34-41), and in less detail in the tables below: Formal teaching as conducted by the extension departments of the agricultural colleges. Persons taught. Number aa States States : = Days of Kinds of schools. pO re- ys re- struction porting.| S°°ViCe- |norting| Regis- States Unreg- States force. tered Eee isteredsy js) aes * |porting. * !porting Movableschools..........--- 296 25 5, 436 26 72, 319 22 | 100,253 11 Correspondenceschools...... 75 12 1, 889 8 7, 649 12 650 2 Ruralstudy clubs....-..---. 26 6 1, 227 6 19, 669 5 3, 540 2 Normalschools.......------- 23 7 242 7 9, 084 5 595 2 ighischools, 622 224.52 -2 252 Om 11 942 8 5, 720 4 16, 757 F TNOURUIGE SBD e eta Soe 5 eer Came meme ra tea 9 MoO Moe aaa 114,441 |......-. TAL Oe aoesede Informal teaching as conducted by the extension departments of the agricultural colleges. Number | St@tes | p ays ot States | pjaces | States | atteng. | States Methods employed. engaged - _| service re; | visited z ance Ee 848eC. | porting, - lporting. - |porting. > porting. NOCANAGWISCES Ss - 2252 25- = - 298 24 4,995 13 1, 933 9 7, 888 5 Itinerantlecturers.....---..- 426 25 6, 154 15 4,012 18 | 590,570 18 Educational trains.........-.. 175 22 1,193 19 1, 244 20 | 491,519 20 paral glub monks po ear. 2b 113 28 4,570 i 2,057 11 | 179,133 12 emonstration: Imifieldsirs scot k 2 ose 157 26 18, 442 18 42,724 16 | 240,734 12 In animal husbandry.... 56 17 2,676 il 498 10 | 312,676 7 In home economics...... 50 14 1, 241 10 575 9 46, 486 8 Miscellaneous extension serv- GO o minceiciie daa ee aaa 359 12 2,372 10 1, 644 10 |1, 073, 652 9 BINA tea ye eet ye TN, cies pt le Ail 6434 lopped BANGS, aaa DOA ING S) eaee ee Publications issued by the extension departments of the agricultural colleges. Pe rin Number] States States Character of publication. issued. |reporting. Pages. reporting. TPES LOU STON os ot ee ale i ae RR a 413 21 1,079 17 Bulletins and leaflets --| 102,323 25 3, 443 26 Courses of Study.....---.-.-- 199 9 1,275 a Owmbhinessandimepontsiiei. ss 2.0. si sc 5 ae See ee oe Ae ae 19 Uf 124 6 Tate 3's oats, cetera mara me, 4 em UR cei Ue ete 10240540 eevee cee 5 40) eee Financial statement of the extension departments of the agricultural colleges reporting. : States Source of income. Amount. reporting. ANCE DLO DEA OTS amie ta ese i oo. cd eee. 5) AMR a ergy ales Hobe hese yah os a $663, 316. 00 33 HOC ANCOMTINUTIONSH 5 Patt k). 2. See ho tp IN AT TAS EE ee a 160, 404. 57 17 WO THCTSOULCOS Sayonara eats ocats wie 2 3) Semen ere a ere a eae Sc ee LIE oe 166, 783. 63 19 OLA (Gms tates TepOLtine):. «<1. 4eepeeee sas ase eee ees eae 990; 504,20 5.25... .- COStIAStAY Calg yee eee eee mek asl. meme lS ae E g ee eee ea ces 761, 113. 53 32 PME PEOOEIAGIONL OTS 1 Ae OP ees 580. TAPS ars Ae ee Ce EO Phy OM 718, 835. 00 29 31542°—14__2 10 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. There was general expansion of the extension work of the colleges during the past year. The increase in number of persons engaged in this work was 66 and in the amount of time given to the work over 50 per cent, while the increased amount of time devoted by each person to extension work averaged 27.6 per cent. Thirty-one of the colleges employed 182 persons for their whole time, an aver- age of 5.87 persons per institute, while the number employed for part of their time amounted to 217. The amount of money appro- priated increased from $548,352.82 in 1912 to $990,504.20 in 1913. The days of service devoted to movable schools increased from 2,386 to 5,436 and the registered attendance from 36,241 to 73,319. The States reporting correspondence schools in 1912 were 7; in 1913, 12. The days of service devoted to this work in 1912 were 656; in 1913, 1,889; and the number of students registered increased from 2,162 to 7,649. The States reporting rural study clubs in 1912 were 2; in 1913, 6. The registered attendance had increased from 2,060 in 1912 to 19,669. The number of local advisers in 1912 was 82; in 1913 there were 298; itinerant lecturers had increased from 322 to 426; the places visited by those engaged in informal teaching in 1912 was 12,142; and the persons in attendance, 1,800,513; in 1913 the places visited num- bered 54,687; the persons reported in attendance, 2,942,652. The number of publications issued had increased from 1,949 to 102,954. It is clear that the extension work of the agricultural colleges is developing very rapidly and along a wide range of effort and that the different institutions are endeavoring to introduce forms of serv- ice along extension lines that will be specially adapted to the condi- tions in their several States. SECTION ON EXTENSION WORK OF .THE ASSOCIATION OF AMERICAN AGRICULTURAL COLLEGES AND EXPERIMENT STATIONS. At meetings of this section at Washington, D. C., November 12 and 13, 1913, the following topics were discussed: (1) Organization in a college for extension; (2) problems confronting the agricultural colleges in their extension work and suggestions for meeting them; (3) things the coilege should undertake to accomplish through its extension division and how they should be undertaken; (4) coopera- tion with other agencies in agricultural extension; and (5) organiza- tion in a county or community for extension. The papers and the discussion of them are published in full in the proceedings of the association. Two very important reports were presented by committees ap- pointed at the Atlanta meeting of the association: One, a committee on organization of courses for preparation of extension workers; the FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. pl other, a committee on types of organization. The chairman of the first committee presented a set of tables showing the results of the investigations of the committee respecting the kind of preparation desired by the colleges. As to practical farm experience, the great majority were in favor of this experience as an accompaniment of collegiate training. The second table gave an outline of the courses of study at present required for the preparation of extension workers. In this English predominated, followed by natural science, studies in chemistry, physics, zoology, physiology, and bacteriology. By far the greatest attention was given to chemistry in this preparation. The third group related to lines of work offered by the colleges. Of those reporting, 37 offered work in agronomy, 36 in horticulture, 34 in. animal husbandry, 30 in soil management, 17 in farm engineering, 32 in farm management, 27 in home economics, 31 in farmers’ insti- tutes. In all, 17 subjects were enumerated, the number of colleges presenting them varying from 17 to 37. A permanent committee on extension organization and policy was appointed, consisting of W. D. Hurd, Amherst, Mass., three years; K. L. Hatch, Madison, Wis., two years; and G. I. Christie, Lafayette, Ind., one year. ‘The following officers of the section were chosen for the ensuing year: President, W. D. Hurd, Massachusetts; secretary, E. G. Peterson, Utah; recording secretary, John Hamilton, Washing- ton, D.C. ILLUSTRATED LECTURES. The series of illustrated lectures issued by this office has abun- dantly proven its right to a place in itinerant instruction in agricul- ture. During the past year, from November 1, 1912, to October 27, 1913, the 14 illustrated lectures published by the department were out in use 4,962 days, and a large number of applications for their use was refused on account of inability to supply the lantern slides accompanying the lectures. CORRESPONDENCE SCHOOLS. During the year two classes in correspondence work were organ- ized and operated in cooperation with the Pennsylvania State Col- lege, one for men and the other for women. The class for men con- sisted of 21 members and that for women of 15. The classes at the outset engaged to meet twice each week and to continue the study according to the plan outlined by this office, the work to be in charge of a local lay reader under the general supervision of the college of agriculture. The classes were organized by a member of the institute office visiting the college, and with the advice of the extension director locating the school, enlisting members for the courses, and selecting leaders to supervise the work. This department officer remained on 12 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. the ground during most of the continuation of the school as an observer to see the character of the work and to note such defects in its operation as might occur. After witnessing the progress of the classes for three consecutive weeks this officer reports that the experiment up to that time was successful in every respect. The lay leaders were fully able to oversee the work. The members of the classes were thoroughly interested in the reading and practice exercises. The weekly written examination as reviewed by college experts showed that the students comprehended what they had studied, although some had difficulty in expressing their thoughts clearly in writing owing to their lack of training in this direction. The oral examinations, however, were uniformly good and the attendance was prompt and satisfactory. AID TO AGRICULTURE BY TRANSPORTATION COMPANIES. During the year data were collected from railroad presidents and industrial agents in the United States regarding the character of the extension work in agriculture pursued by the roads, viz: (1) Infor- mation giving, (2) aid in marketing products, (3) soil improvement, (4) demonstration work, (5) organizing agricultural associations, (6) operating agricultural instruction traims, (7) other activities, and (8) results accomplished. Returns were received from 57 roads. The mileage represented by these roads was 152,492, or 61 per cent of the mileage of the railroads of the United States operated in 1912. Thirty companies have industrial departments giving special attention to the development of agriculture and employ 144 men in this service. One road reports a force of 45 experts in the employ of the company during the entire year, giving attention to the development of agricultural extension and demonstration work. Twelve railroad companies each conducted one or more demon- stration farms. One has demonstration plats on 133 farms and another conducts 16 farms for demonstration purposes and still another cooperates with 400 farmers in demonstration work. One company furnishes land to farmers for use as demonstration plats. One road reports having organized a farm improvement department consisting of a manager, three assistant managers, and 29 field agents. There is a dairy agent with 7 assistants, and a car fitted up as a model farm dairy at their disposal. There is also a live stock agent with three assistants, and four market agents. Of the 57 companies reporting, 41 give particulars respecting their work in the dissemination of information, 29 with respect to market- ing, 26 on soil improvement, 22 on demonstration work, 17 in organ- izing agricultural associations, 41 in operating agricultural instruction trains, 28 enumerate other extension activities not embraced by the FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 13 other queries, and 26 report satisfaction with the results accom- plished. The transportation companies are evidently awake to the impor- tance of increasing production, partly in that it provides subsistence for the rapidly increasing population, but mainly in its effect upon the revenues of these corporations. Whatever motive may be assigned for the interest that they have manifested, the fact is that much has been accomplished by them in promoting a better agricul- ture and in securing cordial feeling and close cooperation between these companies and the individual farmer. AGRICULTURAL EXTENSION WORK IN FOREIGN COUNTRIES. In order that institute directors and lecturers may be kept informed the following notes by the assistant farmers’ institute specialist showing the progress of agricultural extension in foreign countries during the past year are presented: EneLtanp.—In a memorandum recently issued by the Board of Agriculture and Fisheries to local authorities in England and Wales, grants are offered from a newly established fund known as the “development fund” for use in the furtherance of technical instruction in agriculture and horticulture. The grants are declared to be in aid first: “For the establishment of advisory coun- cils to be set up in each county or group of counties for the purpose of reviewing, governing, coordinating, or initiating schemes for providing higher agricultural edu- cation and educational experiments in connection therewith.’”’ Second. “For the provision and maintenance of buildings and lands for farm schools and farm institutes at which young agriculturists and others whose daily business is connected with the land may obtain scientific and practical instruction in the technicalities of their art.’ At each of these schools and institutes it is intended that a highly efficient staff shall be maintained to give short courses of instruction suited to the requirements of the district, and also to conduct experimental and research work The classes and courses of instruction which the Board of Agriculture and Fisheries aids are for ‘“‘persons of 16 years of age or more who have finished their school educa- tion and are either pursuing technical studies with a view of becoming agriculturists, or are already engaged in agriculture and desire to improve their knowledge of the subject.” Prof. T. H. Middleton in his introduction to the report states that it is clearly the duty both of the central and local authorities to devise means for applying to practical farming the knowledge provided by workers in research institutions. He states that until the knowledge of the laboratory has been translated into practice in the field the work of agricultural research is incomplete, and that all the knowledge hitherto obtained in research laboratories will be valueless to any particular locality until it has been applied by farmers to the cultivation of their land. He asks, How is this application of scientific discoveries to the commercial questions of the ordinary farm to be accomplished? Can farmers be expected to study scientific treatises? If farmers did study and understand the publications of research stations, could they afford the time and cost involved in the adaptation of the new principles to the par- ticular circumstances of their own farms? He refers to the fact that the important task hitherto of the local committees charged with agricultural education has been to provide for the instruction of young persons up to the time when they leave school or college, or to supply itinerant teachers capable, as a rule, of instructing novices only. Now they will be expected to make 14 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. provision for advising experienced farmers on the means to be adopted in applying scientific discoveries to practice. He alleges that it is a mistake to suppose that the proper way to introduce the results of scientific research to farmers is to spread information by means of lectures or leaflets; that information can be spread by these means, but not as a rule the results of research as first published by the research institutions; that few of the dis- coveries made by research workers are likely to be immediately applicable to the farm practice of a particular district, but must be modified before they can be utilized. When, however, on a particular farm the success of the new method has been estab- lished, neighbors will learn by imitation and the improvement may with advantage then be brought to the notice of others by lecturers and leaflets. For the purpose, therefore, of translating the results of research into successful practice, a highly trained scientific man is required who has special knowledge of some particular branch of science and a sufficient acquaintance with agriculture to command the respect of skillful and enlightened practical farmers. He states further that for the present all that is practicable is to lay the foundation of a system having as its object the bringing into existence of a class of well-qualified specialists who shall devote themselves to the service of agriculture. The first essential is that the specialist to be employed should really be a specialist. The second essential is that the persons who are to be engaged in the work of promoting agriculture should be of the same caliber as those who have advanced arts like medicine and engineering. Since no class of agricultural specialists corresponding to the medical specialist . exists, it will be necessary to train up men for the work and, therefore, to employ at the outset young and inexperienced persons. For the first few years the work must suffer from this lack of experience, but just as well-trained young medical men quickly acquire experience so will these specialists who are being trained to help agriculturists. To be really useful either to the large farmer or the small holder the teacher must be a specialist, and if he is a scientific man his attainments in some branch of science should be high; if a practical man he must be a more skillful practitioner than the majority of those whom he instructs. This announcement of the purpose of the grants by the Board of Agriculture and Fisheries for the furtherance of technical instruction in agriculture and horticulture, and of the policy to be pursued in the expenditure of the funds, is of value to those who are in charge of extension work in the United States because of its careful analysis of the methods to be pursued and the qualifications of the individuals who are to disseminate the information. The declaration that the discoveries by the experiment stations should, first of all, be placed in the hands of learned scientists who have at the same time practical acquaintance with agriculture, for testing before these truths are given over to ordinary lecturers to promulgate for general adoption is worthy of serious attention. The two classes of extension men are differentiated as to their duties in disseminating in- formation. The observance of the distinction made will help to clear away some of the difficulties that at present embarrass institute and extension directors in this country in organizing their extension work. AxeeRiIA.—Under the direction of the Algerian Commission of Technical Agri- cultural Instruction, Industry and Commerce, a reorganization of Algerian agriculture is taking place which includes the establishing of demonstration farms in all the agricultural regions of the colony. This reorganization is of interest to extension workers in the United States because of its providing a method of teaching advanced agriculture by means of farms attached to the experiment stations for the purpose of exhibiting in a practical way and upon a considerable scale the results of the researches made by the stations. To these demon- stration farms farmers are invited to witness what has been accomplished and to re- ceive instruction respecting the methods employed and the cost incurred in securing the results. FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 15 The experiment stations and the demonstration farms are to serve for the instruction of the people by example and also for the propagation and dissemination by sale of the best varieties of seeds and tested plants. They are to conduct researches and experi- ments in plant and animal production, cultivation, fertilizers, and all farm and garden operations. These demonstration farms are by example also to teach economy and show how to check the many sources of waste and avoid unprofitable practices. They are to keep at the front in agricultural progress and set an example not in a theoretical but in a practical manner for the small as well as the large farmer by demonstrating the method of producing the largest net revenue in each case. : Each station and demonstration farm is located so as to represent the average con- dition of the different soils, climatic and other conditions in the several regions, and at the same time be easy of access to visitors and have at least some irrigation waters, in order to conduct the vegetable garden and nurseries. The current farm practices of each region are followed, and improvements, as a result of experiments in the experi- ment stations, joined to each demonstration farm, will be made gradually each year in order that no mistakes may be made and bad examples set. The land for these farms is rented for a long term of years with privilege of purchase, and each farm does not exceed 600 acres except in the dry farming region, where it may include 1,200 - acres. The purely experimental portion of the farm is conducted independently of the demonstration portion and is not expected to be self-supporting. Hach demonstration or model farm is self-supporting and all improvements are made out of its income. The Government, however, contributes the original funds with which first to stock and equip each experiment station and demonstration farm and makes an annual grant for the experimental work which is connected with each model farm and which, of necessity, can not be expected to be self-supporting. In order that there may be coordination, harmony, and systematic effort a director, whose salary is paid by the Government, has general charge of all the experiment stations and demonstration farms, and each station has a chief, whose salary is paid out of the annual grant to the experiment stations, while each demonstration farm likewise has a subdirector. The commission also employs scientists to conduct the expert scientific work of the stations, and expert teachers have charge of the instruc- tional work at the demonstration farms. The supreme object of all the experiment stations and demonstration or model farm work is the practical instruction of farmers in better and improved farm practices. The immediate practical instruction of those now actually engaged in farming is re- garded as most important since it reflects at once and directly on the production of the country, and the demonstration by the model farm method is deemed the quickest and surest method of accomplishing thisend. Accordingly, farmers’ meetings are held at frequent intervals at the model farms, and practical instruction by demonstration- is given to those in attendance. No theoretical instruction is attempted, and nothing not fully proven and demonstrated is given. The model farm thus becomes a per- manent agricultural exposition and demonstration school where the farmers go to see the things they are to learn, and to discuss them in the fields as they are conducted about the farm. After certain improved practices have become fully and surely demonstrated at the model farm, small fields on many individual farms are used to dis- seminate still further the information by practical demonstration under the direction of the central farm, but the entire actual work is there done by the farmer himself. During the lax or dormant season farmers’ meetings are held throughout the country in order to interest the farmers in the demonstration farms and to sell improved seeds, plants, and animals from the model farms. Betcrium.—Meetings or conferences for the instruction along agricultural lines of adults actually engaged in agriculture have been held for a number of years in various villages in Belgium by the agricultural supervisors, agricultural engineers, professors of agriculture, and others holding diplomas permitting them to give such instruction. 16 BULLETIN 838, U. 8. DEPARTMENT OF AGRICULTURE. » The subjects discussed at these meetings include fertilizers, feeding of domestic animals, hygiene, dairying, cooperative association, rural law, the combating of the enemies of plants and animals, apiculture, poultry, and farriery. The following lists of meetings of adult farmers with the attendance for the last three years show the progress of the work. Meetings of adult farmers, with attendance for 3 years, 1908-1911. Kinds of meetings. 1908-9 1909-10 1910-11 Meetings by the agricultural supervisors: Nunthberof COnlereueese case jaemen- sts e te ee eee eee ee oer 1,154 1,157 1,119 Average attendance at each conference......-......---..-------- 50 50 50 Totalattendancel: i. b2...to ee Se 57, 700 57,800 55,900 Meetings during the winter: Niimberoficonferenees 22445. Set. sage sae hee aac 3,170 3, 440 3, 670 Average attendance at each conference.............-..---------- 49 53 55 Total athendance.. . 2 icc senisa piel te setleaew ete eee es ease 155, 330 182, 320 201, 850 Agricultural meetings for the army: | Ninm ber of conterencesa-c--eeeeee = sence eee ee eee oe 550 528 572 Average attendance at each conference........--...--..--------- 27 23 26 Totalattendance’, se. 2 ace ese ke eee Se Sree coca airs ae nee 14,850 12,144 14, 872 Meetings on apiculture: ; Number of conterencess 2 sae as ae eee eae 388 330 366 Average attendance at each conference.................----.---- 26 26 26 Motal.attendancex zeke Hate Hiss te ee ee ee eee ee 10, 088 8, 580 10, 248 Meetings on poultry culture: , Number of conferences: = -2h eae. 2-25 eee eee eres 355 336 437 Average attendance at each conference........--......--..-..--- 46 44 53 Totalarvendante) ee sete cme. shinee eae cee eeaaeeere 16, 330 14, 784 23, 161 Meetings on farriery: Number of conferences? e-2 eho teh eee eee se ee ee ce eee 252 240 252 Average attendance at each conference.........-...--.---.--.-.-- 31 29 28 Motalattendances cy Wet Seaeey ecm ae cee a eee ce sere ee eee 7,812 6, 960 7,056 Special meetings: Nii berioli Conferences - 2. sectee= = eee ae eel eee 655 752 614 Average attendance at each conference.........-...------------- 50 50 60 Notal attendance. " 9ITGSdUIBH AMON re a S25 | SS | eee | hee | ees (Poe | aes =e er ese Sie “S| se |S = S| Eee eee * ({BPBAON 61 | ~~~" "| 008 TT |°° 77> "| F6T a2] eeapual Ee type | ees — tam i se) S| oe ae ~**"B¥SB1qeN Sect pee “""| 99T isee| esse [269R Sal Vs mal |e eae ee | |S ple Poa: Sse ee os SC OUSIOO YY 72h 26 9Té ~~" ") 61 646 = ae € ie al (een, ae OT SiN | eee ~~ Tmosst fl paeuice. Ses 18& Sao ae | O0G: ee | sme Pie eS ea | ee el peal ee WC) te | ogee ~1ddississipy Ese asada Md sane SR SSeS gah eee eee ir set (ieee oes se a SoS So Set 2 SSB OSORULT T | #¢ 10g LT | ¥¢ 61F Te ge 2 eee alee IE cee a Dea EV Sa OPE aa ar ee wesIqoOy onal tee See 8&1 = seal (eens tL See | pce | ae | een NE Ss eS ae ae “777s os" "-“s}esnyoesse yy ees | ey 19 SE basal |e} Ne acer] RO al NS |e 2 cee eet ae aes naam kL) ue fc | eel I) lec pd | ee ~* puv[Areyy wae lee oe eh Se [pe eee COr el |e |e See i |e ae wes pel he cosa Sen te tee CMU ee ae aa end (3s oo | eae lee [ae RRS OS Ce Sa Mae (ae bee eres, | os Se 1 VURISMOT Peal eee Fao OGbs ol eee ees, 6h Pye Ba ll Sere |e eel Meee Shims ES eee allie eae eo ea Ayonque xy €T | €2 60S €T | 2 GLP = — Pee | ee 3 eae She a od STH|RG2 | Shee ie se eee sesue yy poe | eee OLE =| Saar a (te Y Wiel eee [Se ¥8 Se |= ee | 3 et cea eee ae (a er 2S aE BAOT 35/5089 TSSS/SSo SSS RTP oS ses Seelam fe sal eben es] HO teen eden. S| LOG s/s See eee eueIpuy Scien ere a ot 98 S| |e 1) eee bee Va Sea | AC OP rg ares ieee CO ee alee |e || - = pen] = eee oe STOUTTIE Boag 8¢ po) (AS Socal op selle eae | lea Seg See | OF = aoe a eee “OUepy Sot pe ae | Ses See |e SS la a ee (ea | ake ae ea | | a a “""ZT@aey PORE PEO aS legal Soi celine s Mayr Tee alle sas Base |S cee | en | Pecaare eal|E? sep ee | Sea eae a| Oe Pee ae 5 “** RIsI0eH ASB RG 98 nae (RG 68 eed fe cw Pence cae ae |e Baca EL Sess N=) feat coe |i pe “* °°" BpLIOTT poe ee Oe Gc te POSe aS deen | fee ot ese See |S aiameag |e aaa Cae | base Wesel esol seal 2 [LS sean wee “*OIVMRTOC SSG ee he eine LG Soe EN ee | ee eee Siege (a lee ae fan | Re NP A heen |= Sid Bere - 22 qnoT.eunoD Cog oe a 90T Br cae REL pee | See) tal pce See ine =p e+ OPIOID weed e L81 eae (V4 €ST Bagel oc ge ae eg en eee a LOR eerie ee ae *** BIUIOFTVD Se | eee % Fe OTIS 4 Be | SSS SS SS SE OSE ae ee | octo| eae SP CEE ee aloes Peo °° SesuByly Wea Sea aL 8 aise [Seare > oie = “IOI, 10 97819 "1e0h . eq} SULINp ppey *soqnqiqsur sduyjeour ‘ssurjoour Aep *s8urjoour Avp “SI6L ‘0G aune papua woah oy) burinp aunpuayyo anurxcoiddn ayz pun pray sanzysur fo 4aquinay 27 FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. “ytodel ON z “Plo So]NINSUT ON r TFT O0T ‘Ze | 680‘F8 | ZSz ‘162 ‘Z| 26 | 9202] zze‘sT | 68 | Eze‘T] 99T‘6 | 18) 860‘T] 2FzZ‘°9 |°~-"] ZT 67% 8 | T6x | 126‘T | €2| 068 | 22¢%% |-----*7- een (22000 0g ea ee “| oFe po). eeeel UE : “SuTU0d My “| @8F ‘TE | Sco ‘O0T |7--"| 48. | 189 18 | le | oe OfTees eee tee 4[ 0 Be | OP = aPC Docs SI a | Se gh es ee ISOS, Sea RCO ee eee (CC games| IU coats Fg cre 8 (Oem ol rat Se Be: [eee | 225 ese a Gisele ToT T°RTOISIEA 989 MA GE SB QE SGia [BER Oc SS 2] AREQOTISY RES HOeC De oc SI6G Peat Ipgeeoe| Fete 00K oes] 2280 E PO 2 00 0Re eica aeroc| et cagor| Eek ei 25 Oc ociog Ia SADOMEGO toh fetnane (Si \ ee ofacecoste]soscsced|Scoonadece|scoeloseced|suscuncd|[oobe)soscc0 SRS be RSS SG SSS Se (So bed lee oood moe nee BGG [SON OnSRIODOOG san NIyAN TS ee OS a ees cor‘ gce ‘9 rere weneenseeesneetoteermgaty 99... .| OGG !TE |7 7777777) 889 ‘STE | 99. SOL Tee| 08 |e T 99. SSM ey ose || ells Fe eee ULE cet posse oacoasescoce=cp sexe pith 80 Soe e eee ROCA Ta Tel (PL "1 gar | 129 “"""| 8@L_ | or “~*"| 800 | 692 Bees aes eS, LOL = oe a ee OO), ce Soe |S ae OZ eee | ae SOL Se | a en SOT SEL ORE OT LOS wecesere[eeceseee] ggg’ [eseefeeee e+ ** puvIsy Opoty *2 OOLY 0110g =a| S00s8C Deas le oes |ROLG eel 55. (20 Sal Reeee|RV OL geeg laces ee s| 0G eee Se Seog Se 6c OT te 329 BT 86 ele stb eee eke oe |e EE ee ee ot eae ZAG) eg ee 000g] OOO Sco =a] SORT OR es eon Gee srl ep. | 20 | | TL | 9 “111| 888 | 2 sl RVB 02 © ee | ae eee ee 81 Soe eel UEC RUE | OB ane alp 2s pe at CCU ce || 0G dice le ee ede | Oye Slee ep ee) 28 Sg ele 4-680 8 Se) Pa) 0S BEES Rene bs td EOS RES 8 lines (BU PS || - BONE WHION ¢9 "777777"] 89 ‘oz | g9z‘6e |-**"| 09% Fee fee sec Ges | eee s/o Once ( (CCG oa| al hee Na Seeal sce eee OGG | ree |e SUNOIE MON, $8 eee fee aR lee eles |e CO eal: alee es 00 I ea Pe ee Sel eet (3 Seely 2008 = HOR ASN 28 BULLETIN 83, U. S. DEPARTMENT OF AGRICULTURE. Financial statistics of the farmers’ institutes for the year ended June 30, 1918. Funds appropriated. Cost of institutes. Appropria- ee By the tion for Bisteior erritory. By the | College and Cost per | the season State. : receive : Total cost. pecerarts 1914. sources. PUIAD AMA o's cabs eos seo pesen eae nea eee $600. 00 600. 00 $36.36 $1, 600. 00 ATASKA 1? 0... cece cccncecmecccencsvececes|oensstusesne| dee cs cochidll < aaa Sent Maeet Rees See EEE oe, LTE, 5 i SR RS A aes a Sera 2,500. 00 898. 88 161.05 4, 400. 00 PARE ANSASES «ok boo eee Cent nen eee ERE ee 4,000. 00 200. 00 87.50 3, 750. 00 Malone =i. See eee ee ee 15, 000. 00 000. 00 40.00 25, 000. 00 ROLOTAH DSC. o.oo aoe ee er eee men ew 2,500. 000. 00 AS ASHE ELE Re CGNHECHICUL - 22h cae hoe ere eee 900. 00 050. 00 LG VADEIEE weiceatera sit LESS 0S a Sy RR Ga 1, 000. 00 150. 00 17.96 600. 00: MTA oo. oop ate et eee See a 7, 500. 00 500. 00 40.32 10,000. 00: Gregrpra. 222). Carer ee came eee 25, 000. 00 000. 00 125.00} see awaits ee ct eee ee eee es ac ramen | REC maT Nanna LTE Te Si is i ee 4,000. 00 000. 00 28.90 12,500. 00: ATIONSY 6 Soc BSNS SE oat CP ee 650. 00 650. 00 28. 80 24, 550. 00 LEG PAV ae Se gt ae = ee eS 10, 000. 00 000. 00 15.12 10, 000. 00 LD Fl oe Sea ei ni eee 7,559.21 987. 80 Siesoilesakckeseres Sets: oy Sees ne 16, 650. 00 085. 00 23. 82 22, 400. 00 Kentucky 000. 866.13 33.95 20, 000. 00 Powisiang). 2... ooo .scsse see ses cose sees bac |see sine sioce-e| t-te Gon Soe Ree eee ie ce ae eee eee ne Maine.......... 300. 050. 00 20.19 2,300. 00 Maryland 000. 437.86 35.54 6, 000. 00. Massachusetts - 000. 411.51 15.65 6,000. 00 Michigan 500. 900. 00 C74 a let aay Minnesota 000. 557.09 55. 67 23, 000. 00: Mississippi 500. 700. 00 a ES Re ae SSOTIPI So oe ae Shee Sh 2 ee ee 2 Py , 750. 750. 00 LUQOR eee Fee Montana 10, 000. 00 000. 00 36. 76 10, 000. 00 Nebraska 17, 500. 00 500. 00 28.55 25, 000. 00: Nevada? 22. 2. csnakcccca snes cncpe ses wcts|beacescmoanalee ccs eeu Soe eer cee cele | Cece eee eee New) Hampshire. * 92s ae ean as 1,200.00) 5 er So-eee 995. 00 33.16 2, 000. 00 INOW Jersey ci ed nes ee Sr ai ASG7Oi12| sae eae 4,679.12 BOGE | ererotn dare ING WsMexICO 2: J Ste cote Sh OE ke ace eee ae 500.00) |Peee a... sol eawincigaatetanl pees oe amar a INGE WRYOLK 62 > tee ie A Aes See aad 38500000) 5-225 eee 31, 641. 56 22. 74 20, 000. 00 LTA AE COUNT) Fee WE ae Pee ie as Tac GRE TE 10)\000:00 2222 so ceee 10, 000. 00 10. 75 12, 500. 00 NOTH yak OAs: Pee oe Fee ee ae 6, 000. 00 1, 185.00 5, 769. 00 53. 91 6, 000. 00 OUTS 5 Se a Ea See ee a 28, 716276) 22.2 oaeceeee 28, 716. 76 15.70 26, 400. 00 ORs oni ag Pe eens pocorn seer eee eee 10°500500))|: S223 See 000. 8.67 5,000. 00 Oreconee eh Atk ee ae Sh ae An 25, 000;.00 2-2. 4-2 2, 500. 00 22.12 2,500. 00 SECITE LISS 2 Lipton SP eg 22;,500;00)| 225-3. 2 23 22, 500. 00 22.23 27, 500. 00 POTIO RICO 23. 5s. sie = ae in a on anind oon aecace|ocsicees-cbbeladeleees -Se ee a eee Eee ee | pete mee ets | See enee meee RVHOGGMSIANG! Cae. oe ee saecaceeetecoe See eee 700. 00 546.12 ST Wome ticncneeuie NOHMEBUCATONING 2. 5545-552. -2 eee nee 2,000: 00) Seam ce ceeee 2, 200. 00 DOR. Ff Ae So ee Bonba Oak ota: = 22 2c eee) cea eee 16;000:.00) 2223.35 558 16, 000. 00 20. 02 20, 000. 00 PONIMICSSOO 5 ooo a wo we ne sence cs ooacnenccup|eeeessmatone| ode sie d- cence See eee EERE Ee ee Sete Sees Eeeee eee PRORAGN EA see ee E eto Pee Pee ae 17, 500. 00 3,010.17 | 20,510.17 ROROOnforeee nonce DDT oot oe eS DORIS ONT SE 10, 000. 00 775.00 | 10,000.00 53.48 | 10,000.00 Wermont3 ._ 2. eee ne en eee ed cee ee cwn|e wen ccc ot cbc| codes cstceec al BREE EE OR Ee Sera Ee ee nee ere ae Wargimig® eo. nn chek ee SL ET i 20 eng en eaten Washington's... . 2.2.2. os coset eosin |c eek esc e ote kel cke 6 SUN Meee eer | tcc ete er] eee meng WVESE WOPPIN. . oice od oonb eo eo eee Se BPN. ea 6,332. 02 7s | Ea RS ESTINTTD Vee ome as med eae EL 20: 000 00N/er ee. ee 20, 000. 00 26. 04 20,000. 00 RUN OININ Ee ook) fac feshk oe. Oae Eee cee 200.00 200. 18.19 1, 500.00 MObale she eee te ok eek eee ee 430,837.11 | 79,947.68 | 474,384.02 22.99 | 360,500.00 1 No institutes held. 2 No report. FARMERS’ INSTITUTE AND EXTENSION WORK, 1913. 29 Number of lecturers employed by the State directors of farmers’ institutes and reports of proceedings published for the year ended June 30, 1918. Reports of pro- ceedings. Num- Pub- | ber of lished. | copies. Number of| Numberof| Number of State lecturers members | days con- giving agricultur: al instruc- Total ofagri- |tributed to] tion at— number | cultural- | institute : of college and| work by State or Territory. | lecturers| experi- | agricultur- on the | ment-sta- | al-college | Teach- Wow. || Gara State | tion staffs |andexperi-| ers’ High quel a i force. | engaged in ment- insti- |schools. hool aha institute | station | tutes. SE BONS SCO S work. lecturers. 15 15 74 Nooonsoes|lsosoodes|ecigseass 10 WO) oe noeac-cucsllsoootced|sesoodcs|lecackso 25 10 153 6 34 34) | adeeb. 14 42 20 Bil) |soeeoces|jacags+sallccssoace 15 4 ZL \losoccesallosodnacs|enscosed 16 iG PAB) Incoocossladeoossc|leocsosas 23 23 361 5 15 7 210 1 Cie Ms ee Ra ae ee OSI Sees aece eee ee 55 14 WG |lsseocessllosecoccallecescoecls- 19 18 108 6 8 11] of ana oe 1 23 5 LOM eeest sa ecmcteleci|cree SOS Maryland.......... 15 7 Ady |Vernj rate eal eee ene OT OO NT G60 ‘FT Speiee|| Cals MN ay ree ARO TOC OB. Pere WOGm glee ileal emer [a eee es a(S tole ieee See ea aie alo ieee aap sees PRTC Ee NOG To AOR ma ege ae sea RGU ATT 611 ‘OT Baas lRCOT z SPSS TT aloes Peale! ae ties a aan a ROOR ME nO Geen O09) Tee noes a aloL 611 Or {2 toot r 5°" BOB TTOPL BS aia ns eaten ane Cina es | SG DY lp See ats oleae ecetilincais cel ne sue [sama cole cecal cine a call eeeon neal a eemeraloe ce mee omen gk eo. SORES obey alee LMOSSTPy 090 ‘9% pale ae a alee ali teen en ume elpe se TODS Tile OT co 6 ose‘oz | & OSF os |g RSP SS CSRS S = Tele unos Bese SSTS SEE 908 ‘18 Tee | beg eee ee eka || eovnz Soom s| ns eel Ve mena |°L0S ay 4 Paley 2/2 om aESRST| oul sp satura fr cr | [ey pa aio Ce Maca easel (WNP) 2 (HNO) ahs 77" >> - B]OSOUUTPT C02 ‘L Sees poses PSA SS Stayt 1 ON I Serbo 95) ees ian OO Tete ng 192% Ir T 298 P I soos Tresor, 082 ‘T aes eel Oee 8 G Re an ES AE ol ee oa] gets | ae gee | peel |e tp ame eer | eat ata gek Ae ces ee eet Si ee deci ee Si “>> "“S}jJesNyoVssepy #89 ‘2 SSO PRO Fc poem anaes ees SSals ssa g pean c ssa" sicin la eee ReeOumea COD eI¢ 0g T G ge tgere|| Beesa lapeaes| eee ~-> = puepArepy L6P'P ADEE SBC OC ee SS ae all ke Pie | Senso iss elas aieiaiais ae OUTER TT a aaa (> Sana coat] tron, elms 1 eet aN (alana Wiebe abe Dm =i Rve dK Boal IO) anaes rata MRC eG To ess "7 BUBISTNO’T 008 ‘8 RITE RS OSS) (ATS faa tel I 0) Sok: ee cent Fa ya Kare et ASI FITS I bale dite bel soo 77> Kon} UeyT 2986 ecu ta ar Meee | KOO0! tal re T nae i ~~“SBSUB YT ee ie al | Ie at | Re is | eR | Race P| 9 ce| ey | | oe a |g een ee ene eS RTE [a nn ee ence ee ee a eee eee ae Se Nes Ta NO oes hoe Re Paes alae eee ei GG DE Pte GIG a) 000 ‘ST oe is a SN ae ze ual i beat | Epa ole a bm pe le Sees ees sTOnTITT eo ‘9 a 2p al oA Tecate |= appear ||' es e|| Be ae Sao —| Nae bee A a | i Saal Nears Fel (04 React EX 0) Some [acicleg SR “-oyBepy caer eee S| etn Ge ag] bate) peal fas ne tet po SS Se ese $18 ‘8 8 g "777 = "= BES108 1) TLL‘G 18 OLED HES Sy Se es a Sar shoe Ih Pn deem pe ca cae wae alll oe cpt tee ae dn fp ces eines eae Meee ume | Rea rs eg ae ee > Bplopy Z6P ‘TL ities! [eect pita tl (capes a weeeees = “OIBA BOC 002 ‘T 8 T 002 norjoouuo,) LLL ‘GP iia ee ny [eA oo oat [FS oa ~ 5475" >*OpBIgIoy 118 ‘08 Soe amyee ell (gna RIWIOJT]BD Z9Z ‘82 rae Zz SNRs “susuByIy 868 ‘62 ee ee eee es 868 ‘T eecesccesses euozZlly aye ee ame | SSL | | ae S| AL a | OE) eS) ml OS Seg mlm ei. pistols Ray eS y BYSLLV 008 -|--+-++1 ggg BUIBqRLy | — —o *sqaod *sommy *(por09 “xo | ‘oq | “ooUB |SUOIS] *1oq | “OOM |*suOTS| *Aoq | ‘ooUG |-suOTS| “Aoq | ‘oOUw | -00T | ..5, sdoqg *1oq | -siSo1) JO 10q |-WnN|-puo}}, y} -Sog |-WInN|-puej7y| -Sog |-tunN|-puoj}y] -sog |-uinN|-puoe}}y| Jo z0q TON S}-crn N| ooue ‘aou | oorAdos -puoy| Jo ‘souspuoy} *¥ | 84°C Pom =UWnLN -puoj}y *10q “WON -8 1810.1, * IOP, 10 0}UIS “sur “070 ‘STOT]WOA *soyny “90714 “sreloods proayrey “s[ootpos oyq es “ool UOLPEAJSuUOTMOP Poly | -Woo ‘survey ‘soyuorg | -Ysutdn-punoxy | -1ysuryuepuedopur Teyoods pwosyey [OOS O[TBAORY ‘ST6T ‘08 aunp papua svak ayy of sburjoowu UoynsuoUuap ppaif pun ‘suoyuaruod ‘surf ‘sovuid ‘saanjusur dn-punos pun quopuadapur ‘sppwads ppowpps ‘spooyos apqnrow Hupnpour ‘sagnpuysus powed y ol *po}yVUMLIST ¢ "q10d01 ON ¢ “poy SoyNILSUL ON 1 119 ZOO‘T |°""*""| #69 ‘ST ““-"="| 602 °6 | 6S¢ | OFE | OOF‘ZcT| 6zE | 99 SPS ‘26T| 998 ‘T] 89L | Szo‘TOS| car | ScL‘bs | e66 | Sz 289°G8 | 6F6 | 28E |7------ [e100 soesess=-3miT04 A Toe 5" == * UISHOOST AA **-BIUTS. 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DEPARTMENT OF AGRICULTURE. 32 196 ‘G8 Fz ‘SS OOT ‘ET 16 SLI 9IT 662 18¥ 00°000‘9T | 00°000‘E | 92°69F ‘OL [77 ---""g10HBq WINog 000 ‘sé 01 *€ 000 £26 COT €81 82 01% 628 OOR00S2Z= 2 | CORODGES = [92.0 E.G Te ites amen areas epee anes “777-7 "gUTjOIeO yng 008 % 969 ‘% 079% 66 LG 8% 98 ze 00002 00009 8I ‘08h “Tosh ht 217i 2 PERSP @pey 7 OTE TE Sia aay Ce cere | [cae aa acl ae Nareraa eisai (eke coer eke oan al are ate ol (ana o> te 4 [ieee PEGS Se ee SUSE FRE ene eee aS Wee Ee oF atl a cae *z O01 010g 800 ‘Ser TH8 ‘PST | 608 ‘Z9T =|: OT 986 18 BOs (Oru ty 216008009 Ce4|20000G Ses |OOTDNY Scrat cate cum ye lose mea ~-~eueAyAsumeg 626 ‘ET €€9 (OT 0S ‘ST 16 BL ge rag SIT G0 U0G5 9 |c00 GeO a |00K00 OS Siisaee Ai) rg ees eee “*""* "103010 826 ‘88 G9 ‘TL 068 (S pos oS aa! OT ‘T TES OOK00S 100 3 gO COSROser|COOKODD De MMie ge: eo tt eee nee ~-*-BuLOyeT{O STG (368 GPS L6E GBI 928 ore Tre &6E 088 °T GOL ‘T. 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OG Sasa be cee IUISILA 4S TS sree wees z UOJSULYS AA weeee n-ne { oS eS TBlUIsITA prretssssss* -Nelo[Op eo dae SG ecg 7 }UOULIO A eae cele p91olopn seneeee o7]>"">">=puRysy epoury Ee Be BSooe too 22=-O9TN7 OF10G 5 Beem hate Thee ermvA[ ASU 7 Acta eee | ade ets “*"""="-1103010, epaata te D ctee a | betes eaters (S CXLOLCT GS [pT (a) foe oe dee ee OO BULEE TIN OF Pre USDEPARTMENT OFAGRICULTURE *, No. 84 ge) Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. April 16, 1914. EXPERIMENTS WITH UDO, THE NEW JAPANESE VEGETABLE. By Davib FaircHiLpD, Agricultural Haplorer in Charge of the Office of Foreign Seed and Plant Introduction. INTRODUCTION. A decade has passed since the udo of Japan was first proposed as a vegetable to be grown by Americans. This is a short time for the introduction of a new vegetable, when one considers that it means simply that at ten different times experimenters have had a chance to taste its blanched shoots. But it is appropriate now that there be put in print some account of the experiences which various experimenters have had with this new vegetable. Enough data are at hand for the production of an extensive bulletin on the udo, but, as much yet remains to be done, the important conclu- sions regarding its culture can be stated in a few paragraphs for the guidance of those who are interested in trying this new vegetable. The writer first published, in 1902, a short account of the udo which he wrote in Japan while traveling as Mr. Barbour Lathrop’s explorer’ and before he had had any opportunity to experiment with the plant in America. Necessarily that account lacks any back- ground of personal experience with the difficulties of cultivation. Since 1906 the writer has had growing on his own place in Mary- land just such a patch of udo as he is encouraging others to plant. (Figs. 1 and 2.) Each spring he has had the pleasure of experiment- ing with it in his kitchen, as well as of blanching it in the garden, and he can speak now regarding it with a degree of confidence not possessed heretofore. As a commercial proposition he has had only the chance of watching an experiment in California made by a large asparagus grower.on the Sacramento River, who has now for three years been growing several acres of udo and has shipped crates of it to the eastern market, where, as was to be expected, he has found commission merchants slow to take it up. (Figs. 3 and 4.) 1U. 8S. Department of Agriculture, Bureau of Plant Industry, Bulletin 42, 1903, pp. 17=20. Notr.—Results of experiments in Maryland. Gives methods of cultivation, preparing, ard cooking. Adapted to New England, the Atlantic States as far south as the Caro- linas, the rainy region of Puget Sound, and the truck sections of California about Sacramento. 32790°—14 2 BULLETIN 84, U. 8S. DEPARTMENT OF AGRICULTURE. Fic, 1.—Plant of udo at “In the Woods,” Chevy Chase, Md., Oct. 12, 1909, from seed planted in the spring of 1906, showing the ornamental character of the growth. Fic, 2.—Field of udo at Chevy Chase, Md., showing draintiles used to blanch the shoots in the spring. : EXPERIMENTS WITH UDO. 3 | Fie. 3.—The first field of commercial udo in the United States, on the asparagus farm of Mr. M. EH. Meek, Antioch, Cal. : Fic. 4.—A crate of udo as it appeared after being shipped from Antioch, Cal., to Wash- ington, D. C. The shoots were blanched by mounding up the soil, and many of the tips were green from exposure to sunlight above the mounds. Though slightly dis- colored, these were of good quality when prepared for the table. 4 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. There is no doubt that the udo is worthy of adding to our list of spring vegetables, for it is easily grown, its shoots are readily blanched, and it requires little care. A patch of it can be forced every spring for at least six years, and probably much longer. When properly prepared its blanched shoots are delicious; they have their own characteristic flavor, can be prepared for the table in a great variety of ways, and are keenly appreciated by people cf discriminat- ing taste. Space for space, udo will yield about the same amount of focd for the table as asparagus and will be ready for use at about the same time in the spring. Possibly more labor is required to blanch the shoots of the udo than those of asparagus, but the udo is probably scmewhat easier to take care of and yields sooner. Fic. 5.—Plantation of udo one season from_seed at the Arlington (Va.) Field Station, 1905. As an ornamental, udo has been known to nurserymen for twenty years or more under the name of Aralia cordata Thunb. It might be termed a rank-growing, shrubby perennial with a large, fleshy rootstock (fig. 5). It dies down each fall after the first frost and comes up again, much as asparagus and rhubarb do. It grows to a height of 10 feet or more if on rich soil, producing a very ornamental mass of large green leaves, and, in the late summer, long, loose flower clusters, sometimes 3 feet in length. The flowers attract bees and flies in great numbers, and as a honey plant the udo would appear to warrant the attention of beekeepers (fig. 6). A field of udo is generally humming with insects. EXPERIMENTS WITH UDO. 3) EARLY EXPERIMENTS WITH UDO. Siebold and Zuccarini,’ in their Flora of Japan, called special attention as long ago as 1835 to the good qualities of the udo as a vegetable and recommended it for introduction into Europe, with Fic. 6.—Flowers and fruit of the udo. The flowers are visited throughout the season by honeybees and flies, and the dark fruit clusters are ornamental. the remark that “the young shoots form a delicious vegetable,” as follows: This plant probably came from China, where it is employed as a sudorific; it is cultivated throughout Japan in the gardens and as a field culture. 9 5) 1Siebold and Zuccarini. Flora Japonica, vol. 1, p. 57, 1835. 6 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. It is cultivated essentially for its root, which has an agreeable flavor, aro- matic and bitter, and is eaten in winter prepared as we do the scorzonera (S. hispanica L.). The young shoots form a delicious vegetable. As the plant grows well all over Japan, it will acclimate itself quite as well to our gardens; and this is why, cultivated with us, it may increase the number of our fresh vegetables by the addition of one which is good, whole- some, and nourishing. (Free translation.) In that remarkable book by Paillieux and Bois, Le Potager d’un Curieux,! the authors give their experience with ne at their gardens near Crosnes. They eed such difficulty in raising the plant from seed that they concluded, quite erroneously, as we have dis- covered, that udo seed must be sown as soon as mature or it will not germinate. 7 me After several attempts to get living plants, ate ioe 1879, they were finally able to secure 10 of them. These grew very soe ee torily in their garden and, according to their report, they obtained, by blanching, very appetizing- ere shoots, resembling those of medium-sized asparagus. ager the taste did not strike them favorably. They objected to the faint suggestion of turpen- tine and predicted the failure of udo in Europe. How extensive the trials of Paillieux and Bois were the writer has not ascertained, but from his own experience he realizes how easy it is to form an unfavorable impression regarding the flavor of a new vegetable, and, judging from seven years of trial, in which he has submitted udo to the judgment of a great many people, he believes it is fair to conclude, since no recipes and only the barest details are given in their report, that the culinary trials made by these authors were quite inadequate to do justice to its excellent qualities. — Notwithstanding the fact that raw potatoes, improperly blanched celery, raw asparagus, and raw beets are all most disagreeable to the taste, he tendency is to overlook this and to condemn raw udo, comparing it with blanched celery, when in reality it has too strong a flavor to be eaten without first preparing it for the table in the proper way. RELATIVES OF DO. There are two native species of the genus to which the udo belongs which resemble it quite closely in appearance—the spikenard or petty morel of our rich woodlands (Aralia racemosa L.) and a Cali- fornia species (Avralia californica 8. Wats.). The spikenard is said to grow in the shade to a height of 4 or 5 feet, but a plant which the writer has had in his experimental garden in full sunlight for four years has never grown more than 3 feet high. This plant flowers much earlier than Aralia cordata, about the middle of July 1 Paris, 1899, 3d ed. EXPERIMENTS WITH UDO. i. instead of in September, and is altogether a much smaller plant. The root is said to be pleasant to the taste and was used as an ingre- dient of homemade beers in colonial times. The writer has never had an opportunity to blanch the shoots of the plant and test them. The California species is considerably larger than the spikenard and has leaves which are of a thicker, more leathery character than either the udo or the spikenard. In Maryland a plant of this species has lived through the mild winter of 1912-13, but it gives the im- pression of being distinctly not hardy there. It has not yet flowered and is not large enough to furnish shoots for comparison with the Japanese species. As material for breeding, these American forms, and possibly the wild sarsaparilla (A. nudicaulis L.), are promising, and there is room here for an interesting piece of breeding work, since it is the vegetative portion of the plant which is used and asexual methods of propagation are a success. No crossing of these species seems to have been attempted. VARIETIES OF UDO. When first introduced into America as a garden vegetable there were supposed to be two varieties only, the Kan udo and the Moyashi udo. Although grown side by side, there never appeared to be any marked difference between these two kinds, and the writer is con- vineed that they are identical varieties, Kan udo being seedling udo and Moyashi udo simply forcing udo. Much the same distinction exists between sea kale from seed and sea kale “ crowns.” Since this tirst introduction, the writer’s attention was called by Prof. Y. Kozai, director of the Imperial Agricultural Experiment Station, Nishigahara, Tokyo, Japan, to the fact that in Japan what are really believed to be distinct strains do exist, and these have been given distinctive names. Through the kindness of Prof. Kozai these varieties were introduced and are now growing in America. They are S. P. I. Nos. 33250, “ Yozaemon, red, early ”; 33251, “ Hanza, late”; 33259, “ Fushiaka, node red, midseason ” ; 33253, “‘ Shiro, white, very early ”; 33254, “ Nakate, Usu-Aka, rosy, midseason ”; and 33255, “Kan udo, red, extra early.” The writer has grown these and forced them once only, and they appear to be very similar in appearance, but whereas seedling or Kan udo in this latitude is ready to cut in April, the Hanza and Fushiaka varieties are at least three weeks or a month later. The Yozaemon has produced its shoots at almost the same time as the Kan udo. The two later starting strains will pro- long the cutting season well into the middle of May in the latitude of Washington, D. C., which will be a great advantage, and it is probable that other characteristics will be discovered as experimenters become familiar with these strains. 8 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. METHOD OF CULTURE. | Much remains to be done in the working out of the most inexpen- sive methods of cultivating udo. Conditions of labor and materials are so different here from those in Japan that the methods of the Japanese have to be adapted to our own circumstances. The climate in America, at least in the Eastern States, is so different from that of Japan that methods of forcing used there are not applicable here. As a home garden vegetable the experience of the past 10 years indicates that the udo, when once started, is a very easy plant to grow. Amateurs have experienced some difficulty in growing udo from seed, but anyone with greenhouse or cold-frame facilities should have no difficulty with fresh seed if it is sown one-fourth inch deep Fic, 7.—Young udo plants as distributed to experimenters. Seedlings from seed planted in February should attain this size by the first of June. in March or April in what is known as screened potting soil, consist- ing of 1 part loam, 1 part leaf soil or mold, and 1 part sand. In two or three weeks the seeds should be up. From the flats, the young seedlings can be planted out in the ground as soon as they are 3 or 4 inches high, or they can be potted off and later set out in the field (fig. 7). Seedlings started in boxes or flats in March will often grow 4 or even 6 feet tall the first year and will flower freely if not prevented from doing so, as they should be, by cutting or pinching out the round flower buds in midsummer. Where the questicn is not one of propagating a horticultural strain, the seedling method of propagation is undoubtedly the best. Where, however, it is desired to perpetuate a particular strain, udo plants may be grown from cuttings of the green shoots. To do — ee a ee a te : j , ‘ . EXPERIMENTS WITH UDO. 9 this, terminal shoots should be taken when they are three-eighths of an inch in diameter and cut 5 inches or more long, care being taken to make the cut just below one of the joints, or nodes, in order to insure that the cuttings form a proper callus. In California, the head gardener of the State University, Mr. Mansell, got 80 per cent of his cuttings so made to grow satisfactorily. He took them in late summer or early fall and put them in clean sand. The writer has rooted cuttings of this kind in garden soil in Maryland. While it is possible that cuttings of the root might grow, the writer’s experiments with them have been failures, at least unless a bud from the base of the stem was included in the cutting, in which case it grew satisfactorily. Fig. 8.—General view of one-half acre plantation of udo at the Yarrow Field Station, near Rockville, Md. The plants set from thumb pots in the spring here averaged from 23 to 4 feet high in late summer. The udo is a coarse feeder, with great succulent roots which travel rapidly through loose, rich soil. They can consume astonishing amounts of nitrogenous manures and turn them into succulent shoots. Planting udo on poor, dry lands is not recommended, for, though it would probably live, it would make no growth there. A specially constructed bed, such as is often made for asparagus, is, however, not necessary. Three and a half feet apart is close enough for plants of the udo to stand, for as they grow older the crowns become at least a foot across. On very rich soil the writer has found 4 feet not too great a distance. When grown even with this space between them the plants will touch each other and make horse cultivation impossible late in the summer. (Fig. 8.) 10 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. Seedling plants have often produced by the following spring roots large enough to give a small crop of shoots, but it is advisable to delay cutting the crop until the second year in order not to weaken the plants at first—following in this practice that usual with asparagus. ¢ THE BLANCHING OF THE SHOOTS. The stems of the udo when green are rank in flavor, and although the green shoots when pulled, peeled, and stewed are said to make excellent greens, it is the blanched shoots first produced in the spring that form the table delicacy. The blanching of these shoots has been done in a variety of ways. At first the method followed was that of mounding up the earth over each plant in early spring, but in this climate it was found that the late frosts make the soil too cold, and Fic. 9.—Udo planting at Baddeck, Nova Scotia, showing on the right two mounds of earth which cover plants which were cut down in midsummer. The shoots blanched under these mounds were of excellent quality. While successful in the cool summer of Nova Scotia, this method will probably not be practicable in warmer climates. the shoots are slow in coming through it. (Fig. 9.) In California, however, on the asparagus lands near Antioch, on the Sacramento River, Mr. W. H. Meek has produced excellent udo by mounding up the hills, much as he does those of asparagus; but there the soil is almost as light as sawdust. A very satisfactory method for blanching udo in a small home garden is to put over each hill before growth starts in the spring a large draintile which has one end plugged with a cement cap or covering. The shoots coming up inside of the tile are well blanched, and’this method has the advantage of making it possible to examine the shoots at any time to see how they are coming along. It has at least one disadvantage, however, in that the shoots have a tendency to leaf out and produce a number of unopened leafstalks which take EXPERIMENTS WITH UDO. 11 away from the robust growth of the shoots. A method which has obviated this defect in using tiles is to put around each hill a deep box er small half cask from which the bottom has been removed and fill it with hght sand or such a light material as sifted coal ashes. Shocts which come up through such a medium are almost free from the elongated leafstalks which are developed when the shoots are produced in the dark air chambers under the tiles. Care must be taken in any method of mounding up or filling in dirt or ashes over the crowns that the shoots do not break through into the sunlight, ~ Wicg. 10.—The blanched shoots from a single crown of udo from which the draintile has just been removed. Note the slender leafstalks rising from the main stems. This forms an objection to the use of the draintile or any method of forcing in a closed air chamber. for as soon as they do this they become green and take on a rank, objectionable flavor. Properly grown udo shoots produced from 3-year-old plants should be from 12 to 18 inches long and 1 inch to 1% inches in diameter at their bases (fig. 10). Such shoots cre tender throughout, with no trace of fiber except in the rather thick “bark,” which can be easily removed. Naturally, if one is impatient for the very first udo shoots, + Thinking to overcome this difficulty, the experiment was made of filling the tiles with soil before inverting them over the crowns, but the plants refused to grow up through this soil. 12 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. he can cut them when only 6 inches long, but if he will wait he will be rewarded by getting shoots of somewhat astonishing proportions. In point of season the udo crop in the latitude of Washington approaches that of asparagus. It is perhaps a few days earlier under the draintiles. If 6-inch instead of 18-inch shoots are satis- factory, a crop of udo can be taken ten days or two weeks earlier than asparagus. Just as with asparagus, sea kale, and endive, udo can be forced by packing the roots together in a trench over a layer of heating manure, but this method makes a very expensive vegetable of it and would be resorted to only by the gardeners on large estates. Shoots can be produced in this way in March, and doubtless also in Novem- ber or December. After the removal of the crop of udo shoots in the spring, the crowns of the plants should be completely uncovered and the plants allowed to grow normally throughout the summer, but they should not be permitted to flower unless seed is required, the flower clusters being pinched or cut back as they form. This latter is not a necessary precaution, but it tends to throw the growth of the plants into the roots and increase the size of the shoots for the table the following year. PREPARATION FOR THE TABLE. The flavor of udo is distinctly aromatic, like celery or parsnip, but different from either. When properly prepared it is one of the most delicious of vegetables, but unless properly cooked it is sure to meet with ridicule. The reason for this lies in the fact that its stems con- tain a resinous substance which gives them a decided flavor of pine when tasted raw. There are many people who never get farther than this first taste and condemn udo on the spot, forgetting how disagree- ably raw vegetables often taste. It is a simple culinary practice to boil strong-flavored vegetables in two (or even three) waters, and this is advisable as a general recommendation, although when used for soup it does not appear to be always necessary. An hour’s stay in ice water will remove this resin from the shoots, provided they are cut into thin slices or shavings. Little is known regarding the food value of“udo further than that analyses show it to have about the same dietetic value as celery or asparagus. The Chinese, who are prone to ascribe mysterious properties to many of their foods, have given to udo, which they call Dotooki, Dokii quatz, or Dosjen, medicinal properties which are more curious than probable. EXPERIMENTS WITH UDO. 13 RECIPES. The following recipes for preparing udo are recommended: Udo on toast.—Peel the shoots and drop them into cold water. Cut them into 4-inch lengths. Boil them in salt water for 10 minutes, then change the water, adding a fresh quantity of salted water and boiling until quite soft. Fic. 11.—Udo on toast with cream sauce. The entire shoot can be eaten. Prepare a white sauce, such as is used for cauliflower or asparagus, put the udo in it, and aliow it to simmer until thoroughly soft. Serve on toast (fig. 11) in the usual way. If there is too much of the pine flavor, as there may be if the shoots are not thoroughly blanched, a second change of water will remedy this. Wie. 12.—Udo as a salad. The shoots have been peeled and cut into thin shavings and left in ice water until the strong flavor has been removed, then dressed with a French dressing. Udo salad.—Peel the shoots, cut them into 3-inch lengths, and then split them into thin shavings, letting these fall into ice water as they are made. Allow them to soak in the water for a half hour or an hour, so as to remove the resinous material in them. Serve with a French dressing of pepper, salt, oil, and vinegar. Do not dress the shavings until just before serving, as they become stringy on standing in oil. (Wig. 12.) 14 BULLETIN 84, U. S. DEPARTMENT OF AGRICULTURE. Udo soup.—Remoye the skin from the shoots. Cut in pieces one-half inch long and wash thoroughly in cold water. Cook until tender and mash through a colander. Add a pint and a half of milk, one-half pint of cream, two table- spoonfuls of butter, and one tablespoonful of flour, mixing the flour and butter until smooth. Season with pepper and salt. (Recipe for one bunch of udo; enough for five persons. ) CLIMATIC REQUIREMENTS OF UDO. From the fact that udo is grown all over Japan, cne might assume that it is adapted to a wide range of climate, but it must be borne in mind that Japan has an insular climate and that none of its plants are subjected to drought. The udo has done best in the moist regions of this country, especially in the New England States, Canada, and the Atlantic States as far south as the Carolinas, in the rainy region of Puget Sound, and in the trucking sections of Cali- fornia, about Sacramento. The fact that it dies down in the winter and can be covered makes it possible to grow it where temperatures go far below zero. A temperature of —17° F. for a few days has not injured it in the least. DISEASES OF UDO. Like almost every other plant, udo has its diseases. Dr. B. D. Halsted, of New Brunswick, N. J., has had trouble with his plants because a leaf spot (Colletotrichum?) attacked the foliage and did much damage. The writer discovered a soft rot of the roots which killed a number of apparently vigorous plants on the farm of the Department of Agriculture at Arlington, Va., the cause of which proved to be a sclerotium-producing fungus, the mature form of which has not yet been observed. These diseases, however serious — they may seem, should not discourage the trial by thousands of Americans of this easily grown early-spring vegetable, which will thrive under so many and varied conditions. REASONS FOR THE INTRODUCTION OF UDO. The writer is not certain that from a purely money-making stand- point udo will prove superior in any detail or combination of details to vegetables which are already under cultivation in America, but it has a distinctive flavor, and many people are beginning to like it, as they have learned to like celery, asparagus, and eggplant. Notwith- standing its centuries of culture in the Orient, it is still a vegetable whose potentiality remains quite undetermined. It is highly desir- able that many amateurs should experiment with it and the public get acquainted with it in order that a sufficient demand may be cre- ated to encourage growers to investigate it on a sufficiently extensive scale to determine whether it has any really economic advantages EXPERIMENTS WITH UDO. 15 over such annual crops as celery or such perennial crops as asparagus. It has been estimated that when grown on a large scale it would require much less labor than celery and that it furnishes a crop from seed at least a year sooner than asparagus, and there may be other advantages which will appear during the long process of adaptation through which every new plant introduction must pass before it becomes a real factor in the diversification of our agriculture. Udo has already won many adherents among those who care for new vegetables, and, although it can not by any means be said to be a well-known table vegetable, it has arrived at a point where it might be pushed by any careful, enterprising advertiser of fancy vegetables. Tt has been served successfully at large dinner parties in Washington and on the private tables of those who have their own gardens. It is winning its way steadily, as evidenced by the increased call for plants and the fact that importations of seed from Japan have become con- siderable, according to recent advices from an important nursery firm there. In Europe, so far as the writer is aware, udo has not made any headway; but this is not to be wondered at when we consider the conservatism it must meet there. Mr. Philippe de Vilmorin, of the firm of Vilmorin-Andrieux & Cie., of Paris, admits, however, that udo is the one Japanese vegetable which deserves to be introduced into cultivation in France. O WASHINGTON : GOVERNMENT PRINTING OFFICE : 1914 | Paki. 5k oe aio PO EBB ea ue Ph een mre x pest ae ye i nae ae eae 1 Waa K / Zk aS @ MN) GB) USDEDARIMENT OP AGRICULTURE No. 85 Yess ne Contribution from the Bureau of Animal Industry, A. D. Melvin, Chief. April 27, 1914. (PROFESSIONAL PAPER.) THE COST OF PASTEURIZING MILK AND CREAM. By Joun T. Bowen, Technologist, Dairy Division. INTRODUCTORY. In the pasteurization of milk and cream there are two systems in use at the present time, known as the ‘‘holder” and the ‘‘flash” processes. The holder process consists in holding the milk or cream for about 30 minutes after it has been heated to the pasteurizing temperature of 140° to 150° F., either in the same apparatus in which the pasteurization takes place or in separate holding tanks arranged ~ for the purpose, after which it flows to the coolers. In the flash or continuous process the milk or cream flows from the receiving tank to the pasteurizer, where it is heated to a temperature of from 160° to 165° F. in from 30 seconds to 1 minute, and from thence direct to the coolers, where it is cooled. It is obvious that there is more heat required to pasteurize a given amount: of milk or cream in the latter process than in the former; for example, assuming that the initial temperature of the incoming milk is 60° F. and that in the holder process it is heated to 150° F. and in the flash process to 165° F., then for every 1,000 pounds of milk to be pasteurized by each of these processes the actual number of heat units required to raise the temperature of the milk to the pasteurizing temperature is: B. t. u.!=1,000 0.95 ? (150-60) =85,500, holder process. B. t. u. =1,0000.95 (165-60)=99,750, flash process. It will be noted from the above figures that the flash process of pasteurization requires 16.6 per cent more heat to pasteurize a given 1B. t. u. (British thermal unit) is the quantity of heat required to raise 1 pound of pure water 1° F. at or near its maximum density, 39.1° F. For practical purposes, however, it may be considered the heat required to raise the temperature of 1 pound of water 1° F. 2 The specific heat of milkis taken as 0.95. The specificheat of any substance isits capacity forabsorbing heat compared with that of water taken as unity. Notre.—This bulletin deals with the cost of pasteurization from an engineering point of view. It con- tains desirable information for proprietors of creamer’es and milk plants and for designers and manu- facturers of pasteurizing apparatus. 33347°—14 2 BULLETIN 85, U.S. DEPARTMENT OF AGRICULTURE. amount of milk than the holder process. Furthermore, the milk must be cooled through a correspondingly wider range. These figures, however, deal only with the heat absorbed by the milk, and do not take into consideration that radiated to the air and absorbed by the metal and other materials used in the construction of the apparatus. TESTS OF MILK-PASTEURIZING APPARATUS. The following tests were made on the pasteurizing equipment of five city milk plants. They were considered as representing average city plants. The pasteurizing equipment in each case consisted of heater, holding tank, regenerator, and cooler._ In plants 1 and 2 the heater and regenerator were combined in one unit, and in plants 3, 4, and 5 they were separate. In plant 3 the regenerator was in the form of an ordinary tubular cooler, and the hot milk from the holding tank was pumped through the coils while the cold raw milk flowed over the tubes. In plants 4 and 5 the regenerators consisted of double-pipe arrangements, the hot milk flowing through the inner pipe and the cold milk through the outer and therefore surrounding the inner pipe. The boilers were in good condition and were provided with exhaust steam feed-water heaters which heated the boiler feed water from an initial temperature of 60° F. to a final temperature of 180° F. The boiler pressure in all cases was approximately 80 pounds. The efficiency of the boiler and setting is assumed to be 50 per cent in all cases, which is believed to be a fair average. However, if there was a variation of 10 per cent in the estimated efficiency of the boiler and setting, it would affect the cost of pasteurization by approximately one-half of 1 per cent. It is further assumed that the coal cost $4 per ton (2,240 pounds) delivered in the bunker and that it had a heat value of 12,500 B. t. u. per pound. The condensed steam was caught as it came from the heater and weighed and its temperature taken, the average temperature being 180° F. The pressure of the steam entering the heater was reduced from the boiler pressure of 80 pounds gauge to from 3 to 5 pounds. Therefore, the heat absorbed in the heater per pound of steam sup- plied was 1,155 — (180-32) =1,007 B.t.u. For the sake of simplicity the heat absorbed in the heater per pound of steam supplied is taken as 1,000 B. t. u. The temperatures of the milk were taken at each stage of the process and are recorded in Table 1, “‘Temperature balance.” It will be noted from an inspection of the temperature balance that the cycle of operation consisted in starting with the initial temperature of the raw milk and raising its temperature to the pasteurizing point, about 145° F., then cooling the milk down to the temperature of the raw milk. | } | / THE COST OF PASTHUBIZING MILK AND CREAM. o No account was taken of the cooling below the temperature of the milk in the receiving vat, as this had nothing to do with the pasteurizing cycle. Based on the foregoing data and assumptions the following calcu- lations are made: TaBLE 1.—Results of tests at five milk-pasteurvzing plants. HEATING. Plant number. 1 2 3 4 5 Time of operation.............--- hours. . 4. 366 3. 216 2.0 4.0 3.6 Amount of milk pasteurized....pounds..| 40,577 20, 236 7, 628 29, 799 22,055 Amount ofsteam used in the pasteurizer, (DOWING So soclouecdanssesdoncuaeeoesuueeR 2, 258 1,383 263. 5 1, 128 572.7 Heat in the steam supplied direct from the boiler to pasteurizer....... B.t.u..|2,601,595 —|1, 593, 405 305,499 | 1,299, 542 659, 796 Heat in the steam required to drive the pasteurizing equipment......-. B. t. w..}1, 006, 259 444, 704 276, 519 921, 664 829, 439 Total heat Shae by boiler for pas- COURIZ IT eh aera heen B.t. u..|3, 607,854 — |2,038, 109 582,018 | 2,221,206 | 1,489,235 Heat absorbed in the pasteurizer..do.... 2 258, 000 1,383, 000 263, 500 1, 128, 000 572, 700 Total boiler horsepower developed for pasteurizing ~~. 222... -.- 26. Beye 108.3 61. 2 17.5 66. 7 44,7 Boiler horsepower per hour developed for pasteurizing..-..........- 13), 1851 5- 24,8 19.0 8. 75) 16.7 12,4 Total heater horsepower consumed in pasteunizinp 2 ke ese ke By Ee Pee 67.8 41.5 7.9 33. 9} 17.2 Heater horsepower per hour consumed in pasteuiigg Baca ees Meee B.H.P.. 15.6 12.9 3.9 8.5 4.8 Milk pasteurized per boiler horsepower, POU SEee ese e ce orca sees 375 330 435 446 493, Milk pasteurized per heater horsepower, DOUNGSMAN ene hae seen ee ewe ee 598 487 965 879 1, 282 Coal consumed for pasteurizing- pounds. . 578 326 93 355 "938 Milk pasteurized per pound of coal.do.... 70 62 82 84 93 COOLING Cooling water required in water section ‘oncoolers=s 32 22 hes 2 cubic feet. - 1,697 960 219 Sie eeccsiee eae Refrigeration extracted by brine. .tons.. f a - 46 - 206 1.7 - 886 COSTS. Capital invested in pasteurizing equip- ment (pasteurizers, vats, coolers, etc.)..| $5,332. 00 $3,000.00 $2,065.00 $3,470.00 |$6, 250.00 Interest per day on investment at 6 per cent per annum..............-. - 876 - 493 2339 - 570 1.027 Depreciation and repairs per day at 25 per cent per annum............. 3. 652 2.055 1. 414 2.380 4, 281 Capital invested in mechanical equip- ment used for pasteurizing (engine, i boiler, shafting, etc.)........----...--. 1,000. 00 800. 00 300. 00 500. 00 700. 00 Interest per day on investment at 6 per cent per annum.......-..-..... - 164 131 - 049 - 087 elitey Depreciation and repairs per day at 10 per cent per annum..........--. 274 > 219 . 082 - 137 - 192 Labor, for pactounizing BOI eat Vw i 3. 500 1. 750 1. 500 3. 000 3. 000 Cost of coal at $4 per ton (2,240 pounds). - 1.032 . 582 - 166 - 634 - 425 Cost of cooling water at 50 cents per 1 000 (Gull OWT es Sata aac im sea Ae eee sae . 848 , 480 . 109 . 158 . 009 Cost of refrigeration at $1 per ton......... . 480 - 460 . 206 1.700 . 886 Cost of pasteurizing daily supply of ilies od AUN canary aba 10. 826 6. 170 3. 865 8. 666 9. 935 Cost of pasteurizing one gallon of Taal De BO aU aie Shy She iE Ns lee SiS as » .00229 - 00262 - 00436 . 00251 - 60387 Average cost for the five plants of pasteurizing 1 gallon of milk...... POOSTS ie eerie acer Bs Rie te ali tea by ea a ae 4 BULLETIN 85, U. S. DEPARTMENT OF AGRICULTURE. Taste 1.—Results of tests at five milk-pasteurizing plants—Continued. HEAT BALANCE. P= |count-| S4P= | count-| S4P= | count-| SYP- | count- lied. | oq for. | Plied- | oq for. | Plied- | ed for. | Plied- | ed for. Total heat in steam supplied Pe CLP. ct. | Be Ct.)|\ Ps eta Ps Ch. \PaChs | ee Chae Cha eC ere iCee to pasteurizer_....-.-------- 00. 00 10000)) 25 == 100.00 }....-.- 100! 00' |e TOOSOOH eee. Heat returned by regenerator. a 86 Heat remaining in liquid (con- densed’steam) ==>. een ees somes ee Heat required to raise tem- perature of initial cnarge of WALOM ©) oor = SP se ae ce eee eeleees cso Heat absorbed in regenerator Dy incomimpe milk. 27 eek Heat absorbed in cooler in reducing temperature to heat otraw milks >> 25e saece|seee ee: Loss fn radiation, exclusive of 1115.56 (=) eee pe res = ol ae Motels ceases sete 143.86 |143.86 |141.00 |141.00 fen 87 (251.87 |224.76 |224. 76 364.27 | 364.27 11 21 | 32 Bee 2A enm--s- ans) ABHB ABD sobs 4 Sh86s5s5604 om. 63.50 57.86 59. 40 DEE OE eae paeeee es nocssaocoeenossesae4 ules Bassoeecon beesacosss 131.30 Rise in regenerator. Dewe wate eule Sees sonics caee ase il OE) [ee Lie ira he 71.90 BS CORE TISD: Scio cosessansessosse sees Per Cénba.| ees se cee pees 84.00 27 Te eee eee eee chee 150. 40 145.00 Bise in heater......... ws Shecwinelsna since saesee econ oH 92.54 13.70 il 77 UTE eee ee ae Der Cente |lsse eens lease eee 16.00 Total per cent rise....... weigisseoeaseess per cent... 100.00 100.00 Holder......... AR AOROCE aasdase elec ice ase eee ae °F..| 146.00 150. 40 145.00 Drop in holder.......... Aeasoues cae tecteeetnrs sat CBee 8.00 4.24 2.25 Per cent drop: zeosesosesecessseeteereee per cent.. 9.70 4.58 2.63 RGPONCTHLOL. -o~ onacccconenancoressacweres sees san °F..} 138.00 146.16 142.75 PrppP 1 TEPene aor a. 2o 2 enciewriecescee ee seo a= Soee i fe 29.75 34.16 63.45 Per Cen MOD .-+.. scans sess ee eeee ee & per cent... 36.00 36.85 74.12 Cogler ee csessadetaacs ocgssepeeeaesses cee Ciee), 6108.25 112.00 79.30 DrOPI COOIET: | 2 oa 3 oe ees cocoate was one oee a 44.75 54.14 19.90 Percent arops =: : 2 jn0 sess knee nee oot per cent.. 54.30 58.57 23525 Potal per cent Grop-_----2-2-ce-seso~ oa per cent..| 100.00 100.00 100.00 1 Regenerator in heater. 3 Direct expansion coils in cooler. 2 Surface cooler used as regenerator. 4 Cooled entirely by refrigerated water. ECONOMY IN USE OF REGENERATORS. Referring to the heat balance for the foregomg plants in which regenerators, or heat exchangers, were used, it will be noted that in some cases the heat returned by the regenerator is considerably in excess of the total amount supplied by the heater. It should be borne in mind, however, that this heat is exchanged from the hot milk leaving the holder to the cold incoming milk, the heat supplied by the steam going to make up the losses; consequently the greater the efficiency of the regenerator the less heat is required from the steam. The hot milk from the holder is transferred to the cooler usually through the inner pipe of the regenerator; consequently THE COST OF PASTEURIZING MILK AND CREAM. 5 the milk entering the heater is thus heated, while that entering the cooler is partly cooled, the cooler proper reducing the temperature to the point desired. The function of the regenerator is therefore to economize heat by transferring the heat from the hot to the cold milk, The hot milk coming from the heater flows into the holding vat and is here held for about 30 minutes. It then flows through the regenerator to the cooler, where it is cooled by water and brine circulation, direct expansion of ammonia in the cooler pipes some- times being used instead of brine. Just the reverse is true in the case of the cold milk; that is, the cold milk comes from the receiving vat, where it is at a temperature of about 55° F., and goes through the outer coils of the regenerator, where it is heated by the returning hot milk. It is obvious, therefore, that any heat transferred from the hot to the cold milk represents just so much gain in economy. If it were possible to transfer all the heat in the hot milk above the initial temperature of the raw to the cold incoming milk after the first charge had been once heated to the pasteurizing temperature, the heater could be dispensed with entirely, and the pasteurizing would go on indefinitely. This would constitute, however, a theoretically perfect machine, which is an impossibility; but the more perfect the regenerative apparatus the less heat will have to be supplied by the heater. The heat balance in test No. 5 shows that it would have taken over two and a half times the heat had no regenerator been used. In all of the foregoing tests the pasteurizing was done with live steam taken direct from the boiler but reduced in pressure to from 3 to 5 pounds. Subsequent tests show that the pasteurization could just as well have been done with exhaust steam, and by so doing a load of from 8.75 to 24.8 boiler horsepower could have been taken off the boiler plant except in plant 1, where the exhaust steam was utilized for making ice in an absorption ice plant. Attention is invited to the saving obtained by the use of regenera- tors in the foregoing tests. The boiler horsepower per hour required for pasteurizing in tests Nos. 1, 2, 3, 4, and 5 was 24.8, 19, 8.75, 16.7, and 12.4, respectively. Without the regenerator, or heat exchanger, the boiler horsepower per hour required for pasteurizing would have been increased to 35.6, 26.78, 22, 37.5, and 45.1, respectively. Thus the average increase in fuel would have been 96.8 per cent, or practi- cally doubled. In addition to the direct saving in fuel due to exchang- ing the heat from the hot milk coming from the holding tank to the cold raw milk on its way to the heater, there is an average saving in refrigeration of approximately 60 per cent, for it is evident that the heat taken out of the hot milk m the regenerator takes just so much work off the cooler. By referrmg to the temperature bal- ance in the table it will be noted that the drop in temperature in the 6 BULLETIN 85, U. S. DEPARTMENT OF AGRICULTURE. regenerator varied from 292° to 83° F., an average of 534° F. In. other words, the milk arrived at the cooler 534° F. lower in tempera- ture than it would have done had no regenerator been used. The regenerator is an efficient piece of apparatus when viewed from an engineering standpoint, but it has its disadvantages when viewed from the bacteriological standpoint, as it is difficult to keep absolutely clean and sterile unless given particular attention. DEPRECIATION OF DAIRY EQUIPMENT. Owing to the rough usage to which dairy apparatus is subjected, having to be taken apart for the purpose of thorough cleaning after each operation, and to the rapid development and improvement in this line of apparatus, it is assumed that about four years is its average useful life, at which time it is either worn out or antiquated and must be replaced. Therefore, it has been depreciated at the rate of 25 per cent per annum. The mechanical equipment (engine, boiler, shafting, etc.) necessary for the operation of the pasteurizing apparatus and which has been depreciated at the rate of 10 per cent per annum covers only that part of the total equipment which is used for pasteurizing. In other words, the total value of the mechanical equipment of the plant is prorated among the various processes through which market milk passes in a modern city milk plant. TESTS OF CREAM-PASTEURIZING APPARATUS. Tests made on the pasteurizing equipment in creameries covered . both the flash and the holder processes. The pasteurizing was also accomplished by using (1) live steam direct from the boiler, (2) ex- haust steam from the engine or from steam-driven pumps, and (3) hot water heated by the exhaust steam from the steam-driven auxiliaries. In calculating the heat absorbed by the cream in the following tests, the specific heat of cream is taken as 0.90. In this connection it is well to state that there seems to be very little known at the present time concerning the specific heat of cream. It does, of course, vary to a certain extent with its chemical and physical composition. At a certain point on the temperature scale its specific heat is greatly increased, apparently above unity. This is attributed, however, to the melting of the butterfat and a part of the absorbed heat being used to effect the change. In Table 2 are given the results of tests on the pasteurizing equip- ment of four creameries. The tests were made under actual working conditions. In tests Nos. 1, 2, and 3 the pasteurizing was done by employing exhaust steam, and in test No. 4 live steam was taken direct from the boiler through a reducing valve. THE COST OF PASTEURIZING MILK AND CREAM, % TEST NO. 1. Referring to test No. 1, the pasteurizing was done with hot water which was heated by exhaust steam from five steam-driven turbine separators and five reciprocating steam pumps. The arrangement for utilizing the heat in the exhaust steam is illustrated diagrammati- callyin figure 1. Asitwasimpracticable to put a back pressure on the small steam turbines used for driving the separators, as would be done if they were allowed to exhaust under water or into a milk heater, the arrangement shown was resorted to. The exhaust from the separators and pumps was piped into the box above the water level. The hot- water circulating pump took the water from the box and forced it through the internal tubular heater and back into the box. The spray pipe, located in the top of the box, above the water level, was In HOT CREAIP U5 OUTLET CONTAOL VALVE FLAN OF OXHAUST. GOX a ae VAPOR FYFE EXHAUST FROVT SEPARATOR i CONTROL TALE, Reeelg THI SE Se rr) ae 3 HOT. WATER AETURN LUE OVERFLOW Pipe. = R GOHUST Bak Fic. 1.—Elementary diagram of hot water pasteurizing equipment. perforated with a large number of small holes through which the re- turn water was sprayed. The heat contained in the exhaust steam was taken up by the water, the equipment acting on the principle of the jet condenser. There was a valve placed on the end of the spray pipe for controlling the temperature of the water. By opening this valve the return water was allowed to pour out into the box without absorbing much heat from the steam, while, on the other hand, if the _ valve was closed all of the return water was sprayed, thereby absorb- ing the maximum amount of heat. The temperature of the water was controlled very satisfactorily by this arrangement. There was an overflow pipe placed in the box, as indicated, which kept the water at a constant level by allowing the condensed steam to overflow into the sewer. There was a vapor pipe on one end of the box which 8 BULLETIN 85, U. S. DEPARTMENT OF AGRICULTURR. allowed the uncondensed steam to escape to the atmosphere. The ex- haust box was built up of cypress lumber, being about 12 inches square by 14 feet long. The heat contained in the exhaust steam from the five steam turbine driven separators and five reciprocating pumps was sufficient for pasteurizing 17 per cent cream at the rate of 18,360 pounds, or 9.18 tons, per hour. This was actually done during the first hour of test. The initial temperature of the cream was 49.5° F., and it was raised to a pasteurizing temperature of 147° F., or through a range of 97.5° F. As 1 boiler horsepower is equivalent to the evaporating of 344 pounds of water from and at 212° F., the boiler horsepower per hour required for pasteurizing under the above conditions was 67.1. It is therefore obvious that had this exhaust steam been allowed to go to waste and live steam been taken direct from the boiler for pasteuriz- ing, the boiler capacity of the plant would have had to be increased by this amount, viz., 67.1 horsepower. In other words, there was a saving in boiler capacity, by using the heat in the exhaust steam for pasteurizing, of 67.1 horsepower. As has been previously explained, it was necessary to employ some such arrangement as that illustrated in the diagram in order to avoid putting a back pressure on the turbine separators, although this arrangement entailed a loss of heat due to the double heat transfer from the exhaust steam to the water and from the water to the cream. Assuming that the boiler and furnace efficiency was 50 per cent and that the coal used had a heating value of 12,500 B. t. u. per pound, then the fuel saved per hour with this arrangement is 67.1 X84.5X970.4 _ a5 9 pounds. If the pasteurizing equipment is 12,500 X .50 run 4 hours a day for 310 days in the year, the annual saving in . 399X4X310 a ; fuel is —3 940 = 198.7 tons, which at $4 per ton would amount to $794.80. In addition to the fuel saved, there is a further saving due to the decreased boiler capacity of the plant. It is evident that if the exhaust steam from the separators and pumps had been allowed to escape it would have been necessary to have taken live steam from the boilers for the purpose of pasteur- izing, and this would have taken an additional 70-horsepower boiler, which would have cost approximately $14.75 per boiler horsepower installed, or $1,032.50. Figuring the interest on the money invested at 6 per cent per annum and depreciation and repairs at 10 per cent, there is a saving in addition to the fuel of $165.45, making a total saving of $794.80 + $165.45 = $960.25, to say nothing of the increased labor of firing the boiler. Adding this to the actual cost would bring the cost of pasteurizing 100 pounds of cream in this particular plant up to $0.0512, or an increase of 12.3 per cent. The fuel cost, THE COST OF PASTEURIZING MILK AND CREAM. 9 however, is practically doubled when steam is taken direct from the boiler for pasteurizing instead of utilizing the exhaust steam. The steam pressure is reduced from boiler pressure to about 3 pounds by some form of reducing valve, consequently there is approximately as much heat in the exhaust steam from the engine, or steam-driven auxiliaries, as there is in steam taken from the boiler. The amount of fuel mentioned above is for pasteurizing, and is not to be confused with the total amount used in firing the boilers. In other words, it is the fuel required to evaporate in the boiler a certain amount of water which is used for the purpose of pasteurizing the cream. With this arrangement the pasteurizing was done with heat that would otherwise have been wasted, and furthermore it took a load of 67.1 horsepower off the boiler plant. TESTS NOS. 2, 3, AND 4. Tests Nos. 2 and 3 were also made with exhaust steam, but the arrangements were different from the foregoing, as the exhaust from the engines was piped directly into the heater. The only load on the engines at the time was the pasteurizers and the centrif- ugal cream separators, which amounted to very little. The exhaust. steam available, however, was sufficient to operate the pasteurizers up to their full capacity. Referring to the summary of the tests in Table 2 it will be noted that the fifth item, ‘‘Heat in steam required to drive pasteurizing equipment,” is blank except for test No. 4. The reason for this is that the engine or steam-driven auxiliaries from which exhaust steam was used for pasteurizing are considered in the light of pressure- reducing valves, the mechanical power being, so to speak, a by- product. That is to say, there is a loss of heat in steam due to drop in pressure, and while the wire drawing of the steam through the valve will superheat the steam to a certain extent, the loss may be con- sidered the same for the purpose of this paper, regardless of whether this drop is caused by passing through a pressure-reducing valve or through a steam engine. In test No. 4 the steam used for pasteuriz- ing was reduced in pressure by a valve, consequently the energy represented by the difference in pressure and temperature of the steam before and after passing through the reducing valve is a clear loss. In neither case, however, was the heat lost due to drop in pressure of the steam available for heating the cream. The 380,800 B. t. u. in column 4 represents the heat in the steam at - boiler pressure which was used in the engine for driving the pasteur- izer, separator, shafting, etc., required in the process of pasteurizing, and as the exhaust from the engine was allowed to go to waste it is 1The use of exhaust steam for other purposes in milk plants is treated in Bureau of Animal Industry Circular 209. 10 BULLETIN 85, U. S. DEPARTMENT OF AGRICULTURE. obvious that the 380,800 B. t. u. represented so much additional] heat over the exhaust-steam systems in tests Nos. 1, 2, and 3. As stated above, in test No. 4 the pasteurizing was done by live steam from the boiler instead of exhaust steam, and by referring to the tabulated results of tests it will be noted that the over-all thermal efficiency of test No. 4 is only 43.7 per cent while that of tests Nos. 1, 2, and 3 is 69.1, 60.6, and 69.7 per cent, respectively; although the thermal efficiency of the heater in test No. 4 was the greatest. The over-all efficiency is here taken as the ratio of the heat supplied by the boiler to the steam to that absorbed by the cream. The thermal efficiency of the heater is the ratio of the available heat in the steam supplied to the heater to that absorbed by the cream. — HEAT BALANCE. No heat balance is given in Table 2 because the pasteurizing equipments in tests Nos. 1, 2, and 3 were installed in market cream plants, that is, plants whose business consisted in the handling and marketing of cream. The cream as received from auxiliary creameries was first run through separators, the result bemg a heavy cream containing about 40 per cent fat. This heavy cream on the way to the coolers was mixed with skimmed milk in the correct proportion to produce a cream containing a predetermined amount of fat. In view of the methods employed in these plants, it was impractical to get out a heat balance showing the distribution of heat in the pasteurizing cycle. TaBLe 2.—Results of tests of four cream-pasteurizing plants. HEATING. Plant No. 1 2 3 4 Dimeiofoperation s.s 32 Mase cesses same tee eee ee hours. . 3.53 1. 733 1.5 1. 166 Amount of cream pasteurized...........-.....-- pounds..} 50,683 6,928 5,019.5) 4,571 Amount of steam used in the pasteurizer.........-.do.... 5, 589. 5 1, 088 647. 5 "529 Heat Be ih boiler to steam, 80 pounds pressure, B.t.u. 6s 437,646 1,253,478 746,003 {617,113 380,800 Heat supplied to pasteurizer................----..- oe --|5,589,500 {1,088,000 647,500 [529 000 Total boiler horsepower developed for sia 193. 2 37.6 22.4 29.9 Boiler horsepower per hour developed for pasteurizing, Beebe: 54.7 21.7 14.9) 25.6 Total heater horsepower consumed for pasteurizing.do.... 167.7 32.6 19. 4 15.9 Heater horsepower per hour consumed for pasteurizing, Bats Bs: 47.5 18.8 : H Cream pasteurized per boiler horsepower........ pounds. . 262 184 224 153 Cream pasteurized per heater horsepower.......... Gove 302 212 258 287 Coal burned in Dash Sapiens clas nic «0's aioaine Clos 1, 030 200 119 160 Cream pasteurized OUNG OLCORIEL Es. conweee do... 49.2 34.6 42. 2) 29.0 Total B.t. u.absor a CUOAKIUBp rte a eis «sien B.t.u.. 14 , 447, 433 760, 030 520,171 |436,176 The over-all thermal efficiency of pasteurizing equip- H0(2) Ch oe ee ee Ae oer) Se 2c). Sa per cent... 69. 1 60.6 69.7 43.7 Thermal efficiency of heater. ............--..---0«- do.... 79.4 69. 8 80.3 82.5 THE COST OF PASTEURIZING MILK AND CREAM, 11 TapiE 2.—Results of tests of four cream-pasteurizing plants—Continued. COOLING. Plant No. = 1 2 3 4 Cooling water used in water section of cooler. .cubic feet. - 1,877 704 169 148 Ice used in cooling cream to its original temperature, LQTS ree ae taic leita wate aici wie sl rere lela ch sjala: epyuiele ew sis Means 3. 44 . 92 83 1.72 COSTS. Capital invested in pasteurizing equipment (pasteurizer, WALS ACOCICIS MOLE) Me cis citei = icinieinieisin vin wisn tes ae cise see as $7, 400. 00 $1, 255. 00 $600.00 |$700.00 Interest per day on investment at 6 per cent per an- TIED 63 eciicbeee Gs GaSe eS ne See ae ae Heeeeraee 1. 233 . 206 . 098 115 Repairs and depreciation per day at 25 per cent per EAIVEA UTM RAE Se AER i nia wie ele Sisson le cies Sis ae ode 5. 068 . 586 411 _ - 489 Capital invested in mechanical equipment used for pas-. teurizing- (engine, boiler, shafting, etc.)............-..-- 1, 350. 00 1, 000. 00 500. 00 800. 00 Interest on investment per day at 6 per cent per an- TG EED BONE e CGE SOS eS SE eae cae a etek ene eNO . 222 . 164 . 082 131 Repairs and depreciation per day at 10 per cent per AIDIN UD o ne ates ae oes eA nawisis oe ae So eee .370 274 . 137 - 219 WAbpoOTHON PAStCUPIZING i... is oe joe 2 sees dicieieicw «ines ae 10. 000 2. 600 2. 000 2. 000 Cost of coal at $4 per ton (2,240 pounds) .................- 1. 839 3857 . 203 . 285 Cost of cooling water at 50 cents per 1,000 cubic feet.....-.- . 938 . 302 . 084 . 074 Cost ofrefrigeration at PUPOL LOW: es ceysine setae sles seis eine 3. 440 . 920 . 830 1.720 Cost of pasteurizing daily supply ofcream............ 23. 110 4. 857 3. 845 5. 033 Cost of pasteurizing 1 gallon ofcream................. . 00378 00582 . 00636 . 00939 Cost of pasteurizing 100 pounds ofcream............. . 0456 . 0701 . 0765 . 1101 Average cost of pasteurizing 1 gallon of cream in the HOUISLCSES Sys se ee late) deteinio w= sales oats rete ee ee ee ROB eo mcncdeearoriicdase peadce laaroobooss Average cost of pasteurizing 100 pounds of cream in hienourCeStsiseeemceioel= = sine sie seelelose ce eee yeeemee SUED bos nosuacenodladaconseccciodusondacc TEMPERATURE BALANCE. 1 2 31 42 Temperature Of raywamiliccere eee Cae 8a ek ed Ss °F..| 49.5 42.0 39.3 56. 25 Temperature of milk in heater. ...........-..--.----------+-------- °F..| 147.0} 169.6] 160.2} 167.25 Rise of temperature in heater...........-.....--.---------.-------- °F..| 97.5] 127.6] 120.9) 111.00 MoOtaliperiCenGrise’s ase oesee = sek cee nes te scot eee per cent..| 100 100 100 100 Temperature of milk in holder...............-------------se-ceeee Seo MeO) IGG |esobecadlleseucese Drop of temperature in holder.................---.---------------- WS 6 BOs GIG Ne seecoslsoosccee er cent drop in holder....................-------------- per cent... Co Gr ERG) eee lleseisooes Temperature of milk in separator. ................-.----.---------- oR.) 144.0 | 15258) 160: 2 5222-2. Drop of temperature in separator (milk)...............---..+..-..- FSS 9.2 7.2 TESST [asia sre Per cent drop in separator (milk).--...........--.--.--.. per cent. . 9. 4 5.6 UG) eg Sees Drop of temperature in separator (cream) a Sin 12.8 15.3 FO Wososocse Per cent drop in separator (cream) . per cent. 13.2 12.0 pS be areas Temperature of milk in cooler............--..------------+--+----- --| 184.8] 145.6} 158.4 ].....-.- Drop of temperature in cooler (milk)...........-.....-------.------ CATs | en Sept e [feel Ose Gout freLi 1:0 ples | oats eee fo Per cent drop in cooler (milk).. -per cent. 87.5 81.2 985 OU ie eee see Temperature ofcream in cooler........ eooelMse|) TBS |) FeyeGy 1) Ieee yh TG Drop of temperature in cooler (cream) . SSIS eDiets itch Wa? 95.5 | 115.9} 111.00 Per cent drop in cooler (cream)......- -percent..| 83.7 74.8 95259N| ees aes oOtalpericentiadrop sees - o.ceeeeresosce cs: J-ce ead eee eee do 100 100 100 100 1 No holder. 3 Large drop in holder was due to stirring apparatus. 2 No holder or separator. The summary of the tests in Table 2 gives the cost of pasteurizing at the different plants under the conditions at which each particular plant was operating at the time of the test. Therefore the cost of pasteurizing 100 pounds of cream will vary slightly in the different plants due to the varying conditions. It will be noted from an inspection of the temperature balance that the initial temperature of the raw cream varied in the different plants and also the final or pasteurizing temperatures. In order to make a comparison of cost 12 BULLETIN 85, U. S. DEPARTMENT OF AGRICULTURE. it becomes necessary to put them all on an equal basis, so far as it is possible to do so, and for this purpose it is assumed that the pasteur- izing cycle consisted in raising and lowering the temperature of the cream through a range of 100° F., all other conditions remaining the same. The cost of pasteurizing 100 pounds of cream in the different plants, corrected as above, is $0.0459, $0.0650, $0.0726, and $0.1056 for tests Nos. 1, 2, 3, and 4, respectively. The amount of cream handled will, of course, affect the unit cost to a great extent, as may be gathered from the summary of tests. Referring to test No. 4, the power required for driving the pasteur- izing equipment was excessive, as a considerable amount of line shafting was uselessly driven while pasteurizing. This, together with taking steam from the boiler through a reducing valve instead of using the heat from the exhaust steam, accounts for the high cost of pasteurizing at this plant. CONCLUSIONS. The conclusions drawn from the foregoing tests are as follows: 1. The flash process of pasteurization requires approximately 17 per cent more heat than the holder process. There is a correspond- ingly wider range through which the milk or cream must be cooled, both adding extra cost to the pasteurizing cycle. 2. The proper design and arrangement of the heater, regenerator, cooler, piping, and refrigerating apparatus have much to do with the efficient operation of the plant. 3. With poorly arranged apparatus and leaky piping the loss in heat may reach approximately 30 per cent of that required to pas- teurize, which it is practicable to reduce to a negligible amount. 4. It is practicable to use exhaust steam from the engine and steam-driven auxiliaries, or water heated by exhaust steam, to furnish heat with which to pasteurize both milk and cream. 5. Usually there is sufficient heat in the exhaust steam which is allowed to waste in milk plants and creameries to do the pasteurizing. 6. For every 400 pounds of milk pasteurized per hour with exhaust steam, approximately one horsepower is taken off the boiler plant. 7. The average cost of pasteurizing 1 gallon of milk is shown to be $0.00313. 8. The average cost of pasteurizing 1 gallon of cream is shown to be $0.00634, or $0.0756 per 100 pounds. 9. It must be understood that the cost of pasteurizing as figured in this paper deals only with the pasteurizing cycle, viz, starting with the initial temperature of the raw milk and raising its temperature to the pasteurizing point, then cooling the milk down to the initial temperature of the raw milk. In other words, it hasbeen attempted to show the additional expense encountered in producing pasteurized milk and cream over the raw product. O BULLETIN, OF THE USDEPARTHENT OF AGRICULTURE %, No. 86 Contribution from the Forest Products Laboratory, Forest Service, Henry S. Graves, Forester. March 14, 1914. (PROFESSIONAL PAPER.) TESTS OF WOODEN BARRELS. By J. A. Newuin, Engineer in Charge of Timber Tests. OBJECT OF THE TESTS. The object of the tests described in this bulletin, made in coopera- tion with the Bureau for the Safe Transportation of Dangerous Explosives, was to obtain data upon which specifications and changes in the design of wooden barrels used in the transportation of danger- ous liquids might be based. The tests do not offer any comparisons between barrels made of different material or of different species of timber. MATERIAL. . The barrels used in the test were made by the St. Louis Cooperage Co., and were received in six groups of 8 barrels each (48 in all) as follows: Thickness Group Barrel No. | of staves abet c and heads. Olek Inches. 1 1to8 54 6 2 la to 8a 54 8 3 9 to 16 34 6 4 9a to 16a 34 8 5 17 to 24 i% 6 6 17a to 24a WZ 8 The barrels were made from quarter-sawed white oak. (One stave which seemed to be particularly porous was identified as red oak.) The material was practically straight grained and free from defects. The barrels were of excellent workmanship and were well coated with paraffin on the inside. The staves varied in width from about 24 inches to about 7 inches. Thirty-one barrels had 19 staves each, 12 had 20 each, and 4 had 21 each. The heads were usually Notr.—This bulletin describes tests that are of special interest to barrel manufacturers and to manu- facturers and shippers of dangerous liquids. 32797°—14 2 BULLETIN 86, U. S. DEPARTMENT OF AGRICULTURE. composed of four pieces, though two heads were each composed of three pieces. The pieces of the head were joined together with 3;-inch hickory dowels. There were two dowels per joint, each about one-third or one-fourth the length of the joint from its end. The head and bilge hoops were 1? inches by 17 gauge, while the quarter hoops were 14 inches by 18 gauge. The average thick- nesses of hoops used for tension tests (see p. 4) were 0.051 inch and 0.061 inch for the 18 and 17 gauge, respectively, while the U. S. standard gauges of these numbers are 0.05 inch and 0.05625 inch. The average hoop spacing, dimensions, weights, and capacities of the barrels are shown on figure 1. The hoop splices were always placed over the bung stave, and the heads were placed with their end grain toward this stave as shown in I and IJ, figure 1. The barrels were received at the laboratory on November 24, and were stored in a closed and unheated shed until the tests were begun on December 10. BARREL TESTS. The barrels were brought in from the storage shed shortly before the time for test. Each barrel was then carefully inspected and the hoops driven tight by a representative of the St. Louis Cooperage — Co. Just before test each barrel was completely filled with water, and with the exception of those barrels to which a pressure gauge was attached, was closed with a wooden bung. These bungs, after soaking for a few seconds in warm water, were driven to a tight fit. They were placed with their grain parallel to that of the staves. The bungs bore the brand ‘‘U. S. Bung Mfg. Co., Cincinnati, O.” No bung straps were used. ‘ Two barrels of each group were tested in side compression, two in diagonal compression, one each in side and diagonal drop, and two by internal pressure. SIDE-COMPRESSION TESTS. In this test the barrel was placed between two flat surfaces and compressed in the direction of its diameter. The rate of compression was 0.25 inch per minute. Simultaneous readings of load, com- pression, and loss of water from the barrel were taken. The test was discontinued when one-half the water had escaped. Notes were made of the character and sequence of failures. In about one-half of these tests a pressure gauge was attached to the barrel, and read- ings of internal pressure were taken. The method of test is shown in Plate I. DIAGONAL-COMPRESSION TEST. In this test the barrel was compressed between two flat surfaces, being supported upon one point of the chime and loaded at a poimt on the other and diagonally opposite. The rate of compression was 0.25 inch per minute. Notes were taken as in the side compression test. The test on the first barrel of each group was discontinued as Ne PA Oe ee ey ed Wo a" ” SF ” 1475, 3 Py a 2 $37 | Ui 75, a” “197 ts LTT —- MADEUP SARREL-EIGHT HOOPS S6(sTraves FE HEAD nigh 24.9 inches; average diameter at the head was 21.2 inches. a diagonal-drop tests ‘‘C’’ was the top point. Outside diameters of all CT ee %4 bb1 -Tote| 52.73" For 34 bh -Jote/ 32.80" ii for 2 b4L- Total 92.34 158 psc 1475) 2.06 \450 a For B bb) -Jolo/ 39.25 TL -— STANOARD 5/X:HOOP BARREL Thickness) We ight Jnches | Pounds Ye | 648 Va / TOME Copacity 427.2) 5/12 1.0 \421.5| 505 722 \4129 | SOL | Fi@. 1.—In the compression and drop tests all barrels were placed with plane A B C D (1) vertical. Inthe side-compression and side-drop tests ‘B” was the top point. In the dia; regular barrels were practically the same, the total variations being about one-third inch in bung diameter and about one-tenth inch in diameter at the head. Acyerage bung diameter was 24.9 inches; average diameter at the head was 21.2 inches. (To face page 2.) Tacks) ight /netes |Peonds 73 674 |426.7| IZ Ya | 746 |\¥204| 50F % | G26 \4#/73| 500 4 8 SB 150, 1 W475, 2. 150, LIT — MADEUP BARREL-EIGHT HOOPS 26 sTaAVES = 76 HEAD Weight Capacity Pounds ‘onal-compression and diagonal-drop tests ‘‘C’’ was the top point. Outside diameters of all TESTS OF WOODEN BARRELS. 3 in the preceding test, while the second was discontinued whenever one-half the contents had escaped or would have escaped had the barrel been in the reverse position. This test is illustrated in Plate II. SIDE-DROP TEST. In this test the barrels were dropped on a wooden platform about 34 inches thick resting on the concrete floor of the laboratory. On top of this platform was a steel plate one-eighth inch in thickness. The barrel was suspended with its axis horizontal. The first drop was 3 inches, the next 6 inches, etc., increasing each time by 3 inches. Each drop was upon the same point of the barrel. After the first apparent leak the drops were made at 3-minute intervals. The weight of the barrel and contents was taken immediately before each drop. The test was continued until half the contents of the barrel had escaped. Complete notes were made to show the character and sequence of the failures. A picture of this test is shown in Plate IIT. DIAGONAL-DROP TEST. This test was conducted in the manner described for the side-drop test, except that the barrel was suspended so that the lowest point of the chime was directly below the center of the barrel, which was dropped on the chime. Each drop was upon the same point. A picture of this test is shown in Plate IV. INTERNAL-PRESSURE TEST. In this test the barrel and connecting pipes were filled with water in such a way as to exclude as nearly as possible all air. The pressure was then raised to 2 pounds per square inch and held for 2 minutes. It was then raised to 4 pounds and there held for 2 minutes. This was repeated, increasing the pressure 2 pounds each time and holding it constant for 2 minutes after each increase, until 1 pound of water ran from the barrel in 1 minute or less. The test was then discon- tinued. Complete notes were made as to the character and sequence of the failures. In these tests connection to the barrel was made by screwing a special tapered bush into the bunghole. The apparatus is shown in Plate V. MINOR TESTS. STAVE TESTS. In order to find out something of the variability of the barrel material tests were made on 36 staves, two from each of 6 barrels of each thickness. The best and poorest appearing stave of each barrel was chosen. Pieces 2 inches in width, cut from these staves, were tested in static bending under center loading. The span was 28 inches. The staves were placed with the outer side up. —— 4 BULLETIN 86, U. S. DEPARTMENT OF AGRICULTURE. HOOP TESTS. A 14-inch piece was taken from one hoop of each gauge from each of three barrels of each group. These pieces were machined down to have a parallel section approximately 1 inch by 9 inches, and were then subjected to tension tests. The maximum load and load at yield point, as determined from the drop of the scale beam of the testing machine, were recorded. RESULTS. BARREL TESTS. The results of the barrel tests are given in Tables 3 to 6, inclusive. The internal-pressure readings on the barrels to which a pressure gauge was attached in the side-compression test have been omitted. The highest internal pressure developed in these barrels was 7 pounds per square inch. In all the test only two or three cases of leakage at the bung was observed. These also have been omitted from the tabulated results. MINOR TESTS. The average, maximum, and minimum results of the stave and hoop tests are given in Tables 1 and 2. In Table 1 “modulus of rupture” is the fiber stress at maximum load and represents the strength of the timber. “Work to maximum load” is proportional to the shock- resisting ability of the timber. ; TaBLe 1.—Results of stave tests. Static bending, 28-inch span. 8-inch staves. +-inch staves. #inch staves. Measured thickness at stave, INCHES 55 5-55558 -SGFiS-2-te INES Seapets per inch.. 21 30 14 Specific gravity....-......--- 0.663 | 0.723 0.544 GISTULEGs ss -- - per cent. . 12.6 14.8 10.0 Maximum load.....- pounds. 387 510 240 Modulus of rupture, pounds Pensquare INCH eens. nae Work to maximum load, inch-pounds per cubic E11) | ee en Se Pe 10,120 | 12,860 | 6,330 10.0 16.7 3.8 TaBLe 2.—Results of hoop tests. Tension, specimens 1 inch wide. 18-gauge hoops. 17-gauge hoops. Average. |Maximum. | Minimum. | Average. | Maximum. | Minimum. Measured thickness of hoops, Inches sy. sia nase see aoe ade Hei 0.051 0.058 0.047 0. 061 0. 063 0. 058 Loadat yield point as determined , by drop of beam .....- pounds. . 2,360 2,900 2,100 2,480 2,620 2,330 Maximum load..........-.- do:--- 3,955 4,530 3,580 4,925 5,130 4, 605 Fiber stress at yield point, pounds ; Per Square Wich. o052 oie pense 44,580 49,500 41, 200 39,515 42, 400 36, 000 Fiber stress at maximum load, pounds per square inch...-...... 74, 210 78, 600 70, 200 78, 060 82, 400 71, 600 } wl x PLATE |}. Bul. 86, U. S. Dept, of Agriculture. METHOD OF TEST—SIDE COMPRESSION. Bul. 86, U. S. Dept. of Agriculture. . : “ @ PROJ: Li7s SHIP 279 BBL.NO.204 HOOPS: & THICKNESS *74"1N FIRST LEAt e LOAl HDOO LES COMP. * 527IN "BOTTOM HEAL BREAKING * 16506 -L&S METHOD OF TEST—DIAGONAL COMPRESSION. PLATE II. i Bul. 86, U. S. Dept. of Agriculture. PLATE III. METHOD OF TEST—SIDE DRop. Bul. 86, U. S. Dept. of Agriculture. PLATE IV. METHOD OF TEST—DIAGONAL DROP. PLATE V. Bul. 86, U, S. Dept. of Agriculture. = a YNSSSYd IWNYSLN |—LS3_. JO GOHLIW LSEL 16 OH Day WSaad TW Nar Z"] df Ne} ALNG a Hs ae 2 EE coy. TESTS OF WOODEN BARRELS. 5 GENERAL OBSERVATIONS OF NATURE OF FAILURES. In each kind of test the first water to appear on the outside of the barrel was usually from the seepage through the pores of the wood at the chime. The first leak usually occurred either between the staves and the head or between the staves at the chime. In all the tests except the internal pressure the first leak was usually coincident with the slipping of the staves. In the internal-pressure test there were two general classes of failures: (1) By springing and breaking of the head; and (2) by leaking between the staves at the bilge. In the diagonal-compression test the failure was a general failure of the head combined with the slipping of the staves. In the com pression-perpendicular test the failure was a general leaking at the heads and slipping of the staves followed by the breaking of the staves at the bilge. In the side-drop test the slipping of the staves caused loosening of the hoops and leakage at the heads. This was followed by breaking of the staves at the bilge. In three of the six tests the failure of the barrels was due to the heads being broken or forced out by the internal pressure produced by the impact. The lower heads of all barrels tested by dropping on the chime were broken or forced out by the pressure due to the impact. CHANGES IN DESIGN AS INDICATED BY THE CHARACTER OF THE FAILURES. A slight increase in the length of the chime from croze to the end of the stave would lessen the amount of seepage without any marked increase of liability to breakage at the croze by dropping the barrel on the chime. The chimes of the test barrels were made exceptionally short (three-fourths of an inch from outer side of croze to end of stave) to reduce the danger of breakage when dropped on the chime. Chimes 1 inch long would probably have given better results. The internal-pressure test and the side-drop test indicated that the bilge hoops were too wide apart. A spacing of not more than 8 inches between the bilge hoops would have materially strengthened the bar- rels for the internal pressure without any weakening for the other tests. The weakest parts of the barrels were the heads. The first leak in most of the tests was due either to the springing of the head or to the slipping of the staves at the head, or to both these causes. The ultimate failure of a large per cent of the barrels was at the head. It appears that a head much thicker than the staves would give mate- rially better results. Heads should probably be made about one and one-half times as thick as the staves. The heads appeared to be materially weakened by the dowel holes and not infrequently the flagging was forced out. It would seem that these head joints could be improved. 6 BULLETIN 86, U. S. DEPARTMENT OF AGRICULTURE. None of the hoops failed during the test. A inch oak barrel should probably have not less then eight hoops of the sizes of those used on the barrels tested, as the swelling of the wood might break the hoops. Variation in strength of barrels of the same design i is due in large measure to. the variability of the wood composing the head and staves. Test specimens taken from these barrels show that some of the staves may have less than one-fourth the strength of others. (See Table 1, p. 4.) Evidently no attempt had been made to grade the staves on the basis of strength, the only criterion of fitness being that the staves should be clear and straight grained. The dry weight per cubic foot of clear straight-grained wood is a splendid guide as to probable strength, the heavier, denser wood being the stronger. The advisability of grading staves and heading with reference to the strength might el be considered. TESTS OF MADE-UP BARRELS. BARRELS. - In order to try out the effect of some of the changes in design as suggested above, barrels were made up with 3-inch staves, $-inch head, and eight hoops. The staves and hoops were from the two 8-hoop, 3inch barrels, the heads from {-inch barrels and previously tested under internal pressure. In order to make these heads fit, it was necessary to joint fifteen-sixteenths inch off of one stave of each barrel. The bilge and quarter hoops were not changed, but were permitted to drive farther onto the barrels. The head hoops were shortened 14 inches and were driven flush with the ends of the staves. (In the original tests the head hoops were driven beyond the ends of the staves, as shown in IJ and II of fig. 1.) The spacing of the hoops, weight, capacity, etc., of these barrels are shown in III, figure 1. In assembling the barrels the hoop joints were placed at random. INTERNAL-PRESSURE TESTS. The two made-up barrels were tested under internal pressure. The results of these tests showed them to be fully equal to the barrels with 7-inch heads and staves. One of these barrels withstood a pressure of 34 pounds per square inch up to the time the head began to fail, when the pressure was released. The increased capacity of the barrel under this pressure, due primarily to the springing of the heads, was 8} pounds of water. On release of the pressure the barrel resumed its original form with no apparent leakage. The head of the second barrel was broken out by a pressure of 38 pounds per square inch. Neither of these made-up barrels showed any leakage between the staves during the tests. TESTS OF WOODEN BARRELS. 4 ( DROP TESTS. The broken heads of the made-up barrels were replaced by other Z-inch heads, and the barrels subjected to drop tests. The barrel dropped upon the side showed much better resistance than the 8-hoop barrel five-eighths inch in thickness throughout, but was not quite the equal of the $-inch barrels. _ In dropping on the chime the made-up barrel was the equal of any barrel tested. These tests of made-up barrels seem to justify the previously sug- gested changes in thickness of head and spacing of hoops. The detailed results of these tests are given in Table 5. SUGGESTIONS REGARDING TESTS OF SHIPPING CONTAINERS. There are two classes of tests to which containers such as barrels may be subjected: First. Tests, such as the ones described in this bulletin, where the object is to determine the most economical and efficient designs. Tests of this class are usually carried to the destruction of the con- tainer and entail damage or complete loss of contents. It is neces- sary to fill the containers with material which is relatively inexpensive, safe to the investigators, and which will produce stresses similar in character to those which would be produced by the commodity which the container is intended to carry. Second. Tests to determine the suitability of the container for specified commodities under practical conditions. Such tests should be made upon containers filled with the material to be shipped in them or with some other very similar in its action on the container. Tn the case of the first class of tests seepage through the pores and the first leak depend largely upon the nature of the lining and of the contained liquid. A material difference might be expected in the behavior of barrels lined with paraffin and filled with water as com- pared with barrels lined with glue and filled with gasoline. In the drop test the height of drop also depends upon the specific gravity of the contained liquid. The height of drop required to produce given stresses is In approximately inverse proportion to the combined weight of barrel and contents. : Having made tests of the first class, and so determined the best construction, it then remains to manufacture containers in accordance with specifications based upon the results of these tests. Tests of the second class made upon such containers lined according to-com- mercial practice and filled with the commodity they are to carry would show their limitations under practical conditions. In the case of barrels internal-pressure and side-drop tests are recommended for this purpose. BULLETIN 86, U. S. DEPARTMENT OF AGRICULTURE, Taste 3.—Individual tests—Side compression. sINCH BARRELS. No Num. Rate of ber of Piece: Load of Remarks. barrel. | hoops ot, leaking Lbs. per minute. 1 6 0.81 DO0Dy |. 22. -2% Seepage through pores. 1.412 aT. | Eases Staves slip. 1.24 6; SAO URES eA Leak between staves. 2.35 Oe ae ee Stave broke. 3. 80 11,000 1.6 | Horizontal shear in top stave. 5.38 14,380 6.5 | Stave broke. 6.35 13,640 42.8 | One-half contents escaped. 2 6 .88 DOOR a tee seee Leak at chime. 1.20 B2000 iE 22 ase Stave slipped. 2.54 8,500 1.7 | Stave sheared. 5.97 10,850 29.0 | One-half contents escaped. la 8 85 5,900 Finca 22s Leak between staves. 1.08 GFDON Eons neces Staves slip. 2.80 9, 460 2.1 | Bottom stave sheared. 3. 80 11, 250 15.0 | Stave split. 4.37 11,000 23.0 | Stave broke. 5.40 12,310 31.0 Do. 5.70 11, 880 32.0 | One-half contents escaped. 2a 8 .60 BOO bel sso cmece Seepage through pores. 64 ADO! fas Seeee ee Leakage around end at bottom. 1.55 £5000) |e sce Staves slip. 3.80 12,320 2.9 | Stave broke. 4.62 12,070 2.0 | Bottom stave broke. 7.11 15,040 28.0 | Stave broke. 7.61 15,370 52.0 | One-half contents escaped. 2-INCH BARRELS. 9 6 0.57 DSQ00 Mee ab es-tae Leak at chime. ott 6000 essen Seepage through pores. - 86 BS500 ene. see te Staves slip. 2.35 9,730 10.5 | Stave broke. 3.36 10,830 37.0 Do. i 3.7. 11,380 39.4 | One-half contents escaped. 10 6 Ar ith D500) |Weatanmoce Seepage through pores. .90 G 000 Ate eae oe Staves slip. 1.24 (EU D) pee ee Leak between staves and at chimes. 2.88 10,910 9.0 | Bottom stave broke. 4.00 11,110 39.0 | Increased breaking. 4.30 10, 420 57.0 | One-half contents escaped. 9a 8 . 64 SIU Lan Rome eee Leak between staves. . 86 CAG b Ding eels baie Leak at chime. 1.15 BUOROS | sae cones Staves slip. 3. 60 11,590 25.2 | Top stave sheared. 4.35 12, 430 37.5 | Bottom stave broke. 4.53 12,390 33.6 | One-half contents escaped. 10a 8 SDL 000 Meee Leak at chime. 1.03 Te OOW eee eae Staves slip. 1.70 8, 860 1.0 | Leak between staves. 3. 80 12,010 34.0 | One-half contents escaped. ZINCH BARRELS. 17 6 0. 86 5,5 Leak at chime. 1.20 Staves slip. 4.27 7 Top stave broke. 4.40 Do. 4.91 Stave broke. 5.58 ‘ One-half contents escaped. 18 6 .90 Leak through joint of head. 1.10 SeepSge through pores. | 1.63 Leak between staves. 2.14 Stave broke. 5. 78 One-half contents escaped. 17a 8 56 Leak at chime. . 92 ; Seepage through pores. 1,22 Staves slip. 2.75 5 Head coming loose. 3.75 Top stave broke. 4.15 Do. 4.65 5 Stave broke. 4.88 } One-half contents escaped. 18a 8 83 pL ULE ek Se Leak at chime; staves slip. 1.00 ia) | Seppe Leak between staves. 2.95 11,100 1.0 | Top stave broke. 5. 43 16, 280 20.0 | Bottom stave broke. } 5.50 15,190 20.0 0. 6. 40 14, 090 40.5 | One-half contents escaped. TESTS OF WOODEN BARRELS. Taste 4.—Individual tests—Diagonal compression. §-INCH BARRELS. No. | Num- Rate of ber of Deite Cl Load. of Remarks. | barrel. | hoops. leaking. Lbs. per minute. 3 6 0. 56 Co Died eee Leak at chime. 1. 45 11, 000 1.0 | Staves sheared. 3. 40 15, 620 6.0 | Bottom head broke. 3. 56 TORO20 ii eee eet One-half contents escaped. 4 6 217 S000 beeen resoe Leak at chime; staves slipping. 3.78 16, 240 13.5 | Bottom head broke. 4. 48 16, 990 80.0 | One-half contents escaped. 3a 8 . 85 S000 sees Leak at bottom chime. 1.38 BAO TO NE Se eae Leak at top chime. 1.55 T4000" Wears sine Staves slipping. 2. 26 16, 400 4.5 | Top head breaking. 2.85 15, 000 7.5 | Top head broke. 4a, 8 97 SOOO! gle ase ce Leaks at top and bottom chimes. 1.73 14, 480 4.0 | Staves slip; bottom head breaking. 2.50 15, 440 14.5 | Bottom head broke. 3-INCH BARRELS. il 6 0. 62 UZEUD” |leascecdsde Leak at chime. 1.18 LD 000k ea acrsne Leak at bearing. 1.50 12 ACO |Past aese Top head broke; staves sheared. 5.73 17, 000 0.5 | Staves breaking at top. : 8. 42 17, 850 39.0 | One-half contents escaped. 12 6 90 OOD Weocccsoece Leak at bottom stave. 1. 26 11500) an Beereeeee Stave splitting at top. 1.50 12 50D isl Boece Leak at bottom chime. 3.20 16, 530 8.8 | Bottom head broke. lla 8 . 58 Si000 mice cetece Leak at bottom chime. 1. 48 14, 500 2 Staves slipping. 2.10 16, 000 6.0 | Top head broke. 12a 8 A) SiOOOM eter ete Leak at top chime. 1.53 14000 See eee Staves slipping. 2.47 16, 970 4.7 | Top head broke. 9. 25 24, 260 16.0 | Test discontinued. Z-INCH BARRELS. 19 6 0. 42 Leak at bottom chime. ot Staves slipping. 1. 68 Leak at top chime. 3.73 Top head splitting. 5. 50 Top head broke. 7.47 One-half contents escaped. 20 6 81 Leak at bottom chime; staves slipping. 1.12 Leak between staves at bottom. 2.34 Staves slipping. 4, 20 Top head breaking. 5. 00 Top head broke. 19a 8 . 62 Leak at bottom chime. 1.43 Staves slipping. 3. 83 Staves sheared at chime. 4.85 Top head broke. 5.05 One-half contents escaped. 20a, 8 82 Leak at bottom chime. 95 Staves slipping. 1.27 Leak at top chime. 2.35 Bottom head breaking. 2.70 Bottom head broke. 10 BULLETIN 86, U. S. DEPARTMENT OF AGRICULTURE. Tasie 5.—Individual tests—Drop tests. INCH BARRELS. No. of | N°™- | Heicht| Rate of barrel. pean |ofdrop.| leakage. Remarks. SIDE DROP, Lbs. per Inches.| minute. | 5 6 (a) | een ei Stave slipped; leak at chimes. Ae fore Leak between staves. 18 0.3 | Stave cracked. 24 .7 | Head cracked; hoops slipped at head. 30 2.0 | Head broke out. 5a 8 Gumicae cece Leak at chime and between staves. Osa eae casee Staves slipping. | {Oi ae es ae Stave broke. | 24 .3 | Flag coming out at head. | 27 2.0 | Head broke out; split at dowels. | DIAGONAL DROP. | 6 6 1S). | 2 eee tape oe Leak at chime. | DPA Eee ee epg Head broke. 6a 8 | CS le Bee a Head broke out. 3-INCH BARRELS. SIDE DROP. 13 | 6 (Seed |e ey een Leaking slightly. el baci Leak of chime and between staves. 15 0.2 | Stave broke. 24 1.0 | Hoop slipped at head. | 39 23.2 | Test discontinued. | 13a | 8 Gar eee Leak at chime; stave slipped. LV eeemoe Sate Stave broke. 21 35.7 | Bilge hoop slipped. | DIAGONAL DROP. 14 6 Tal Pe seis Leak at chime. 1 ee eee Head failing. 18): )|2b 2c sees Head broke out. l4a 8 eal pees cease Leak between staves. 1 Seal ceetee 5. Flag coming out. } 18 0.3 | Head broke out. I Z7-INCH BARRELS. SIDE DROP. 21 6 le Boseceenc Leaks at chimes; staves slipped. | VA a ee Stave broke. py a Peri oes ae Are Bilge hoop slips. 27 2.0 | Head hoop slipped. | 48 11.3 | Test discontinued. |} 21a | 8 9.) sets ese Stave slips. | 21 ioe. eel Leak at chime. | 33 .3 | Head broke. 36 .7 | Head broke out. DIAGONAL DROP. 22 6 (| Ae era Leak at chime. | 1 Lael Shei Pa ae Stave sheared. | 15 0.7 | Leak through joint of head. >A .3 | Head broke out. 22a, 8 15 .6 | Head breaking. 18 .4 | Head broke out. 8a 15 16 15a 16a TESTS OF WOODEN BARRELS. TaBLE 6.—Indwidual tests—Internal pressure. INCH BARRELS. Raa Rate of leakage. Remarks. Lbs. per| Drops per| Lbs. per sq. inch.| minute. | minute. Dia De Sap se as eee ies Seepage through pores. 4 i Baeeise aoe Leak between staves. 8 120 ge Pees aie eB Head bulged flush with chime. 10) 0) ees PES eee Leak at chime; broken stream. PT eens Leak between staves. 3 Dio aaeuae abelinc six ceeee Leak at chime. 4 D0 bs | Bia. =the hydraulic radius in feet, and s=the slope. Each step was carried out to three significant figures. The following values for ce and r were used: : Slant depth. | c | r || Slantdepth. ¢ r | Slantdepth. | r Inches | Inches. | | Inches 20 108 | 0.417 34 121 | 0.708 48 128 | 1.00 22 111 | .458 | 36 122 | .750 50 129 | 1.04 24 113 | .500 38 123 | .792 52 130 | 1.08 26 115 | .542 40 124 | .833 54 131 | 1.12 28 116 | .583 42 125 | .875 56 132 | 1.17 30 118} .625 44 126 |. .917 58 132 | 1.21 32 119 | .667 46 127 | .958 60 133 | 1.25 This formula is based upon experiments with slopes of less than 10 per cent, and while its application to steeper grades has not been thoroughly checked by actual determinations of velocity, the results are considered sufficiently accurate for use in the design of timber flumes. TasLe 4.—Estimate of approximate amount of material required for construction of flumes. 26-INCH “V” FLUME WITH 13-INCH BATTENED BOX. Lumber required per mile. Nails required per mile. Dj ; : fs | | 2 Beale gee Kinds of lum- Hates a S 3 3 | g a 3 ber. =} ANG 2 be ha d : . Br on 2 2 = 4 5 a ° fe) Po) a a oo Size. n wes) + no ;Q n n as el 3 Be: 52 oe all eepal es Se |) lane 5 | & SS ® © J © AS) ° ® a) i) wa 4 ios a Fy Ay 9 is Ay iw Inches.| Ft. in.| Ft. in. Ft. in Mud sills... -.-- Bey AA tee 3| (Ol eS Lr eiOa8 330) 330) 3,190} 10-penny..| 763 73 Posts:--2 = c g 5 $ | 3 g ee Ne Gee S 5 | 2 a = & ae is ey fea ies ay 4 Inches. | Ft. in. | Ft. in. Ft. in. Mud sills....--.. 4x 6 7 8 15 4 1} 15 4 330| 330} 5,060) 10-penny..| 500) 5 IBOStS ata eas 4x 6 7 3) 14 6 2} 29 O 660} 330) 9,570|| 12-penny..} 528 54 Gapsa ee ae 4x6 4 7) 9 2 ahs BE 330} 330} 3,025|| 16-penny..| 948 9% Braces, sway.--| 1 x 6 9 2 47 249 2 660} 330} 3,025)| 20-penny..| 156 iy Braces, lateral..| 1 x 6 7 AGS Bid 4) 15 0|11,100) 1275) 14,125 Stringers....... 4x 8 16 0} 42 8 2} 85 4 660} 330] 28,160), One keg of 40-penny IG a ee 2ix 5 5 4 5 «62 3] 16 8 990} 330) 5,500 nails and one keg of IBTACeS 2-2-2. 2 3 24x 5 ih ile aly as 6| 6 9} 1,980) 330) 2,228)| 60-penny nails should SATTNS= eyes te 23x 5 2 6 2 74 6) 15 73) 1,980) 330) 5,157 usually be allowed for Box poardse |) 2)°x62| ©9169 0) (2)P eee eee: 65a 4a eee 330} 54,560 such preliminary work Running boards} 13x10} 16 0} 20 0 i 2M. © 330| 330) 6,600 as bridging, etc. 127,010 UNG GROTAWASUO Eee soe eal sen ctec|escee sen hee alt cote] Se EAS 7, 990 “Iteayiell 2 cL poe a ees ee a res Sa ete 8 ene eee 135,000|| Total...-| 2,132} 213 30-INCH “V” FLUME WITH 14INCH BATTENED BOX. Mud sills......- 4x 6 Cf “tell. ates 23 1) 15 4 330} 330! 5,060 iseny. | 763 72 IBGStSEe ese e saan: Avec 6 7 3) 14 6 2} 29 0 660} 330) 9,570)/) 12penny..| 780 72. apse ans 4 x 6 Aa One 2 i 2 330} 330) 3,025]] 16-penny-.- 113 1 Braces, sway..-| 1 x 6 Bi ah Pd eee! 274 660) 330! 3,025|| 20-penny-.- 425 44 Braces, lateral..| 1 x 6 1 6| 3) 9 4) 15 0 |11,100) 1275) 14,125) | Stringers...__.. 4x8} 16 0) “42 8 2) 85 4 660} 330} 28,160|| One keg of 40-penny SiIbG =o. Seen eeee 2x 5 5 4 5 6% 3} 16 8 990} 330) 5,500)} nails and 1 keg of 60- IBTACES: ec 2-5-2 2x 5 EPA ee 1 6} 6 9} 1,980} 330) 2,228} penny nails should SATIS Mee cosy =~ 24x 5 AAG 24 18H 6} 15 74) 1,980) 330) 5,157 usually be allowed for Box boards. ---|- 14x62) 6 0} ()_ |s------ 124 05 )/e22238- 330} 40, 920 such preliminary work Battens-.-..._- iexee4 BG lB 12} 20 0| 3,960} 330! 6,600 as bridging, etc. Running boards} 13x10) 16 0 20 0 1) 20 0 330} 330} 6,600 | 119,970 | Add for waste. -|_....-.- lee aes eens ae Wiiecege Wrens « epee eee 5, 030) | | | SS Mota leeee Me eles EE Ne fe eo er oe Bese ce Besoee | 125, 000; Total... 2,091|- 20% | | | | 36-INCH “V” FLUME WITH 13-INCH BATTENED BOX. | Mud sills.....-- 4 x 6 8 6 17 0 aly 440} 440 7,480|| 10-penny.-| 1,300) 13 ROSstseeenice= ==: 4 x 6 holla G 2; 29 0 880} 440 | 12,760)| 12-penny..| 396 4 Capsie e522. 4x 6 5 0| 10 0 1} 10 0 440| 440 | 4,400|| 16-penny..| 1,075) 102 Braces, sway.--| 1 x 6} 10 0} 5 0 2} 10 O 880} 440 4,400 LEE 447 45 Braces, lateral..| 1 x 6) i, ee) 4, 15 0 | 11,467) 13662) 15,500 Stringers....... 4 x0 8)2 12) 0|=-32) (0 2) 64 0 880! 440 | 28,160|| One keg of 40-penny lilies 552 See emo} G0 ee enG 3} 22 6] 1,320) 440 9,900 nails and one keg of IBTACES= se soa 3 = 5 1 5} -L 94 6 10 73) 2,640) 440 4,675 60-penny nails should PGi Sere eee) 3 8x) /5| 3 0) 3 9 6} 22 6] 2,640} 440 9, 900 usually be allowed for ‘Box poards.-- =| 14% 74) 12'°0)) (©): \ee--2-2 DT On eee 440 | 48,840 such preliminary work Battens........ Tos gh) MEG Sil 18} 24 0} 7,920) 440] 10,560|| as bridging, etc. Running boards} 14 x 10 12 0) 15 0 1) 15 0 440) 440 6, 600 153, 175| Add for waste. .|......-- TEC E OE he Seen Seen PE bee |S ators sae | Sates 6, 825) Rotalees== oe Se R Eee CO ones eee earner cca] a eat Mert as 160,000}; Total.... ps 324 1 Lateral braces are only figured for five-sixths of a mile, as at least one-sixth ofeach mile, on an average, we too close to the ground to require the use of these braces. arious sizes. 36 BULLETIN 87, U. S. DEPARTMENT OF AGRICULTURE. TABLE 4.—Estimate of approximate amount of material required for construction of Jjlumes—Continued. 54-INCH “V” FLUME WITH 2-INCH BATTENED BOX. Randeollures Dimensions. ber. c= . iets) S 5 na =) Inches. | Ft. in. Mud’ silis===-2e- o-i TE) Postsi-2255-s-¢ Gse6l) ed 3S Caps sees. Jee 625556] a7, 0 Braces, sway 1ix 6] 11 0 Braces, lateral..| 14x 6) 7 6 Stringers... .--. 6x 8 12 0 Silsie ee cece AK: 956) und» (0 IBTACES aan sae - 4 Xa}, ahi. OF ATMS sees 4x 6 4 6 Box boards....} 2 x110} 12 0 Battems.......-. Iix 4, 4 0 Running boards} 2 x 12) 12 0 Lumber required per mile. Nails required per mile. > Was 3 oy ee | cae | Soe fi eile a 5 = = 7 a 4 eé rs} 2 Re Size v 2 nQ Ss n a 2é + Ks} 5 ge ee |e S| ed es a |. & 2 — ® = i) =) So oa = & & x i Ba | s Ft. in. Ft. in. 30 0 1} 30 0 440} 440 | 13,200)) 12-penny.-.| 1,700) 17 21 9 2} 43 6| 880} 440| 19,140] 16-penny..| 1,075] 103 21 0 1} 21 O} 440) 440] 9,240] 20-penny..| 390] 4 Ses 2} 16 6| 880} 440| 7,260] 40-penny..| 3,625| 364 5 73 4} 22 6]11,467]13663] 8, 250) 48 0 2} 96 0 880} 440 | 42,240} One keg of 40-penny 14 0 3) 42 O} 1,320) 440] 18,480)| mails and one keg of Sia T: 6} 21 6) 2,640) 440 9, 460 60-penny nails should 9) 0 6| 54 O} 2,640) 440] 23,760); usually be allowed for Ca eee eal 22D iO 5 5e 440 | 96,800 such preliminary work eS 24| 40 0} 10,560} 440} 17,600 as bridging, etc. 24 0 lj °24 0 440} 440 | 10,560 275, 990 Bp Sate (ia aaree| ee Seregecal ame Sl ya 9, 010 we iaderere Hetero le gh eal eels 285,000|| Total....| 6,790} 68 1 Lateral braces are only figured for five-sixths of a mile, as at least one-sixth ofeach mile, on an average, will be too close to the ground to require the use of these braces. 2 Various sizes. O WASHINGTON } GOVERNMENT PRINTING OFFICE: 1914 BULL A TIN OP THE “5 USENET aR No. 88 Contribution from the Bureau of Entomology, L. O. Howard, Chief. April 30, 1914. THE CONTROL OF THE CODLING MOTH IN THE PECOS VALLEY IN NEW MEXICO. By A. L. Quatntance, in Charge of Deciduous Fruit Insect Investigations. INTRODUCTION. For some years complaints have been received by the Bureau of Entomology from the fruit growers in the Pecos Valley, N. Mex., of the severe injury to apples and pears by the codling moth (Carpocapsa pomonella Li.). ‘The methods employed in the control of this insect in other apple-growing regions have, in the Pecos Valley, been stated to be there much less efficient, so that a considerable pers of the crop of fruit has been wormy ona unsalable. The codling moth should yield as readily to treatment in the Pecos Valley as Jeeta. though, owing to favorable climatic conditions, it was surmised that it might develop an additional generation. It was not believed, however, that the behavior of the sect in that region was essentially different from its behavior in other sections, and the lack of satisfactory results from spraying operations, it was thought, probably resulted from failure to accomplish this work in a thorough and timely manner. Beginning in the spring of 1912 an investigation of the codling moth was undertaken by the Bureau of Entomology, with head- quarters at Roswell, N. Mex., and Mr. A. G. Hammar, who had had much experience with this insect at other field stations of the bureau, was assigned to the work. During that year he was assisted by Mr. Earl R. Van Leeuwen, and during 1913 by Mr. L. L. Scott and Mr. EK. W. Geyer. Owing to the unfortunate death of Mr. Hammar there devolves upon the writer the necessity of preparing for publication, for the benefit of the Pecos Valley fruit growers, the results of Mr. Hammar’s experiments. The investigations carried out by Mr. Hammar comprise a thorough inquiry into the life history and habits of the codlng moth in that region, and experiments with sprays in orchards. The results of the life-history studies will be given in, another paper. NotE.—This bulletin describes the codling moth as it affects fruit growing in the Pecos Valley, N. Mex. It is of interest to fruit growers in the Southwest. 34853°—14 2 BULLETIN 88, U. S. DEPARTMENT OF AGRICULTURE. The present article deals with results obtained in spraying in 1913. Work was carried out in two orchards, namely, that of Messrs. Sherman & Johnson and that of Mr. Robert Beers. Unfortunately the report of results in the latter orchard is not entirely complete, so that the details of these experiments can not be given. In general, however, the results obtained in the Beers orchard agree with those secured in the Sherman & Johnson orchard, and the latter are given in detail in the following pages. EXPERIMENTS IN THE SHERMAN & JOHNSON ORCHARD. A portion of the Sherman & Johnson orchard, about 5 acres in extent, was selected for spraying experiments and was subdivided into plats, as shown in figure 1. The trees were large, and codling-moth conditions were fairly typical for the valley. Plat I received three applications; Plat II, four applications; and Plat III, five applications of arsenate of lead spray. Plat IV was left unsprayed throughout the season for pur- poses of comparison. A good power sprayer was used, capable of supplying three or four leads of hose, and maintaining a pressure of 200 to 225 pounds. (See fig. 2, showing outfit in operation, and size of trees used.) Further information concerning the treatments and the dates of spray applications for the respective plats is given in Table I. TasLe 1.—Treatments and dates of applications of sprays for codling moth, Sherman & Johnson orchard, Roswell, N. Mez., 1913. Dates of appli- | p). = Se ca Plat II (4 applica- Plat II (5 applica- Plat IV aa Plat I (3 applications). tions). tions). | (unsprayed). as, Apr. 24-25......... Arsenate of lead, 6| Arsenate of lead, 6/| Arsenate of lead, 6 | Unsprayed. (After falling of | pounds to 200 gal- pounds to 200 gal- pounds to 200 gal- petals.) | lons of water. Bor- lons of water. Bor- lons of water. Bor- deaux nozzles. 164 deaux nozzles. 163 deaux nozzles. 163 | gallons per tree. gallons per tree. gallons per tree. | 225 pounds pres- 225 pounds pres- 225 pounds pres- } - sure. sure. sure. Mayi7-S-2-e hace As Arsenate of lead, 8] Arsenate of lead, 8 | Arsenate of lead, 8 Do. ounds to 200 gal-; pounds to 200 gal- ounds to 200 gal- ons of water. Ver-| lons of water. Ver- ons of water. Ver- morel type nozzles. | morel type nozzles. morel type nozzles. 13% gallons per tree. 13% gallons per tree. 132 gallons per tree. 200 pounds pres- | 200 pounds pres- 200 pounds pres- sure. | sure. sure. June 16-17_......- Arsenate of lead, 8 | Arsenate of lead, 8 | Arsenate of lead, 8 Do. unds to 200 gal- ounds to 200 gal- ounds to 200 gal- ons of water. Ver- ons of water. Ver- ons of water. Ver- morel type nozzles. morel type nozzles. morel type nozzles. 15% gallons per tree. 15% gallons per tree. 153 gallons per tree. pil kgs! 3 Re Oe (ba ee eee eee eee | Arsenate of lead, 8 | Arsenate of lead, 8 Do. ounds to 200 gal- ounds to 200 gal- ons of water. Ver- ons of water. Ver- morel type nozzles. morel type nozzles. 17} gallons per tiee. 17} gallons per tree. BAT pape en a ae ee Seg ee oer Re eee apy be Arsenate of lead, 8 Do. ounds to 200 gal- i ons of water. Ver- | morel type nozzles. 93 gallons per tree. SHERMAW AND JOHINSON ORCHARD-GEN LAWIS- 5 ACHES. 6) QO Cl Ole Ce OO 2 Oo Oe OO OOo @ OO G © Ola © CONTROL OF THE CODLING MOTH IN NEW MEXICO. O © 90 0;/0/0 0 0000 0/0 O © 0 0;0/0 00000 0/9 9 2 © © © CG @ © ©} © © © oO © © © © G2 © © © © © PLAT lH-F3 TREES-5S SPRAYS. ©) ©) oe) O (2) QO 12) O (ox HK (2) fe) Oo O oO oO o =} 9 orchard, Roswell, N. Mex. KS) ) ©) © 0 OO O M0 000 to 00 0 4 9 0 OC ay) ce) (2) 12) (e) ©) yy ‘ 4 ce) 12) O GO 9/0/09 0 o (e) Oo oO TREL. O y O20 O10);0 O O Gj O07 9/0} 0 © QO @ 9 © O%0 O1010 0 oO oo O10/0 0 oO Q@ OSO/Ol® © © © OO OO © O RSS SS y 6) OO} © 6) ©) ©. O.© OGIO © @ © B10 OOOO © G/& © (oe) (Original.) 1e) (oy) (e) Orchard continued —> CQ © OF O Oo Ole © 6.6 8 6 6lo%o x © OO © © © © © 0 0101/0 0 060900 0/0 O OO 0010/0 00000 0/0 .0;4 O 0 0/01!0 00000 0/0 o 9 Soe ale 6 6 6 O oO ye OS ROAD | Fic. 1.—Diagram showing arrangement of trees used in codling-moth experiments, Sherman & Johnson Fic. 2.—View in Sherman & Johnson orchard, Roswell, N. Mex., showing size of trees and power sprayer in operation. (Original. ) BULLETIN 88, U. S. DEPARTMENT OF AGRICULTURE. It will be noted from Table I that the amount of spray used in all applications was large, and probably considerably in excess of that used by the average fruit grower in the valley. The amount of spray applied immediately following the falling of the petals (April 24-25) exceeded somewhat the amount given in any subsequent application. It will be noted also that Bordeaux nozzles were used at this time, whereas in subsequent treatments the so-called eddy chamber or Vermorel type of nozzle was used, producing a fine cone- shaped spray. In Table II are shown the number and percentage of sound fruit from each of five trees of each plat, as well as the total number and total percentage of sound and wormy fruit for the five trees of the respective plats. Taste II].—Number of sound and wormy apples from each tree of each plat, Sherman & Johnson orchard, Roswell, N. Mex., 1913. Total |-Tsea" Plat and condition of fruit. Tree 1. | Tree 2.| Tree 3. | Tree 4. | Tree 5. fut cent lat sound is fruit. Plat I. Worn yea: oo sare ae hese ences eee 138 144 153 179 152 766 SOU Seas SS ee eee en oe nee 2,918 | 2,022 |) 3,382] 3,418] 3,239 | 14,979 S015) Ease ier parece age RE, Be 3,056 2,166 3,535 3,597 3,391 | 15,745 iPericent:sound ese epee eee ae eee 95.48 | 93.35 | 95.67 | 95.02 | 95.52-).._____- 95.13 Plat I. WiOrimtty co. 25.5 20 See eee 86 39 33 37 70 265 Sound = 3 Sesee eee eee eee eee 4,271 | 4,086 | 3,378 | 3,344] 5,504 | 20,583 Mota). = cs38 Soe ee ee eee oa ere ee 4,357 | 4,125 | 3,411] 3,381 | 5,574 | 20,848 Percent Sound Soe ee ee ee ee ee ese 98.02 | 99:05 | 99.03 98.90 | 98.74 |.......- 98. 72 Plat IIT. WYOTIN is oo on oc e iss hee nee eee 51 18 40 25 14 148 Sommde j:ciclsckcc. Seen eee eae | 6,283 | 4,479 | 4,494] 4,618 | 4,442 | 24,316 Ota ee ec ss ce 552th eee eee 6,334 | 4,497 | 4,534 | 4,643 | 4,456 | 24,464 Percent SOUNGE. 5: eee o- eee eee eee 99.19 | 99.59} 99.12] 99.46] 99.68 |......_. 99.39 Plat IV. : WVOLHLY Sete oes adccice ve oe ee Eee 5,308 | 2,671 | 3,813 | 3,486] 3,336 | 18,614. Sonndieee sore ee ee eee eee 2,871 | 2,349 | 2,873 | 2,765 | 1,958 | 12,816 STO tale te ett eM orate eae 8,179 | 5,020 | 6,686 | 6,251 | 5,294 | 31,430 IR Cr CON SOU GM ease neers 5 tat ie eons 35.12 46.79 42. 97 44, 23 BOS: | eeeeees 40.77 It will be seen that Plat I, which received a total of three applica- tions of an arsenate of lead spray, gave 95.13 per cent sound fruit. Plat IJ, with four applications, yielded a somewhat higher quantity of sound fruit, namely, 98.72 per cent; while from Plat III, which received five spray applications, 99.39 per cent of the fruit for the season was sound. Plat IV, which was not sprayed during the season, shows only 40.77 per cent of the fruit free from codling moth injury. In determining these results, examinations were made as to worminess of all the apples produced on the five count trees ‘throughout the season; that is, the fruit which fell, the fruit which was picked from the trees in thinning, and that picked at harvest time. CONTROL OF THE CODLING MOTH IN NEW MEXICO. 5 It would appear that with the minimum of three applications, made as shown in Table J, injury from the codling moth in the Pecos Valley may be reduced to less than 5 per cent of the total crop of apples produced. For each of the two additional applications an increase in sound fruit is shown, but probably not in proportion to the expense involved. It should be borne in mind, however, that in these experiments applications were made with much thoroughness, and unless the orchardist will do equally as thorough work it will be better for him to make the additional applications. PLACES OF ENTRANCE OF FRUIT BY CODLING MOTH LARVA. Many observations in different parts of the country have shown that the majority of codling moth larve normally enter the apple at Fic. 3.—Showing condition of calyx lobes of Ben Davis apple: a, Two days after falling of petals; 6, ten days after falling of petals. (Original.) the calyx end. A careful study of the places of entering sprayed fruit by larve, whether at calyx, side, or stem, throws much lght on the relative effectiveness of the respective spray applications. All experiments corroborate the statement that the treatment given immediately after the falling of the petals is by far the most im- portant one and that its omission can not be corrected by subsequent treatments, however thoroughly made. A study of the behavior of the calyx lobes of the recently set apples in the Roswell section furnishes evidence of value in timing spray applications. Ordinarily in the Fast there is a period of about 10 days following the dropping of apple blossoms during which the 6 BULLETIN 88, U. S. DEPARTMENT OF AGRICULTURE. calyx lobes remain open, so that the spray may be successfully directed into the calyx cups. In New Mexico, however, it would appear that the calyx lobes of the little apples do not draw together nearly so quickly after the falling of the petals and may remain open in suitable condition for calyx spraying for a period of from two to three weeks, varying somewhat with the variety and season. (Figs. 3 and 4.) This condition renders it possible to apply the second spray in a way to supplement the first spray into the calyx cups. Fic. 4.—Showing condition of calyx.lobes of Ben Davis apple: a, 18 days after falling of petals; 6, 30 days after faTine, of petals. (Ome ) The effect of spraying in changing the relative: propor on of larvee which succeed in entering the fruit at the calyx, side, and stem is shown for Plats I to III in Table III. The normal behavior of the larvee in entering the fruit may be seen by referring to the figures for Plat IV of this table. It will be noted that on the unsprayed plat somewhat over one-half (53.72 per cent) of the total larve for the season entered the fruit at the calyx end. Tasie I1l.—Number and percentage of codling moth larve entering fruit at calyx, ie, and stem for Plats I-IV, Sherman & Johnson orchard, Roswell, N. Mex., 1913. Total larvee for plat for season en- | Plat , Plat |. Plath | Plat 5 tering at— 7 Per cent. Il. Per cent. TIL. Per cent. | Iv. Per cent. Up eee wens 3 3 13 Average per day...--.- 5s Average per day. ...-.-- 3 == ae Mar. ° "7. oscar eerie ste 5 Winged female, red form; gave birth pS iit, Waa 5 3s ates 5 to first young Mar. 3, 1910: Qsindal AN Ste eet os 7 1X a re ie ogc es a as 8 5 TOS ee ROE ee (7) 7 es EP Pe Ee Be er eee 5 Da setigh hs Garay age 9 Totalescs: Hees Saal Gacresacrtpe techs Se 5 Average per day.....-. 5% Two females were observed that produced 30 and 40 young, respec- tively, after which they died under normal conditions. They pro- duced young on an average of 2 and 24 per day for 15 and 20 days, respectively, during the month of December. Other females observed during the same period, but lost possibly before reproduction was completed, gave birth to from 15 to 45 young at an average of 34 per day. Two females observed in the month of March, however, pro- duced young at the rate of 54 and 52 a day, showing quite plainly how the reproduction was accelerated during the prevalence of warmer temperatures. Two females in October reproduced young at the rate of 54 a day for 6 days, or until lost. From these observations it may be said that this insect is able to reproduce for at least 20 days during the winter in southern California and to give birth to as many as 45 young, while in the warmer seasons the number of young is probably greater and the period of reproduc- tion is considerably shorter. The reproduction experiments were too few in number to justify making any statements more generalized than these. LIFE HISTORY AND REPRODUCTION IN THE GREENHOUSE. During the fall of 1912 the rose aphis was under the direct observa- tion of the writer in the insectary greenhouse at Washington, D. C., and the life cycle was observed for a few individuals. A wingless female born October 10 matured and gave birth to young on October 19, or in 9 days. During the next 7 days she gave birth to 45 young, or an average of 63 per day. 1 Aphis lost. THE ROSE APHIS, 9 Of four other aphides, born on October 10, two became adult and gave birth to young on October 22, or in 11 days, while another required 12 days, and the fourth 13 days. Another aphis was born on October 19 and emerged as a winged female on November 3, reaching maturity in 15 days. This insect lived as an adult for 17 days and gave birth to living young for 14 days. During this time she gave birth to 87 young, or an average of 633; per day. During this time the average mean temperature was 67° F. LIFE CYCLE IN CALIFORNIA. During the winter months of 1909-10 the life cycle was observed in California in anumber of cases. Aphides born on the 18th of Novem- ber became adult wingless females and began to reproduce young in from 15 to 18 days, and in two cases the offspring of these same insects became mature and began to reproduce in from 18 days for wingless females to 21 days for winged females. Aphides born November 26 emerged from nymphal skins as winged adults in from 23 to 25 days. Thus the wingless forms developed in all cases from 7 to 8 days sooner than winged forms. This was the maximum life cycle, and during the rest of the year the growth must have been much faster, but observations were not made owing to press of other matters. GENERATIONS. Taking 25 days as a maximum, this would allow more than 12 generations annually, but with the shorter life cycle required during the warmer part of the year this number must be exceeded by at least 7 or 8 generations. In greenhouses there are probably 25 to 30 generations in a year. LONGEVITY. During the winter these insects are long lived for such delicate creatures. One lived under the direct observation of the writer for 40 days and another for 33 days. Probably this is longer than for the same insect the rest of the year. NATURAL CONTROL. RAINS. In southern California the rainy season extends from about October 1toMayorJune. Usually before the rains set in the weather becomes cooler, but the rains are not as a rule hard and dashing, as are those so fatal to aphides in the East, and this apparently explains their slight effects as observed on the rose aphis. Undoubtedly some are washed away and destroyed by rain, but not to the extent occurring in the Kast, although reproduction seems to be greatly checked during arainstorm. In the East this insect is many times nearly extermi- nated by a hard, dashing rain. 10 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. HEAT. During the early part of April, 1910, when the aphis was very abun- dant on the roses throughout the entire city of Los Angeles, three or four very hot days occurred during which the temperature rose as high as 100° F., and within a day or two thereafter the numbers of this aphis had become very much diminished. After thisit did not seem to occur in large numbers again until about the middle of August. BIRDS. On March 19, 1910, the writer, with field glasses, watched a white- crowned sparrow (Zonotrichia leucophrys leucophrys) on a rosebush, 10 feet away, eating the rose aphides as fast as it could pick them from the bush. This was continued for fully 10 minutes, during which time many hundreds must have been eaten, as the plant was almost cleaned up by this bird. | On March 30, 1910, a California house finch (Carpodacus mexicanu frontalis) was observed by the writer eating this aphis from a rose- bush for fully 15 minutes. PARASITIC INSECT ENEMIES. There are many different species of parasitic insect enemies that attack aphides, and some of these will attack the rose aphis. On June 13, 1910, many specimens of Macrosiphum rose were found which showed signs of parasitism by an undetermined insect. These aphides were rounded and fastened to the underside of the rose leaves. The parasite when full grown had killed the host and, cutting its way out beneath the body, spun a tiny cocoon between it and the leaf. Unfortunately all of the parasites failed to emerge. While the para- site was not rare, at least during the past year, it did not seem to check the rose aphis to any extent. Ephedrus incompletus Prov., a braconid, was reared by the writer from this aphis at Washington, D. C., in 1912. PREDACEOUS INSECTS. Among the predaceous enemies the larvee of syrphus flies and lady- birds were observed feeding on the rose aphis, and without a doubt the most important check to this insect in 1910 was due to the larvee of syrphus flies. While these did not seem able to clear a plant alto- gether, still it was many times observed that strong thriving colonies of 50 to 60 aphides or more would be reduced by these insects in one or two days to a mere scattering here and there. During the year 1910 five different species of Syrphide were reared from larve feeding on Macrosiphum rose. These were Syrphus ribesti L. (fig. 3), Syrphus opinator O.8., Allograpta fracta O. 8., Eupeodcs volucris O.S. (fig. 4), and Lasiophthicus pyrasti L. : THE ROSE APHIS. py The adults of all these species seemed to have similar habits. They flew swiftly from twig to twig and hovered over them in the bright sunlight, the wings moving with extreme rapidity, always with a distinct humming sound. From time to time they alight- ed on the twigs or leaves and searched here and there for colonies of the aphis. The abdo- men was generally kept in throbbing motion, and when an ege was to be laid a long siender Ovipositor was thrust out and the ege was placed on Fig. 3.—Syrphus ribesii, an enemy of the rose aphis: a, Fly; 6, lateral view of head; c, larva or active immature form; d, anal spiracles; e, thoracic spiracle ofsame. Allmuchenlarged. (From Chittenden.) a leaf or twig in the midst of or near the colony of the host insect. It was noticed that certain bushes shaded from the sun after 1.30 p. m. were immediately deserted by these flies until the next day. Fig. 4.—Eupeodes volucris, an enemy of the rose aphis: a, Female fly; b, abdomen of male fly; c, hypopy- gium of male fly. Muchenlarged. (From Webster and Phillips.) The rearing of five different species of syrphus flies from larve found feeding on the rose aphis rather surprised the writer, and he regrets that lack of time has prevented a continuation of the work 12 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. that it might be ascertained if other species would also be commonly reared. Although the ladybird Hippodamia ambigua Lec. was observed during the entire time occupied by the observations on the rose aphis, it occurred in small numbers, and on only one or two occasions did it seem to be feeding on Macrosiphum rose. DISEASE. On March 14, 1910, after a night of rain, one winged and two wingless aphides were found enlarged to fully five times their regular size, as if bloated. This was probably due to a fungous disease. ~ EXPERIMENTS WITH REMEDIES. The abundance of the rose aphis is so marked in many years that frequently almost daily complaints of damage are made in the Dis- trict of Columbia and vicinity. Wherever it has been convenient or desirable to eradicate this species on small acreages of plants, water, applied with a garden hose or syringe, has been the remedy employed, not alone by the writer but by many persons resident in Washington. Indeed this treatment, which, consists in directing a forcible stream of water against the affected portions of the plants has been one of the standard remedies advised. Experiments have been made by Dr. F. H. Chittenden, by Mr. C. H. Popenoe, and by Mr. A. B. Duckett, allin the District of Columbia and vicinity. In otherregions, Mr. W. B. Parker has undertaken experiments with, nicotine sulphate, and the writer has conducted quite a series of experiments with the same compound. Among other compounds used by Messrs. Chittenden and Popenoe for this species are aphis punk and other nicotine papers, always with gratifying success. While treating other forms of insects on roses, such as “‘slugs’”’ and thrips, the aphides were always the first to perish. EXPERIMENTS IN THE DISTRICT OF COLUMBIA AND VICINITY. 1 On March 28, 1913, at Washington, D. C., four rosebushes in the greenhouse, well infested by the rose aphis, were sprayed with, “ black- leaf 40,” a preparation guaranteed to contain 40 per cent of nicotine sulphate, in combination with whale-oil soap in the following formula: Nicotine sulphatese: 228. \55..- 5. 2 See ase in are oc ounce... 4 Whale-o1l soaps siocsk.- 052. +o Scie een one ae oe pound.. 4 WADCE: cS cs Se ar teeiclete arn SM. = 2 2p eral redMaiale wed Soll nel 0 te er gallons.. 25 Although the solution slightly injured the terminal buds and the tender shoots, the results were all that could be expected, 100 per cent of the aphides being killed. It is believed that the solution could have been reduced 25 per cent in strength with equally good results. 1 By A. B. Duckett. Bul. 90, U. S. Dept. of Agriculture. PLATE III. SPRAYING ROSE BUSH WITH COMPRESSED-AIR SPRAYER BY HAND. THE ROSE APHIS. 13 On April 23, at a Virginia station near Washington, a number of large rosebushes trained on the side of a house and well infested with aphides were sprayed. Both winged and wingless forms of aphides were present. Nicotine sulphate was applied, with and without the use of soap as in the previous formula, at the rate of 1 part to 1,000 of water. In the experiments without the use of soap some diffi- culty was found in obtaining a spreading action of the spray, and con- sequently only about 90 per cent of the aphides were reached. It is believed that all reached by the spray were killed. When nicotine sulphate was used at the rate of 1 part to 1,400 parts of water and 1 part to 1,500 parts of water, results were not satisfactory, only about 25 and 10 per cent, respectively, being destroyed. With the use of soap 100 per cent of the aphides on the vines were killed, the results being very satisfactory. At the rate of 1 part of nicotine sulphate to 1,400 of water with a laundry soap added, 90 per cent of the aphides were killed; whereas the results with nicotine sulphate at 1 part to 1,600 of water and 1 part to 1,800 of water in combination with soap were unsatisfactory, only 70 per cent and 50 per cent being lalled. In these experiments a compressed-air sprayer with Bordeaux type of nozzle was used at an estimated pressure of 90 pounds, and a fine but driving spray was employed. ‘The water used for the dilution of the insecticide was particularly soft, but contained a very small proportion of sulphur. From these experiments it may be concluded that nicotine sulphate at the higher dilutions as used in these experiments is much more effective against the rose aphis when used in combination with, whale- oil or other soaps, since the spreading action thus induced is much more favorable. The plants may, however, be injured in case the spray solution is too strong. Itis not believed that the injury shown in the experiments was caused by nicotine sulphate used at too great. a strength, since it has been applied experimentally to roses in the ereenhouse at the rate of 1 part nicotine sulphate to 15 parts of water without injury other than the appearance of mildew, undoubtedly superinduced by the spraying. It is apparent from the results obtained that a spray can not be employed weaker than 1 part of 40 per cent nicotine sulphate to 1,400 parts of water with satisfactory results unless in combination with whale-oil or other soap. ARTIFICIAL CONTROL IN THE GARDEN. Experiments have been conducted against the rose aphis with different nicotine extracts under different conditions as to strength and weather. In no case, in the writer’s experience, were 'the plants injured, whereas the insect was destroyed in enormous numbers. The aphis is easily controlled by spraying with nicotine solutions 14 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. containing 40 per cent of nicotine at the rate of 1 part of the solution to from 1,000 to 2,000 parts of water, with whale-oil soap at the rate of 1 pound to 50 gallons of spray mixture. When only a few rose bushes require treatment the spray may be prepared in small amounts as follows: To 1 teaspoonful of 40 per cent nicotine solution add 1 to 2 gallons of water and one-half ounce of whale-oil soap. The soap should be shaved fine and dissolved in hot water. There are on the market numbers of solutions containing less nico- tine than the foregoing which may be used with good results with the addition of whale-oil soap, as advised, at the strength recom- mended by the manufacturers. If these are not obtainable, very good results may be accomplished by dissolving 1 pound of whale- oil soap or 2 pounds of common laundry soap in from 4 to 6 gallons of water. Wherever possible, however, the nicotine solutions should be used, as better results will be obtained. This species, like practically all of the green aphides, can also be controlled by repeated applications of a forcible stream of cold water. Since the roses in California and some other localities are much sub- ject to mildew, repeated use of this method has the disadvantage of increasing injury by this disease. In the case of the appearance of mildew, however, either through syringing with water or through the application of nicotine sulphate, this disease may be readily con- trolled by adding to the nicotine sulphate solution copper sulphate or blue vitriol at the rate of 1 pound to 50 gallons of water (approxi- mately 1 ounce to 3 gallons). A solution of copper sulphate used at this strength and sprayed on the plants after the application of the water treatment is effective in controlling the mildew. Another common practice of florists for the prevention of mildew is to dust the plants immediately after sprinkling or watering with common flowers of sulphur. in order successfully to fight this insect these sprays should be applied with a compressed-air sprayer (Pl. IIT) or bucket pump capable of creating a fine penetrating spray. These pumps can usually be purchased at the seed stores at from $3.50 up to $15. The nicotine solutions are also carried by most seed stores. Where a pump is not to be obtained much can be accomplished by dipping the infested twigs into a pail of the solution of nicotine. From the experiments of the writer it is evident that this insect can be destroyed easily by the use of nicotine solutions of considera- bly less strength than have heretofore been used, but the treatment must be repeated at intervals to kill the aphides missed by former applications. ‘With the different styles of pumps now on the market at low prices no one who cares for roses has the slightest excuse for allowing them to be injured by this insect. THE ROSE APHIS. 15 TREATMENT IN THE GREENHOUSE. For the treatment of the rose aphis as it occurs in greenhouses the nicotine solutions may be used, but at a lower strength than advised in the preceding paragraphs. Conditions vary somewhat, but it is believed that in most cases if the nicotine solution is used at the strength of 1 part to 2,000 of water it will not injure the rose plants if applied on a dark day or late in the afternoon so that the plants will not be exposed to reflected sunlight through the glass. When greenhouses containing different forms of plants are syringed with a forcible stream of water or with neutral soaps of the castile or similar types for the red spider and other insects, the rose aphis and other green aphides will also be killed. The same is true in regard to fumigations with hydrocyanic-acid gas for other rose pests. Directions for the use of hydrocyanic-acid gas for the fumigation of greenhouses and cold frames are given in Circular No. 37 of the Bureau of Entomology. In the experience of Dr. A. F. Woods, the author of that publication, the young growth of roses is particularly sensitive and has been more or less injured in experiments in the use of this gas. This is particularly true of such varieties as ‘‘ Perle des jardins,”’ “‘Mermet,’’ and “ Bride.” ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFTICE WASHINGTON, D. C AT 5 CENTS PER COPY Vv BULLETIN OF THE 1) USDEPARTNENT OFAGRCULTURE & No. 91 Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. May 16, 1914. COST AND METHODS OF CLEARING LAND IN THE LAKE STATES. By Harry THompson, Agriculturist, and Earu D. Srrair, Scientific Assistant Office of Farm Management. INTRODUCTION. Practically the entire northeastern part of Minnesota and all of Michigan and Wisconsin were originally forest land. Nearly ali the southern parts of Michigan and Wisconsin are now cleared except for scattering farm wood lots. At the present time large areas of undeveloped land are found in northeastern Minnesota and the northern half of Michigan and Wisconsin. In Table I the figures showing the area of improved and unimproved lands were taken from the census of 1910; the statistics regarding the area of merchantable timber land and of logged-off land and the land values were compiled from data obtained from State, county, and township officials, lumber companies, and other companies or individuals well informed on these matters. The figures obtained furnish a fairly close ap- proximation to the actual acreage of merchantable timber and - logged-off land in the three States mentioned. A part of the logged-off land in the three States specified probably would give better returns if put into permanent forest, but there is much good agricultural land in nearly every county in which these investigations have been conducted which at the present time is not growing desirable timber and is an idle waste (fig. 1), giving no re- turns whatever. Because of the danger from fire, these waste areas form a menace to the communities. _ At the present rate of cutting, most of the remaining merchantable timber will be cut within the next 25 years. This means that in many counties there will be a change from lumbering to farming. Nore.—This bulletin gives details of cost and methods of clearing land in the Lake States and is of spe- cialinterest to settlers in the logged-off sections of Michigan, Wisconsin, and Minnesota. 36156°—Bull. 91—14—_1 BULLETIN 9 ies Loe’ DEPARTMENT OF AGRICULTURE. TABLE I.—Acreage of improved and unimproved lands, merchantable timber, and logged-off land and values of the improved and logged-off lands in the various counties of Michigan, Wisconsin, and Minnesota. Michigan: Wisconsin: State and county. Atcona 5: fasseeee ks ss sees AAUOND. 2 epee = we = Seka ANiinim: % see sso eens oo See | Charlevoix. See. 225-5 2.3854 Gheboy eater ----.-.2-- 1: Ghippewa- e522 Ue eos IRTG UL he te eee Seats @rawiOrden soe eee ae GOgebiG.. = See. esse Grand Traverse..-.22/2.2- GrTahlotise saeete 32) ses ee Hourh ton eeer ses. 2 sae TOSCO! S22 See nae S Pe MOTs Ce PS ae ees [sabellai =. Se8e 2 saps ee oe Kalikas rails tee rt eee WROD sic Bees tae oo ee akews) sea ieee nos ee Ma mIStCO 3. J. eeth Vee ok Mason 5. ios ee ee MGCOStAM. 2726 2 eee seer Menomineess .) a5... a.2- Midland! 1. 285). Bee Pn r2ee . 2 | Missatikee!s3..4...5...52% MONT Calm >. we eee eee Montmorency.-:--.---.--- Muskeron er ees. - ees Newayforsjeest.. 2 .bscSsce Oceanae.: Sef i esceeee Ovremawe: = Sees: see Osceolate. - tess. knoe ae Ottawa) sv eee oe oles Pesce Tal ewes ea RVOSCOMIIMOM sees ale aoe Saoinis wl wee Jos 2a, Schooleratts. sees see. Wiexond eerste oe eee: All other counties!........ Ashland? 2e¢ ss ceemererer e SAVHBIG: Hows scp ecieay BOrneit:). 22. - oo eee eae Chippewa-ec.:)- cee Clavisk:. ae...) eens IDUNNIDEs - nee es to eee 3 1The only timber in the county is in farm wood lots, 2 Orchard land, Acreage. Value per acre. i as E - Ec Unim- Merchant- Improved. proved. lemle Gacineas Logged-off. Improved. | Logged-off. 38, 037 399, 723 3, 000 327,700 | $40 to $60 $5 to $15 5, 634 583, 157 375, 000 125, 000 30 6 51, 403 322, 357 1, 200 222, 357 25 10 78, 810 225, 190 16, 000 179, 190 60 10to 15 55, 571 ASS SO. = sees ae 113, 800 60 10 9,344 577, 536 297, 280 240, 256 75 7to 25 142, 635 TAO S85 wie epee 45, 100 100 15 tor 25 48, 856 152, 104 2, 000 132, 100 50 10to 25 61, 587 201, 463 16, 000 175,400 | 40 up 10 up 50, 925 413,075 43, 280 300, 795 30 10 79,336 927,384 233, 360 348,400 | 50to 55 6to 25 53, 921 BUSS O59 |e ay eee 293, 559 60 15 10, 701 357, 299 15, 000 320, 000 35 8 42, 932 705, 228 150, 000 450, 000 40 10 8, 342 488, 298 174, 397 269,846 | 75to 100 3to 25 54, 265 256, 135 40, 200 174,720 | 20to 30 10 54, 123 278, 037 2,000 240, 592 40 7to 10 4, 742 720, 378 597,327 69,319 |} 50to 80 5to 12 109,378 189, 502 15, 360 134, 192 50 12 248, 899 1216618) |S aes HO}O0ON He Be Ae alee ce oe. se 35, 921 616, 239 217, 200 299,040 | 50to 75 10 40, 735 BPA Ob) le neaaeaccoce 232,000 | 20to 50 5to 20 9,008 758, 992 366, 833 325,575 | 30to 50 pitol 12 193, 124 128500 | sence re aes 122, 800 60 10to 15 42, 563 324, 157 59, 640 172,500 | 20to 50 15 365, 717 1845 683) gobs Na 134, 700 65 30 1, 236 353, 324 253, 324 50, 000 15 5 33, 884 CE GEGi lls wena bees ae 296,700 | 30to 50| 10to 15 83, 812 132, 508 7,000 89,300 | 30to 70 15 7, 926 580, 874 125, 000 225, 000 50 6to 20 21,118 647, 042 173, 440 374,400 | 40to 60 5to 15 75, 031 284, 649 3, 000 231, 649 40. 15 23,041 | 1,173,759 | + 500,000 550,000 | 25to 50 8to 15 100,925 215, 235 2, 000 144, 000 50 12to 15 159, 794 20546460 eae menses 23, 080 50 10 up 64, 590 611, 250 138, 338 372, 912 50 3to 15 94,717 DAS RAB eRe Nees ER 174,800 | 75to 100 to 15 60,918 SME WiGoaae od else 211,500 | 20to 50 5to 20 266, 401 196, 959 3, 000 175,000 | 60 to 100 15 17,506 341, 534 42, 200 IGT 500), paced ee lee relat tersinie oe 109, 656 PABA IE tee SAMS nc 152,900 | 35to 70 3 up 166, 072 Skshtlehel|- Serene - 240,600 | 25 up 10 up 151, 782 195, 738 8, 500 179,900 | 50 up 2.50 to 25 55, 437 315, 763 2,000 260,800 | 40to 50 10 11, 992 841, 128 510, 000 300,000 | 25to 50 3to 10 129, 303 239, 977 1, 760 215, 900 50 20 16, 218 352, 422 10, 000 296,400 | 25to 50 10to 15 27, 627 310, 293 70, 840 196,500 | 20to 40} 8.50to 15 247, 236 TWAS SGASIRE Sec). Pees 75,200 | 60to 70] 30up 39, 925 393, 995 9, 960 245,800 | 30to 35 10 8, 951 335, 369 30, 000 245,000 |} 25to 50] 7.50to 25 304, 738 225 1182 Ml berate: aoe 125 200 il een eS eeeeayel et atcha) te 15, 431 757, 049 100, 000 400,000 | 30to 75 5: to.) 1h 79, 044 290, 236 33, 960 226,000 | 25 up 5 to 12.50 cca] of a 4a ers iO 2 le ies) Ae rmcisscis|eseieeicccietel|- ec ckistetaes [oo Aon Na Bee RE ee 4, 587,261" |’ 11), 954628) |tsenee ee nee |e oe 24, 400 668, 000 150, 000 450, 000 50 3to 35 170, 203 396, 197 3, 000 400,000 | 20to 60] 10to 15 21,700 940, 200 200, 000 600,000 | 60 to 2150 3 to 2100 56, 600 493, 800 15,000 265, 000 50 | 10to 20 196, 000 468, 900 46, 800 315,600 | 40to 50 12to 20 151, 900 627, 600 1, 250 625,000 | 50 to 100 6to 10 19, 900 835, 800 22,000 700,000 | 20to 35 5to 10 245, 100 311, 100 1,000 300,000 | 20to 35 5to 10 185, 861 223, 459 2,000 113,000} 20to 50] 7to 20 8, 500 309, 600 93, 500 202, 200 50 4to 10 6, 100 889, 900 335, O85 490, 800 50 10 3,900 503, 000 165, 000 335,000 | 75 to 100 3to 25 47, 800 512, 200 240, 000 250,000! 25to 60 3to 20 CLEARING LAND IN THE LAKE STATES. 3) Tasie I.—Acreage of improved and unimproved lands, merchantable timber, and logged-off land and values of the improved and logged-off lands in the various counties of Michigan, Wisconsin, and Minnesota—Continued. Acreage. Value per acre. State and county. ae Improved. aueeeen ae Logged-off. | Improved. | Logged-off. Wisconsin—Continued. : Nena COME eee sts < fe. 8 t= 33,590 543,730 203, 000 307,000 | $40 to $80 $8 to $20 IMI MeN OVO) oe See ee Seen See 184, 150 810, 410 86, 500 700,000 | 25to 60 10 to 20 WGI sopeaee sonebcoer 79, 474 826, 126 210, 000 575,000 | 20to 60 5to 10 (OCOMIGHE ASHE Me Ses eee aoe 134, 000 581, 500 125, 000 110,000 | 40to 60 yO) 15) Ome dasecin oe ecu 17, 700 558, 900 37, 000 485,000 | 30to 60 5to 12 IPG\oi Ot Sp Swen Bee Se eee eaee 70,175 80, 865 1,000 2,500 25 10 IPOs Go Sa eeeeeseseeeeeeras 149, 600 448, 800 15,000 225, 000 40 12 RO MIA EO ater Sees aSemeaee 218, 149 301, 530 7,500 197,500 | 25to 50 5to 10 TACOS = BSS eer gee 23, 100 795, 500 180, 480 500,000 | 25to 60 | 6to 15 IRiskemerscect ss cates ci aches 25, 900 566, 100 90, 000 400,000 | 50 to 100 9to 20 10, 400 834,400 | - 225,000 550, 000 50 5to 25 170, 200 370, 900 211, 600 185,000 | 30to 40 8to 10 33, 900 600, 300 200, 320 300,000 | 40to 60 10to 20 4,600 528, 500 85, 000 350,000 | 30to 60 5to 12 41, 600 492, 800 18, 000 365,000 | 20to 70 5to 15 221, 248 264, 512 1, 250 97,500 | 25to 60 10 to 20 108, 000 409, 800 1,000 396,000 | 50to 75 8to 20 All other counties.....-.-- 9, 243,896 | 7,060,800 CI el RR Shes 2 Ce Re le Se eae Motel ghee 6 el | ie MR UES aon Bea7D) ORs) 107702; 100s ean eae coal eee Minnesota: | PAU EGA re seat et cosa cieinseierate Ss 34,750 | 1,136, 450 100, 000 800,000 | 40up 5 to 10 WAU ON everett a iS Sea 101,575 192, 000 1, 200 110,000 | 30to 90 15 to 30 IBeCKCrAR ee eee ee. ok ie | 178, 892 684, 468 200, 000 450,000 | 30to 60 10to 30 IBeltramye Fes ee Se 33,253 | 2,413,000 500,000) 1,350,000 | 20te 60 6to. 165 IBOMtOMee ee sae ees easton 108, 847 150, 000 22,500 110,000 | 35 to 100 15to 30 WaTlihOMee es ase sees ot s8 27,518 527, 362 10,000 510,000 | 50 up 10 up WASH eae eect sole 52 40,262 | 1,300,000 300, 000 900,000 | 25to 75 5to 16 (Ghia oes EE Ct 104, 670 168, 600 15,000 112,000 | 20to 50] 10to 20 Clearwater. .....--.:.-/.-- 40, 000 612, 000 60, 000 400,000 | 20to 40 5to 15 OOKkape see tease sont aes 1,568 957, 152 450, 000 J BOOROOOS | Sasso. se eeel eee pees cae Crowe Win eyes eee oe 51, 989 | 624, 491 165, 000 410,000 | 20to 30 10to 1d IBQbI OO ENO ae aorma se eee 55, 699 597, 400 79, 000 400,000 | 20to 30 3 to 5 TSE TSE eee Een eee 109,642) 173, 246 1, 200 100,000 | 20to 50} 10to 20 GAS CaS en ets Sai oe e4 13,636 | 1,733,600 510,000 | 1,050,000 40 10 IKREITT NID OCU 02 ecieee Ot 37,370 | 304, 400 18, 000 278,000 | 15 to 100 10to 30 [Walco Ween here LN. 2,381 | 1,341,000 500, 000 GOO OO ON See 0s a eee Mahnoment.S2o22 20225 20: 24, 123 | 341, 967 95, 000 200,000 | 30to 60 10to 30 Memsheall Guns! ela 380, 677 763, 600 32,500 EOSOIONO) gen eee delel| dinar eka a he IWGING WES Ae ese ool eer 48, 438 324, 682 30, 000 283,000 | 35 to 100 15 to 30 Morrison): oaie = Pot 184, 150 547, 370 20, 000 450,000 | 25to 40 10to 15 OttersRail ages shoe ae ue 592,598 712, 362 250, 000 2005 O00) rere rhe. Ae Eee rae Renminpiomien oss 424: 136, 735 252, 000 None. SOO ROOM Be tear er. Cea) ac sala 3 at eee ote ak tes 0 64, 768 839, 552 125, 500 640, 000 50 8 TO Ugo een Se TN rs ~ 643, 946 622, 614 10, C00} 8 KO 000) ee seecbeeoeelibbeadeosecod edpuaker) Mas sansa es 77, 138 199, 342 3, 000 S20 SOOO epee ik oe calls Selecta -ee RYO SE ATI ee rc oeets eee ee 157, 332 911, 000 60, 000 350;000 | 20 to 60 5to 20 Si@@ouise sos esc) 41,111} 4,120, 809 300,000 | 1,200,000] 40to 50 5to 25 Sern urMer. sane se ase aoe 110, 927 175, 793 1,000 100,000] 40to 90 15 to 40 Wiiclenamaos: aos um ole S00! 69, 703 274, 617 40, 000 180,000 | 20to 40 8to 15 All other counties......--- GL aka caro) ME AO ae 2 oe Eee ee el ee eemseee. olssoceenes cos "TERE stacy Aas lls DR aap Pea SSE GOO iil, 7S.) [be te eae scenes ee SUMMARY. Classification. Michigan. | Wisconsin. | Minnesota. E Acres. Acres. Acres. Ap promunmateland area a4 2.420 sk cascener ene julie -tade be oe 36, 787,200 | 35,363,840 | 51,749,120 urtpromesl arcane, Hens. case essed th 21S. pam eee ic Sh 12, 832,078 | 11,907,606 | 19, 643,533 Wainaiprowedilan dit. Ge temae Sebo be) oe Rae Re ee weit ho Na 23,955, 122 | 23, 456,234 | 32, 105,587 Merehamtaible timbers. 424 2. st | 1 ih ee ee ee 4,587,261. | 2,972,285 3, 894, 900 MOP CeCe Otel densi eres kh cae ak al pe Dy.cemem ore ay EN 11, 954,628 | 10,792,100 | 11,768,000 1 Wood lots only. 2 Large burns, 3 Brush land, 4 BULLETIN 91, U.S. DEPARTMENT OF AGRICULTURE. The clearing and management of the logged-off lands is the most pressing problem in most of these counties. The object of the inves- tigations conducted by the Office of Farm Management has been to obtain data from which to acquaint the public with the large areas of undeveloped land in these sections and the nature of the wore neces- sary to make them available for agricultural purposes. A study has also been made of all the different conditions of clearing and the best methods practiced in the different sections, with the object of com- bining the best practices into a system or number of systems of clear- ing adapted to the region. Fic. 1.—Characteristic stump land in the Lake region. At the present time very little logged-off land that would make de- sirable farm land can be bought for less than $15 to $25 per acre. As the cost of clearing varies from $20 to $90 per acre, the cost of farm land cleared of stumps will run from $35 to $115 per acre, the average being about $65. When the cost of other necessary improvements is added to this, it makes the ultimate cost of animproved farm higher than the price of equally as good a farm in many of the older, well- settled agricultural sections of the United States. The high price of the logged-off land and the high cost of clearing seriously retard its development. The methods given in this bulletin, while extensively used, are not necessarily the best possible. There is plenty of room for improve- ment in all the methods now practiced. CLEARING LAND IN THE LAKE STATES, 5 METHODS OF CLEARING. All methods of clearing have to deal with the removal of the stumps, brush, and second growth. In a few localities the second growth can be disposed of to charcoal and wood-extract companies, to mining companies (for use as ties and timbers), to wood-pulp mills, or for use as fuel for enough to pay for its removal. It usually does not pay, however, to haul the wood more than 4 or 5 miles. In most cases the second growth (fig. 2) has no value except as firewood for the use of the settler, and its removal must be considered an expense of clearing. Fic. 2.—Typical logged-off land of the Lake region. Tt is cheapest to cut the brush as soon after logging as possible. It should be cut close to the ground when in full leaf, heaped into com- pact piles, and burned as soon as it will burn well. The best time for burning is during the summer. On account of the danger of the fire spreading at this time, the local or State fire warden should be con- sulted and a permit obtained from him before any burning is at- tempted. Some make a practice of harrowing or disking the ground imme- diately after burning and then sowing timothy seed. The following spring, as the frost leaves the ground, clover seed is added. Others sow all the grass seed in the spring. Where possible it is a good plan to leave the land in pasture or meadow several years before removing any stumps. (Fig. 3.) 6 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. On hardwood land the cost of removing green stumps is much more than that of removing similar stumps that have decayed for six or seven years. In the case of pine stumps growing in the heavier Fic. 3.—Stump land that has been pastured for several years. soils, the settling of the land and the heaving action of the frost gradually work the stumps out of the ground, so that the expense of removing them will be somewhat less where the land has been in grass several years. - (Fig. 4.) A serious drawback to leaving the Fic. 4.—Blasting stumps from land that has been in pasture for several years. land in grass without stumping is the sprout growth. To keep down this sprout growth requires persistent work for several years. Sheep and goats have been used successfully in some localities, but the dairy herd has taken the place of nearly all the flocks and is considered more profitable. CLEARING LAND IN THE LAKE STATRS. 7 In cultivating a field covered with stumps, it is impossible to use modern farm machinery efficiently. Stumps are removed (1) by explosives alone, (2) by explosives used in connection with stump pullers or block and line, (3) by stump pullers alone, and (4) by power machines. EXPLOSIVES. ‘Explosives alone are used effectively and economically in all stump- ing operations on the heavier soils and for well-decayed hardwood stumps on the lighter soils. .They have the advantages of thor- oughly breaking up the stumps, of not requiring a large force of men for clearing operations or a large cash outlay at one time, and of enabling the work to be done quickly. The rather high cost of explosives when bought in small quantities and the fact that only experienced men should handle them are their chief drawbacks. Direct cooperative buying in wholesale lots will reduce materially the cost of the explosives. Satisfactory instructions | regarding the use of explosives are now published by practically all manufacturers. The chief faults of the average man in blasting stumps are his tendency to place the charge too shallow and his failure to put it under the center of resistance of the stump. On most of the land-clearing operations in Michigan dynamite containing 40 per cent of nitroglycerin or its equivalent is used. In a few sections dynamite containing 20 to 30 per cent of nitroglycerin or its equivalent has been used with very satisfactory results. On the Pacific coast 20 per cent nitroglycerin dynamite or its equivalent is used, almost exclusively. Dynamite containing the smaller per- centages is cheaper, less dangerous to use, and does not pack the soil to such an extent as the stronger preparations. On the heavier soils the lower strength explosives will give just as good results pound for pound as the higher. The lower strengths act more slowly, with much less shattering, and have almost the same lifting force as those containing higher percentages of nitroglycerin. It is commonly believed that dynamite with 60 per cent of nitro- glycerin is twice as effective as that with 30 per cent and that that with 40 per cent of nitroglycerin has twice the effectiveness of 20 per cent. Tests by the United States Bureau of Mines? have demonstrated 1 Valuable information regarding the proper use of explosives in stumping may be found in the following publications: MeGuire, A. J. Land clearing. University of Minnesota Agricultural Experiment Station, Bulletin 134, 32 p., 21 fig., 1913. Kadonsky, J. F. The use of explosives inclearing land. University of Wisconsin Agricultural Experi- ment Station, Bulletin 216, 19 p., 20 fig., 1911. Thompson, Harry. Cost and methods of clearing land in western Washington. U.S. Department of Agriculture, Bureau of Plant Industry, Bulletin 239, 60 p., 25 fig., 1912. 2 Hall, Clarence, and Howell, Spencer P. The selection of explosives used in engineering and mining operations. U.S. Department of the Interior, Bureau of Mines, Bulletin 48, 50 p., 3 pl., 7 fig., 1913. 8 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. that the propulsive or lifting force of 60 per cent “‘straight’’ nitro- glycerin dynamite is only 18.7 per cent more than that with 30 per cent. On the other hand, its disruptive or shattering force is 42.5 per cent more. Carefully conducted field tests in stump blasting have shown that the propulsive or lifting effect of 40 per cent nitro- glycerin dynamite is but little more than that of 20 per cent, while the disruptive or shattering effect of the 40 per cent is considerably more than that of the 20 per cent preparation. In stump blasting a high propulsive force and a comparatively low disruptive effect are desirable. For this reason.ammonia dynamite (powders containing some ammonia and branded ‘“extra’’) and powders containing no nitroglycerin, because of their slower action and consequent low Fic. 5.—Capstan stump puller. This type requires an anchor stump from which all stumps within a radius equal to the length of the pulling cable can be pulled. disruptive effect, are generally to be preferred to the straight nitro- glycerin powders. In case the lower nitroglycerin powders or their equivalent are employed, No. 6 or stronger caps should be used. STUMP PULLERS. Two types of stump pullers are used—those that pull from the side, as the capstan (fig. 5), and the tripod type, which lifts the stump vertically (figs. 6 and 7). THE CAPSTAN TYPE OF MACHINE. The capstan type has the advantage that an acre or more of stumps can be pulled at a single setting. In pulling small stumps like scrub oak, jack pine, and certain kinds of hardwood, the saving in time is CLEARING LAND IN THE LAKE STATES. 9 quite an item. In pulling small, sound stumps considerable time is saved in not having to dig root holes, which are necessary when using a tripod type of machine. With large stumps which are partly decayed, this saving of time over that re- quired in the use of the tripod type is about offset by the loss of time due to stumps breaking off. When this occurs, each large root must be dug and pulled outseparately. The capstan machine will work on steeper land than the tripod, though no machine will do very satisfac- tory work on a steep hillside. By using the double and triple power arrangements of lines, the capstan machines will pull any white-pine stump in the Lake States. Many practical land-clearing operators using the cap- stan machines do not favor the use of the double or triple power in connection with these machines because of the time lost in ad- justing the blocks and hauling the extra cable. They prefer to use a small quan- tity of dynamite un- der the larger stumps to split and loosen them. With the tri- pod type of machine the use of dynamite to loosen the stump is unnecessary, because these machines are powerful enough to pull any white-pine stump. Fic. 6.—Typical tripod stump puller. Pullers of this type must be set directly over each stump pulled. Fig. 7.—Another stump puller of the tripod type. THE TRIPOD TYPE OF MACHINE. Many stumping contractors clearing white-pine land in Michigan use the tripod type of machine. Any stump pulls more easily when lifted vertically than when pulled from the side. No anchor stump 36156°—Bull. 9J]—14——2 10 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. is required with this type. The vertical-lift machines are more pow- erful and seem to require less repairs than the average capstan machine. On the other hand, the machine must be moved for each stump, requiring four or five horses. Holes must be dug under the roots of each stump. POWER MACHINES.! Power machines have been used to a limited degree throughout this region. On large tracts of land, with a good outfit and an effi- cient crew, the clearing probably can be done with a power machine as cheaply as and considerably faster than by any other method in use at the present time. COST OF CLEARING LAND. The cost of clearmg land in the Lake States varies greatly. It runs from $5 to about $100 per acre. The cut-over jack-pme land is the cheapest to clear and green hardwood and unburned swamp land the most expensive. The cost of clearmg depends on the fol- lowing factors: : (1) The quantity of second growth and logs per acre: The cost of disposing of these runs from $5 to $25 per acre, and even higher, with an average of about $10. (2) The kind of stumps and the number of years since logging: All green hardwood stumps are very expensive to remove. Green birch and basswood are perhaps the most difficult. Most hardwoods decay so that they can easily be removed within 10 years from the time of logging, provided the sprout growth is not allowed to develop. Jack pine and hemlock will decay at about the same rate as hardwood. Scrub oak is more resistant to decay than the other hardwoods. White pine and Norway pine will not decay in 50 years. The cost of removing pine stumps from 5 years to 25 years after logging is practically the same. (3) The size and number of stumps per acre: The number of white-pine stumps per acre varies from 10 to 100, with an average of about 45. Some hardwood lands have more than 400 stumps per acre. Some contractors taking work by the job count the stumps and then add 10 per cent to the number to cover those that were overlooked or burned close to the ground. It usually is more expensive to remove severely burned white-pine stumps than it is to remove a sound stump. For this reason any system of burning that will not burn the roots below plow depth does not reduce the cost of stump- ing. A pretty close approximation of the average number of stumps per acre may be obtained by counting the number of stumps on several sample acres. A circle of 117.8 feet radius contains an area of 1 acre. A rapid and convenient method is to stand on a stump and count all the stumps within 118 feet of it. (4) Soiland topography: Where stump-pulling machines are used, the cost of stump- ing in sandy soils is less than in heavier soils. Where dynamite is used, the cost in heavier soils is less than in sandy soils. On many tracts the land was swampy at the . time of the tree growth, and the rooting system was consequently shallow. After the tract shown in figure 8 was logged, fires burned off all the litter and most of the humus, leaving nearly all of the roots exposed. On many such areas a heavy team will tip out most of the stumps by a direct pull. For this reason this type of clearing is not usually expensive. (See ‘Tract No. 20,’ p. 22.) Itis more expensive to pull stumps on steep land than it ison levelland. It is more expensive to stump stony land than land free from stones, because the cleaning of the stumps is more difficult. 1 See Thompson, Harry, Cost and methods of clearing land in western Washington, U. 8. Department of Agriculture, Bureau of Plant Industry, Bulletin 239, 60 p., 25 fig., 1912, for use of power machines for land clearing. CLEARING LAND IN THE LAKE STATES. aL (5) Size of area to be cleared and proximity to other clearings: Stump-pulling machines will usually reduce the cost of clearing, but it is not economical to buy one for the clearing of a small tract. Explosives cost considerably less when bought in large quantities. In a locality where much clearing is being done it may be possible to cooperate in the purchase of stump pullers and explosives, and experienced help can be hired cheaper in such a region. Table II gives an approximate idea of the cost of clearing white- pine land in this region. Additional data of the conditions of clearing Fig. 8.—Swampy lands of the Lake region that have been burned over, showing the shallow root- F ing system. on the 16 tracts summarized in this table, as well as details of the clear- ing of several additional tracts, are given in the pages which follow. TaBLE Il.—Approximate cost of removing stumps on 16 tracts of white-pine land, com- piled from records kept during actual operations. Stumps. Cost, including labor. Aver- Pulling.! Tract. |Acres.| 0. | Ave age |Soilandsubsoil.| Method. |" A cae - - e . ber. |ameter oer “a ; Con-| Ac- | Tl.) acre. nae (inches). EG. tract.) tual. posal. IN@s escas 40 2,000) 20.2 fS0)) Spenavby 5 Soccc BE gGoOshSs||eooscallsccons $925. 20/323. 13] $0. 463 IN@; Boccae 3 297|18-36 Yoaece done Sac s Bee lO meta th Saleen meee 258.00} 86.00) .86 INGE @sc4e5 7 Bod Sosneece 48| \Clayeeeeeeeeee COO ese wis|aeceae eee 200. 00} 28. 57 . 60 No. 4....- 24, 21 290) 19.85 WAL Senaighys 5c ssc Capstan...|--.-.- 50. 259) 145.00} 5.99} .850 INGORE shee 50 1,018} 22 20) Sandy loamei2ss|2esdOs 2.2 o\aeeee- . 372! 698. 91] 13.98) - . 686 INGOs sense 1 78 18.6 Hel) Sehowhyo oo coe8 BRU OR eee seer . 144) 25.65) 25.65 - 329 INGE Gacsee 60 2,464] 24.6 Ali @ lays a Tripod..-.-.|$0.32 | .26 |1,444.00] 24.07} 3.586 Not S2e2_- 30 2,464 24 82) Sandy loam. -.}...do...... -19 | . 102) 868.00) 28.93} 3.352 INOS Weccks 30 2,000} 28 G7 See COsaneeese peted One aes .25 | .105) 710.00} 23.67) 3.355 No. 10....| 46 1,812} 28.6 39} Silt and clay..|...do....-- 280 | .32/ 115283°82| 27.91) 3.71 INOS dul Sel eeeeee aul PEG NeSeocossllocoue Coste ae ae BERG Oa eos aan - 465/1,063.87|..... - 3, 806 No. 12....| 40 2,400]...-..-- 60] Sandy.......-. PEO \aaan he -18 | .14 | 768.00) 19.20) 3.32 No. 13....| 20 1,293 23.2 Galea domes ae BEACO Sass sei loboons 500. 00) 25.00} 8. 387 No. 14....| 7.4 204) 26.77 28) Sandy loam...|...do.._..- -50 | .563) 184. 93] 25.06] .907 No. 15....| 40 3,600]...----- CO) SehaGhy. = kee Redon | Sei -25 -25 | 900.00) 22.50} 3.25 No. 16....| 35 OR scodeeds BO] s5560 do.2....... ee COm sete BoB eee ce 700. 00) 20. 00 . 666 1 The operation of “pulling” includes getting the stump out of the ground, cleaning the dirt from its roots, and leaving it where it will not settle back into the ground. 2 Clay subsoil. 3 Tracts Nos. 7 to 13 and 15 were stumped by experienced contractors, who were well equipped and employed experienced men with heavy teams accustomed to the werk. The average landowner can not safely figure on getting his stumps pulled for less than these contract prices, ¢ 12 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. TRACT NO. 1. Tract No. 1 contained 40 acres of level land. The soil to root depth varied from medium to fine sand. The blasting was done in the spring of 1913 at a time when the ground was wet. The tract was logged 32 years before. Since that time it had been burned repeat- edly, and there was no undergrowth. The tract. averaged 4 or 5 small logs per acre. Of the stumps on the tract 16 per cent were so severely burned that it was necessary to partially dig the roots out and pull them with a team. The average number of stumps per acre was 50, of which 20 per cent were Norway pine and 80 per cent were white pine. The diameter of the stumps at the cut-off varied from 6 to 30 inches, the average being 20.2 inches. The owners of this tract had recently purchased a capstan stump puller. With an inexperienced crew the cost of pulling and disposing of the stumps, as shown in Table III, was practically the same as with dynamite. Tasie II1.—Cost of labor and material in clearing an acre of tract No. 1 Cost. | Days em- ployed. Perdiem.! Total. Blasting stumps: ‘ 1 powder Mane ee eee ee 2 eee ee eee 1 $2. 00 $2. 00 Dynamite, 75 pounds atd3icents! > 215 ee eee [eae aaa ee Ses | 9.75 Caps and fOS0. 0 ee cen SER a oer leg ee 1.13 Pulling roots and piling and burning stumps: 3 men, Iiday eaehe).. . ..ot.cicseee = 3282S ee Sees ee eee eee 3 SE 5.25 A THATL With team te ores ane eee en Ce 1] 5.00 5.00 Motalicost Pewacre: _ <2 25 ase ee er elae Pe eee eee ae eee fence at eee BAIS Total cost per'stump : ---2. i-0- 22-2 2- e bee b yee abd <3) eee ee ice ee ee eee eee eee - 463 TRACT NO. 2. Three acres of pasture land having a sandy soil, containing 297 white-pine stumps 18 to 36 inches in diameter, were blasted by the use of 1,200 pounds of powder containing no nitroglycerin. This is an average of 43 cents per stump, including the cost of labor for doing the powder work. The cost of piling and burning is equal to the cost of blasting, which makes an average of 86 cents per stump and approx- imates $86 per acre. TRACT NO. 3. Seven acres containing 334 white-pine stumps upon pasture land haying a clay soil were blasted, piled, and burned at a cost of $200, an average of 60 cents per stump and $28.57 per acre. TRACT NO. 4. Tract No. 4 contained 24.21 acres of level land having a sandy- loam soil within root depth and practically no stones. The outfit used was a capstan stump puller, with 200 feet of 1-inch cable on a drum and an additional length of 150 feet of 1-inch cable, giving the CLEARING LAND IN THE LAKE STATES. machine a pulling radius of nearly 350 feet. were 15 feet of 14-inch double-power cable, 14 feet of 14-inch cable, shovels, axes, a bar, and a mattock. The pine of the tract had been logged about 30 years ago. The hardwood had been cut off seven or eight years ago, except where noted. The hardwood stumps were so rotten that they were The tract had been burned repeatedly since very easy to remove. 13 The other tools used logging. Scarcely any vegetation or sod was left to retard the There was a very scat- tering growth of poplar and bird cherry, averaging about 3 feet in work of cleaning the soil from the stumps: height on the tract. Included in the 290 stumps were 76 “snags’’— stumps that had been burned close to the ground, leaving the roots in the ground. These snags are fully as hard to remove as the average stump. The stumps were piled later in the year by means of a gin pole. ‘Details as to the kinds and sizes of the stumps and particulars relative to the cost of stumping are given in Table IV. TaBLe [V.—Stumps pulled and cost of labor and material used on tract No. 4. IXINDS AND SIZES OF STUMPS. Diameter of stumps (inches). 7 Total Kind of stumps. { | 6 | 8 | 10 | 12] 14 | 16 | 18] 20 | 22 | 24 | 26 | 28 | 30 | B41036) | ear de stumps. Number of stumps. ore | aa ~| Waltinenpinierens soso =e seas Lecoell My Mop 4 BS Gf st PWG pS) sy) es ee |) a 149 Norway pine....--.-.-.-- Bees | Seay raya ete esol WAU) at ee Honea) Ral VE SIL. | rere Age 14 Peech weer pegs 5 fee Seslgropl te ren en 22 eee ae | eet He a ie A Ss ioe 2 Bai eae 11 Menlo i| 2 3 | Fale ie dlciiale Tufte ile er cae vale Ie 16 Hemlock s.26e: 2. 222... Uy Gy wy Gy Bille a } = al 17 IR iah.,..2 aaa i pea A eee eee | 2 Seruibioales 6) bili iA omeley | 8 ik(| seh ag Os ee asa ee deal 2 a 2 IRODIAIE ee re isso. ooo ce eel esl aysyeteitt | ame etsy ellie [ce hao [ca re aI A [Ses see 23) 1 Green hard maple.._...-. Ste eel Saal epee il eeeel Beeel esheets ee eee [Bess 225 1 Green white pine....__.. Bee aes eee I Ee Es al getter ee tel feet ete Rese seelae Foe ea es ae +] 1 | Movaleay ecg 8e: 1) 8) 11) 12] 15) 11 | 9] 18/36) 18) 21) 16)14/17) 1) 6, 1214 Number of snags... .._-- pe) | este U3 Pen bea Les cafe pe ee ee UI el 76 Wataliton 2722 ACKes) te sa Peerte et |5-- S| Meal es Por tice eal real seas FU geal Del 2 290 | \ | LABOR AND MATERIAL USED IN STUMPING. 3 Cost. Days em- Item. ployed. : Perdiem.} Total. Crew: PEM ACHITMEMTTET TO MAVS\|CACh( yt snt «22: Seems Skee eee ee ae 12 $1.75 $21.00 2men to clean stumps, 6 days each 12 1.75 21. 00 Nteam and teamster:-=-)-552...:-.2.-22-4 ce 6 4.00 24. 00 WSofatemiachine/saeeu Nea snans Ula Se eS Lye ts ot ae 6 1.50 9. 00 Piling and burning (estimated)..............-...-...--: a IY Nk SO: UR ie Ce fe || SN 70. 00 ‘GME Se Roe setc CC LEBE SOp Seabee SRE EES 15 -)Soe Hee a Lene aa 3 2) De ae] be 145. 00 ANTIGIAED DST CIGHO,, ce no Ode Cobo CHE ROEE e ae onan SOE Rae RS eee tc Ems (econ ea ba a 5.99 AMGUBIES TOs? Gib ha0 ) 4S She ks eis Ee eae ae Se ee eae ae ety | De na eS ce a 50 1 Average diameter of the 214 stumps, 19.85 inches. 2 Average number of stumps per acre, 12. 3 Time of clearing, 6 days, July 28 to Aug. 4, 1913. 14 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. The average height of the pine stumps was 33 inches. The average number pulled each day was 48. The cost of pulling, cleaning, and tipping was 25.9 cents per stump. Dynamite had been used in stump- ing this land, but be- cause of the loose nature of the soil it had proved too expensive. Co ee y Sy TRI erg e, TRACT NO. 5. ) Tract No. 5 contained 50 acres of very gently rolling pasture land with sandy-loam soil and clay subsoil. The outfit consisted of a capstan stump puller, shovels, axes, and bars. The stumps were piled by the device shown in figure 9. Details of the cost of removing 1,018 stumps from this field are given in Table V. eo eee Fic. 9.—Device for piling stumps. TABLE V.—-Cost of stumping tract No. 5. Cost. Item Days £8 0 Ns HRS De ae ol) ployed. |per diem.| Total. Pulling stumps: ; MAES ereererae’s ain ays ibistarcratetcictereers Be Se aA SAO aera Saecsdes0O 45 $1. 75 $78. 75 TV aa. Pee = os cc hare eenrce ee cists 3 1,75 5,25 Timantwithiteam. ...5.. {hese Bales Vee esc . ee 45 4.50 202.50 Use ofstummqiiller..°: Seats: Fa oe ee Benes 6 cee eee 45 1.50 67.50 Dynamite, 200 pounds, at T2Ficentsay. noc ae mec eis oe nee eee te Ree ee Eee eee 25.50 Caps and fUseeetese oa. 6 secs ee cee aes es ey eee. Oe Nee ella eas gas|lboeossooen 1.41 Piling and burning stumps: 3 Meniwithtteams, 20days eachie. ss. 5. ou. 4s eeteeeere «. see eee eee 60 4.50 270.00 L MAM Iss ~ lpesietote siete ois sk oS ce eee ee ng 20 1.7. 35. 00 Use of stump piler............ Tye rss 20 7 15.00 A No) AS ae Sere ee nie: Byala: daalin.a ela S aleca Re Stel eras, 2\c\ Sree ha pmeenate opal | RPS are eae Ree ----| 698.91 Average per acre.......... SRE aS Tees G ESR iors win whole BOR aerate ce tell Neve sl eater Mae a 13.98 (2) i222] 012) f= L110 U4 0 PR ee Re Bee NS AUR EAS EO Oa I ciacotel te ee aes . 686 Average;peristump for pulling >... 23.022. kie os. = seen ane een amen ee eee eee eee eee .372 AverapepenspumMp for Piling.) . 2s. Secs l ee eke s is tee eee Pee ee eae ts | tee .314 The pulling was done in 45 days, an average of 23 per day. The average number of stumps per acre was about 20. This tract was logged 30 years ago. Tires had kept down all underbrush. All logs had been removed. The rooting system of the stumps was shallow. In burning, the stumps were placed about 50 in a pile. They were set on fire at night, and usually the following morning the unburned stumps were repiled. The sizes of 87 white-pine stumps measured CLEARING LAND IN THE LAKE STATES. 15 on this tract were as follows: 16-inch, 7; 18-inch, 12; 20-inch, 18; 22-inch, 17; 24-inch, 16; 26-inch, 10; 28-inch, 4; 30-inch, 2; 32-inch, 1. The average diameter was 22 inches and the average height 33 inches. On a neighboring tract, similar in all respects, the stumps were pulled and cleaned under contract for 40 cents each. Here three men with a hght team, using a capstan machine, pulled an average of 20 stumps a day. The man for whom the stumps were pulled under contract formerly used dynamite of 40 per cent strength and pulled the remaining roots with a team, using a block and line. He also tried heavy blocks and line. All these methods were found less satisfactory than a contract at 40 cents per stump. In piling stumps the device shown in figure 9 was used, and with the same crew an average of 50 stumps a day was piled. TRACT NO. 6. Tract No. 6 contained 1 acre of level land, having a loose, sandy soil. It was cleared in August, 1913. The outfit used was a capstan stump puller. At the time of tree growth this tract was wet; as a result the stumps were shallow rooted. The tract was logged about 35 years ago. Repeated fires since that time had burned off the litter until the roots of the stumps were well exposed, and there was prac- tically no undergrowth or logs on the tract. The sizes of 62 white- pine stumps, selected at random and measured on this tract, were as follows: 12-inch, 4; 14-inch, 8; 16-inch, 9; 18-inch, 12; 20-inch, 11; 22-inch, 9; 24-inch, 9. The average diameter was 18.6 inches and _ the average number per acre was 78. The low cost per stump of clearing this tract, as shown in Table VI, was due to the small size of the stumps and to the fact that the rooting system was very shallow. On this farm the actual cost of clearing over a hundred acres of land has been $39.30 per acre. About 50 per cent of this land is as described above. The remainder is low, wet, sandy land with cedar, tamarack, and occasional white-pine or Norway-pine stumps. The average number of stumps per acre was about 12, and their average diameter was about 10 inches. TasBLE VI.—Cost of clearing tract No. 6. Daysem- pee ployed. Perdiem.|} Total. Item. ba) Be Fe BRR cst wn oc oF See be i bo or oan oon Orb 1 1 WScroRs Gump pullenteryr ss ci” 2's Abe meee ere ee eee weet) le hy. vena e 1 Piling and burning stumps: 1 1 ou FBC. gla Oe Ma ee ae a 2c ci Sane eC Re stumps (time estimated): 2 1 tea 2 Repiling 2d TORS oe ete sc GOR ORE ECO GEE OE Sen S RE oc OU GO SeaDoo Ae ter eae -6 6 oo oo con me in) a Sk or) loo co PIN O GEV TOC Ty ETC sy apes asa eg crescent vee che pen ge ee aaltepet )eAI RE T INOUE TOPS UI CN 0). A Ae Bere idle SSCS RRO a oe Ohad HORE cette [meee eit |e gee ee 16 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. Because of the shallow rooting system and small size of the stumps, most of them could be pulled by a 2,800-pound team without the use of blocks and line. The stumps that could not be pulled by a team were split by a small charge of dynamite, and the remaining pieces were pulled out by a team. The second growth on this land consisted of poplar and bird cherry. Small logs were numerous. The various items entering into the cost of clearing were not kept sepa- rately. The superimtendent said that they were #pproximately as follows: To cut, pile, and burn brush, peracre........5...--2--- ae $10. 00 To pileiand burn logs, per acres =o Ss. 2e Ye ee ee eee 12. 00 To pull? pile, and burnstumps, peracre.. . -. 52542 eee 17. 30 Totalicost per'deres. om see eerie ne ee. : sk ee 39. 30 TRACT NO. 7. _ Tract No. 7 contained 60 acres, principally of heavy clay soil, in a few places having sandy-loam soil with a heavy clay subsoil 6 inches below the surface. The land was nearly free from stones and was gently rollimg. The outfit used was a tripod stump puller. This tract had been logged 20 years before. All the stumps were white pine. There was no undergrowth or logs. The tract had been pas- tured several years and at the time of stumping was covered with a fairly good clover sod. The sizes of 354 white-pine stumps selected at random and meas- ured on this tract were as follows: 12-inch, 2; 14-inch, 2; 16-inch, 11; 18-inch, 28; 20-inch, 37; 22-inch, 35; 24-inch, 88; 26-inch, 65; 28-inch, 42; 30-inch, 21; 32-inch, 13; 34-inch, 6; 36-inch, 4. The average diameter was 24.6inches. The average height was 36 inches. The total number of stumps pulled was 2,464, the average per day being 54. The average number per acre was about 41. Details of the cost are given in Table VII. The stumps on this tract were piled in the fall of the year and will be permitted to dry out for about two years before any attempt will be made to burn them. Tasie VII.—Cost of stumping tract No. 7. Cost. \Days em- Item. ployed. Per diem.| Total. Pulling, cleaning, and tipping stumps: 2 men, 46:daysicach: er eeeeane. -- es oio0 beet canoes oe ote ae eee eee 92 $1.75 | $161.00 2 men with team, 46 days each..............-. ninjele etepete/ ns eIaD Spee tee ee 92 4. 50 414.00 Use of miagiiie. 2 4 ee aera caps eink won oie Sinica EU Ee pees Cae 46 1.50 69. 00 Piling and burnime (estimatediaee..---- ea. -2--2222 esnetes se ctesenoeee wae [2.52 deh eos eee 800. 00 Total : } sss o> oo aa eae eee ome o> seats eric aaen's sets oleae caper ess == en | 1,444.00 AVeTALCDELACTE « «oo eee oer ~ Soins pote ee sc.ce As ees |: dt emo el een ee aes ) 24.07 AVCTALC PEDSHIM) (2c emad estes sores came en nans nee s = a2 oen eee eee | ae - 586 CLEARING LAND IN THE LAKE STATES. ANG The work of stumping this tract was difficult because of the nature of the soil and size of the stumps. It was done under contract by one of the largest stumping contractors in Michigan. All of the crew were experienced men. The contract price for pulling, cleaning, and tipping the stumps on this tract was $788, or about 32 cents per stump. The actual cost was 26 cents. The average farmer or set- tler, even though he had the equipment, probably could not do the work as cheaply as it was done by this contractor. TRACT NO. 8. Tract No. 8 contained 30 acres of nearly level land with sandy- loam soil. The outfit used was a tripod stump puller. The total number of stumps pulled was 2,464. The average number pulled per day was 137. The average number per acre was about 82. The average diameter per stump was about 24 inches. This work was done under contract at 19 cents per stump for pulling, cleaning, and tipping. The actual cost was 10.2 cents, as shown in Table VIII. The low cost of stumping was largely due to the sandy nature of the soil and the fact that the stumping crew was experienced. These stumps were to be piled and burned later in the year. TaBLe VIII.—Cost of stumping tract No. 8 Cost. ‘Days em-| Item. ployed. |Perdiem. Total. Pulling, cleaning, and tipping: PANIC TIME Say S Ca GH. eg) Jeeee 2 eee eri= fj See Peete ea a 36 $1.75 $63.00 SMHS Wii Leas, 1o; ays Caches. eee ne) sn le eres ee ae 36 4.50 162. 00 WISCTOMMACHING went ssae = = a0 Tey les re te SE LP ee Oe Ee 18 1.50 27.00 evlnresan adap unrnineas(CS timated) 22). 5- sees aio = 1 ae eae eee = = [Ee syays sees |e en acme | | 616.00 BIRO bet epee Pooh ee Shove ays ee Anos aa( etre ele ais y= Sen See eerie)! wane | mas te Le a eee Sia 868. 00 PAV era Ce Peace ss ele ese oy). 2. Ao aes - 2S oe eens SY eee eR ee 2 2 has foeietseuna 8 28. 93 ANU ZIBGD [OSE HON o pees cob ee aeeeeeo > acecsues shen a= pnosone sees anes weomeouees ie eee - 302 1 Tract stumped in thefall of 1912. TRACT NO. 9. Tract No. 9 contained 30 acres of nearly level land with sandy-loam soil. The outfit used was a tripod stump puller. The total number of stumps pulled was 2,000. The average number pulled per day was 134. The average number per acre was about’ 67. The average diameter per stump was about 28 inches. This work was done under contract at 25 cents per stump for pulling, cleaning, and tipping. The actual cost was 10.5 cents, as shown in Table IX. 18 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. TaBLE IX.—Cost of stumping tract No. 9.! Cost. Days em- Item. ployed. Per diem. Total. Pulling, cleaning, and tipping: Bonen: Wotdaynionch ers ket asso: sss ca 5c see ics ads > ee 2 men with teams, 15 days each... Wsevol machinesee. cls seeiee Piling and burning (estimated) Motal 2 ecpebisecte sn ccc-ese secede See sabes tee Siecle cme cies ck sae eee eee } I AV ELAS OMICWACTO 2 85.2 2sSe 2 = cela nine Ane nice ae ie nee ees eee eee | smiesisiniersiallls = etme eles | 23. 67 . 300 Ay Geeks) | O12) 8 UCL Nee o nem SBS odeS ose saa soso sb eaceadedesocnoceeoosa tomoceencallecscenme ss | 1 Tract stumped in the summer of 1913. The low cost of stumping was largely due to the sandy nature of the soil and the fact that the stumping crew was experienced. This work was done by the same contractor who stumped tracts Nos. 7 and 8. The stumps were piled and burned later in the year. TRACT NO. 10. Tract No. 10 contained 46 acres of nearly level silt-loam to clay- loam soil. In places the tract was very stony; round cobblestones predominated. The outfit used was a tripod stump puller. This tract had been logged 30 years before. The second growth and logs had been previously removed. The sizes of 114 white-pine stumps selected at random and meas- ured on this tract were as follows: 12-inch, 1; 18-inch, 2; 20-inch, 8; 22-inch, 7; 24-inch, 22; 26-inch, 9; 28-inch, 10; 30-inch, 12; 32-inch, 17; 34-inch, 9; 36-inch, 10; 38-inch, 1; 40-inch, 3; 42-inch, 1; 44-inch, 1; 48-inch, 1. The average diameter was 28.6 inches and the average height 36 inches. The total number of stumps pulled was 1,812. The average number pulled per day was 48. The average number per acre was 39. This work was done under contract at 35 cents per stump for pulling and cleaning. The actual cost of pulling and clean- ing was 32 cents per stump, as shown in Table X. TABLE X.—Cost of stumping tract No. 10.' Cost. Days em- r Item. ployed. | Perdiem.} Total. Pulling and cleaning stumps: 2 Men; Siaaye CACM eee meer: a2 )3- Meese sine Spee cee = aca eeeeae 754 $1.75 $132. 12 I’ man withiteam: tasae eee. 5 eB. Oe ce ee. See | 374 4.50 169. 88 1 TUG PR ALOTROS ee eree te oc x2 ase in, asic stare’, 9 elute Btwn 2)< oe oie eee 374 5. 85 220. 84 Use of machine: . op csp oeee... hee: 5230 eee e See aoe eee 373 1.50 56. 62 Tipping stumps (estimated/ats cents each)... 25. nec ee oe ne ace oe re eee ele oe eee cee 54. 36 Piling and burninp (estimated ees... eo... ose seca) coro es aoe ee nee eee eS es 650. 00 DOUA SS oe sae eis: oes ioe Ee soem wes Sie bo cide efor iain wake c= asia see ee ete et eee | pe see 1, 283. 82 JAVOTA PO PON BCLO. 25 esse sie en mw nseinislane cee eee «lea ai s)< = Se Ee «/6l6| 9) 27.91 PX pe he) [Of] U I pe S-sacep C DE DEAT DOS DED DDOGUPUBOBE DS oJ500d0c% sercaccatosmcd ao sce aif! 1 Tract stumped from June 27 to Aug. 12, 1913, CLEARING LAND IN THE LAKE STATES. 19 The work was done by an extensive stumping contractor. The stony ground made digging holes under the roots and cleaning the stumps expensive. The large size of the stumps made their removal costly. The stumps were to be piled later in the year by the use of a log jammer. TRACT NO. 11. The operation on tract No. 11 consisted of pulling 1,319 large white- pine and scattering hardwood stumps on silt-loam to clay-loam soil. In places this tract was very stony. The outfit was a tripod stump puller, the same as that used for tract No. 10, which was adjacent. It had been logged 30 years before. All the second growth and logs had been removed. The average size of the stumps was slightly larger than those on tract No. 10. The average number of stumps pulled per day was 37, and the cost was as shown in Table XI. TaBLE XI.—Cost of stumping tract No. 11.! Cost. Days em- Item. | ployed. Perdiem.| Total. Pulling and Gleamins stumps: Ohne so O ays CACM AS ie ob Ja. Sb a ceteleeSte ta hakeinwsie mene tee ae eee TA. 2, $1.75 | $124.50 [man with etme 35. 6 4.50 160. 20 praia Luly wh OLSCS|eyeyyarery- ioe te wie ool nicysyetacemisie emis jars Sais rote aeiastee ters | 35. 6 5. 85 208. 26 US Oli SEAN) OWE os tan sees aes oH ee ste see de seesoeosscodaecuse 35.6 1.50 53. 40 Dynamite “ per cent strength), 500 pounds, at 13 cents...:.....-...-|..2----.-.|..--.---.- | 65. 00 (CeigS BING! WSO so occ cass onssocpsHoseessosssascsnas cess aoomesdeccoeDesaa|>sassucbeq|aoccoucass 2.51 Piling and Warning (eStimM ated) ess = ae oe ee ean) ce eee | Oe aE BE Marais secs 450. 00 SNH 5 5 = SRN NS eg Aa eae eae ene re eye Ue UE papel ee | 1,063. 87 Average per stump. .-.-.-----.--- Sedosocssbcassocvesescqusecseceesselloaccsscosalocsocnseos . 806 | 1 Time of stumping, Aug. 12 to Sept. 26, 1913. A small charge of dynamite was placed under the larger stumps in order to split and loosen them. In commenting on the use of dyna- mite here, the contractor said: ‘‘This is the only job in my seven years of stumping where it would pay to use dynamite under nearly every stump.” The owner of this tract had previously used dynamite in stumping on his land. TRACT NO. 12. _ Tract No. 12 contamed 40 acres of nearly level land with sandy- loam soil. The outfit was the same as for tract No. 11. The total number of stumps pulled was 2,400. The total number of stumps per acre was 60. The average number of stumps pulled per day was 100. The stumps averaged somewhat smaller than in the two pre- ceding tracts, and the soil was sandy loam and free from stones. This work was done at a contract price of 18 cents per stump for pullmg, cleaning, and tipping. The actual cost was 14 cents per stump, as shown in Table XII. 20 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. TaBLE XII.—Cost of stumping tract No. 12.! Cost. Days em- Ttem. ployed. Perdiem.| Total. Pulling, cleaning, and tipping stumps: PMO) PAHOA CACM ICE osc cee se ons whe 5 ee acorns © ~S eae See 48 $1.75 384. 00 2 Men WHthitieamMsS, 24 GaAySeaCD on 2. oo jn sere 4 2 ace a 3 Ree 48 4.50 216. 00 Use:ofmachine! 21.2. sos241 5. 224. in be 9. SE ee 24 1.50 36. 00 Pilingvand burning (estimated): =. 2 oi... 2 cin) are = ooo «0a hee esi ee 432. 00 Dotal secon oe icane-d epg sex steeper sabes ee 768.00 AV OLAR ATCT ACLO=- 20 22: daca ea eee ea oc ee |e ee re 19. 20 BESS ET) NOS LT 32 1 Stumped in the spring of 1913. TRACT NO. 13. Tract No. 13 contained 20 acres of practically level pasture land having a sandy, and in places a gravelly, surface soil. The subsoil was generally below root depth. This land had been logged 25 years before. There were no logs or underbrush. The outfit used was a tri- pod stump puller. Stumps to the number of 1,293 were pulled, piled, and burned at a contract price of $500, or 38.7 centsperstump. By means of the tripod Fic. 10.—Tripod stump piler (at left) and tripod stump puller (at piler shown in figure right). 10 all these stumps were put into four piles. The stumps were pulled in November, 1912. The sizes of 98 white-pine stumps selected at random and meas- ured on this tract were as follows: 12-inch, 6; 14-inch, 8; 16-inch, 8; 18-inch, 5; 20-inch, 10; 22-inch, 16; 24-inch, 16; 26-inch, 11; 28-inch, 5; 30-inch, 8; 32-inch, 2; 34-inch, 1; 38-inch, 2. The average diameter was 23.2 inches. Several other owners in this neighborhood had contracted to have stumps pulled, cleaned, and tipped for 25 cents each. The general clearing conditions on these contracts were the same as for tract No. 10. TRACT NO. 14. Tract No. 14 contained 7.4 acres of very gently rolling pasture land, having a loose, sandy-loam soil. The outfit used was a tripod CLEARING LAND IN THE LAKE STATES. Pah machine mounted on two wheels. This tract had been logged 45 years before. There were no logs or underbrush. The sizes of 98 white-pine stumps selected at random and meas- ured on this tract were as follows: 16-inch, 7; 18-inch, 10; 20-inch, 3; 22-inch, 9; 24-inch, 15; 26-inch, 14; Oeil 8; 30-inch, 6; 32- inch, 7; 34-inch, 4; 36-inch, 6; 38-inch, 3; 40-inch, 1; 42-inch, 4 48-inch, 1. The average diameter was 26.77 inches. The high cost of stumping this tract, shown in Table XIII, was principally due to the inexperience of the contractor and crew and to the fact that only one light team was used. The contract price for pulling, cleaning, and tipping the stumps was 50 cents each. The actual cost was 56.3 cents. The owner of the tract was utilizing the roots for fuel. The total number of stumps was 204 and the number per acre 28. The number pulled per day was 15. P) TaBLe XII1.—Cost of stumping tract No. 14.1 Cost. Days em- sly Item. ployed. Perdiem.| Total. Pulls, Sees and tipping: at aye i ere aN aitelmin = bisjatajniSieiciewie sens eS cian eisai eee 134 $1. 00 $13. 25 i es Ree ek on SRE cee rae Te MM Lol! 4 oh ee UMN 8 Sy ON OE am 3 Se 134 iis 22.19 IBITFATIRWAL Mt e abe youre eres =~ kamera (area ck Ee alls o ars apenas 134 4.50 59. 62 Wiseko minachine Mae yy eyes eens 0.22 ete po SEB Sa Ue Sin bree Sel | 134 1.50 19. 87 Pailin evade burning (estimaved)) 2 =. - ces seen = lesa Sense gen be looansobees 70. 00 ANON = cede 5 Wiese eevee lia at She ee Uh SS Ral Pi eA aN ya | re gehenerercets 184. 93 ANY CTRIR® [DOP OWE 256 apace cosas eee eter ses yssc55oeossecede saadeanos (son Fs5cgna(pseeossacc 25. 05 AN CTACeHPEL SUMP se neaee osteo ee ese Sen eee ney se caee [Se oSeeRNe | 2s eres oe . 90 1 Time of stumping, July 19 to Aug. 8, 1913. TRACT NO. 15. Tract No. 15 contained 40 acres of very gently rolling land, having a sandy soil. The clearing was done in the spring of 1912. The outfit consisted of a tripod stump puller, two teams, and five men. This outfit and crew pulled 2,132 stumps in 204 days, an average of 104 stumps per day. This tract had:an average of 90 stumps per acre, of which 20 were Norway pine and 70 were white pine. The clearing was done at a contract price of $30 an acre. The price included the delivery of the Norway-pine stumps to a turpentine plant 3 miles distant from the tract, the hauling of nearly one-third of the white-pine stumps to build fences, and the burning of the re- | mainder of the white-pine stumps. The Norway-pine stumps had been burned to the surface of the ground on nearly 10 acres of this tract. A total of 60 cords of Norway-pine stumps was delivered at the plant. The price received was $5 per cord of 4,000 pounds. It took an average of 10 Norway-pine stumps to the cord. Two cords of stumps per acre were obtained. After deducting the amount received for the stumps, the net cost of clearing the tract was $900, 29 BULLETIN 91, U. S. DEPARTMENT OF AGRICULTURE. or $22.50 per acre. The contractor still considers $30 a fair price, but owing to circumstances and bad weather wages were not made upon this work. In another case in this neighborhood the owner of 640 acres of land gave all the Norway-pine stumps on it for the clearing of 15 acres ready for the plow. TRACT NO. 16. On a tract of 35 acres of nearly level land, having a sandy-loam surface soil and a clay subsoil, which had been logged 30 years before, 1,050 white-pine stumps, averaging 26 inches in diameter, were pulled with a tripod machine at a contract price of 334 cents per stump for pulling, cleaning, and tipping. TRACT NO. i7. On another tract of 105 acres of nearly level land, having a sandy- loam surface soil and a clay subsoil averaging 18 inches below the surface, which had been logged 25 to 40 vears before, 7,000 white-pine stumps, averaging 22 inches in diameter, were pulled with a tripod machine at a contract price of 25 cents per stump for pulling, cleaning, and tipping. These stumps were hauled into fence rows for 18 cents per stump, contract price. TRACT NO. 18. On a tract of 10 acres of gently rolling land having a sandy and gravelly loam surface soil and in places a clay subsoil, which had been logged 25 years before, 600 white-pine stumps, averaging 18 inches in diameter, were pulled with a tripod machine at a contract price of 30 cents each for pulling, cleaning, and tipping. >) TRACT NO. 19. On an adjoining tract of 16 acres, with soil the same as in tract No. 18, and using the same outfit, 330 stumps were pulled, cleaned, and tipped for 30 cents each. _ The contractor took both jobs at a flat rate of 30 cents per stump. TRACT NO. 20. Tract No. 20 contained 18 acres of cedar-swamp land that had been very severely burned in 1908 and 1911. The soil varied from a clay loam to a heavy clay. Practically all the roots had been burned off. The stumps rested on top of the ground. One horse could easily pull nearly every stump on this tract. The few stumps that were too firmly rooted to be pulled by a horse were loosened by the use of dynamite. The number of trees and stumps per acre on adjoining similar tracts was about 300. The stumping and part of the piling was done from July 15 to October 1,1912. The remainder of the piling and all of the burning was done after April 12, 1913. The work of clearing was thorough. The details of cost are shown in Table XTV. i a CLEARING LAND IN THE LAKE STATES. 28 TaBLe XIV.—Cost of labor and material used in clearing tract No. 20. Cost. Days em- Ttem. ployed. Per diem. Total. Stumping and piling: feaIMyASH AM OLEAN ATIVeRss3 ao e celts eee thee aes ene eek Ona one 60 $1. 75 $105. 00 eMmenas a goren and pOwGer mean 2) vere ee ese | ee ee ee 60 errs 105. 00 LO USE een Rea ee Pe ene cece A epee: CAMS) oe ee Ser 60 iy) 75.00 HO Ca OLACOSTEE® = SEE ie oye Seen ee Ne ee Bey TE EC Pe es eat See St eee 285. 00 Dynamite 40 per cent Strength), 50, pounds, at 20 cents.2........-...-|/...4...--|...-.2...- 10. 00 pHuseyandicapst 2)... S25. ..2.-1/.-5 SAE Ly Oe hs Ap ede AA ee eee |e ee ae ee eee Pa ; 73 Burning stumps and completing clearing: BENT Te ee eS vss ea cian cele day micta) 4 pe LAE eRe K eS Dae eae ad, MERI ose 18 1.75 31.50 UL TTC TT Typat ion aka cE ATS oi Poe SR ATA Serer ee eae eS Si oe ae Ses 18 4,25 76.50 ATO Let asi ch etree eee aes EM Rac R nee REM AEE is BN ee. eran ER as 2 | esas 5 ees 403.75 PAS ETAL CICOS UND Cie CLO esta nie fees). eer als Meee nt totes ae male, CR eRe So) Ae Tse | 22. 43 ‘This swamp clearing is typical of the cost of clearing much of the severely burned swamp land of Cheboygan and Presque Isle Coun- ties, Mich. DISPOSAL OF STUMPS AFTER PULLING. Where medium-sized stumps have been well blasted the problem of stump disposal is relatively simple. It is considered cheaper to start several small, conveniently located fires in the holes made by blastmg the stumps and then haul the remaining pieces to these fires than it is to build a few large piles and not set them on fire until all the stumps are piled. Where the stumps have been pulled by a stump puller without the use of powder the problem of disposal is more difficult. The general opimion throughout this region is that the cost of disposal practically equals the expense of pullmg. All data secured seem to verify the accuracy of this estimate. In the early days of clearing, the stumps were hauled mto rows to serve as fences. At the present time very few such fences are bemg built. The usual contract price for hauling stumps into fences is 15 to 18 cents each. PILING STUMPS. Large stumps are very hard to pile. Some owners split the stumps | by the use of a small charge of dynamite placed either in a hole bored into the base of the stump or in a notch chopped between two promi- nent roots. Often the heart of the stump is sufficiently decayed so that the charge may be placed mit. A smali quantity of dynamite used in this manner will usually split the stump as well as a much larger charge would have done before the stump was pulled. By using a tripod, such as is shown in figure 10, with legs 40 or 45 feet long and equipped with a double block and 150 feet of half- inch cable, the stumps can be piled 25 or 30 feet high. This tripod was used on tract No. 13. Another good method of piling is to use 24 BULLETIN 91, U. 8. DEPARTMENT OF AGRICULTURE. a piler with a swinging boom, as shown in figure 9. The mast of this piler is 30 feet high and the swingmg boom 25 feet long. In using this boom piler the mast is set so that it leans slightly toward the pue. This causes the boom to swing to the center each time. This piler was used in clearing tract No. 5. Dropping stumps into a fire by means of piling devices is impracticable, because the heat soon becomes so intense that the pilmg operations must be abandoned. The work of piling stumps could be hastened materially if some satisfactory tripping device could be used. The usual self-tripping tongs and rope trips frequently catch on projecting roots and drop the load before it is at the desired position. OTHER WAYS OF DISPOSING OF STUMPS. In the past a considerable number of Norway-pime stumps have been used by turpentine manufacturers for distillation. The present low price of turpentine and naval stores has made the distillation of Norway-pine stumps unprofitable, and none of the turpentine plants are now in operation. ‘The white-pine stump contaims too small a quantity of the properties of the Norway-pine stump to make it of any value. SUMMARY AND SUGGESTIONS. There are approximately 11,954,628 acres of logged-off land in Michigan, 10,792,100 acres in Wisconsin, and 11,768,000 acres in Minnesota. A large part of this area will make good agricultural land if cleared and properly managed. In many localities poor methods make the clearing of this land unprofitable. Cutting and burning the second growth pasturing for several years, and keepmg down all sprout growth is the most economical method of handling all logged-off lands before stumping them. Explosives play an impor- tant part in clearing land. On the heavier soils dynamite, with 20 to 30 per cent of nitroglycerin or its equivalent, is to be preferred. Cooperative buying in large quantities is recommended. Stump pullers reduce the cost of stumping on lighter soils. On the heavier soils the difference between the cost of clearmg by explosives and by the use of stump pullers is very slight. The cost of clearing the better grade of white-pine logged-off land will average $10 per acre for disposing of the brush and $25 to $30 per acre for disposing of the stumps, making the cost of clearing $35 to $40 per acre. Some green hardwood lands and unburned swamp lands will cost as much as $100 per acre. Some of the poorer jack- pine lands can be cleared for $5 per acre or less.'_ The cost of dispos- ing of the stumps after pulling practically equals the cost of pulling. | Those contemplating farming the jack-pine lands are urged to study Smith, C. Beaman, Clover farming on the sandy jack-pine lands of the North, U. S. Department of Agriculture, Farmers’ Bulletin 3238, 24 p., 1 fig., 1908. CLEARING LAND IN THE LAKE STATES. Pays, A tripod or a boom piler is recommended to facilitate piling and burning. The settler with little capital and without experience who expects to make a farm out of a tract of logged-off land will find his problem a most trying one. The experiences of those who have attempted it . are not encouraging. The man who starts farming with even 10 acres of his farm cleared will be much more likely to succeed than the man, who begins on a tract covered with second growth and stumps. The former will have land on which to grow hay and other crops the first year. He can devote his extra time the first three or four years to the disposal of the second growth on the remainder of his tract. By seeding this, he will increase the area of his pasture or hay land materially and will be employing the best preparatory means of reducing the cost of stumping later. The settler should not forget that the cheapest and best land clearing is always done by experienced men with proper equipment. For these reasons it is recommended that, in all localities where land companies are selling lands to settlers, no tract of land be sold unless it contains at least 10 acres of land cleared ready for the plow. ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 5 CENTS PER COPY V WASHINGTON : SOVERNMENT PRINTING OFFICE: 1914 et Ut Lert sother} sah ast © PWarcts ; oa awe : Sonliny’ Tig i : a v BULLETIN OF THE ) USDEPARTMENT OF AGRICULTURE No. 92 Contribution from the Bureau of Entomology, L. O. Howard, Chief. May 15, 1914. DESTRUCTION OF GERMS OF INFECTIOUS BEE DISEASES BY HEATING. By G. F. Wuirte, M. D., Ph. D., Expert, Engaged in the Investigation ef Bee Diseases. INTRODUCTION. To reduce the losses due to bee diseases beekeepers have often employed heat in one form or another. The direct flame has been used in scorching or burning the inside of hives that have housed infected colonies. Before being fed back to bees honey is often heated for the purpose of destroying the germs of bee diseases, should any be present. Heat is used in the rendering of wax and in the mak- ing of comb foundation. It is natural and very appropriate, there- fore, that beekeepers should inquire about the amount of heating that is necessary to destroy the germs that produce diseases among bees. : As no work had been done to determine the facts relative to this question with any degree of accuracy, the writer has performed during the last two years a number of experiments for the purpose of ascer- taining them. Of these experiments 55 are summarized in the three tables included in this paper. It may be of interest to beekeepers to know in a general way how these experiments were made. A brief description of the methods used will serve also to make the tables more readily understood. An aqueous suspension of larve sick or dead of the disease is made and placed in a small glass tube. This tube is immersed in water of the temperature desired in the heating. After the germ-containing material is heated in this way it must be tested to determine whether or not the germs have been destroyed. In the case of American foul brood this can be done by inoculating a suitable artificial medium with the heated material and observing the presence or absence of growth of Bacillus larve, the germ of this dis- ease. As there is no artificial medium now known suitable for culti- vating the infecting agent of either European, foul brood, sacbrood, Nore.—This paper is of interest to beekeepers in all parts of the United States; it was read before the New York State Beekeepers’ Association, February 10, 1914, at Ithaca, N. Y. 35960°—14 2 BULLETIN 92, U..S.. DEPARTMENT OF AGRICULTURE. or Nosema disease, healthy colonies of bees must be inoculated in making the test in case of these diseases. This is done by feeding the bees the heated germ-containing material in sirup. If the disease is produced by this feeding, naturally the infecting agent has not been destroyed by the heating; but if the disease is not produced, it vir- tually has been destroyed by it. By repeated experiments of this kind in which the temperature used in the heating is varied, the minimum temperature at which any virus is killed can be determined. As will be seen from the tables, 13 experiments for European foul brood, 22 for sacbrood, and 20 for Nosema disease were made in which healthy colonies were inoculated with heated germ-containing material from these three diseases, respectively. In the last disease the stomachs from diseased bees furnished the germ-containing material for heating and feeding. In these experiments the ere 2 a was maintained for 10 minutes as a rule. DISEASES OF THE BROOD OF BEES. Nearly a century and a half ago the name “‘foul brood”’ was used for a destructive brood disorder of bees, and for almost a century later it was apparently the custom to diagnose as foul brood any destructive disease of the brood. About half a century ago bee- keepers began to note that all of the brood diseases are not the same. They began, therefore, to write of different forms of foul brood. At the present time it is known that there are at least three infectious diseases of the brood of bees. All of these diseases are more or less destructive, and it is quite likely that each of them has now and then been diagnosed as foul brood. In America these brood diseases are now known as European foul brood, American foul brood, and sac- brood. EUROPEAN FOUL BROOD. In European foul brood death occurs early, the larve dying usually before the time for cell capping. There is no viscidity (ropiness) to the decaying larve as a rule, and no pronounced odor present. Numerous samples of this disease have been examined from the United States, and some from Canada. Its presence also in England, Germany, Switzerland, and Denmark is strongly suggested by written reports from these countries. It is very probable that the disease has a much wider geographical distribution than these facts indicate. Two years ago the fact was demonstrated that the germ causing European foul brood is the microorganism to which the name Bacillus - pluton is given. In a paper? announcing the fact it was stated that the studies then made indicated that the germ is easily killed by heat. This belief has been confirmed by further experiments. 1 White, G. F.,1912. The Cause of European Foul Brood. U.S. Dept. Agriculture, Bureau of Ento- mology, Cir. No. 157. DESTRUCTION OF GERMS OF BEE (DISEASES BY HEATING. 3 Table I gives a brief summary of 13 inoculation experiments per- formed for the purpose of determining approximately the amount of heating necessary to destroy the germ of European foul brood. TaBie I.—A summary of the experiments made to determine approximately the minimum amount of heating necessary to destroy the germ causing European foul brood. ° Dee Oca eee es heteae Results of inoculation. EOE Min Sept. 12, 1912 75 to 80 10 | No disease preduced. Dorie cs 65 to 70 10 Do. Sept. 23, 1912 64 to 66 10 Do. Oct. 12,1912 64 to 65 10 Do. Oct. 1,1912 62 to 63 ; ee Do. Oct. 8, 1912 G2j00iG3 |b seen Do. Oct. 10,1912 62 to 63 10 | Disease produced. Oct. 4,1912 61 to 62 10 Do. Aug. 8, 1913 60 20 Do. Sept. 3,1912 60 10 Do. Sept. 20, 1912 58 to 60 10 Do. Sept. 28, 1912 57 to 60 20 Do. Sept. 20, 1912 55 to 56 10 Do. It will be observed by an inspection of Table I that European foul brood was produced in every instance where healthy colonies were fed disease material which had been heated for 10 minutes at tempera- tures below 63° C. (145.4° F.), but that no disease was produced when temperatures higher than 63° C. (145.4° F.) were used for the same length of time. The minimum temperature that can be used, there- fore, in destroying the germ of European foul brocd, if it is applied for 10 minutes, lies somewhere between 60° C. (140° F.) and 65° C. (149° F.), being near 63° C. (145.4° F.). AMERICAN FOUL BROOD. American foul brood is the disease of the brood of bees that is best known to beekeepers and is the one the presence of which they have been able to recognize most easily. In this disease the larve usually die after the cells containing them are capped. The disease is charac- terized especially by the marked viscidity (ropiness) manifested by the decaying larve that are dead of the disease. The pronounced odor noticeable within hives housing colonies affected by this disease, espe- cially in its later stages, is another well-known characteristic. This disease is very widely distributed geographically. Samples of it have been received from many localities in the United States, from Switzerland, New Zealand, Germany, England, and France, and it is very probable that it has a much wider geographical distribution even than is indicated by these facts. Until seven years ago the cause* of American foul brood was not known. At that time the fact was demonstrated positively that the 1 White, G. F., 1907. The Cause of American Foul Breod. U.S. Dept.of Agriculture, Bureau of Ento- mology, Cir. No.94. 4 BULLETIN 92, U. S. DEPARTMENT OF AGRICULTURE. germ causing the disease is the one to which the name Bacillus larve is given. The facts obtained to date are too meager to justify anything more than a general statement regarding the minimum amount of heating that can be employed in rendering material containing the germ of American foul brood noninfectious. Taking rather wide limits, it may safely be said that the minimum temperature at which this can be done, if the temperature is applied for 10 minutes, lies somewhere between 90° C. (194° F.) and 100° C. (212° F.). Itseems quite probable, indeed, that a temperature less than 98° C. (208.4° F.) will suffice if applied for 10 minutes. When 100° C. was used the spores of Bacillus larve were killed in less than five minutes. SACBROOD. Observant beekeepers have for many years noted the presence of dead brood which seemed to them to be different from that dead of foul brood. Some were inclined to believe that the disease was an infectious one; a larger number apparently were disposed to ascribe the trouble to such causes as an unsatisfactory queen, starva- tion, and thelike. This brood disease has been recently demonstrated to be an infectious one, and the name ‘“‘sacbrood”’ has been given to it. Larve that die of this disease do so almost invariably after the time of cell capping. The most characteristic symptom of the disease is the saclike appearance of the dead larve when they are removed from the cell. This fact suggested the name “‘sacbrood”’ for the disease. Sacbrood is frequently met with. Its presence has been diagnosed by Dr. A. H. McCray and the writer in 367 samples received from 44 States of the Union and in 13 samples received from Canada. Reports from England, Switzerland, and Australia indicate strongly that this disease exists in these countries also. It is very probable that it has a much wider geographical distribution than is shown by these facts. More than a year ago it was again the writer’s fortune to determine the cause of another brood disease. Unlike the cause of either European foul brood or American foul brood, the infecting agent causing sacbrood has not yet been seen. It was demonstrated, however, that the infecting agent in this disease passes through the pores of earthenware filters. For this reason the cause of sacbrood is spoken of as a filterable virus. In a paper’ announcing the cause of sacbrood the statement is made that the germ causing the disease is destroyed by a com- paratively small amount of heat. This belief is confirmed by the results of the experiments summarized in Table II. 1 White, G. F., 1913. Sacbrood,a Disease of Bees. U.S. Dept. of Agriculture, Bureau of Entomology, Cir. No. 169. DESTRUCTION OF GERMS OF BEE DISEASES BY HEATING. 5 Taste II.—A summary of the experiments made to determine approximately the minimum amount of heating necessary to render sacbrood material noninfectious. D Be Onc Temperature. Rae Results of inoculation. GE Minutes. July 27,1912 95 to 100 2 | No disease produced. Aug. 8,1912 95 to 100 2 Do. Aug. 29,1912 75 to 80 10 Do. Sept. 5,1912 65 to 70 20 Do. Sept. 3,1912 55 to 60 20 Do. Aug. 26,1913 80 15 Do. Do. 75 15 Do Do 70 15 Do Do 65 15 Do te) 65 15 Do Sept. 2,1913 65 15 Do Sept. 3,1913 60 20 Do Sept. 9, 1913 60 15 Do Sept. 10, 1913 60 15 Do Sept. 17, 1913 60 10 Do Sept. 10, 1913 58 10 Do. Sept. 17, 1913 58 10 Do. Sept. 18, 1913 57 10 | Sacbrood produced. Sept. 9,1913 55 20 Do. Sept. 10, 1913 53 10 Do. Sept. 17, 1913 55 10 Do. Aug 6,1913 50 30 Do From Table IT it will be observed that when larve dead of sacbrood were heated 10 minutes at a temperature of 57° C. (134.6° F.) or less and then fed to a healthy colony, sacbrood was produced; if, on the other hand, the dead larve used in making the feeding were heated to 58° C. (136.4° F.) or higher, the disease was not produced. The conclusion to be drawn from these experiments is that the minimum temperature, when maintained for 10 minutes, at which the infecting agent causing sacbrood is destroyed lies somewhere between 55° C. (131° F.) and 60° C. (140° F.), being near 58° C. (136.4° F.). DISEASES OF ADULT BEES. Very little is known about the diseases of adult bees. Many names have been used for the purpose of designating them, but the number of such diseases is probably small. There is only one adult disease that can be diagnosed at present by laboratory methods. This one is the Nosema disease. NOSEMA DISEASE. Fifty-seven years ago Dr. Dénhoff made a more or less brief study of a disease of adult beesin Germany. He observed that the stomach was the organ that was primarily affected. By feeding to healthy colonies in sirup the crushed stomachs from affected bees Dénhoff demonstrated that the disease could be transmitted to healthy colo- nies. It was therefore infectious. The work by Dénhoff had been practically forgotten, apparently, when Zander,' of Erlangen, Germany, five years ago observed the 1 Zander, E., Aug., 1909. Tierische Parasiten als Krankheitserreger bei der Biene. Miinchener Bienen- zeitung. 6 BULLETIN 92, U. S. DEPARTMENT OF AGRICULTURE. presence of a disease among adult bees. From the evidence at hand it seems most probable that the disorder encountered by Dénhoff and the one encountered by Zander are one and the same disease. Aside from rediscovering the disease Zander has identified the germ causing it as a protozoan (a one-celled animal parasite) and has given to it the name Nosema apis. For the disease he has used the name ‘‘Nosema Seuche.” This is an appropriate one, as it suggests some- what the nature of the disease. The name ‘‘ Nosema disease,’ which the writer suggests as the common name for this disease, is, it will be observed, only a translation of the German name used by Zander. The germ Nosema apis gains entrance to the body of the bee by way of the alimentary canal. In the walls of the stomach the growth and multiplication of the parasite take place to an enormous extent, causing the abnormal appearance manifested by the organ. When the disease reaches an advanced stage the stomach is white and fragile and reveals upon a microscopic examination the presence of the para- site in very large numbers. In:the spring of the year, especially, many weak colonies show upon examination a high percentage of Nosema-infected bees. Quite often, indeed, in the examinations that have been made of such colonies, 50 to 90 per cent of the bees in sam- ples taken from them were found to be infected with the parasite. It is an interesting and important fact that a very large number of colonies which are strong and apparently doing well are found upon examination to contain at least a small percentage of Nosema-infected bees. Nosema apis has a very wide geographic distribution. It has al- ready been encountered in Germany by a number of investigators; it has been found in Australia, Switzerland, and England. The writer has found it in samples of bees received from 27 different States in the United States and in two samples of adult bees from Canada. From the facts gathered it would seem that many of the cases called ‘‘spring dwindling”’ by the beekeepers are caused, in part at least, by Nosema apis. This statement is not by any means to be interpreted as saying that Nosema disease and spring dwindling are always the same. It has been demonstrated experimentally that colonies can be weakened and killed by feeding to them material containing Nosema apis. For this and other reasons it seems certain that the disease causes a loss to apiaries, but, for want of sufficient data, the extent of such loss can not now be estimated at all definitely. From the facts at hand one is justified in at least drawing the conclusion that Nosema infection in a colony tends to weaken the colony. Nosema apis is therefore a germ in which the beekeeper is economically interested. DESTRUCTION OF GERMS OF BEE DISEASES BY HEATING. 5 For the purpose of determining approximately the minimum amount of heating that is sufficient to destroy the germ Nosema apis the inoc- ulation experiments summarized in Table II] were made. TABLE III.—Summary of experiments in which the germ, Nosema apis, was heated and fed to healthy colonies. pi Tempera- A ee eeun ocu-| ture used eee Results of inoculation. . in heating. 8 a. Minutes. Oct. 29,1912 95 to 100 5 | No Nosema infection produced. Noy. 12, 1912 95 to 100 5 Do. Oct. 29, 1912 80 20 Do. Nov. 9, 1912 80 10 Do. Nov. 11, 1912 68 to 70 10 Do. 1D Ys eNeeare 68 to 70 10 Do. Nov. 12,1912 65 20 Do. Jan. 8,1913 65 10 Do. Nov. 11, 1912 60 10 Do Depts 60 10 Do. Nov. 20, 1912 60 10 ‘Do. Feb. 8, 1913 58 10 Do. Oct. 4, 1913 58 10 Do. Feb. 8, 1913 57 to 58 15 Do. Oct. 15, 1913 57 10 Do. e Do. 57 10 Do. Oct. 4,1913 56 10 | Nosema infection produced. Oct. 15,1913 56 10 Do. Jan. -8, 1913 55 20 Do. Jan. 31,1913 55 10 Do. It will be observed from Table III that when Nosema apis was heated to 57° C. (134.6° F.) or higher for 10 minutes and fed to healthy bees no infection took place, but when held at tempera- tures below 57° C. (134.6° F.) for the same period of time the bees became Nosema infected. It is shown, therefore, that the minimum temperature that will destroy the germ Nosema apis in 10 minutes lies somewhere between 55° C. (131° F.) and 60° C. (140° F.), being quite near 57° C, (134.6° F.). By way of parenthesis it might be well to say a word or two further regarding Nosema disease. The studies of this disease disclose the interesting fact that it is not a new one in American apiaries. There is no cause, therefore, for anticipatmg any additional losses to our apiaries. Indeed, since the presence of the disease is known, hopes may be entertained that methods will be determined for reducing the losses due to it. Considerable work must yet be done, however, ‘before methods for its control can be recommended. Nosema disease is being studied in England, Germany, Switzer- land, and Australia. During the last two years the writer has de- voted considerable time to its study in America. The plan is to continue the studies during the present year, after which it is hoped a further discussion of this disease will be justified. & BULLETIN 92, U. S. DEPARTMENT OF AGRICULTURE. SUMMARY AND GENERAL REMARKS. The results of these experiments show that when they are main- tained for 10 minutes the minimum temperatures that can be used for destroying the germs of the four bee diseases now known to be infectious are as follows: (1) The minimum temperature for European foul brood lies some- where between 60° C. (140° F.) and 65° C. (149° F.), being approxi- mately 63° C. (145.4° F.). (2) The minimum temperature for American foul brood lies some- where between 90° C. (194° F.) and 100° C. (212°) F., being probably less than 98° C. (208.4° F.). (3) The minimum temperature for sacbrood lies somewhere between 55° C. (131° F.) and 60° C. (140° F.), bemg approximately 58° C. (136.4° F.). | (4) The minimum temperature for Nosema disease lies between 55° C. (131° F.) and 60° C. (140° F.), bemg approximately 57° C. (134.6° F.). It will be noted, therefore, that 63° C. (145.4° F.) for European foul brood, 98° C. (208.4° F.) for American foul brood, 58° C. (136.4° F.) for sacbrood, and 57° C. (134.6° F.) for Nosema disease are the ap- proximate minimum temperatures at which the germs of these dis- eases, respectively, are destroyed. Since there are varying factors in experiments of this nature that tend to produce slight variations in results, these temperatures are referred to as bemg approxi- mate. It is probable that future experiments may cause slight changes to be made in these conclusions. Nothing more than a com- paratively slight variation is to be expected, however. In practice the beekeeper, in destroying these germs by heating, will naturally use a quantity of heat somewhat in excess of the minimum amount that is absolutely necessary. Some generalizations may now be made which will be of interest to the beekeeper. The melting point of beeswax is between 62° C. (143.6° F.) and 64° C. (147.2° F.), inclusive. It will be observed that this same temperature in 10 minutes will destroy the germ causing European foul brood, and that it is about 10° F. above that which will destroy the germs of sacbrood and Nosema disease. A further inter- esting generalization may be made concerning the heating of honey. Honey when heated to 160° F. reaches a temperature 15° F. above the temperature necessary to destroy the germ of European foul brood and about 25° F. above the temperature that will destroy the infect- ing agents of sacbrood and Nosema disease. The infecting agents of these three diseases of the bee, therefore, will be destroyed when the temperature of 160° F. is used in the commercial handling of honey. Finally, it is believed that the results of this work on the thermal death point of the viruses of the bee diseases will be directly applica- ble to the control of these diseases. | O BULLETIN OF THE PUSDEPARTMENT OFAGRICULTURE * b y No. 93 Contribution from the Bureau of Entomology, L. O. Howard, Chief. April 30, 1914. THE TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. By E. F. Putts, Ph. D., In Charge of Bee Culture Investigations, and Grorce S. DemutH, Apicultural Assistant. INTRODUCTION. The care of bees in winter is one of the most perplexing problems confronting the beekeeper, especially in the North. This appears to be due chiefly to the fact that it is difficult to determine by direct ob- servation the normal activities of the bee colony in winter, and conse- quently it is well-nigh impossible to determine what external condi- tions are most favorable except by the gross results of experience. Nor can we by a study of our wintering successes and failures deter- mine definitely whether the same conditions of temperature and humidity are desirable throughout the entire winter. On account, therefore, of the lack of accurate knowledge of the activities of bees in the winter season this problem has been taken up with the aid of certain special apparatus and equipment. This preliminary report is not to be considered as giving definite recommendations as to the care of bees in winter, but rather is issued to make known to beekeepers some of the interesting results obtained in the first season’s work on the behavior of the bees during the winter season. American beekeepers lose thousands of dollars annually in winter from the actual death of colonies and even still more from those colonies that do not die, but which are reduced in numbers and vitality. The wintering problem is therefore a vitally important one. The factors influencing the welfare of the colony and the behavior of the bees are numerous and closely interrelated. Of the chief ones may be mentioned external temperature, food, ventilation, humidity, the condition of the colony at the beginning of winter, and various forms of irritation. In the present paper special emphasis is placed on heat production, by which is meant the responses of the bees of the cluster to the outer temperature and to changes in the outer tem- perature as manifested in the generation of heat by the bees. Notnu.—This bulletin presents studies of bees as affected by temperature conditions during winter and is of special interest to beekeepers in the North. 36157°—Bull. 93—14 2 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE, A special reason for this emphasis in a preliminary paper is that all previous work on the temperature of the cluster in winter, of which there has been considerable, has failed to show definitely what the normal responses are. The data are often those of abnormal con- ditions and are therefore misleading, making them almost valueless for purposes of application, One source of error which is to be found in all the records known to the authors is the use of the mer- cury thermometer, for, when such a thermometer is used, it is almost impossible to avoid disturbing the cluster at each reading so that it reacts abnormally. Furthermore, as the authors will attempt to show at a later time, disturbances of the colony may influence the temperature of the cluster for a considerable period, often more than one day. Usually no account has been taken of the necessary cor- rections to be made for the mercury thermometer. Because of the errors in other work on the subject, due to the use © of mercury thermometers, the thermometers chosen for the work here recorded are of another kind.. Electrical thermometers are used, by means of which readings can be made without approaching the hive, and the thermometers (couples) are of course permanently fastened in place. These are of the type known as thermocouples or thermal junctions and the readings are made by means of a poten- tiometer indicator and a sensitive galvanometer of the. d’Arsonval type. The wires used in the thermocouples are copper and con- _stantin (a copper-nickel alloy), giving an electromotive force of about 40 uV per degree centigrade. A detailed description of the appara- tus is impossible here, and it need only be stated that the method as used gives readings to an accuracy of 0.09° F. (0.05° C.); the ther- mometers are practically instantaneous in their action—that is, show changes in temperature without a “lag”; the readings of many thermometers can be made consecutively on one carefully calibrated instrument, insuring uniformity, which is impossible in using many mercury thermometers; and, a point of importance in such work, the readings can be made at the rate of two a minute, which would be impossible with widely scattered instruments. In all, 161,617 tem- perature readings were made during the winter 1912-13, and the work is being continued. Part of the colonies are kept in a well-insulated room (used as a “bee cellar”) in the zoological laboratory of the University of Penn- sylvania, Philadelphia, Pa., which can be kept at a temperature usually varying not over 2° F., far more uniform than the ordinary bee cellar. Abundant ventilation is provided, and the room is com- pletely darkened to avoid possible disturbance by light. The tem- peratures of the indoor colonies are read from an adjoining labora- tory to eliminate the possible errors due to disturbance, and the room is entered rarely (about once a week on an average and, if possible, - TEMPERATURE OF THE HONEYBEE ‘CLUSTER IN WINTER. 3 only after the day’s records are made) and only when absolutely necessary. It is found that entering the constant-temperature room may under some conditions influence the behavior of the bees in a marked manner. Other colonies are kept on the roof of the same laboratory, where they are left untouched from the beginning to the end of a series of readings. The wires of the thermometers are led to the room below through rubber tubes, and all the temperature readings are made at a distance, as is absolutely necessary to eliminate disturbance. Disturbances of outside colonies have also been found to influence their behavior in a pronounced manner, especially in cold weather. By studying the temperature of various fixed points within each hive it has been found possible to use the temperature readings as a substitute for direct observations. After becoming familiar with the normal temperature and the temperatures incident to various activities one can tell the shape, location, and various activities of -the cluster by a study of the temperature of different points within the hive and can, in fact, form an opinion as to the welfare of the colony. It has therefore been possible to follow closely the activities of each cluster without opening the hives and even without going near them. THE INFLUENCE OF EXTERNAL TEMPERATURE ON HEAT PRODUCTION. The colony (A) to be discussed under this heading was wintered out of doors (1912-13) on the roof, where the bees were free to fly whenever the weather permitted. It was in a 10-frame Langstroth hive, with the entrance reduced to 2 inch deep and 8 inches wide, and was not packed or given additional protection. This hive contained 19 of the electrical thermometers—12 among the combs, 4 in the cor- ners of the hive, and 3 on the bottom board. Readings were made hourly from 9 a. m. to 4 p. m. through the winter (Sept. 26 to Mar. 28), except Sundays and holidays, and at intervals additional read-- ings were made every 15 minutes (or sometimes every 30 minutes) during the night (5 p. m. to 8.45 a. m.) for periods of several days each. In all, 41,413 temperature records were made for colony A. The reaction of the cluster in heat production, as induced by changes in external temperature, is well shown by the records made from noon November 13 to 2 p. m., November 15 (1912), when read- ings were made hourly from 9 a. m. to 4 p. m. and every 15 minutes at night. From noon on November 18 the outside temperature dropped slowly until 6 a. m., November 15, and the weather was cloudy, so that the bees did not fly. It will be seen from the accom- panying diagram (fig. 1) that at noon on the 13th the outside tem- perature was about 69.2° F. and all the points within the hive were BULLETIN 93, U. 8. DEPARTMENT OF AGRICULTURE. ‘ LECKEES CSCS CE XS Q SekRAR | |B oH | + MUAAEEOA\GRERREEROEEL Hee TERN LS PLETE Yo X i PMT rote LAT PETE eee EEE AUT ETT CEE PALLET LEE LEE UE EE LA CLE HATH PUMAARRRRDDEUEE INURL RAN R ® & ¥ 8 8 LLSHNSHANEY eS 72 NOV IG, FG PLZ. o & § R Short lines show temperatures of couples on the Outdoor temperatures are indicated by the heavy line, 15, 1912. Fic. 1.—The outdoor temperature and temperature of the center of the cluster of bees in colony A from noon Noy. 15 to 2 p. m. Noy. outer edge of the cluster at the time of first heat production. TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 5 then cooler than the outside air, due to the fact that it took some time for the inside of the hive to warm up. At 4 p. m. the outside temperature had dropped to 65.3° F., when it was lower than any of the points within the cluster, which had in the meantime become warmer. From this time until 6 p. m. the next day (14th) the tem- perature within the cluster gradually dropped as the outer air cooled, until the lowest one (No. 9) was 57° F. (Outside temperature, 48.2° F.) The generation of heat began at 6.15 p. m. at this point, which was to one side of the cluster, and is to be attributed to the movement of the bees in forming a definite cluster. At 6.30 p. m. a rise in temperature was noticed on thermometer 19, at the other side of the cluster. Until 10.15 p. m. the changes in temperature are probably to be interpreted as incidental to the formation of a compact cluster, and from this time until the next day at the close of the series of readings the thermometers within the cluster showed a considerably higher temperature than the outer air, or than the thermometers outside the cluster. The maximum in this series was reached at 3.15 a. m., November 15, when thermometer 12 in the center of the cluster registered over 89.4° F. After the coldest outside temperature was reached and the outer air began to get warmer (6.15 a. m., November 15), there was a tendency for the cluster temperatures to drop. This is somewhat noticeable in the case now being discussed, and is more clearly seen in records obtained in other series. In general, after a period of cold, when the outside temperature begins to rise, the cluster temper- atures drop slowly to meet the outside temperature. The generation of heat is reduced, or even discontinued, only to be increased when the outside temperature again drops, or when it gets high enough to induce greater activity, as in flight. It is found also by taking more frequent readings when the cluster temperature is above about 69° F. that it is less constant than when it is below this temperature, indi- cating that at temperatures above this point the bees move about to some extent, while between 57° and 69° they are quiet, unless flight is desirable owing to a long confinement. This series of readings is supported by numerous records taken on this and other colonies throughout the winter and, since all the ob- servations tend to confirm what was first seen on the record pre- sented here, the authors feel justified in presenting a definite state- ment of the reactions of the cluster to outside temperatures. It may be added that a careful study of the records of previous investigators fails to show a similar statement on this subject. When a colony is without brood, if the bees do not fly and are not disturbed and if the temperature does not go too high, the bees generate practically no heat until the coolest point among the bees reaches a temperature of about 57° F. At temperatures above 57° F. a compact cluster is not formed, but the bees are widely distributed over the combs. At 6 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. the lower critical temperature, which is for the present stated as 57° F., the bees begin to form a compact cluster, and if the tempera- ture of the air surrounding them continues to drop they begin to gen- erate heat within the cluster, often reaching temperatures consider- ably higher than those at which they were formerly quiet and satis- fied. It is evident, therefore, that the temperature within the cluster is far from being uniform in winter, as has been, in a sense, assumed among practical beekeepers. At the temperature at which other in- sects become less active (begin hibernation) the honeybee becomes more active and generates heat, in some cases until the temperature within the cluster is as high as that of the brood nest in summer. To sum up, when the temperature of a colony of undisturbed broodless bees is above 57° F. and below about 69° F. the bees are quiet and their temperature drifts with the outer temperature; at lower tem- peratures they form a compact cluster, and the temperature within it is raised by heat generated by the bees. The authors desire to state that while the lower critical point, 57° F., appears rather well established, the observations up to the present do not justify too definite a statement concerning the upper limit of quiescence. It must be emphasized that these conditions do not apply when the colony-has brood. The rearing of brood in win- ter causes a marked increase in heat production and constitutes a condition which may become one of the most disastrous that can be- fall a confined colony. This will be discussed at a later time. When the heat production of the colony is explained, we are able to understand to some extent the divergence in the records obtained by other observers. It has, of course, long been known that bees generate heat, and it has been pointed out that during cold weather the temperature of the cluster is often higher than during warmer weather. While the temperatures previously recorded are in most cases abnormal, due to disturbance, the chief difficulty in under- standing the phenomena which take place is due to insufficient ob- servations. For example, if between noon November 13 and 2 p. m. November 15 only a half dozen temperature records had been made for the cluster (and perhaps without finding the warmest part of it) and the outside air, it would have been impossible to determine the limits of heat production. Most observers have been satisfied with a few observations, and seemingly everyone who has inserted a ther- mometer in a hive has felt called upon to publish the results, thereby only confusing the problem. THE EFFECT OF CONFINEMENT AND THE ACCUMULATION OF FECES. Before beginning a discussion of the effect of confinement and the accumulation of feces, it may be recalled that during the active summer season the length of life of worker bees is in a sense deter- TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 7 mined by the work done by them, rather than by days or weeks. The greater the necessity for excessive activity the shorter the term of life. The authors believe that they have evidence to prove that this applies to the winter also, and this belief is entirely supported by the experience of beekeepers everywhere. That bees may come out of winter quarters strong in numbers and vitality it follows that the work to be done by the bees in the winter should be reduced to a minimum; and the winter problem, as thus interpreted, is therefore to find the conditions under which broodless bees do the least work. The work which broodless bees do in winter consists, so far as has been determined, solely in the production of heat or in activity inci- dent to flying on warm days (if free to fly), and therefore the prob- lem, so far as it is under the control of the beekeeper, is primarily to obviate the necessity for the production of heat. If brood is reared the work of the bees is necessarily enormously increased, and their vitality is correspondingly decreased. So far as evidence is available in this work, the colony is not fully recompensed for this expenditure of energy by an increase in the strength of the colony by bees thus reared. The colonies? to be discussed under this heading (Nos. 1 and 3) were wintered in the constant-temperature room in special 6-frame hives (to economize space and concentrate the colony so that fewer thermometers would be required) with full entrances and were not propolized or sealed at the top. During the regular series of read- ings the room was kept at a temperature which rarely dropped below 40° F. or went above 45° F., and the average temperature from October 14 to March 6 was 42.67° F. This temperature was chosen as being nearly the one usually considered best by beekeepers. The foods given these colonies were stored in the combs, just as placed. by the bees. There was some pollen available in colony No. 1. (Fig. 2.) According to what has been said in the previous section, we should expect bees at such a temperature to maintain a compact cluster and to generate some heat at all times. This was actually the case, the temperature of the interior of the clusters dropping below 64° F. only a few times in either colony. Colony No. 1, on honey stores, was in the constant-temperature room from October 12, 1912, to March 24, 1913, or 163 days.? It 1In order that the young bees might all get a flight before the winter confinement, the two colonies here discussed were placed in the constant-temperature room after the brood had been removed. They were kept here several days, removed for a flight, and then returned to the room for the regular series. The significance of this manipulation must be reserved for a later discussion. This explanation is made to show how it was possible to put these colonies in the room so early in a climate as mild as that at Philadelphia. The object was, of course, to increase the time available for observation. Bees are usually not wintered in cellars in climates as mild as that of Philadelphia. 2Tn all, 24,077 temperature records were made for this colony. 8 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. was then removed for a flight and put back the same evening, where it remained until March 28. From March 7 at 9 a. m. until March 28 at 4 p. m. readings were made on this colony every 15 minutes night and day, with the exception of the period between 9 a. m. and 7 p. m. on the 24th, when it was out of doors. During this period of three weeks the temperature of the room was changed slowly, being raised as high as 64° F. and cooled to 13° F, ae Ewe 70 Pe a | a pata ine TEETH Ee CIO pbs ay CASAS at as a OF ee : S a g S N ‘ @ : 488 | e tHe Ee ia LI - A CARS ee Te al fala a ee eee Fic. 2.—Average daily temperatures of the center of the cluster of bees in colonies 1 and 3 and room temperatures, Oct. 14, 1912, to Mar. 6, 1913. Taken from readings made hourly from 9 a. m, to 4 p. m. The room temperatures are indicated by the heavy line. When this colony was first placed in the room for the regular series of readings, after a preliminary confinement, October 12 (the readings were begun Monday, Oct. 14), it maintained a cluster tem- perature which usually lay between 64° and 68° F., the daily average temperature departing from these rather narrow limits only four times up tc November 22. The average temperature is 66.5° F. During the first five weeks the temperature of the room was less regular than later (due to faulty working of the regulating apparatus), and this doubtless accounts for some irregularities in the cluster temperature. At first the three thermometers in the cluster (1, 2, and 5) gave tem- TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. - 9Q perature readings quite close together, while thermometer 6, which was near the cluster, gave readings intermediate between the three thermometers of the cluster and the four others in the hive, farther from the cluster. After November 22 the records of the thermometers in the cluster were more widely separated and the temperature of the center of the cluster (shown on thermometer 5) tended to rise gradu- ally. It varied constantly, but by December 7 and from then until the end of the month, it averaged between 69° and 75° F. On Novem- ber 29 and December 12 the cluster temperature rose to over 88° F. From the ist of January until March 6, which ended the regular series of readings, the cluster temperature became more and more irregular, and on January 20 the cluster moved (probably to accom- modate itself to the stores) until thermometer 2 was nearer the center and showed a higher temperature than thermometer 5. The size of the cluster was gradually decreased by the death of bees, and all the thermometers except 2 and 6 show a gradual decrease in temperature until finally, from about February 25 to March 6, they are all low and of nearly equal temperature. The two thermometers giving high readings continued to show in general a higher and higher average temperature and to become more irregular (except from February 15 to March 1), the periods of increased heat becoming more frequent. There was absolutely no regularity in these intervals, After Febru- ary 1 the temperature of the cluster varied between 75° and 91° F., the average from February 1 being 85.4° F. On March 6 all colonies in the constant-temperature room except two were removed. The colony described above (No. 1) and one other (No. 12), not to be described at present, were left. On March 7 at 9 a. m. the temperature of the room stood at 42° F., and the temperature of the interior of the cluster was about 84° F. The brine which cooled the room was then shut off and the temperature of the room rose very slowly and regularly, until on March 11 at 8.45 a. m. it was 64° F. For the first day the temperature of the cluster was slightly variable, and at 10.45 p. m. thermometer 6, which had been cooler than thermometer 2, showed a rise in temperature (probably due to a shifting of the cluster), and from then on to the 24th they were nearly of the same temperature at all times. On March 8, at 3 a. m., thermometer 2 rose to 87° F. (room temperature, 48.5° F.), having previously shown a cooling. The cluster tempera- ture then dropped slightly, showing relatively little variation until at 4.15 p. m., March 9, it stood at 77.3° F. (room temperature, 55.7° F.). As the room temperature continued to rise, the cluster temperature increased still more rapidly, until at 8.15 a. m., March 11, it reached 93° F. (room temperature, 64.2° F.). A little brine was now turned on, sufficient to lower the temperature gradually to 58° F. at 9 a. m., March 12, and it again rose to 63.8° F. at 5.45 p. m., 10 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. March 15. During this period the cluster temperature followed the room temperature, but remained constantly over 20° warmer. The room was again cooled slowly, and the cluster temperature dropped until on March 16, at 3 p. m., the room was 49° F. and the cluster 77.5° F. As the room continued to cool, the cluster temperature in- creased, the bees responding to the colder temperature, until at 4.15 a. m., March 17, the room was 48° F. and the cluster 88° F. The room then gradually warmed, and again the temperature of the cluster dropped and then again rose with the room temperature, remaining always over 20° warmer. At 6.45 p. m., March 19, the brine was turned on full and the room cooled rapidly, reaching the minimum of 13° F. at 9 p. m., March 20. At no time, however, did any of the thermometers in the hive record a temperature below 33° F. Here it remained constant within 0.1° F. for about six hours, during which time the cluster temperature varied between 86.5° and 89.5° F. (a difference between the room and the cluster temperatures of 73° to 76° F.). The brine was now shut off and the room again warmed until 9 a. m., March 24, when it reached a temperature of 44.5° F. During this warming the cluster cooled until at the close it was varying between 72° and 79° F. As stated above, the colony was now (9 a. m., March 24) removed for a flight and put back the same day at 7 p.m. In the meantime the room was cooled to 33° F. When the bees were put back into the room the temperature of the entire inside of the hive showed great variation and naturally an increase due to the warming up while out of doors and to the activities of a good flight. The points outside the cluster dropped rapidly, but it was midnight, March 25 (31 hours), before the curves of temperature again appeared normal. The room was slowly warmed to 63.2° F. at 6.30 p. m., March 26, and then slightly cooled to 54° F. at 6 a. m., March 27, and again warmed to 58.5° F. at the close of the series, 4 p. m., March 28. After the flight the temperature of the cluster never dropped below 89.5° F., and the highest temperature reached was over 95° F. (soon after the flight). Thermometer 6 remained high, but thermometer 2, which had previously been high, now approached the other ther- mometers, probably due to a rapid loss of bees and to a decrease in the number of bees during the flight. It must be recalled that these bees had been confined for an abnormally long time and were sub- jected to treatment which is at least unusual. After this colony was taken from the room for the last time it was found that thermometer 6 was over a patch of larvee, and, estimating as accurately as possible, the eggs from which these hatched must have been laid at the time when the room was coldest (March 20-21) and when the cluster tem- perature was at its highest point. There had been no brood previ- ously, according to the temperature records as compared with those | TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 11 of this colony earlier and with those of other colonies, nor was there much evidence of increased heat production due to the presence of brood until after the flight. Probably no extra heat was produced for the eggs, and possibly the hatching of the eggs was somewhat delayed by the low outer temperature. The effects on the cluster temperature which might be expected from a flight, in relieving the accumulation of feces, were not observed, because brood rearing had been begun. Colony No. 3 was placed in the constant-temperature room October 12, 1912, after a good flight, and readings were begun cn Monday, the 14th. In all, 2,165 temperature records were made on Colony 3. The stores provided this colony consisted of honeydew honey, which was gathered in the department apiary and which, since it granulated almost at once, had been removed by melting up the combs which contained it. After this operation it remained liquid. During the summer of 1912 some of this honeydew honey was fed to a colony in the open, during a dearth of nectar, and was stored in new combs above the brood chamber, in which no cells of pollen were to be found. After the second storing the honeydew honey was clear, well ripened, and did not granulate. This colony was also in a 6-frame hive, as previously described, and contained five thermometers (Nos. 14-18) among the combs. It is of course well known to beekeepers that honeydew honey is not a good food for winter. When this colony was first put into the constant-temperature room it behaved much as did Colony No. 1, except that the temperature varied between 69° and 78.7° F. for the first week, being slightly higher and more variable than that of Colony No. 1. The second week it remained much the same, the temperature, however, varying between 69° and 80° F. From this time on the temperature of the center of the cluster rose rapidly, never dropping below 79° F. from October 29 almost to the close of the readings. After November 4 the temperature remained above 86° F., and after November 11 it dropped below 89° F. only twice until the end. Thermometer 17 at first read about 4° below thermometer 14, but after November 11 they were close together until November 25, when thermometer 17 began to cool rapidly, due to loss of bees, and after November 30 thermometer 14 cooled rapidly until, on December 9, it showed that no more bees remained alive. From December 2 to 7, inclusive, there was little heat generated, due to the scarcity of bees. It is of interest to observe the records of thermometer 16, near the cluster, but usually _ outside of it. It at first showed a temperature but little higher than the two thermometers away from the cluster, but on October 31 it _ began to rise until, on November 12, it reached 80.5° F., when it was doubtless covered by the bees. Even the two thermometers (15 and 18) clear to the back of the hive rose until, on November 13, they 12 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. recorded 61.5° F. These thermometers showed about the same tem- peratures for about 10 days, and then these two and thermometer 16 showed a cooling, since the bees were dying so fast that there were no longer enough to warm up these thermometers away from the center of activity. It was to be expected that this colony would die, and the experiment was performed to learn the phenomena, incident to the loss. Before summing up the results of these two colonies, Nos. 1 and 3, it may be stated that, so far as the evidence here presented is con- cerned, the results as far as here discussed are confirmed by records from 10 other colonies kept in the constant-temperature room, but fed other foods and otherwise different. There is in all of the records no evidence which the authors can interpret as at all contrary to the views here stated. A discussion of these other colonies is reserved. It is evident from the behavior of colony No. 1 that at least one factor entered which gradually caused the bees in the cluster to generate more and more heat until at the beginning of the special series, March 7, the cluster temperature was about 20° warmer than it was at the same room temperature at the beginning of the confine- ment. It is also seen that during the special series, March 7-24, the cluster temperature always remained at least 20° above the room temperature, whereas from the discussion of bees~ unconfined (Colony A) we might expect them to cease heat generation when above the lower critical temperature (57° F.). In the case of colony 3, fed on honeydew honey stores, the factor which caused more heat to be produced evidently increased much more rapidly. As stated previously, honeydew honey is a poor food for winter and is so recognized. It contains the same sugars as honey, but contains in addition a considerable amount of dextrin, the particular lot fed to colony 3 containing 4.55 per cent while good honeys contain only a fraction of 1 per cent. From the evidence at hand it appears that dextrin can not be digested by bees and, whether or not this is the explanation, honeydew honey causes a rapid accumulation of feces which usually results in the condition known as dysentery, in bad cases of which the feces are voided in the hive. In the case of colony 3 the whole hive inside and out, as well as the frames and combs, were spotted badly, the inside of the hive being practically covered. Even with fine honey stores such a spotting is usually noticed after a pro- longed confinement, especially in severe weather (or during brood rearing). It therefore appears that the accumulation of feces acts as an irritant, causing the bees to become more active and conse- quently (see later section) to maintain a higher temperature. We are therefore justified in believing that the cause of poor wintering on honeydew honey is due to excessive activity, resulting in the bees wearing themselves out and ultimately in the death of the colony. .. TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 13 In the case of colonies on good stores (e. g., colony 1) the feces accumulate more slowly and the excess activity is not so marked and is induced more gradually. The accumulation of feces due to con- finement causes increased activity and this in turn is the cause of excessive heat production, resulting in a reduction in the vitality of the bees. It therefore follows that excessive activity causes the consumption of more food, resulting in turn in more feces, so that colonies on poor stores are traveling in a vicious circle, which, if the feces can not be discharged, results in the death of the colony. In the work here recorded no attention was paid to the theory that dysentery is due to an infection, since there is nothing in the observations made that lends any support to that idea. If there is more than one kind of dysentery, as has been held, then the observations here recorded must be considered as applying only to the type which can be in- duced at will in any confined colony by giving poor food and which, as has been long recognized, can be relieved at once by an opportu- nity for flight. While the activity of the cluster is greater at some times than at others, there are not, as has been held, regular intervals of activity at which the colony rouses itself to take food. At no time is a colony kept at a room temperature of 45° F. or less in a condition which can be characterized as inactive. Presumably the reported “ inter- vals of activity ” have occurred when the colony made a noise due to disturbance by the beekeeper. The bees in colony 3 were compelled to work constantly to main- tain so high a cluster temperature. In fact, they did more work than colonies wintered in the open air. Keeping these bees in a cel- lar protected them from low outside temperatures, but the lack of opportunity for a normal ejection of feces caused a condition more serious than extreme cold weather. We seem to have here an expla- nation of the fact, often observed by beekeepers, that some colonies wintered in the cellar are in worse condition in the spring than col- onies that are exposed to severe cold. Poor food is evidently a more serious handicap than low temperature. METHODS OF HEAT PRODUCTION AND CONSERVATION. A colony of bees in cold weather forms a compact, approximately spherical cluster, but this cluster is not, as is usually believed, uni- formly compact. In order to study the formation of the cluster and as an ald to interpreting the temperature records in terms of action, a colony (C) was placed out of doors in a narrow hive with double- glass sides and top, and the stores were so arranged that the only space available for the formation of the cluster was next to the glass on one side, where it could be kept under direct observation. Since 14 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. the bees did not have room for a spherical cluster, they formed a ring on the glass. Thermometers were then placed close together in the outside space, so that the temperatures of various points could be determined as desired. This hive was on the roof, and, while one person watched the bees, constant communication could be kept up with the person reading the temperatures in the room below by means of a telephone, arranged so that the hands of both observers were free. This colony was of course in the light, but the normal cluster was nevertheless observed. It was disturbed as little as possible. The nearly spherical cluster of bees consists, between the combs and sometimes above or below them, of an outer shell of bees close together with their heads toward the center. This ring may be several layers thick. The position with the heads inward is typical, except when condensed moisture drops on the cluster as it often does in cool weather, when the bees at the top turn so that their heads are up- ward. The bees in this outer shell are quiet except for an occasional shifting of position. Inside this rather definite shell the bees be- tween the combs are not so close together nor are they headed in any one way. Considerable movement, such as walking, moving the abdo- men from side to side, and rapid fanning of the wings, takes place inside the sphere and when a bee becomes unusually active the ad- joining bees move away, leaving an open space in which it can move freely. Two bees may often be seen tugging at each other. In addition to the bees between the combs, placed as above described, others are in the empty cells of the comb on which the cluster is always formed, always with their heads in. A verification of these statements is contained in the following observations, and the ex- periment may easily be repeated by anyone. For the purpose of obtaining a colony without combs for another experiment, a hive was opened December 15, 1913, while the outside temperature was low enough to cause the formation of a compact cluster. When the combs were separated the circle of bees in the shell was clearly observed. When a comb from the center of the cluster was shaken the active bees in the center of the circle dropped off readily, and those in the outer shell which were somewhat sluggish were removed with more difficulty. After this was done those occupying empty cells in the center of the sphere backed out of the cells and were shaken off. Finally those occupying cells in the border of the sphere backed out, showing a well-marked circle on the combs. Evidently the bees in. the shell, whether in the cells or between the combs, are less active than those in the interior of the cluster. Naturally such a manipu- lation as this is not to be recommended, except for purposes of demonstration. - It is clear from observations previously recorded that the highest temperatures are those of points in the center of this shell, and this is . TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 15 to be expected, as the heat is generated here. The outer shell consti- tutes an ideal insulator for the conservation of the heat, since the bees arranged so close together form small dead air spaces in their interlacing hairs, especially those of the thorax, and afford still more insulation with their bodies. The abdomens of the bees in the outer row are practically separate one from another, and must often be exposed to severe cold. That this method of conserving heat is effective is shown by observations on undisturbed colonies out of doors. For example, on January 14, 1914, there was at 9 a. m. a difference of 68° F. between thermometers 14 (center of the sphere) and 16 (outside the cluster) of Colony D, which were less than 43 inches apart on the same level in the same space between combs, and a difference of 75° I’. between this couple and the bottom board 44 inches below it. What this difference might sometimes be in colder climates may be imagined. Examples of this kind might be multi- plied indefinitely from the records of these experiments. The source of the heat of the cluster must, of course, be the oxi- dation of the food consumed by the bees. The bee is classed as a cold-blooded animal in that the temperature of the individual bee is practically that of the surrounding medium. There is obviously, from the records just given, no internal regulation of the tempera- ture of the body such as is found in birds and mammals, for the temperature of a broodless cluster varies greatly. From the obser- vations made on the various colonies, especially Colony C, it is clear that heat for the warming of the cluster is produced by muscular activity. While, of course, some heat is doubtless liberated by other life processes, this is practically negligible when bees are quiet, as “in Colony A when above 57° F. That higher temperatures may be produced, greatly increased muscular activity is required, and in Colony C in cold weather bees in the center of the shell of insulating bees were seen fanning vigorously and executing other movements, such as shaking and rapid respiration. We thus have the para- doxical condition that bees fan to heat the cluster in winter as well as to cool the hive in summer. Observations of this kind were repeated beyond number, and this theory of the method of heat pro- duction is entirely supported by the repeated observation of a hum- ming noise from the cluster during cold weather. A few details of the observations on Colony C may be of interest. For example, one bee was observed fanning vigorously for 74 minutes (9.53 to 10.004 a. m., Jan. 23) while the other bees kept a space cleared for it. The temperature of the nearest thermometer rose 4° F. during this time. At 9.52 this thermometer was almost a degree cooler than at the time of greatest heat during the fanning. The rapidity of fan- ning of the wings varied, and toward the end of the time it became so slow that the outline of the wings was distinguishable. After the 16 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. excessive activity this bee stood in the same place for a time. Rapid respiration may play a more important part in heat production than at first appears. One bee was observed to breathe 21 times in 14 seconds and then cease the rapid respiration. On other occasions 50 or more bees would begin shaking their bodies from side to side. It has been shown in earlier sections that feces in the rectum cause irritation, which induces increased activity and causes greater heat production. It has also been found that other kinds of irritation bring about the same result, but a discussion of these points can not be undertaken here. It is at least evident from the records obtained in this work that colonies of bees in winter, either in cellars or out of doors, should be disturbed as little as possible. This appears to apply especially to cold weather out of doors or in the cellar, especially after the colony has been confined for some time. The facts mentioned concerning the ability of the bees to conserve the heat generated will perhaps raise the question as to the tempera- ture of the hive outside the cluster in cold weather, when the cluster is compact. In the case of Colony A the temperature of the hive outside the cluster was often practically as low as the outside tem-~ perature. This colony was not packed and had a rather large en- trance. If the cluster forms such an efficient insulator in itself it might be presumed that packing about the hive is of little value and that it might even be harmful, in that it would not serve to conserve heat and would prevent the heat from the sun from penetrating to the cluster. This line of reasoning, however, does not follow, and in any case it is unsafe to speculate about these things without more facts. The effects of various forms of packing are being studied. In closing it may be desirable again to state that too hasty con- clusions must not be drawn from the facts here presented. For example, the records on heat production might be interpreted as indi- cating the desirability of a cellar temperature higher than beekeepers usually believe to be best. Experiments to test such a theory are now being carried on, and it is found that a broad statement as to the best cellar temperature can not yet be given. Under most conditions colonies can not be brought to the critical temperature, 57° F., with- cut disturbance. It is hoped that more work will throw some much- needed light on this important subject. ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 5 CENTS PER COPY Vv WASHINGTON : GOVERNMENT PRINTING OFFICE ; 1914 BULLETIN OF THE Be) SOREN ea No. 94 Contribution from the Bureau of Animal Industry, A. D. Melvin, Chief. August 17, 1914, DOMESTIC BREEDS OF SHEEP IN AMERICA. By E. L. Saaw and L. L. Heiter, Animal Husbandry Division. INTRODUCTION. All the domestic sheep in America have originated from importa- tions, most of which have been made from European countries since the beginning of the nineteenth century. These breeds have not yet been able to find themselves fully, and there are not the clearly defined areas devoted to certain classes such as are common in England; still there is a gradual tendency toward segregation. The fine wools are grazing upon the western ranges and to a lesser extent through the Ohio fine-wool region. They are undergoing some changes to improve the carcass and increase the length of wool; some foreign blood is being used to do it; nevertheless these sections may still be regarded as being fine wool in character. In Tennessee, Virginia, and Kentucky, the spring-lamb region of America, the Southdown lambs are very popular. To a lesser extent some of the other mutton breeds are gradually gaining precedence. Through the central farming section of the country the medium- wool breeds have taken possession, the long wools largely yielding for a location more favorable to them in the North and Northwest, notably Canada, Utah, Idaho, Montana, and Oregon. It is not always possible to say that there is one best breed for any section. There may be two or three that would do equally as well, but it is undeniable that some breeds are far more suitable than others for a given location. AIl the breeds have their good qualities and most of them, if properly handled, will give good results in some section of America. The problem is to get the ones best adapted to particular conditions. Some breeds have a larger number of high-class individuals than others, but a truly successful breeder can improve any of them. NotE.—This bulletin gives detailed information as to the origin, adaptability, distribution, distinguish- ing characteristics, etc., of the various domestic breeds of sheep. It is of especial interest to sheep breeders and to the sheep grower who is desirous of securing the best breed adapted to his particular locality. 36158°—14——1 2 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. As a rule, but one breed should be selected. Where there is more than one breed upon a farm it is a difficult matter to keep the gates all closed at the proper time and prevent crossing. If several farms are available more breeds can be handled, but the difficulties in man- agement are much increased. The most successful sheep breeders in America handle but one breed. The fact that there are more breeds than in any other class of farm animals may in itself make the selection of one breed rather difficult. Some of the deciding factors should be climatic conditions, feeds available, elevations, what particular line of the industry is to be followed, and popularity of the breed. The effect of climate is strikingly illustrated in the evolution of the sheep industry of the extreme Northwest. The Willamette Valley in Oregon, now so famous for its long wools, was once partly occupied by fine-wool sheep. The large amount of rainfall, which comes in a long-continued drizzle, caused the hay and weed seeds that became lodged in the wool to grow and become green upon the sheep’s back. The Merino breeds were decidedly out of place there. After a time the Lincoln and other long-wool breeds were introduced and the industry assumed a different aspect. Their long locks act as a thatch, carrying the water off, and these breeds thrive as they do in few other places éxcept their native counties in England. The kind of feed produced is of importance. The larger breeds have developed upon land that has produced abundantly. They are capable of taking care of a larger amount of feed, such as the moist fertile lowlands produce, while the smaller breeds succeed better upon the less abundant fare of drier and less fertile pastures. There is evidently some connection between the general higher quality of the smaller breeds and the scanty, more nutritious feeds that they receive under natural conditions. If they are removed to the low- land they lose much of their characteristic type and quality. The effect of elevation upon a breed is also apparent, but how much of this effect is due to the amounts and kinds of feed it is difficult to determine. Certain it is that the mountain breeds are smaller, more active, more hardy, and better able to care for themselves than their down or lowland neighbors. The importance of hardiness in the mountain breeds was shown during the last century along the Scottish border. The Cheviot had for a number of years been displacing the Black-faced Highland breed because of its finer quality of wool and somewhat better carcass. A number of severe winters worked havoc among the flocks of the former breed by causing a very heavy lamb loss, and the Highland breed, because of its hardiness, came back into its own. The effect of the soil upon sheep is somewhat obscured in the effects of feed, elevation, etc. That there is some effect can not be denied, but the extent of this is an unsolved problem. DOMESTIC BREEDS OF SHEEP. 3 Whether the breeder expects to specialize upon some particular line of sheep farming should likewise be instrumental in making a decision. If winter lambs are to be produced a breed must be secured that will breed at the right season of the year, and not all will do this. The Dorset, Merino, and Tunis have given the best satisfaction thus far. The popularity of a breed will often have its effect in influencing one’s decision. Some breeds have been developed under conditions that are more general, or else they have a wider range of adaptability than others. The popularity of several breeds in this country is due to this fact. No better illustrations of these can be mentioned than the Merinos and Shropshires that are found from Maine to California. Some of the minor breeds need men who will place them before the public, as there can be no doubt as to the effect of a wide-awake breed association in advancing a breed. It is well before making a selection to consider carefully the most popular breed in yourcommunity. There is usually some good reason for it being popular, but occasionally because of fashion a breed will enjoy a ‘‘boom” that it does not rightly deserve. In some States at the present time there are colonies of breeders handling certain breeds, and buyers are attracted there because there are excellent oppor- tunities for selection in the neighborhood. There are also advantages connected with buying stock near home. The keen competition offered by some of the classes in the show ring has been a lure that has caused some men to take up a certain breed. Others have been con- tent to win more often in the smaller classes where the winnings are easier. : Some breeds are regarded as needing more care than others; at any rate they become more unsightly if denied this attention. However, no flock will thrive upon mismanagement. Good appearance is always desirable, and sometimes it is of prime importance. The use of sheep for keeping the lawns of parks and country places in trim has been in effect in this country for years and here attractiveness is indispensable. ‘The Southdown has proven very popular for this purpose. The cost of foundation stock will undoubtedly have considerable influence with some people in making a selection. However, too much importance should not be attached to this. Often breeding stock of some breed unadapted to your locality can be bought very reasonably, but if the flock was established there would be little demand for its products and the venture would be likely to meet with failure. The characteristics of the breeds as regards the color of the face and legs and whether or not they are horned have been regarded as of considerable weight, but it is doubtful whether these are as important as is sometimes inferred. 4 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. It is the purpose of this bulletin to point out the main characteristics of each breed. Some of the early history given may therefore seem irrelevant, but it is of importance. The age of a breed is largely in- dicative of the degree of fixity of type. A knowledge of the founda- tion stock is important, as it reveals latent characters that might crop out and that should be guarded against by the breeder, and so on. While it is the object to point out the importance of selection, it is not intended to minimize the necessity for proper care and management. Too many purebred flocks of high character have been established in this country only to go to ruin on account of poor care. This side of flock husbandry has been treated in Bulletin No. 20 of the Agricultural Department series. CLASSIFICATION OF THE BREEDS. There are probably nearly as many classifications of the breeds of sheep as there are breeds. Almost every prominent author of litera- ture in the ovine world has expressed views upon the subject. They have approached the task from almost every possible angle; conse- quently we have classifications based upon the color of the face, in- cluding the light and dark faced sheep, upon the presence or absence of horns, and upon the topographical origin of the breed, such as the mountain, upland, and lowland breeds. There are other classifica- tions based upon the geographical origin of the breeds; for instance, the British, Island, and foreign breeds; upon anatomical structure, the fat tails and the broad tails, and soon. It is hardly necessary to say that any classification must be more or less arbitrary, as the dif- ferent divisions grade almost imperceptibly into one another. The most important classifications are those based upon the wool, of which there are several. Some of these are based upon the length, but as this property is more dependent upon the circumstances under which the sheep are kept than is the degree of fineness, we will base our classification upon the latter quality. FINE WOOLS. American A, B, and C type Merinos. Rambouilleta. MEDIUM WOOLS. Southdown. Suffolk. Lonk. Shropshire. : Cheviot. Ryeland. Hampshire. Welsh Mountain. Kerry Hill. Oxford. Tunis. Dorset Horn. Exmoor Horn. COARSE WOOL. Leicester. Romney Marsh. Black faced Highland. Cotswold. Wensleydale. Karakule. Lincoln. Dartmoor. Persian. WOOLLESS. Barbados. Barbary. DOMESTIC BREEDS OF SHEEP. 5 Deciding the order in which to take up the breeds of the different classes is not so easy as it seems upon first thought. The importance | af Ss D CORNWALL DEVON SOMERSET DORSET WILTS HAMPSHIRE SURREY WEST SUSSEX EAST SUSSEX {0. KENT 4) LONDON (2, ESSEX {& MIDDLESEX \¢ HERTS 1S BUCKS 16 BERKS {2 OXFORD 1. GLOUCESTER {2 MONMOUTH 20 HEREFORD 21. WORCESTER 22 WARWICK 2. NORTHAMPTON 24 BEDFORD 24 HUNTS 24 CAMBS. 2¢@ SUFFOLK 2A NORFOLK 24 |.OF ELY $0 PETERBOROUGH 3). RUTLAND 32 HOLLAND 33 KESTEVEN St NOTTS 35 LINOSEY 36 LEICESTER 37 DERBY 38 STAFFORD $8 SALOP 40 CHESTER 4). LANCASTER 42,-YORK 44 DURHAM 44, WESTMORELAND 45 GUMBERLAND WON DUS er — 46 NORTHUMBERLAND 42 BERWICK 48 ROXBURGH 42 SELKIRK SOPEEBLES 51, DUMFRIES $2. KIRKCUDBRIGHT 53 WIGTOWN St AYR S35 LANARK - 56 MIDLOTHIAN 57. HADDINGTON 58 LINLITHGOW. $8. RENFREW 60 DUMBARTON 61. STIRLING 62 FIFE 63 KINROSS G4 CLACK 65 PERTH 66. FORFAR 67 KINCARDINE 76 SUTHERLAND 77 CAITHNESS 78. GLAMORGAN 72 BRECON 60. CAERMARTHEN 8) PEMBROKE 82 CARDIGAN 83 RADNOR 84 MONTGOMERY 65 MERIONETH 86 DENBIGH 87, FLINT 88 CAERNARVON Fic. 1.—Map showing place of origin of the breeds of sheep of Great Britain that have been imported into the United States. of the breed is indicated, but not necessarily decided, by the number of purebred animals recorded. The records usually extend over a number of years and few of the sheep that have died have been noted 6 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. in the records. Hence it is difficult to tell the actual number of living animals. Many breeds have enjoyed periods of unusual prosperity, or “‘booms,’’ as they are commonly called. In some cases these have been more or less.permanent; in others, only temporary occurrences. Thus it is possible that a breed might have a large number of animals recorded and yet not be so important as one having many less because it has passed the zenith of its popularity. But even though we could obtain the actual number of living sheep recorded in each of the breed associations, taking them up in the order of their numerical importance would not be satisfactory because a breed is sometimes important in grading up the common flocks, while the number of its purebred sheep remains comparatively small. Notwithstanding the fact that sheep farming for wool alone is unprofitable, the Merino, distinctly a wool breed, is the foundation of American sheep husbandry. By far the greater number of grade flocks of America, especially through one section centering in Ohio, and another comprising the bulk of territory west of the Mississippi River, are of fine-wool origin. For this reason it is fitting that the Merinos be treated first. In the medium-wool types the Southdown is well down the list in numbers recorded, yet the important part this breed has played in the evolution and development of the other “‘down” breeds warrants it first place in this division. When there is no other preference between breeds, they are placed according to their numerical strength, care being taken to give the minor breeds a subordinate position. Among the long wools we have a case similar to that of the South- down. The Leicester is relatively unimportant in the United States as compared to the other long-wool breeds, notably the Cotswold and Lincoln. Yet the Leicester entered the foundation stock of the long wools, and therefore it should be placed first in the long-wool class. The unimportant woolless sheep are dealt with last. THE MERINO. The Spanish Merino is the progenitor of all the various Merino breeds, eds and types. Fine-wool sheep, presumably the ances- tors of the present breeds, were well established in Spain at the dawn of the Christian era, and as early as the eighth century extensive textile arts were carried on by the Saracens at Seville and the wool was furnished by the flocks of the surrounding country. There were two great groups of Spanish Merinos, known as the Estantes, or Stationary, and the Transhumantes, or Migratory. The latter group was considered much superior. These groups were tur- ther divided into a number of more or less important families. Little improvement took place in this breed in Spain, especially with regards : to mutton qualities, which were very inferior, but the wool of these sheep has been noted for its fineness for centuries. Merinos were introduced into Sweden about 1723; Saxony, 1765; Silesia, 1768; France, 1783; United States, 1793; Cape of Good Hope, 1797, and shortly afterwards into Australia. In all these countries distinct types or breeds have arisen, and marked improvements have taken place in many instances. In France the size, mutton qualities, and amount of fleece have been increased; in Saxony the fiber is of finer quality than that of the Spanish Merino; and similar improve- ments have taken place in other foreign lands. The improvements that have taken place in the United States will be discussed in a later paragraph. The world-wide siicibsdtion of the Merino can be accounted for by some of its peculiar qualities. The most important of these are its wide range of adaptability, its marked degree of hardiness (contrary to its apparently weak conformation), its inherent characteristic of producing a heavy fleece of superior quality, and its habit of grazing, these sheep banding together in large herds while feeding. The history of the Merino in this country has been marked by alternating periods of popularity. The first importation was brought over by Mr. William Foster, of Boston, Mass., in 1793. The ship- ment consisted of one ram and two ewes, and they were presented to Mr. Andrew Craigue, of Cambridge. The latter gentleman failed to realize their value, and he had them slaughtered for mutton purposes. Later, when he paid $1,000 for a single ram, he recognized his mistake. In 1801 other small importations came over, and the Merinos grad- ually increased in popularity and numbers until 1810, when the fine- wool craze started and they were literally imported by the thousands. In that year alone it is said that 10,000 were brought over. Ewes sold for as much as $1,000 and rams for $1,500. After the war of 1812 the boom died down, and sheep that formerly sold for hundreds of dollars could now be purchased for $1 a head. Spanish Merinos have not been imported into this country since that period, though Saxon and French Merinos were subsequently introduced. Half a century elapsed before the Merino was again in its glory. The second craze swept over the country during the early sixties. At this time rams were frequently valued as highly as $2,500, and an offer of $10,000 for one ram. was reported. The American type known as the Vermont Merino was developed mainly in New England. It became the heaviest wool-producing sheep in the world and the fiber was of exceptional strength and fine- ness. These sheep are distinctive in having heavy folds over the body, with the exception of on the back, these folds giving a larger surface for the production of wool. The wool extends over the head in a compact cap, often obscuring the eyes. Only the ears, the lower DOMESTIC BREEDS OF SHEEP. 7 8 BULLETIN 94, U. 8. DEPARTMENT OF AGRICULTURE. part of the nose, and the muzzle are woolless, and these are covered with white, silky hair. The wool also extends down the legs to the hoofs. A large amount of yolk or oil is desired, as this is regarded essential to the production of the best quality of fiber, but in a great many cases it has been overdone. The skin is a beautiful shade of pink, the ideal color. The form is rather inferior; the neck is long, shoulders sloping, and the chest is narrow. The withers are thin, the spring of ribs only moderate, consequently the back is rather narrow. Behind, they lack development in the leg of mutton, being more or less ‘‘cat-hammed.’’ This type became famous not only in the United States, but in foreign countries as well, and rams were shipped to Australia, South America, and South Africa. Many of the Vermont flocks have been disbanded, but shipments of Merinos © are still made frequently from this State both to South Africa and South America. Some prominent men in early American Merino his- tory were Stephen Atwood, of Woodbury, Conn.; Edwin Hammond, of Middlebury, Vt.; and William Jarvis, of Weathersfield, Vt. Robert Livingston also did a great deal in establishing the breed. The Delaine Merino was developed through Ohio and Pennsylvania and to a lesser extent in Michigan and West Virginia. This type differs from the Vermont Merino in having a smoother body with few or no folds. They possess more size and fatten more readily than the type of American Merino mentioned above. The fiber is consid- erably longer and usually grades as a combing wool. It does not contain as much yolk as that of the American Merino. The Delaine breeders have endeavored to combine mutton qualities with wool, and their success is attested by the present popularity of this type There are several different families of Delaines. The most impor- tant of these are the Dickinson, the National, the Victor Beall, the Black Top, and the Improved Black Top. Merinos in America are to-day divided into three classes, based upon the folds in their skin, fineness of fiber, their mutton qualities, etc., and are registered under these types. At the Columbian Exposition and again at the Louisiana Purchase Exposition in 1904, they were divided into two classes, A and B. Class C has since been added It must be admitted that there has been considerable confusion due to this classification.. The fairs are not uniform in their specifica- tions as to what comprises the different divisions, the judges are not all of the same opinion, and it is evident that the exhibitors have not the classification as clearly in mind as they should, since lightly folded A class sheep are sometimes shown with the B classes and heavily folded B’s occasionally compete with A class sheep for honors. An- other confusing condition is that the different classes do not breed true to type. A B-type ram may sire C-class lambs, or vice versa. Again the number of folds decreases with age, and a lamb that prop- DOMESTIC BREEDS OF SHEEP. 9 erly shows in the A class may belong to class B when it is a yearling or an aged sheep. The following paragraphs give the general idea of the different classes. The A-type Merino is characterized by heavy folds or wrinkles upon the neck, breast, middle, and quarters and a complete covering of wool over the body and legs. The Vermont Merinos would usually fall into this class. Mature rams in breeding condition should weigh about 140 pounds and ewes about 100 pounds. Rams should shear close to 30 pounds of wool for one year’s growth and ewes about 20 pounds. The fleece should be very dense, and the length of the fiber should be about 24 inches for one year’s growth. The fiber should also be very fine, ‘‘crimpy,” soft, and pliable. The yolk should be of a creamy color. It constitutes about 70 per cent of the fleece. Wool from this type grades as fine clothing or combing. B-type Merinos should have folds upon the neck, breast, flank, and about the tail head. The covering of wool over the body and legs is not quite equal to that of the A type. Mature rams in breeding con- dition should weigh from 150 to 175 pounds and ewes from 100 to 115 pounds. Good rams shear in the neighborhood of 25 pounds and ewes about 15 pounds. The fleece is generally less dense than that of the A type. The fiber should be crimpy, soft, and pliable. It should measure from 24 to 3 inches in length. The yolk is preferably of a creamy color and comprises about 65 per cent of the weight of the fleece. The wool grades as fine clothing or delaine. C-type Merinos should be perfectly plain or free from folds, unless to a very slight extent in the neck or breast. The Delaine represents this type. The head, legs, and body are not so well covered. Rams in good breeding condition should weigh about 175 pounds and ewes 125. A ram’s fleece (12 months’ growth) should weigh approxi- mately 18 pounds and that of the ewes 11 pounds. The fleece is much less dense, containing about 20,000 fibers per square inch. The fiber is less crimpy and longer, measuring from 3 to 4 inches. The yolk is white in color and should comprise about 55 per cent of the fleece. The wool from this type grades as fine delaine or staple. In most flocks of any material size all three classes or types are present, and these are crossed at the discretion of the breeder. For instance, if the ewes approach too closely to the angular A type, and their mutton qualities become markedly inferior, a ram is crossed upon them, of perhaps the C type, to remedy this and bring about a balance. If the opposite condition prevails, which is more often the case, an A-type ram might be used to improve the fleece. Some authorities hold that this is the sole purpose of the A type and that it is necessary to maintain a heavy fleece. Despite the fact that the Merino has long since passed the height of its popularity, the Merino blood is more prevalent in America to-day 36158°—14 2 10 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. than that of any other breed. They have two principal strongholds in this country. The first and most important is the range country west of the Mississippi, and the second is the fine-wool section of Ohio, which also embraces parts of Pennsylvania, West Virginia, and Michigan. On the range a hardy sheep that will withstand seasons of drought and scanty food, that will band together in large flocks while feeding, and that will produce a good fleece is desired. The Merino fills these requirements. Butitis also desirable to raise a crop of mutton lambs on the range. The Merino is distinctly inferior for this purpose, and as it seems to be difficult to secure a mutton breed that will suit range conditions in itself, the alternative has been taken of using ewes of Merino foundation and crossing a mutton ram upon them. The Delaine-type ewe has been especially popular for this purpose. In the fine-wool section of Ohio there are many purebred flocks of considerable size and note, and a large majority of the farmers’ flocks are grade or purebred Merino. Much Vermont stock was taken to Ohio. The strongest fine wool of the world is produced in this region. The establishment of the Merino in this section has been to some extent due to the demand for breeding stock through the West. Now that the demand has decreased because of the re- duction of the range and because of the Western States producing most of their own breeding stock, it seems possible that the Merino will remain and a type be developed that will more nearly fulfill the mutton requirements of the markets as they exist to-day. Of late years Merino ewes have been used for the production of “hothouse lambs.” The Merino breed has been hampered with a superabundance of record associations. Some of these have been founded upon certain strains of the breed, only sheep descended from these strains bemg eligible for registry. The confusion caused by crossing A, B, and C types and by the existence of numerous record associations is with- out a parallel in American live-stock history. The number of socie- ties at the present time is not so great as formerly, as some of these have combined and others have dropped out of existence. The American & Delaine Merino Record Association, Delaware, Ohio; the Standard Delaine Merino Sheep Breeders’ Association, Saline, Mich.; the Vermont, New York & Ohio Merimo Sheep Breeders’ As- sociation, Delaware, Ohio; and the Michigan Merino Sheep Breeders’ Association, Ann Arbor, Mich., are the principal remaining societies. THE RAMBOUILLET. The Rambouillet or French Merino breed was developed by the French Government for the purpose of securing a domestic supply of wool, In 1783, Louis XVI bought a large estate near the village of PLATE I. Bul. 94, U. S. Dept. of Agriculture. CLass A MERINO RAM. 1. Fic Fic. 2.—CLass A MERINO EWE. PLATE II. Bul. 94, U. S. Dept. of Agriculture. Fic. 1.—CLAss B MERINO RAM. CLaAss B MERINO EWE. 2) FIG PLATE III. = ai < SS oc Wl 2 e) = z Be (ac ui uw = S © O B wn 2 w twist ,butam er ee Bp tel orig old no 25 Wool: Forehead and cheeks, 2; belly, well covered, 3; quality, 5............... 10 22 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE, THE OXFORD DOWN. The Oxford Down originally was a crossbred sheep, having devel- oped from the direct crossing of well-established types. Although improved blood of other breeds has been used in establishing most of our present ones, evolving an entirely new breed by direct crossing is comparatively rare, the Corriedale of New Zealand and Australia being the only other example. The initial crossing that eventually resulted in the establishment of the Oxford breed took place about 1833 in Oxfordshire. Cotswold rams were used upon Hampshire ewes and some Southdown blood is also said to have been mtroduced. The object was not the estab- lishment of a new breed but improvement in the existing breeds. These crossbred sheep first appeared at the Windsor Royal in 1851 under the name of Down Cotswold. About 1857 their name was changed to Oxfordshire Downs. They did not receive a distinct place at the Royal until it was held at Battersea in 1862. As was to be expected, this breed was at first characterized by a striking lack of uniformity, the judges of the Royal criticizmg the exhibits of the years of 1862, 1865, and 1868 very unfavorably for this defect. Dur- ing the next 10 years there was a very great improvement in this respect, the type becoming much more permanent. Mr. Samuel Druce, of Eynsham, Oxford, and Mr. William Gillette, of Southhigh, were actively identified with the early development of the Oxford breed. The Oxford has extended its sphere of usefulness from its native shire to many parts of England, Scotland, Ireland, and Wales. It 1s especially popular for crossing purposes along the ‘‘border’’ of the first two countries. This breed has also been introduced into many countries of Europe, North and South America, Australia, and New Zealand, in which countries it has generally met with success. The first importation of this breed of sheep to America was made by Clayton Raybold, who brought them to Delaware in 1846. This was in the early days of the breed, and they were still known as Cots- wold crossbred sheep. In 1853 William C. Rives brought some into Virginia, and R.S. Fay, of Lynn, Mass., made an importation the same year. In the United States the greatest number of purebred Oxford flocks are found in New York, Ohio, Michigan, Wisconsin, Illinois, and Iowa. In the West there are some purebred flocks, but here the breed is valued chiefly for crossing purposes. Indeed, many flocks are maintained for supplying the range with rams, as the Oxford, because of its large carcass and heavy fleece, has been very popular during the last decade. Wherever the pasture is abundant the Oxford gives satisfaction, but it is in no sense a short-pasture sheep and does not usually thrive under the latter conditions. The Oxford is generally conceded to be the largest of the medium- wool breeds. Mature rams range in weight from 250 to 350 pounds DOMESTIC BREEDS OF SHEEP. ae and ewes from 180 to 275 pounds. The fleece is heavy, but it derives most of its weight from its length, as it is somewhat open in character, due to Cotswold blood. Superior Oxford flocks should shear 12 pounds of wool, on an average, of quarter and low quarter blood comb- ing wool, though Oxford fleeces occasionally grade as braid wool. The breed does not mature so early as some of the smaller ones, but they are at feast average in this respect. Their fecundity is also about the average. Objections to inferior Oxford Downs are open fleeces, dark spots on the skin, and occasional black fiber. The English Oxford Down Breeders’ Association was established in August, 1888. The American Oxford Down Record Association drew up its articles of incorporation at Cincinnati, Ohio, in January, 1882, after having met at least once during the previous year. The number of sheep recorded by this society up to January 1, 1914, is 67,280. The office of the secretary is now at Hamilton, Ohio. The following is the scale of points of the American Oxford Down Record Association : BREED TYPE FOR ANIMALS. Points. Form of a good general appearance, made by a well-balanced. conformation, free from coarseness in any part, and showing good style both at rest and ATTY EAD TOTO Ss ce a SIA hE el UREN hacen 15 Head of moderate length and dl between the ears and between the eyes, and well covered with wool over poll and down to the eyes. Color of face an even dark gray or brown, either with or without gray spot on tip of nose. 6 When fully matured and in good condition, rams should weigh 250 to 350 ound ssewee 180) toy 20 POUMGSe en: She Se ie a ee Be 5 Ears medium size, not too thick and of an even brown or done gray color.:--- zy Legs short, strong in bone, flat and of even dark gray or brown color, placed squarely under the "pod and? well, aparte.225. Ae sae es tek eg ga rare 2 ——= i) CONSTITUTION. Large around the heart and wide and full in the chest...........-..-..----.- 10 The movement must be bold and vigorous\ 982-40 )-5--440 65-54-22 shee ives poldeyprommuaemt and bright. 92. 22ers soe ae ees oe 4 Skinapbonte lata imketaec lon se ac5 0c) se noes eee eee eS eal) cele sepa 3 Neck strong and muscular in rams and well set on in both sexes...........- 3 — 25 MUTTON FORM AND QUALITY. Wide and straight on top of shoulders, back, loin, and rump, from base of neck Drearatsent paar BSF oA ec an a Se ce CS LS a ce 15 Full shoulders and thighs, well meated both inside and outside.--.......-- 5 Flanks well filled and strong so as to make the lower lines of the body as straight as possibie, and the side lines straight or rather full...-....--..-- 4 The whole carcass evenly covered with good, well-marbled meat........--- 6 —— 30 WOOL. Fleece of moderate length, close and of even quality, covering the whole carcass well, and free from black patches upon the body, neck, or head..-....- 15 24 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. THE DORSET HORN. The Dorset Horn, like the Southdown, is an extremely old breed that has been developed largely through selection. For several centuries there had existed in the county of Dorset in southern Eng- land a type of sheep that were coarse, small, and light of carcass, especially in fore quarters; but with broad, deep loins. They had dark noses and both sexes were horned. In Somerset was a larger, lankier type, producing longer wool and noted for their large lambs. They had white faces and pink noses. These types were probably the ancestors of the Dorset Horn. Little improvement was wrought in this breed until near the middle of the last century, and as mentioned in the preceding paragraph this improvement was effected through well-directed selection. Crossing was tried by a few breeders with both the Devonshire Knots and the Leicesters, but the attempts to introduce foreign blood resulted in failure. Not a little credit for the latter development of this breed is due to Richard Seymour, of Bradpole, who began improving his flock about 1830. Mathew Paul, of Burstock, was another early Dorset breeder of prominence. Although the sheep of Dorset and Somerset have long been recog- nized as distinct in type from those of surrounding counties, they were not assigned a place as a separate breed until 1862, when they were shown as such at the Royal at Battersea. The stronghold of the Dorset Horn is still in its native district of Dorset, Somerset, and Devon. In the former two counties it is the predominant breed. The section about Dorchester and the Isle of Wight possess many flocks of marked excellence. Small flocks are scattered over England, Scotland, and Ireland, but their distribution does not approach that of the more popular down breeds. They have also been exported to the Continent and to America. It is said that Dorset Horn sheep were first introduced into Virginia prior to 1882, but information as to where the shipment was made and who made it is lacking. Some representatives of this breed were shown at the fat stock show at Chicago in 1885, and two years later William Davey, of Lockport, N. Y., purchased some individuals of this breed from Valency E. Fuller, of Canada. The same year direct importations were made from Great Britain by A. Thayer, of Hoosick Falls, and E. F. Boroditch, of Massachusetts. In 1889, T. 8. Cooper, of Pennsylvania, made a large importation, consisting of 153 head. Dorsets can be found to-day in at least 32 States of the Union. New York, Ohio, Illinois, West Virginia, Massachusetts, Pennsyl- vania, Indiana, and New Jersey, in the order named, have the largest number of purebred flocks, and most of the other flocks are to be found in the eastern half of the country. Bul. 94, U. S. Dept. of Agriculture. PLATE IX. Fia. 1.—DORSET RAM. Fic. 2.—DoRSET EWE. PLATE X. Bul. 94, U. S. Dept. of Agriculture. —SUFFOLK RAM. the Fia Fic. 2.—SUFFOLK EWE. DOMESTIC BREEDS OF SHEEP. 25 There are very few Dorset flocks west of the Mississippi. Dorset wethers lack the finish characteristic of the lambs. Their fleece is not as heavy asis desirable. The lack of higher development in these two respects will probably prevent their ever becoming popular upon the range. The Dorset Horn is a medium-sized, somewhat rangy, white-faced breed, both sexes being horned, as the name would indicate. There is considerable variation in the size of American Dorsets, but rams in breeding condition should weigh from 200 to 225 pounds; ewes from 150 to 175 pounds. Their fleeces lack somewhat in weight, but are of excellent quality. The fiber is very white, and discolorations are practically unknown. Ewes produce from 6 to 7 pounds and rams from 8 to 10 pounds of wool. Twenty-five samples of Dorset fleece were graded upon the Philadelphia market, for the United States Department of Agriculture, 15 of which were three-eighths blood combing and the other 10 quarter blood combing wools. The Dorsets are probably the most fertile of all the mutton breeds of sheep, ewes frequently producing twins and triplets, and occasion- ally quadruplets. American breeders report from 140 to 175 per cent lamb crop. The ewes will breed either in the spring or fall, and it is claimed that they will produce two crops of lambs per year, but it is unlikely that this can be successfully accomplished, as most American breeders of prominence condemn the practice as being injurious to the ewes. The ewes are excellent mothers and usually have ample milk for their lambs, whether they be singles, twins, or triplets. In the United States a large percentage of the ewes lamb in the fall, many breeders having the entire crop dropped at this time. In their native shire the ewes were formerly used for dairy purposes. The breed matures early, the lambs growing rapidly and exhibiting a bloom that they often do not retain during the wether stage. Dorset ewes are very highly regarded for the production of ‘‘hot- house”’ lambs, and the grades are considered even better for this purpose than the purebreds. The East, with its large cities and con- sequent favorable market facilities, is especially adapted to the production of this product, which explains the distribution of the breed in this section. The light shearing qualities and the fact that the Dorset is a hard feeder are the main objections to this breed. Dorset lambs are as a rule excellently fleshed, but the criticism has been made that the wethers are deficient upon the shoulders and back. The breed is also criticized for being deficient in heart girth. This is especially true of the rams. The Dorset Horn Sheep Breeders’ Association of England was founded in 1891. The American Dorset Horn Breeders’ Association was founded the same year, but has been inactive of late years. The 36158°—14—4 26 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. Continental Dorset Club was founded in 1897, and up to January 1, 1914, it had recorded 15,030 sheep. The secretary’s address is Mechanicsburg, Ohio. The following is the scale of points of the breed as adopted by the last-named organization: SCALE OF POINTS. Head: Neat, face white, nostrils large, well covered on crown and under jaws WIN WOOL. Soo 2 Soe oe we oe wee eee he ess) ook ae 5 Horns: Small and gracefully curving forward rather close to jaw..........-....- 5 Eyes: ‘Prominent and bright. 22. 231. 3). 1822860 sale eee ee 2 Ears: Medium size, covered with short white hair.....................--:------ 2 Neck: Short, symmetrical, strongly set on shoulders, gradually tapermg to junc- tion ‘of head. . 2... --. aces Te Sa She Cee ee Ee a 3) Shoulders: Broad and full, joining neck forward and chine backward with no depression at either ‘point (important)... 42 ASS ace ae.) Ue eee 15 Brisket: Wide and full, forward, chest full and deep..-.................-.-.--- 8 Fore flank: Quite full, showing little depression behind shoulder... - - et Cork 8 Back and Join: Wide and straight, from which ribs should spring with a. fine, cir- ciulararch . 222.2 2228S et ods wes dee ke ee 10 Quarters: Wide and full, with mutton extending down to hocks.....:..........- 10 Belly: Straight on'under line.!22'. 2.27225 2p eee ee ee ee ae 3 Fleece: Medium grade, of even quality presenting a smooth surface and extend- ing over belly and well:down on legs... 252/222 222 g35e see ene ae eee 12 General conformation: Of the mutton type, body moderately long: short, stout legs, placed squarely under body; skin pink; appearance attractive...-..--.-- 15 Total «02:2 .2.ched. conse deeese- bes eg hak Gee pee eee eee 100 SUFFOLK DOWN. The Suffolk Down is a comparatively new breed of sheep that has originated in Norfolk and neighboring counties of southeastern England. The Suffolks owe their origin to the crossing of Southdown and possibly Hampshire rams upon the Old Norfolk breed. These latter sheep have been described as being active, robust, upstanding, with black faces and legs, and horned in both sexes. They were very prolific and produced fleeces of fine, soft wool averaging about 3 pounds in weight. The Southdown blood improved the carcass, increased the early- maturing qualities, and removed the horns. It is claimed that no foreign blood was introduced after 1850. Separate classes were made for the breed at the Suffolk show in 1859, when they received their present name. Prior to this date, they had been known as Southdown-Norfolks, and locally as Blackfaces. The breed was not considered established well enough to merit a class at the Royal Show until the meeting of 1886. George Dobito, of Ludgate, Suffolk, stands preeminent among the early improvers of this breed, and he began work about 1850. The extent ot distribution of the Suffolk does not approach that of the other Down breeds, but they are fairly common in the counties of DOMESTIC BREEDS OF SHEEP. edi Norfolk, Suffolk, Cambridge, Essex, and Kent, and are found in scattered flocks over other parts of England. The excellent quality of their mutton and their high dressing percentage have won them an enviable position upon the English mutton market, and the prizes won by this breed in carcass contests at the leading shows are espe- cially numerous. The newness of the breed and the fact that they have not been intensively advertised are factors in their limited distribution, but importations have been made into the countries of Holland, Germany, France, Spain, and Saxony, of Europe, and to Australia, New Zealand, South Africa, and North and South America. In the latter country they are quite popular for crossing upon Merino ewes because of the excellence of the resulting lambs. The first importation of Suffolk Downs into this country was made by Mr. M. B. Streeter, of Brooklyn, N. Y., in 1888. Other importa- tions have since followed. Purebred Suffolks have been recorded from 16 States, Iowa, Indiana, Illinois, the Virginias, and New York having the largest number of flocks. The fact that only one or two shows in this country have distinct classes for this breed indicates that the Suffolk has not yet secured a very firm foothold in America. The Suffolk is a rather active, large, upstanding sheep, rams weighing from 200 to 240 pounds and ewes from 150 to 200 pounds. They are characterized by their jet black head and legs, being darker than any of the other breeds in these points. The ears are pointed and are frequently carried pointing upward and backward from the head. They have no wool on the face, or upon the legs from the knees and hocks downward. Though upstanding in appearance, these sheep dress out to good advantage. In 1903 a Suffolk won first in the carcass contest at the International at Chicago. The mutton is of excellent quality, closely approaching that of the Southdown. Their fleeces are light, but the wool is soft and of fair quality, grading low three-eighths and quarter blood combing. Flocks have been reported averaging 9 pounds of wool, but it is probable that the average is considerably below this figure. The fecundity of the Suffolk is very high, ranking near the top. They are an early-maturing sheep, as indicated by the wide use of the ram lambs for breeding purposes. The most serious criticisms of the Suffolk are their light fleeces and upstanding appearance. They are fair in feeding qualities, and if the prejudice against their lanky appearance can be overcome, there is no reason why they should not become much more popular in this country. The English Suffolk Down Sheep Society was organized in 1888 for the purpose of registering purebred flocks. The American Suffolk Flock Registry was founded in 1892 with headquarters at Des Moines, Towa. There were 2,264 Suffolks recorded in the United States and Canada up to January 1, 1914, 28 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. The following is the scale of points of the Suffolk Sheep Society of England: Points. Head: Eornless; face black and long, and muzzle moderatly fine, especially in ewes. (A small quantity of clean, white wool on the forehead not objected to.) Ears, a medium length, black and fine texture. Eyes, bright and full.._..__. 25 Neck: Moderate length and well set (in rams stronger, with a good crest)....... 5 Shoulder: Broadjand: oblique-:..--...!.<... 2-2 cee. - See ee ee 8 Face either white or slightly mixed with gray, or white dappled with brown... -- 4 Nostrils wide and expanded;-nose dark. 22022. 42) 2/2002 . Sos 28 - ee seee eeeee 1 Eyes prominent, but mild looking. -.- - . /:02e2+ js 2-1-2222 -eeeeeee ee eee ee 2 Ears broad, long, moderately thin; and covered with short hair..........---.--- 4 Collar full from breast and shoulders, tapering gradually all the way to where the neck and head join. The neck should be short, thick, and strong, indicating constitutional vigor, and free from coarse and loose skin.........-.----------- 6 Shoulders broad and full, and at the same time join so gradually to the collar for- ward and chine backward as not to leave the least hollow in either place --..- 8 Fore legs: The mutton on the arm or fore thigh should come quite to the knee. Leg upright, with heavy bone, being clear from superfluous skin, with wool to fetlock, and may be mixed with pray......--.--.—- -2- <2 eee eee eee a 4 Breast broad and well forward, keeping the legs wide apart; girth or chest full and deepr Sy iteer ws. oo. BLL 3. Se Se ee 10 Fore flank quite full, not showing hollow behind the shoulders. .............--. 5 Back and Join broad, flat, and straight, from which the ribs must spring with a fine Circwlar ATCB. osc 6 os - n\n oo woe owes wie oe ish op el om 12 Belly straight on underline... ...... 2.2.2. 2c ee ne nee ee ne see 3 Quarters long and full, with mutton quite down to the hock..........-.-------- 8 Hockshould stand neither in nor outs. .s.20 625020 Secs Jak eee 2 DOMESTIC BREEDS OF SHEEP. 45 Points. Twist or junction inside the thighs, deep, wide, and full, which, with a broad breast, will keep the legs open and upright...........-...-2--.-+---.---.+.-: 5 Fleece: The whole body should be covered with long lustrous wool............. 18 Nota. 366 Seo POO BRE OAC DEE SDB SNe ROH ean Na iam ae amanye a eet 100 FOR COTSWOLD EWE. Head moderately fine, broad between the eyes and nostrils, but without a short, thick appearance, and well covered on crown with long, lustrous wool.....-.-- 8 Face either white or slightly mixed with gray, or white dappled with brown.... 4 Nostilsiwideiandvexpanded nose dark 2/2052 ticle. bolle yale. Sole sale ok 1 Pe sanomumen thou mild Lookimer i. 0 0) ees a elec ltee ew cie ct cos nied ale wie /eied 2 Ears broad, long, moderately thin, and covered with short hair.............-.--- 4 Collar full from breast and shoulders, tapering gradually all the way to where the neck and head join; the neck should be fine and graceful, and free from coarse CES Gra SID SYST Byes See Pe mca) Se eee Rg 5 Shoulders broad and full, and at the same time join so gradually to the collar for- ward and chine backward as not to leave the least hollow in either place. ..... 8 Fore legs: The mutton on the arm or fore thigh should come quite to the knee; lee upright with heavy bone, being clear from superfluous skin val wool to LeHoekewamolmany Oe) MICO MWIth STayis = Se. 8S waa sees as ok ue Qos Seles: L Breast broad and well forward, keeping the legs wide apart; girth or-chest full GG! GISEL! «- ae eR Ss A Os Ue rer seh eRe Ie ruase Som RORY am Sees 10 Fore flank quite full, not showing hollow behind the shoulder.................- 4 Back and loin ooedl flat, and straight, from which the ribs must spring with a RRR eMC ULMER C Hie ae cde haga tye a Riera Marcle rare ic eRe oe ais ae ciohle cicle cuaie ecard 12 ec iya sical elit OMG CHIMON ao iaca cits en ieee aia ei olne wicisien ec dane stan ates 5 Quarters long and full, with mutton quite down to the hock................... 8 Hock should stand agen! TED TEL OP YOUN eit Sealey ANE eet eh ails CR a a et ana in Ved 2 Twist or junction inside, the thighs deep, ile and full, which, with a broad breast, will keep the lane QpenVeaTnel Ung rea ek aie Uk nats Se Neale epee 5 Fleece: The whole body should be covered with long, lustrous wool...........- 18 ARCO Tt ee eta ee ee sa Per Sn mt cc Oe hog Niece oe a ge binte Seaedbae Bac e oa NS Cea 100 THE LINCOLN. The Old Lincolns were mentioned as an established breed as early as 1749. The modern type of this breed resulted from crossing Leicester rams upon the Old Lincoln ewes. The breed was recog- nized by the Royal Agricultural Society as distinct in 1862. Their home is in Lincolnshire, in northeastern England, the east side of the county touching the sea. The Old Lincolns were the largest breed of sheep in Britain. They were coarse and had white faces and legs and heavy heads and necks. They lacked spring of ribs and were low in the back. They produced a very heavy, oily fleece, though their bellies and legs were said to have been almost bare. They were slow at reaching maturity and did not feed very well. The Leicester blood improved the symmetry and feeding qualities very greatly; it also induced early maturity. The Dudding family, of Riby Grove, Great Grimbsy, Lincolnshire, 46 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. bred Lincolns for about 175 years. This famous flock was dispersed in July, 1913. Until about 1850 little attention was given the Lincoln outside of its own locality. Since that time it has spread over Lincolnshire, Rutland, and several neighboring counties. The breed has also become famous in Australia, New Zealand, South America, South Africa, Canada, and the United States. Crossed upon fine-wool sheep of Merino blood, the Lincoln has given especially favorable results in Australia, New Zealand, and South America. The large body and long fleece are apparent to such an extent in the cross that a very profitable lamb results. By continuing this crossing the Corriedale breed has been established in the former countries. The Lincoln is also bred pure in these countries, but the type is somewhat different from the English Lincoln. Old-type Lincolns are said to have been brought to America pre- vious to 1796. In 1825 A. A. Lawrence, of Massachusetts, made an importation of 10 head of the improved type, and several other im- portations followed shortly afterwards. A Lincoln ram was recently imported to Oregon from New Zealand. The type varied consider- ably from that of the English breed. The Lincoln is adapted to fairly fertile and arable farming sec- tions, as they do not thrive upon broken pasture. They also require a fairly humid climate for their greatest development, which accounts for their importance in Oregon. In this State they attain a measure of excellence not excelled by those of England. The Willamette Valley is the breeding grounds for Lincoln rams for use upon the range, and the demand is greater than the supply. Ohio and Mich- igan are also noted for their purebred flocks. In Oregon and Mon- tana especially, and in some of the other States to a lesser extent, a great many cross-bred Lincoln fine-wool lambs are produced: The lambs produced by this cross are exceptionally profitable and are very popular upon the market. Taken as a breed, the Lincoln is the largest of all English sheep, but individuals of the Cotswold breed may equal them in size. The rams should weigh from 250 to 375 pounds and the ewes from 225 to 275 pounds. Their mutton is only of fair quality, it bemg some- what coarse and not as palatable as that of the Down breeds. As the Lincoln is the heaviest breed, it also produces the heaviest fleece of all the mutton breeds. The staple is long (samples being reported that measured 21 inches), very lustrous, and hangs together in distinct staples. Fleeces have been reported that weighed 32 pounds washed wool, but they usually range from 12 to 16 pounds, with 14 pounds as a good average for a flock. The commercial grades of this wool are braid and low quarter blood. In the Northwest fleeces are sometimes allowed to grow for longer periods than one year, Bul. 94, U. S. Dept. of Agriculture. PLATE XXI. Fic. 1.—LINCOLN RAM. Fig. 2.—LINCOLN Ewe. Bul. 94, U. S. Dept. of Agriculture. PLATE XXII. Fic. 1.—ROMNEY MARSH RAM. Fla. 2.—ROMNEY MARSH EWE. Bul. 94, U. S. Dept. of Agriculture. PLATE XXIII. Fig. 1.—WENSLEYDALE RAM. Fig. 2.—TRIO OF WENSLEYDALE EWES. . 94, U. S. Dept. of Agriculture. PLATE XXIV. Fic. 1.—DARTMOOR RAM. Bs ee guess ess . 2.—DARTMOOR EWE. ~ DOMESTIC BREEDS OF SHERFP. 47 extra long staple being produced that sells for as much as $1 a pound. However, the amount of this trade is limited. In early maturity and fecundity the Lincoln is similar tothe other long-wool breeds. None of them have these qualities developed as strongly as the Down breeds. The ewes give a fair amount of milk. The Lincoln Longwool Sheep Breeders’ Association of England was organized in 1892. The National American Lincoln Sheep Breeders’ Association was founded at Lansing, Mich., in 1891. They have registered up to January 1, 1914, 26,122 head, and the secretary is now located at Charlotte, Mich. The following standard and scale of points has been adopted: STANDARD AND SCALE OF POINTS OF LINCOLN SHEEP, Points. Constitution: Body deep, back wide and straight; wide and full in the thigh; bright, large eyes; skin soft and of a pink color. . ie Da OZD) Size: Matured rams not less than 250 pounds when? in sand semcittiions magtined EWES, O15 lies ielavena 4 ove vera ke ae esas el sa ge ee 10 Appearance: Good carriage and symmetry of form...-........----------------- 10 Body: Well proportioned, good bone and length; broad hind quarters; legs stand- iuemVvelunmarh, oreast wade and. deep: 522522 2: qye-Ssi2- el glos so. gse2t S 15 Head: Should be covered with wool to the ears; tuft on forehead; eyes expressive; ears fair length; dotted or mottled in color..... ra aL io ek Se am aR 10 Neck: Medium length; good muscle; well set on body.. Se ste 5 Legs: Broad and set well apart; 2508. shape; color white, “bud some piece Gk ae noterequaliy-cwooled tothe knees: ois! Wolly o. ord eet eee io 10 Fleece: Of even length and quality over body; not less than 8 inches long for 1 BRL S LUD WU 5 Lae See Bs ee ee es Pa Wa Uc PP a et ee 10 Quality of wool: Rather fine, long wool; strong, lustrous fiber; no tendency to cot. 5 THE KENT, OR ROMNEY MARSH. The Romney Marsh sheep originated in the low-lying tract of land bearing the same name in the county of Kent, in southeastern Eng- land. The marsh is about 14 miles long and 10 miles broad. Itisa low, level, alluvial plain, and high tide at one time covered it, but since then the sea has been held back by embankments. The exact age of the old-type Romney is unknown, but it is supposed that they roamed the marsh for at least several centuries. Like all other ancient breeds, the prototype of the modern Romney lacked mutton form, symmetry, and quality. They were, however, very hardy and produced a heavy fleece of long wool. They were good grazers and rarely received any feed other than pasture through- out the year. The infusion of Leicester blood, that probably took place, as in all the longwool breeds, was not very successful in the Romneys, espe- cially where the proportion of the foreign blood was at all large. While it improved the form, the quality, and the early-maturing 48 BULLETIN 94, U. 8. DEPARTMENT OF AGRICULTURE. characteristics, it also reduced the size, the weight of fleece, the con- stitution, and their ability to rustle for themselves. This being the case, the breeders later used the Leicester for a type and approached its desirable qualities as nearly as possible through selection within the breed itself. The Romneys are still the favorite sheep in their native marsh. They subsist here without artificial feeding throughout their second winter. From this native habitat they have gradually spread over the county of Kent, and flocks are also to be found in Sussex, Herts, and Rutlandshire. They have been exported in increasing numbers since the establish- ment of the English breed association in 1895, and are especially pop- ular in New Zealand and Argentina. F. W. Harding imported oc William Riddell & Sons in 1904 four ewes and one ram of this breed from England. They were exhibited at the St. Louis Exposition, but did not make a very favorable im- pression. Eleven ewes and one ram were imported in 1909 for the same firm from New Zealand. Those from New Zealand were smaller, had more quality, and were better shearers than the English. The same year Mr. A. T. Hickman, of Egerton, Kent, exported 32 head of rams to America, which were sold during the International Live Stock Exposition of that year. They realized an average of only $24.125 per head, a rather low price when $1,500 has been realized for a single ram in England. As to pee a this breed to this country, much is yet to be determined. Where they have been crossed upon fine wools they have given large, strong lambs, and the promoters are high in their praise of this breed. It is claimed that Romney lambs are larger at birth than those of any other sheep. It seems altogether probable that _ the breed will take a prominent place among the other long wools of this country and enrich our live-stock industry by so doing. Three ewes and one ram were also imported for the Wyoming Experiment Station in the fall of 1906, and they seem to have made a favorable impression, both the purebreds and the crosses that have been produced. The breed is white-faced and hornless and unusually hardy. Rams should weigh from 200 to 225 pounds and ewes from 175 to 200 pounds. The mutton is the best of the long-wool breeds, ranking next to the Downs, and it enters prominently into the frozen-careass trade of New Zealand and Argentina. The fleece is long and dense and has some of the characteristics of the medium wools, the ringlets char- acteristic of long wools being not as much in evidence. The foretop may be either present or absent. Fleeces should weigh from 12 to 16 pounds. The wool ordinarily grades a low quarter blood combing. DOMESTIC BREEDS OF SHEEP. 49 The fecundity of the breed is ordinary, a lamb to a ewe being con- sidered a good average. The breed is criticized in England for lacking fixity of type and for being prominent in the backbone and shoulders. Hardly enough specimens have come to this country to enable one to criticize them justly. The Kent, or Romney Marsh, Sheep Breeders’ Association of Eng- land was founded in 1895, and it has done much to advance the interests of the breed. The New Zealand Romney Marsh Sheep Breeders’ Association was organized about the same time. The Romney Sheep Breeders’ Association of America was organized December 5, 1911, at Chicago. Up to January 1, 1914, they have registered 124 head of sheep. The association has been very active in advancing the breed in every possible way, and a number of other importations have resulted from their endeavors. The offices are at Mechanicsburg, Ohio. THE WENSLEYDALE. The Wensleydale is the modern form of the old Teeswater breed. In some parts of their native country, notably North Lancashire, they are still known by the latter name. They were also locally known by the name of ‘‘Mugs” until 1876, since which time they have borne their present name. It is said that these sheep were used by Bakewell in developing the Leicester, and there is consider- able similarity between the two breeds. However, this likeness may be due to the Leicester blood that was subsequently introduced into the Wensleydale. Mr. R. Outwaite, of Appleton, the ‘‘Patriarch of the Wensleydales,’”’ used a large Leicester ram, a son of which was the sire of the famous ram ‘‘Blue Cap,” shown at the Liverpool Royal in 1841. Mr. Outwaite refused 100 guineas for this famous sire. To him and to his sons can be traced most of the leading characteristics of the modern Wensleydale. The Leicester rams imparted early maturity, smaller, more compact carcasses, better quality of mutton, and a finer, denser fleece to the old breed. The present location of the breed is in north and northwest Yorkshire, Cumberland, and Westmoreland Counties. In July, 1906, F. H. Neal, of Lucan, Ontario, Canada, imported three yearling ewes and one ram of the Wensleydale breed for the Wyoming Experiment Station. These did not prove popular, being too leggy and having open fleeces, and when crossed upon other breeds did not give flattering results. It is possible that the poor showing made was due to the fact that those imported were not good. specimens. 50 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. The Wensleydale is a large, high-standing, hornless, long-wool breed, very active and hardy. The face and legs, and the entire skin to a less degree, are blue. This color is preferable because dark-faced lambs are desired when this breed is crossed upon the Black-faced Highland. These lambs are known as ‘‘crosses,” or ‘‘Mashams,”’ in Britain. The mutton is of good quality, the fleece is long and open, the locks falling in close ringlets, and the fiber is of good quality. They are said to be quite fertile and to make good mothers. In England there are rival breed associations. Both of these asso- ciations were founded about 1890. One was known as the Pure Select Wensleydale Sheep Breeders’ Association, but changed its name later to the Incorporated Wensleydale Sheep Breeders’ Asso- ciation. This society holds its annual fair at Hillifield. The other is called the Wensleydale Longwool Sheep Breeders’ Association, and this society’s fair is held at Northallerton. The scale of points of the latter English Society will be given, as there is no American society. SCALE OF POINTS FOR WENSLEYDALE RAMS. Points. Head: Face dark; ears dark and well set on; head broad and flat between ears; muzzle strong in rams; a tuft of wool on forehead; eyes bright and full; head gaily Carmled 2): 2i2'. 40a. Ue Seo EO ee ee 15 Neck: Moderate length, strong, and well set on to the shoulders....-.....-...-- 10 Shoulder: Broad arid oblique:-2...-3. Miser -2-je-a eens) eae eee eee 5 Chest: “Deep and wide: 5.22 22 rte es gnces cee oe te ee eee eee 10 Wool: Bright luster; curled all over body; all alike in staple..................... 20 Back and loins: Ribs well sprung and deep; loins broad and covered with meat; tail broad: flank fullsz.tisheceh bs. | ee ee eC eee oe 25 Legs and feet: Straight and a little fine wool below the hock; fore legs well set apart; hind Jegs well filled with ‘mutton...12.-2....-2esceeeeeeee see ee eee Th Totals. 2. geri. esse Riseh Laid . Lee ee ee ee ee 100 THE DARTMOOR. On either side of the Dartmoor in Devonshire a type of sheep has developed that is designated as the Dartmoor breed. Some claim that the foundation stock of this breed was the same as that of the Exmoor, and this theory is as plausible as any, but for at least three generations the breed has been distinct from the Exmoor in that they are considerably larger and produce heavier, longer fleeces in which the staples are more distinct. Like the other long-wool breeds, the Dartmoor was considerably improved years ago by the Leicester, Lincoln blood also being intro- duced about this time. The breed has never been very widely distributed, but they have proven an excellent sheep in their native moor. Their extreme hardi- ness enables them to withstand the rigors of the winters of the Dart- DOMESTIC BREEDS OF SHEEP. 51 moor, principally upon grass, but sometimes supplemented with a little hay. They can withstand a very wet climate. Only the show sheep recetve grain or roots. . Wrightson says, ‘‘The Dartmoor sheep of to-day are a large, long wooled variety, rivaling in size the Cotswold, Lincoln, or Romney Marsh breeds.’”’ With the exception of their hardiness they have largely lost the characteristics of a mountain breed. They are pref- erably hornless, but the rams occasionally have short horns, about 2 inches long and extending backward from the head. The face is eray, with black spots frequently about the muzzle and on the ears. Dun spots are objectionable. The wool is long, sometimes reaching — a length of 15 inches in 12 months, of excellent quality, and very strong. It extends over the polls and well down over the hocks and knees, and a little appears upon the hind legs. Fleeces should weigh about 15 pounds. The ewes are excellent mothers and produce early lambs when re- moved to more favorable climates, but few fat lambs are produced in the Dartmoor. Wm. Cooper & Nephews imported 58 head of Dartmoors in 1909 for John Rawlins, of Forest, Ontario. Soon afterwards these sheep were sold and taken to Utah and Wyoming. They greatly resemble a gray-faced Cotswold and are of about the same size as that breed. They are characteristically ewe-necked. The fleece is of exceptional length and quality, and the ringlets are close and distinct. The Dartmoor has been used for the production of extra long wool to a limited extent, and they seem especially suitable for this purpose. However, too few of this breed have been imported and not enough trials have been made to warrant any extended discussion as to their general fitness to American conditions. BLACK-FACED HIGHLAND. The Black-faced Highland is much famed in poetry and legend, and there are many explanations as to its origin. Among these are that the original stock was cast ashore from the Spanish Armada, an already overworked theory, and that they are the result of a cross between a sheep and a goat, something which has never been proved _ to exist, and from present knowledge seems impossible. Other theo- ries are that they came from the mountainous part of England to Perth and Dumbarton, and that the original flock was placed upon the estate of King James IV, in Ettrick Forest, about 1503. Either of these latter two theories is at least possible. At any rate, these black-faced sheep have been well known for a century and a half, and the dispute as to their origin would indicate that they had ranged the Highlands for a still longer period. 52 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. After the establishment of the breed in Perth and Dumbarton, they colonized the neighboring counties and eventually spread over the Highlands of Scotland and much of the mountainous region of England. About a century ago, the Black-face was forced to retreat before the Cheviot, but it later reestablished itself, because of its greater hardiness. These two breeds practically comprise the sheep sections of the Scotch shows. David Dun, of Kirkton, greatly im- proved the breed, and he has been referred to as the Scotch Bakewell. Cross-bred or grade Black-faced Highland sheep meet with much favor in Scotland. Crossing a Leicester ram upon the ewes pro- duces what is known as a “cross” or ‘‘mule”’; a Cheviot ram upon Black-faced ewes produces a “‘half-long.”’ Hugh Brodie, in June, 1861, made an importation of one ram and two ewes to New York Mills, N. Y. In 1867 Isaac Stickney made an importation into Illinois. They have not been especially popular, and consequently their distribution is quite limited. The New York State Fair is the only show in this country where these sheep are exhibited. The breed would probably succeed in some of the mountainous parts of this country and also in Alaska, as they thrive excellently upon coarse pasture, but upon the more fertile, arable districts they are out of place and will not yield returns comparable to those of the breeds adapted to the latter conditions. They are a very picturesque breed and are suitable for keeping in parks, and have been used for this purpose to a certain extent. The Black-faced Highland is the hardiest of all British breeds of sheep. They are small and very active, but not so restless as the Welsh Mountain sheep. ‘Their faces and legs are generally free from wool and covered with black or black and white hair. They usually have a small amount of wool about the top of their heads. When ‘mottled, the markings are always very distinct. The form is rather inferior because of their habits of life, but the mutton is of the highest quality. Rams and ewes in breeding condition should average about 150 pounds and 125 pounds, respectively. The fleece is of very low quality, lacking fineness, luster, and uni- formity. It usually contains considerable hair and kemp and is classed as carpet wool when sold upon our markets. The staple is usually quite long, occasionally attaining a length of 15 inches. Both sexes are horned, and it is sometimes necessary to cut off part of the horns to prevent their growing into the head and to allow them to eat, otherwise they could not get their heads upon the ground. The ewes are good mothers and fair milkers, and the lambs are very strong at birth. These sheep show a marked fondness for their homes. It is claimed that they have traveled 60 miles and swam rivers to return to their native haunts. \ Bul. 94, U. S. Dept. of Agriculture. Fic. 1.—BLACK-FACED HIGHLAND RAM. Fig. 2.—BLACK-FACED HIGHLAND EWE. PLATE XXV. Bul. 94, U. S. Dept. of Agriculture. PLATE XXVI Fig. 2.—KARAKULE EWE AND LAMB. PLATE XXVIII. Bul. 94, U. S, Dept. of Agriculture. PERSIAN RAM. 1 FIG Fic. 2.—PERSIAN EWE AND LAMB. Bu!. 94, U. S. Dept. of Agriculture. PLATE XXVIII. Fic. 1.—BARBADOS RAM. Fic. 2.—BARBADOS EWE. DOMESTIC BREEDS OF SHEEP. 53 Tf Black-faced ewes are fed heavily when they are with lamb, there is danger of growth of the horns of the male lambs to such an extent that death may result to both ewe and lamb. A meeting of the breeders of Black-faced Highland sheep was held January 31, 1907, at New York City, and the American Black-faced Highland Sheep Association was formed. This organization looks after the breed in America. THE KARAKULE OR ARABI. The Karakule sheep has sprung into prominence because of the increase in demand for Persian lambskins. The Persian lambskin is known by such other trade names as krimmer, astrachan, and broad- tail, these different terms representing somewhat different grades, and is the product of the Karakule or Arabi lamb. This demand has increased immensely during the last 15 years, one New York house alone importing from 200,000 to 250,000 skins per year. These skins are practically all imported from Bokhara and the neighboring districts of Russian Turkestan. The large foreign de- mand for skins has caused a great deal of crossing, this having been practiced to such an extent as to threaten the existence of the breed. A well-known authority on this sheep made the statement that there were not more than 5,000 purebred Karakules in existence, and that these were mostly to be found upon the estates of the Bokharan noblemen. There has been a law passed forbidding the exportation of Kara- kules from their native country, and this is rigorously enforced. This edict is said to have been passed for religious reasons, but the desire to keep a monopoly upon the fur industry was probably also a reason for its enactment. The Karakules are one of the fat-tail breeds. The caudal append- age is broad, flat, and tapering toward the end. The lower verte- bre are curled and twisted to such an extent that they resemble a corkscrew, and the entire appendage is used primarily as a storehouse for fat. The head is strikingly characteristic of the breed, the face being narrow and the top and fore part of the skull much rounded. The rams ordinarily have beautiful outspreading spiral horns, but the ewes are generally hornless. The ears are small and pendulous, especially soin the lambs. ‘The face and legs of the adults are covered with short, lustrous black hair, while the wool of the body is coarse, long, and varies in color from gray to black. Very hard outer wool and the absence of soft underwool are said to be indications of purity of blood. The breed is noted for its extreme hardiness, and it is able to exist and thrive under very adverse conditions. In Bokhara the sheep 54 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. are kept entirely in the mountains during the summer and until snow flies; then they are driven to the lowlands, where they are wintered. The mutton is said to be the most palatable of any breed, and the fat is also considered a delicacy by the Bokharans, being used by them instead of butter. The lambs when dropped are strong and active, usually jet black. The wool has a high luster and should be closely curled over the entire body, down the legs, and well over the head. Occasionally golden-brown lambs are dropped, the color of the prophet Mohammed. These are said to be especially highly valued by certain tribes and to have exalted the Karakule to its sacred position. Intermixed gray hairs among the black also rarely occur, producing a skin resembling somewhat the Siberian silver fox. When used for producing fur, the lambs must be killed when not older than 10 days, as the curls open after this period. Formerly the skin of the unborn lamb was used, necessitating the killing of both the ewe and the lamb, but this practice no longer prevails. After the lambs are killed the ewes are milked for a time, and the famous Brinza cheese is made from the product. The value of supe- rior skins ranges from $10 to $15. The first Karakules to come to America were those brought over by Dr. C. C. Young, of Belen, Tex., in December, 1908. This shipment originally consisted of 15 head—3 bucks and 12 ewes. Seven lambs were born, during the journey. Another importation was made by the same person in November, 1912, consisting of 19 head—13 bucks and 6 ewes. One buck died in quarantine and 5 lambs were born, making a total of 23 head. A number of flocks have been established in this country from this stock, in Texas, New Mexico, and Kansas, and recently a flock has been taken to Prince Edward Island. The Department of Agri- culture used two of these rams for experimental purposes, crossing them upon ewes of the American Merino, Barbados, Cotswold, and Cheviot breeds. THalf-blood skins were produced, but they were of poor quality. ‘The crossing upon the Merino and Cheviot breeds has helped to establish the fact that the tight-wool breeds are un- suited for the production of fur. With the Barbados cross there still seems to be possibilities. The second cross, resulting in a three-quarter blood Karakule lamb, shows considerable improvement, and if the high fecundity of the Barbados can be maintained in the higher crosses it may be that this work will prove valuable in increasing the amount of Karakule breeding stock. Of the long-wool crosses with the Karakule, the Lincoln has given the best results. The Karakule has been tried in Texas, Kansas, Maryland, and a number of other places in America, and in every instance has proven extremely hardy. ‘There is no doubt but that the breed will thrive in DOMESTIC BREEDS OF SHEEP. 55 our climate, and from the results that have already been obtained in fur production it seems quite likely that the industry will be more permanently established in America. THE PERSIAN SHEEP. The first importation of Persians to the United States took place in June, 1892. Truxton Beale, United States minister to Persia, brought over six individuals, which he presented to Secretary of Agriculture Rusk. After changing hands several times, they were finally taken to C. P. Bailey’s ranch, at San Jose, Cal. A number of small colonies were disseminated from the parent flock through various Western States, and they were used for crossing upon the fine-wool range sheep, producing what is known as the Persiarino. The cross was said to result in an improvement in mutton form and for a time was popular in a limited way, but less is heard of it during late years. Another importation was made in 1910, consisting of a buck and two ewes. The Persians that have arrived upon our shores have varied con- siderably in color. Some have dark faces, while others are mostly white. The mutton is considered of good quality, and the tail is a delicacy with the Turks, but it is not very highly appreciated by the Americans. The wool is rather long and coarse and grades low quarter blood combing or carpet wool. It has been claimed that the Persian lambskin industry is based upon this breed, but present information shows that the so-called Persian lamb does not come from Persia but from Bokhara and that the young of the Karakule sheep, mentioned elsewhere in this pub- lication, produce these skins. In 1904, just previous to the Louisiana Purchase Exposition, the breeders of Persian sheep in America are said to have organized a society for the promotion of the breed. They have not manifested very much activity of late, the society apparently having ceased to exist. THE BARBADOS. The Barbados, or “‘ Woolless,”’ sheep were imported by the United States Department of Agriculture from the Island of Barbados, West Indies, in 1904. This importation consisted of one ram and four ewes, and represented a present to the Department. The original stock is supposed to have come from Africa. They are a rather small breed, 52 ewes at the Government Farm at Beltsville, Md., ranging from 63 to 115 pounds in weight and averaging 85.4 pounds. Bucks weigh from 125 to 150 pounds. In mutton qualities, these sheep are very deficient. They are nar- row and upstanding, fairly fine in bone, but have very long necks. They are much cut up in the flanks, deficient in heart girth, have a very droopy rump, with a low setting of the tail, are deficient in the 56 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. twist, and have poor development of the hind quarters. They are lacking in covering, not only over the ribs, but generally throughout the body, the bony framework being quite prominent. They are covered with hair, varying in length from one-fourth inch to 2inches. This is usually longer upon the top of the shoulders and neck, and it is more or less crimped. This coat of hair usually ob- scures the small amount of wool, which is short and very fine, but occasionally the wool projects out through the hair. During the spring and early summer the wool loosens and gradually curls up through the hair and is shed in tufts. The head is rather attractive and is light or dark brown, with char- acteristic black bars above and below or alongside the eyes. The inside of the ears is black. The back and sides vary from a light fawn to a sealskin brown, and rarely there are markings of white. The belly and inside of the legs are black. The rest of the body varies in color from a light to a dark brown. Infrequently white spots occur. The rams have a beard and also have long hair along the spine and extending from the lower jaw down along the brisket. They are usually hornless, but short horns occur occasionally. The redeeming features of the Barbados are their breeding qualities and their hardi- ness. Ewes breed at any season of the year and are remarkably pro- lific. One ewe produced six lambs at one time, although they all did not live, and twins and triplets are more common than singles. They are especially good milkers and the milk is very rich. The Govern- ment is crossing these sheep upon some of the mutton breeds for the purpose of determining the degree to which the fecundity is inherited in the cross-bred sheep and whether or not this quality can be utilized. These sheep have also been crossed with the Karakule for the pro- duction of lambskins, but the first cross has produced unsatisfactory results from the fur standpoint. THE BARBARY SHEEP, OR AOUDAD. The Barbary sheep have no commercial value. They are a wild breed; both sexes are horned, and the horns are beautifully banded and are marvels of symmetry. ‘They are commonly seen in the zoo- logical gardens and have been brought over to this country for a great many years for exhibition purposes. They have no wool, but are covered with light-brown hair. The bucks have a decided beard which extends well down their forelegs. Mature males weigh about 200 pounds and ewes from 125 to 150 pounds. The breed is quite prolific, one ewe at the Washington Zoo dropping four lambs in 11 months. They are very active and suspicious, especially with strangers. APPENDIX. Table showing the probable origin of the breeds of sheep in America. American Merino.....-..--.-- Spanish Merino. Rambouillet..........-...--.- Spanish Merino. Southdown)... .0-...5.505..2.-- Sussex. Morfe Common. Southdown. Cotswold. Leicester. Shropshires--2.. joe 522 See Wiltshire Knots. Berkshire Knots. Southdown. Cotswold. Cotswold. amos Southdown. Old Dorset. Tiere Norfolk. {shown Hampshire (?). Old Cheviot. nai Leicdter. Welsh Mountain.............. (2) Old Exmoor. Leicester. CHE VAOts Senos ce once eis cistaere Exmoor Horm... 2-2. 222- 2226. | Breeding of grand champions, reserve champions, cnd winners in the carcass contests at Penistone (?). Te OTN a 2 ae POL Soh hye se oF aaa Faced (?). I Roy Coy Ceo Ley ee oes a (2) Native Sheep. KiernyJeles eer ee se Acerca Clun Forest. Shropshire(?) j 4 Tunis. Tunis (American type)...---- | aatndownt d Old Leicester. Beicester 0.20 ese Sse es Teeswater. Old Cotswold. Cotswold ears esse sest ae a Leicester. Old Lincoln. Wincolne ees she Ae teeu ee ig aes Leicester. 3 Leicester. He URNEESMSo96 coed (2). \ Old Romney. Romney Marsh.........--.--- ee Wnecise aa Teeswater. emsleydale.....------------- Leicester. Old Dartmoor. Danrtmoorescchee tases a osen Lincoln. Leicester. the International Live Stock Exposition, Chicago. Year. Grand champion. 1903 | Grade Shropshire. 1904 | Grade Shropshire. 1905 | Southdown. 1906 | Southdown. 1907 | Southdown. 1908 | Grade Shropshire. 1909 | Southdown. 1910 | Southdown. 1911 | Shropshire-Leicester. 1912 | Shropshire. 1913 | Shropshire-Leicester. Reserve champion. Grade Lincoln. Hampshire. Southdown. Hampshire. Hampshire. Shropshire. Oxford. Oxford. 57 58 BULLETIN 94, U. S. DEPARTMENT OF AGRICULTURE. Breeding of grand champions, reserve champions, and winners in the carcass contests at the International Live Stock Exposition, Chicago—Continued. WINNERS IN CARCASS CONTESTS. Year. Prize. |: Wethers. Wether lambs. 1 | Southdown-Shropshire. Oxford. 1900 2 | Oxford. Southdown-Dorset. 3 | Shropshire. Shropshire- Dorset. 1 | Grade Shropshire. Southdown. 1901 2 | Southdown (?). 3 | Cotswold. 1 | Grade Hampshire. Grade Southdown. 1902 2 | Grade Southdown. Grade Shropshire. 3 | Grade Southdown. Grade Southdown. 1 | Suffolk. Grade Hampshire. 1903 2 | Grade Shropshire. Oxford. 3 | Southdown. Grade Southdown. 1 Grade Southdown (?). 1904 2 Southdown. 3 | Grade Southdown (?). Grade Shropshire. 1 | Oxford-Southdown. Grade Shropshire. 1905 2 | Hampshire. Grade Shropshire. 3 | Cheviot. Grade Shropshire. 1 | Southdown. Southdown. 1906 2 | Southdown. Grade Shropshire. 3 | Cheviot. Dorset. 1 | Southdown. Southdown. 1907 2.| Southdown. Hampshire-Rambouillet. 3 | Grade Southdown. Grade Southdown. 1 | Shropshire. Southdown. 1908 2 | Shropshire. Southdown. 3 | Southdown. Shropshire. 1 | Southdown. Southdown. 1909 2 | Southdown. Southdown. 3 | Southdown. Grade Southdown. 1 | Southdown. Cheviot. 1910 2 | Grade Southdown. Southdown. 3 | Southdown-Shropshire. Southdown. 1 | Southdown. Southdown. 1911 2 | Cheviot. Southdown. 3 | Grade Southdown. Southdown. 1 | Southdown. Southdown. 1912 2 | Southdown. Southdown. 3 | Cheviot. Grade Shropshire. | 1 | Southdown. Southdown. 1913 2 | Southdown. Southdown. | 3 | Southdown. Southdown. DOMESTIC BREEDS OF SHEEP. 59 Table of information upon the breeds of sheep. [F=fine wool; M=medium wool; C=coarse wool; W=woolless.] Number Class at Breed. Rams. | Ewes. Color of face. Grade of wool. recoreee Royal, pple neg- HENS land. Merino A type...F..} Horned .| Polled..} White........... Ions) Gy sorta An aan a a\eormesoanclleedocoes Merino B type...F..}.-.- GOs Sse O se ce) sae don sc Geass CO ek eee ee oa etre ciae fecal stare aye siete Merino C type...F..|... Cos c]coc8lOs a5 olfoocacCscoccnne5s Fine combing ....--...--|----- Pease |esesac Rambouillet.....F..|... os see eacdous sant dOs sch eaaen he oe audeomb= if | 73 a \ Ue Southdown.....M..} Polled..|...do....] Gray...........- 4-blood combing orcloth-| 30,645} 1839 ing; #-blood combing or clothing. Shropshire. ....-. Me eee Go 5calloce do....| Soft black....... glocd combing; 2-blood | 385,411 | 1860 clothing. Hampshire...... Wisellean GOesee eee dOssae plackswes cence Blood combing; 4-blood 49,640 | 1862 combing. Oxford.......... Miseleae CMs se clloccGlscca\) IBM ossscodsas 1-plood combing; braid.. 672280) eee Dorset Horn....M..| Horned .|...do...-| White..........- er ulood combing; 4-blood 15,030 | 1862 combing. Suffolk.......... M..| Polled..|...do....] Black.........-. eloed: combing; 3-blood 2,264 | 1880 combing. Cheviot........-. Mes ss Goer a= GOsee alp WinItesenane ae as +-blood combing......... 8,115 | 1871 MD UAM IS sje 5 cis seis We sede do...-.|...do....| Mottled......... -blood combing; +-blood 2,530 |.-..--.- combing. | WelshMountain.M..| Horned .|...do....| Slightly tanned | 4-blood combing.........)........-- 1885 or speckled, Exmoor Hormn...M..}... does. Horned Wihtitess2 cre ose ee GO Rae Ns ane are es cll ectteaie bee lewteisibee's Ryeland.......- M..| Polled ..| Polled ..|.....do..........|..... CO ars a CH ees Oe 1870 Kerry Hill...... M..|... oman Ge doeeel UM ot bled nen an aan GOMee oases cenios se Soe hasaeecece 1907 Lonk..........-.M..| Horned .| Horned .|..... dose ee Low i-blood combing...|........-- 1877 Shetland........ M..; Hither. .| Hither. - Bree , white, or | Probably 3-blood comb- j..........|.--.---- 0 ing. Leicester. ....... C..| Polled ..| Polled ..| White........... Braid and low 3-blood..| 15,913 | 1839 Cotswold........ Cas | Eetdotaas|pa-dOsee ‘| Light ey, OFAC (6 Lays se i aol re Sea 74,455 | 1862 speckle Lincoln.......... (CP Raed Osee eee Ose White, si slightly Bib CO eee eke een 26,122 | 1862 speck] Romney Marsh..C..|...do....|...do....] White........... Low, +-blood combing... 124 | 1862 Wensleydale..... C.. soc Oa cobllostOOsoco|| BIN Yaa oho) eye S ae SO ee 1883 Dartmoor........C.. ..-d0....|...do....]| Speckled plack |..... Coa ees Ue eGR (ee as Oa 1875 and white. Black-faced High- | Horned .|/ Horned -| Mottled, black | Low, 4+-blood combing ]}.......... 1872 land, C. and white. and carpet wool. Karakule........ Cee eedosee ns Weolledms|@black sess en ssaeleecee GOs eee ee eee clic octasjosial ore Meeiote Persian. 2222. 255: C..|...do....|...do....| Mottled or dark.|..... COGS eS a ee a eae Barbados....... NU PRE Fe ree ech epee ES Tex chs cial fea worl eae nT IG aN Barbary........ rye ieLomiede | Elorned a Browne rca. cul ed mea a OUR OUR RGN KO aiall Dei eas 1 Von Homeyer Association. 2 American Association. PARTIAL INDEX OF RECENT PUBLICATIONS ON THE BREEDS OF SHEEP. Sheeping Farming, by John A. Craig. New York, The Macmillan Co., 1913. Types and Breeds of Farm Animals, by C.S. Plumb. New York, Ginn & Co., 1906. Farm Livestock in Great Britain, by Robert Wallace. Edinburg, Oliver & Boyd, 1907. Sheep Breeds and Management, by John Wrightson. London, Vinton & Co., 1895. The Sheep and its Cousins, by R. Lydekker. London, George Allen & Co., 1912. Cattle, Sheep and Pigs, by F. T. Barton. London, Jarrold & Sons, 1912. Modern Sheep, Breeds and Management, by ‘‘Shepherd Boy.’”’ Chicago, American Sheep Breeder Co., 1907. Sheep Farming in America, by Joseph E. Wing. Chicago, Sanders Publishing Co., 1907. Sheep Management, by Frank Kleinheinz. Cantwell Printing Co., Madison, Wis., 1911. © WASHINGTON : GOVERNMENT PRINTING OFFICH: 1914 igh Wey «tan aN ‘ d Rin Sah ‘i act LORE dg gard LOH arto -% mai 1s nde oe "eye ene Pn (Une one ey ‘ byhlbey ewalame cas Fes daigs vee f out YE ee gy ge ee, TOm ee OAS On i ee ge gee i = ‘ . i ; t i - } ' | ; ; 2 ‘ eT a 4 | = i orale Seated: * ‘ : cesar we se Ee | ie ah tee ot Pelee | a) SiS ciara dae canbe Nea e a MARA. ono *Y ahes, hiasiggaae LF Pie %* JO ghity® mohnehigiicvd nore eae . ~~ + ~ gal hatt ets pitizdinges. Sern) pasatiol oO See UND 18K RR TART PITT OF ) YORORT RE BULLETIN OF THE ) USDRIARNENTOFAGUCULTUE % No. 95. Contribution from the Bureau of Entomology, L. O. Howard, Chief. July 9, 1914, INSECT DAMAGE TO THE CONES AND SEEDS OF PACIFIC COAST CONIFERS.* By Joun M. Muier, Entomological Assistant, Forest Insect Investigations. INTRODUCTION. Recent damage by insects to the cones and seeds of conifers has been brought to notice by the collectors of forest seeds. Com- pared with other commercial seeds the market price of forest seeds is high, owing to the limited demand, the special knowledge required for their collection, and the irregular production of conifer crops. A heavy percentage of damage materially decreases the profits of seed collection and may result in time and money fruitlessly spent. Seed that is badly infested or damaged by insects can not be sold to reliable dealers when its character is recognized. It has been found that insects sometimes destroy practically all of the seed crop of a tree species in one locality in a season. In this respect insects have a certain relation to the future supply of timber, as the natural reproduction of forests is assured only by the produc- tion of a prolific supply of uninjured seed. (Pl. I, fig. a.) The artificial reforestation of denuded areas must also depend upon the collection of sound forest seed. An example of how insects may interfere with reforestation by a desired species has been furnished by the white fir on western national forests. Much of the seed of this species collected recently has been worthless for planting, a great percentage of this loss being due to insect damage in the cones and seeds. Some information regarding insects that affect forest seeds and reproduction has been given in previous publications of the Bureau 1 The names of the insects are not mentioned in this preliminary contribution because many of them are not yet named or described. When this has been done it is intended that a special bulletin on the subject shall be prepared by the same author.—A. D. HopKINs, in Charge of Forest Insect Investigations. Norte.—Information regarding insects that seriously affect forest seeds, especially in the coniferous forests of the Pacific coast. A practical paper, ofinterest to seed collectors, dealers in forest seeds, and planters of forest areas; of particular application to Pacific coast regions. 38961°—14 2 BULLETIN 95, U. S. DEPARTMENT OF AGRICULTURE. of Entomology.t This bulletin gives further facts regarding the character and extent of damage to the seed of coniferous forests of the Pacific slope. It also furnishes preliminary information on the more important groups of insects causing this damage, and _ their habits, that it may be available to seed collectors during the present spring and summer. CHARACTER AND CAUSE OF DAMAGE. Damage to the seed of conifers is caused by various species of insects which feed upon the buds, flowers, immature cones and seed, and mature seed. Great damage is accomplished while the cones are Immature and before the seed ripens. Cones which are infested, or ‘‘wormy,” are often found when the areas for seed collection are being located. Wormy cones and seeds are caused by the adults and grubs of small beetles, the “‘worms”’ or caterpillars of moths, the maggots of gnats, and the larve of tiny wasps known as seed chal- cidids. In his work the seed collector usually encounters these im- mature stages of insects which depend upon the cone scales and seeds as their principal source of food supply. With the exception of the cone beetles the adult insect is seldom found in the immature cone. The insects may be found in almost any part of the cone or seed, the feeding habits varying much with the different species. In many cases the presence of these insects in the cone is evident and may be recognized by the peculiar type or class of injury. Where this is the case the damage may be approximately estimated during the summer. With the more important seed-infesting insects the damage will be recognized in one or more of the following classes: BLIGHTED CONES.? The cones are sometimes killed when small and immature. As a result they wither and dry, and none of the seeds fill. Cones so affected are often described as blighted. Most of the injury of this character occurs in the cones of pine and is caused by the cone beetles. The attack is usually on the second-year cones, although the small first-year cones are sometimes killed. Some of the cone worms, also, bore into the cones in such a manner as to kill them and cause the same blighted condition. Sugar-pine cones attacked by the beetle nearly always fall to the ground during July and August. The cones of other species usually adhere to the tree for a winter or two. Damage of this type is easily recognized and can be estimated after the middle of July. 1 Hopkins, A. D., Catalogue of exhibits of insect enemies of forests and forest products at the Louisiana Purchase Exposition, St. Louis, Mo., 1904. U.S. Dept. Agr., Div. Ent., Bul. 48, p. 13-14, 33, 1904. Hopkins, A. D., Insect enemies of forest reproduction. U.S. Dept. Agr. Yearbook, 1905, p. 250-251, 1906. (Yearbook Separate 381.) Rohwer, S. A., VI, Chalcidids injurious to forest-tree seeds. U.S. Dept. Agr., Bureau of Entomology, Tech. Ser. 20, Pt. VI, p. 157-163, Feb. 10, 1913. + Pl. I, figs. cl, d; Pl. I, figs. a, b. INSECT DAMAGE TO SEEDS OF PACIFIC COAST CONIFERS. 3 WORMY AND ABORTED CONES.1 In some forms of injury the cone is not killed, but may show masses of resin on the surface, castings caused by the feeding of larve, or little burrows through the scales, seed, and pith which contain small larve. In rare cases the cone may be aborted or deformed, forming a peculiar growth or shape. The cone, however, continues to grow and matures at the close of the season very much like a normal one. The seeds which are not mined or eaten by the insects fill and mature. Damage of this character may be found in practically all species of conifers. Much of it is caused by the caterpillars of different species of moths, some of which show nothing on the surface of the cone to indicate their work in the interior. The amount of damage to the seed of western yellow pine and Jeffrey pine throughout northern California and southern Oregon in 1912 was estimated by the writer to vary from 50 to 90 per cent of the crop. WORMY SEED.2 This class of injury is found only in the seeds. The cone is not affected and shows no indication of the insect. Practically all of the reported damage of this type is caused by the larve of tiny wasps called seed chalcidids. A certain percentage of the seeds will be infested by a small, white, headless larva. The infested seeds are of normal size and appearance. The larve feed entirely within the inner lining of the seed. Damage of this type can be found only by cutting the seed open. Seeds which have been attacked are hollow and usually contain the small headless larve of the chalcidid. After the seed has been stored over winter some of the adults emerge, boring small clean-cut holes through the outer shell of the seed. This is the first external indication of these insects. Quite often seed infested by the seed chalcidid is collected and sold before the infesta- tion is detected. Injury of this type is very common in certain species of fir, in which the damage has sometimes been found to run as high as 75 to 90 per cent of the cleaned seed. Species of seed chalcidids have also been found in the seed of western yellow pine and Engelmann spruce. MAGGOTY CONES. Many cones are injured by the maggots of flies and midges, some of which cause no appreciable damage to the seed. Small whitish or pink-colored maggots are found in the cones of nearly all conifers. They are the larve of tiny gnats, or midges. The pinkish maggots cause little masses of resin among the scales but do not seriously affect the seeds. The whitish maggots in fir cones cause considerable damage to both cone and seeds. (See Pl. III, figs. a, ¢.) They are often present in vast numbers and leave the cones when these are 1 Pl.I, fig. b 2 Pl. III, figs. b, d. A BULLETIN 95, U. S. DEPARTMENT OF AGRICULTURE. spread to dry. They are among the most common insects noted in the work of seed collecting. IMPORTANT GROUPS OF SEED-INFESTING INSECTS. There are four important groups of insects which cause practically all of the serious damage under the four classes described. CONE BEETLES. Cone beetles are small, dark, cylindrical beetles which attack the cones of pines. The cones are killed by the attack of the adult, which bores a small tunnel into the axis to deposit its eggs. (PI. II, fig.b 7.) The larve (Pl. I, fig. d) feed on the seeds and seales of the withering cone and develop to the beetle stage within the dead cone, where the beetles usually remain over winter. The attacks of several species of these beetles are very common in western yellow pine and sugar pine. The damage to crops of sugar pine is considerable, as these beetles have been noted in some seasons to kill from 25 to 75 per cent of the cones over large areas. CONE WORMS. Cone worms are most frequently met with in the cones in the caterpillar stage. They represent several species of moths which infest the cones of pines, firs, hemlocks, and spruces, and even the seed of incense cedar has been found to be attacked by the tiny larve. The moths are small and in most species dull colored and inconspicu- ous. The small white larve of one species are very common in the cones of western yellow pine and Jeffrey pie. They feed upon the seeds and scales without killing the cone and overwinter as larve and pups in galleries in the pith of the cone axis. (Pl. I, fig. b.) - Another species is a very common enemy of Douglas fir seed on the Pacific slope. The larve mine a gallery through the scales, leaving an opening at the surface through which resin and larval castings exude. The pups overwinter near the axis in resinous cocoons among the scales. Nearly all species feed without killing the cone, but a large caterpillar feeding on western yellow pine sometimes kills the immature cone, the damage resembling that of the cone beetle. SEED CHALCIDIDS. The adults of seed chalcidids are tiny wasps (PI. III, fig.d). The larve (Pl. III, figs. 6, d) live within the seeds, apparently developing as the seeds grow, so that the infested seeds reach normal size and EXPLANATION OF PLATE I.—a, Photograph near Bray, Cal., showing cones of western yellow pine on ground, but poor reproduction; b, mature western yellow pine cone, showing pith occupied by the cone worm and seeds destroyed by it; c/, blighted western yellow pine cone caused by the cone beetle; c2, normal cone; d, young living western yellow pine cong, greatly enlarged, to show character of damage by the cone beetle and its larve. (Original.) Bul. 95, U.S. Dept. of Agriculture. INSECT DAMAGE TO REPRODUCTION OF WESTERN YELLOW PINE f plate see note at foot of page 4.] 10n oO xplanat Fore [ Bul. 95, U. S. Dept. of Agricuiture. PLATE II. Fic. A.—SUGAR-PINE CONES ATTACKED BY THE CONE BEETLE AT DIFFERENT STAGES OF GROWTH OF THE CONE. (ORIGINAL.) [The longer cone, which is about 14 inches long, resisted attack, while the others were killed.] FiG. B.A—LONGITUDINAL AND TRANSVERSE SECTIONS OF SUGAR-PINE CONES, NATURAL SIZE, SHOWING PRIMARY EGG GALLERIES, B1, MADE BY THE CONE BEETLE. (ORIGINAL. ) WORK OF THE CONE BEETLE IN SUGAR PINE. Bul. 95, U. S. Dept. of Agriculture. PLATE III. WORK OF A CHALCIDID IN SEEDS OF PACIFIC COAST CONIFERS. a, Cross section of sound, mature white fir cone with unaffected seed; b, yellow pine seed, enlarged, infested by larve and newly transformed adults of a seed chalcidid; two un- opened seeds show exit holes made by these insects; ¢, cross sections of two maggoty white fir cones; d, male and female adults of seed chalcidid, larva in opened seed of red fir (Abies magnifica), and exit holes in two other seeds of same. (Original.) a 1 INSECT DAMAGE TO SEEDS OF PACIFIC COAST CONIFERS. a form. There are several species, one of which is very destructive to the seed of Douglas fir, white fir, and red fir. FIR-CONE MAGGOTS. Fir-cone maggots are the larve of small gnats which have been found in the cones of white fir, red fir, and alpine fir. They mine through the scales and seeds, causing great damage. The larvz do not winter in the cones but burrow into the ground as soon as the cones fall. They form small puparia within an inch or so of the surface, and there they overwinter. - ADAPTATION OF THE INSECTS TO THE INTERMITTENT CONE- PRODUCING HABITS OF THE HOST TREES. There is a general life cycle for most of the cone-infesting insects corresponding to the period required by the host tree to develop the seed crop. The adult msect, whether beetle, moth, fly, or seed chalcidid, deposits the eggs in the spring or early summer while the cones are small and undeveloped. With some species the attack is such that the cone is killed; with others the attack and feeding of the larve do not interfere with the growth of the cone, which matures at the normal time, although much of the seed may be destroyed. The feeding of the larve ceases, however, when the cone matures, usually during September. ‘The insects then undergo a long dormant period either as larve, pupz, or new adults. This dormant period continues until there is another crop of cones in a proper condition for attack; that is, the soft, immature cones which are found in the spring or early summer. Some insects pass this dormant period in the pith of the cones or in resinous masses among the scales. Other species leave the cones and form the pupz in the ground or in débris on the surface. The intermittent character of the seed production of conifers is a well-established fact.t A few cones are produced every year, but a good crop occurs at intervals of from two to five years. The years of total failure are known as ‘“‘off years.” It is evident that if the entire brood of any of these species of cone-infesting insects emerges annually, it will sooner or later encounter an off year of the host tree. This would mean the complete failure of the food supply for one generation and would result in the almost complete extinction of the species within the forest area affected by the crop failure. As a matter of fact, observations show that this seldom happens. All the individuals of a brood of overwintered insects do not emerge the following spring. Many of them do emerge after the first winter, but a large percentage of the brood, in some species 50 per cent or more, 1U.8. Dept. Agr., Forest Service, Bul. 98, p. 18, Nov. 18, 1911. 6 BULLETIN 95, U. S. DEPARTMENT OF AGRICULTURE. continues for another year in the same condition in which the first winter was passed. Usually this retarded part of the brood emerges at the end of the second winter or spring. This is an adaptation which to a certain extent accounts for the continued infestation of certain species of insects in the seed of forest trees. In the case of a species of gnat which infests the cones of white fir it was found that the entire brood of insects which destroyed the 1911 crop of seed on an area in northern California did not emerge at all in the spring of 1912, but remained in the pupal state through the summer of 1912 and the following winter. The adult flies finally emerged in the spring of 1913. Under this adaptation it would appear that only a con- tinued failure of the crop through a series of years would result in the reduction of the numbers of the infesting species on a forest area. Undoubtedly other agencies are responsible for the uninfested con- dition of the seeds of certain trees during some seasons. INDICATIONS OF INSECT DAMAGE. Attack of the cone beetle in the seed crop is indicated by a small entrance hole at the base of the cone, with castings or small pitch tubes, during the early summer; later, by the brown, withered appear- ance of the cone. The attack of the cone moth may sometimes be recognized by little masses of pitch and larval castings on the surface of the cone and sometimes by withered cones, but it is best to look for the cater- pillar among the scales and in the seed and pith. It is always best to cut the cone open, sectioning it several different ways, in making the examination. The attack of the fir-cone maggot can also be found by cutting or breaking the cone open. The larval mines will be found in the scales and seeds, in which will usually be found the small, white, active larve. The seed chalcidids show no external evidence, and the seeds must be sectioned or otherwise opened to find the larve of these insects. Unless test is made the amount of damage can not be determined, and seed that is badly infested may be taken as sound. METHODS OF PREVENTING LOSSES. There are areas of light infestation by these insects in certain species of trees, and there are areas where the damage is very heavy. The amount of infestation in the seed may also vary with succeeding seasons. A careful examination of the cones before the seed matures, during July and August, will usually reveal immature stages of the seed-infesting insects. If cones of the past season are examined during the winter and spring, they will indicate whether or not the 1 This retarded emergence has not been observed in the case of the cone beetles, but it has been observed in the more important cone worms, fir-cone maggots, and seed chalcidids. INSECT DAMAGE TO SEEDS OF PACIFIC COAST CONIFERS. % area is infested by these insects. In the collection and cleaning of forest seeds there is opportunity for use of the information which is now being gathered on this subject. An intelligent selection of the seed-collecting areas will prevent much of the loss due to gathering seed which is afterwards found to be infested or worthless. _ A count of the number of infested cones and of damaged seeds wil give a clue to the percentage of damage in the crop. Whether or not the damage is sufficient to make collection of the seed unprofitable on the area will have to be determined by the collector. O WASHINGTON : GOVERNMENT PRINTING OFFICH : 1914 BULLETIN OF THE USDEPARTMENT OPAGRICULTURE No. 96 ait A NG OS \ , WW Contribution from the Bureau of Entomology, L. O. Howard, Chief. July 22, 1914. (PROFESSIONAL PAPER.) THE TEMPERATURE OF THE BEE COLONY.’ By Burton N. Gatss, Ph. D., _ Formerly Apicultural Assistant, Bureau of Entomology. INTRODUCTION. There has been a decided need of accurate knowledge of the temperatures and changes in weight of colonies of bees, particularly ring the winter. Previously existing data have not been gained under controlled conditions, but generally by casual observations, limited in number. Most of the previous work has also been for a short period of the year. In this work an effort has been made to get more reliable information by collecting data for practically the cycle of a year. The knowledge of the changes in temperature and weights is needed in a careful study of methods for successfully wintering bees. This is one of the greatest difficulties which the beekeeper has to meet, and it is hoped that the present work may furnish data for a further study of the wintering problem. The scope of the work here recorded is indicated by the following figures: Period of experimentation, October 22, 1907, to September 26, 1908. Number of observations, 2,576+. Number of separate readings, 20,000-++. APPARATUS. The apparatus was constructed to meet emergencies which might arise, which accounts for its many parts. It was planned so that the complete apparatus could be upon the scales at all times, thus obviating complications from corrections in weighings. THE SCALES. A finely adjusted platform scales was specially constructed, which registered with a sensitivity of 10 grams to a maximum of 200 kilograms. It was expected that it would be possible to record 1 This report of work done for the Bureau of Entomology has been accepted by the faculty of Clark Uni- versity, Worcester, Mass., as a dissertation in partial fulfillment of the requirements for the degree of doctor of philosophy, and accepted upon the recommendation of Dr.C. F. Hodge. Theauthor has been appointed to the position of assistant professor of beekeeping, Massachusetts Agricultural College. Notr.—A study of the effects of temperature on bees, and of interest. to beekeepers generally. -38957°—Bull. 96—14——_1 2 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. slight changes in consumption or*inerease of stores. By means of a double beam it was possible to counterbalance for extra thermometers or other small special apparatus which might be added temporarily, without necessitating a correction of the hourly readings. The scales were found to be relatively satisfactory, but in times of heavy wind extra precaution was necessary in order to overcome the influence of drafts on the scales. In winter this could easily be accomplished by closing the door of the shed in which the experi- ment wascarriedon. For outdoor work, however, some difficulty was experienced, as will be explained. The agate-set bearings were also sensitive to jar, which was con- stantly guarded against. THE THERMOMETERS. Seven mercury thermometers were used, of the type known as incubator thermometers, which have a long stem and can be read to fifths of a degree. One instru- ment, however, used to register the temperature of the outside air was an ordinary chemical ther- mometer. These instruments were standardized and were graduated to the centigrade scale. THE HIVE AND ITS APPLIANCES. Fic. 1.—The hive used in the experiment on the Figure 1 illustrates the general temperature of the bee colony: A, storage cham- ber for accessories, with door; B, bottom board Appearance of the hive, showing with entrance; C , collar with feeder; D, brood the five stories. Only one of these chamber; 2, perforated zine honey board; F, second story for surplus; G,thinboard withholes Was occupied by bees, as will be for thermometers; H, case protecting thermome- explained. The hive was of the ters a-e; I, outside cover. standard 10-frame Langstroth type. Throughout the experiment it stood on the scales (fig.2). The several parts were as follows: A. The lower part consisted of a hive body with one side removed. To the bottom was nailed a thin cover board, which served as the floor of the compart- ment. The purpose of this chamber was to store fixtures, such as frames, ‘‘dum- mies,’ extra thermometers, and the like, while they were notin use. In this way it was unnecessary to compute in the weighings for any change in the apparatus. For example, in the winter, when four frames in the brood chamber were replaced by the ‘‘dummies,’’ these were taken from the storage chamber and the frames hung in their place, without altering the weighings. THE TEMPERATURE OF THE BEE COLONY. 3 B. An ordinary bottom board. C. This wooden collar contained the feeder and increased the space between the bottoms of the brood frames and the bottom board, thus allowing the insertion of a thermometer below the frames. The feeder was what is known as an Alexander feeder. The end may be seen extending out of the collar at the rear of the hive. In this projection, which was provided with a wooden cover, the sugar sirup is poured without disturbing the hive. The cover prevents drafts of air through the feeder. D. Above the collar was the hive body in which the bees were located. The frames were spaced with metal spacers (fig. 3), and wedges between the central frames held all firmly in place. In this way everything was sufficiently secure to enable any possible manipulation, even to turning the hive upside down, should it be necessary , without displacing parts. The wedges also increased the space between the central frames sufficiently to allow for the insertion of the stems of thermom- eters. The gauge in frames 3 and 4 permitted the insertion of thermom- eter e(fig.3). Theframes were wired and filled with full sheets of foundation before insertion. Two holes were bored in the middle of the front above the entrance, for use in case it should become de- sirable to insert thermom- eters. Throughout the experiment these were closed with corks. E. Between bodies D and F was a perforated zine honey board. F, A second body was provided in case more comb space should be- come desirable. G. The top of the hive proper was covered with a thin cover. This, as is shown in figure 3, had four holes drilled in the median line and one directly over the rear part of the space between frames 3 and 4. Through these holes thermometers fitted in corks were inserted. H. This was a special hive body used as a protection for the thermometers. One side, shown in figure 2, was removable so as to permit easy reading of the instruments. In this chamber and around the thermometers were two cushions of ground cork, for the protection of the tops of the thermometers and for the conservation of the heat of the cluster in the extreme of winter. JI, A metal cover. Fic. 2.—Hive on scales in shed where it was kept during the winter. 4 BULLETIN 9%, U. S. DEPARTMENT OF AGRICULTURE. A series of clamps, which drew over screw heads, held the several parts firmly together, preventing the bodies from sliding and snapping the stems of the thermometers. The ‘‘dummies” above mentioned consisted of ordinary frames into which boards were fitted snugly. These were used in the winter months instead of the two outside frames on either side of the hive, thus forcing the cluster to occupy six frames in the center of the brood chamber. In this way it was made certain that the cluster would not shift away from the thermometers during the winter. The Fic. 3.—The hive from above, showing the spacing of the frames. The corks in the cover indicate the location of the thermometers. ‘‘dummies”’ were removed when brood rearing became established in the spring. These were not intended primarily for protection and did not fit the hive tightly. In order to eliminate the annoyance and possible complications from propolizing, all the interior wooden parts were varnished and polished to a piano finish. It should be said that not all of the parts of the apparatus provided were pressed inte service. The extra body, D, was not needed, and consequently the honey board, £, was not used. The outfit as THE TEMPERATURE OF THE BEE COLONY. 5 actually used and as it appeared in position until the writer was forced to move the experiment to the country in July, 1908, is shown in figure 2. THE BEES. Throughout the experiment Caucasian bees were used. Two colo- nies were necessary. The first drew out the foundation in the frames and was used during September and October, 1907. The second was hived in November, 1907, and served throughout the remainder of the experiment. This colony did not swarm. THE ARRANGEMENT OF THE THERMOMETERS. The thermometers were designated a, b,c, d, e, f,ando. Thermom- eters a, b, c, and d were inserted between the central combs. They were arranged at regular intervals, a being at the front of the hive and nearest to the entrance. Thermometer e was placed at the rear of the hive between combs 3 and 4, and was expected to represent the temperature of the margin of the cluster. Thermometer f was inserted beneath the frames through the collar, as is described above. Its purpose was to record the temperature of the air below the cluster and which was likely to be affected by currents from the entrance. Its bulb was directly below the central frames. The first five ther- mometers extended about 7 inches below the cover. The outside thermometer, 0, was suspended close to the hive in such a way as to register the temperature of the air which surrounded the apparatus. LOCATION OF APPARATUS. - The apparatus was installed in a shed on a third-story back piazza in southwest Washington, as is shown in figure 2. While the shed afforded shelter from storms, which was necessary for the protection of the apparatus and in taking observations, windows and door were left open, making the conditions relatively like out of doors. The shed was on the south side of the building. In July, 1908, it was necessary to transport the experiment to College Park, Md. This, however, was found not to have affected the results. The apparatus was arranged in a situation comparable to the shed in Washington. CHECK COLONY. Besides the colony on the scales, in which the thermometers were suspended, a check colony in a hive with glass top and bottom was setup close by. The hive was constructed with a glass bottom board, and a wooden shield te cut out light. The cover was also of glass sealed to the hive, on top of which were several thicknesses of felt paper and an ordinary hive cover. By removing the bottom shield 6 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. and the top protection it was possible at any time of day or night to look between the combs at the cluster. These protective cover- ings were applied so as to be removed with the minimum jar. At night, or even in the daytime, by means of a reflector, lantern light could be thrown up between the frames. In this way the writer was able to watch from day to day the shifting of the cluster and the reaction of the bees to their environment and to compare this with the readings of the thermometers in the hive on the scales. It was necessary to maintain this check only during the winter period. METHODS OF OBSERVATION AND RECORDING. Since none of the instruments recorded automatically, it was nec- essary to make frequent readings of both the weights and tempera- tures. The experiment proper lasted from October 22, 1907, to September 26, 1908. The first colony, used to prepare the combs, was also under close observation, so that the whole period of experi- mentation was almost a year. Readings were taken at least every hour throughout the working day. Whenever the hive was manipu- lated, or when peculiar meteorological conditions prevailed, readings were taken half hourly, or even quarter hourly. On the average of about once in three weeks, by means of assistance, it was possible to take consecutive hourly readings for a period of two or three days. In this way practically the whole activity of the colony for a period of a year was recorded. During the summer months the readings usually covered a period of 14 hours daily. The temperatures were read to fifths of a degree. Weighings were made to 10 grams. Every alteration or manipulation of the colony was recorded. Hourly changes in the weather and activity of the bees were also noted. The readings were recorded on 12.5 by 20 em. cards, the size standard to the office note. file. Later from these tables the curves of the temperature and weights were plotted on millimeter cross- section paper, one sheet to a month. The method of plotting is obvious from examination of the several curves herein presented. THE CONSUMPTION OF STORES IN WINTER. At the outset of the investigations it was hoped by means of deli- cate scales, which have been described, that sufficiently accurate weighings could be made to show whether there is any correlation between the loss in weight and the temperatures of the cluster in winter. For instance, it was desirable to know whether there is any relation or rhythm in the consumption of stores to changes in tem- perature due to metabolism. It has not been possible to detect any such relations. Nevertheless several significant facts concerning the consumption of winter stores have been discovered. THE TEMPERATURE OF THE BEE COLONY. 7 The rate of consumption of stores, as is shown in figure 4, exhibits a relatively constant decrease from month to month. At the begin- ning of the season, before the cluster was well established, when bees were more active and before settled winter weather, food consump- tion was greater than in midwinter. As the season progressed, during February, for instance, consumption slackened. There are several factors which may account for this. In the first place, as the winter advanced there were fewer and fewer bees to be fed. The winter was also less severe, and consequently less generation of heat was necessary. Humidity is another factor which noticeably influenced the daily weights for a considerable part of February. This also occurred 6000 5000 8 8 8 Q iS) WEIG/ATT- /4V GRAISTS. Fig. 4.—Graphic representation of the loss in weight of the bee colony from November 6 to March 7, due to the consumption of stores. periodically in other months. Although condensation tended to prevent a drop or even to raise the curves during a period of bad weather, as will be shown below, the increased weight due to the con- densed water vapor could neither be permanent nor affect the total loss of weight during so long a period as a month. Whatever water condensed during inclement weather would evaporate during the following days of fair weather. Thus, while the scales might reg- ister an increase during bad weather, consumption of stores was actually going on all the time, but could not be detected in the weights until fair weather had dispelled the moisture. Conse- quently the records of single days are less significant than the aver- ages of a month or of the season. 8 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. There was, however, a gradual and constant lessening of the daily consumption of honey, as is apparent in Table I, which presents the monthly and average daily figures. From this table it will be seen that while in November the average daily consumption was 53.2 grams, in February the average was but 30 grams a day. For the entire winter 43.5 grams of honey were consumed, on the average, daily. TABLE !.— Monthly and average daily consumption of stores by wintering bees. P Weight Average daily Time. nfistores! Monthly loss. ee Grams. | Grams.| Pounds. | Grams. | Grains. November (Nov. 6, 9 a. m., to Dec. 1, 9 a. m.—25 days)... 6, 640 5,310 ———| 1,330 2. 932 53. 2 821 December (Dec. 1, 9a. m., to Dec. 31, 9 a. m.—30 days)_. 5,310 3, 820 —— 1,490 3. 284 49.6 765 January (Dec. 31, 9a.m., to Feb. 1, 9 a. m.—32 days)... 3, 820 2,470 ——— 1,350 2.976 42.2 651 February (Feb. 1, 9a. m., to Feb. 29, 9 a. m.—28 days)... 2, 470 1, 630 840 1. 852 30.0 463 Totaliioss for 4months: 20) sac occas aoe dee oe ee ee 5,010 11.045 s Average Gaily JOSS: = 5... 2. dele. S.24 Boe ee ek ee Ce eee eee eee 43.5 671 L TaBLE II.—Daily loss in weight of colony of wintering bees. Loss in | Loss in Loss in Loss in Date. grams. Date. grams. Date. grams. | Date. grams. Noy. 11 120 || Dec. 10 +30 || Jan. 10 70 | Feb. 10 0 12 10 11 70 11 40 || ll 20 13 50 12 70 12 +10 || 12 20 14 70 13 60 13 30 || 13 0 15 50 14 20 14 50 14 +40 16 80 15 25 15 60 | 15 +20 17 90 16 25 16 40 16 130 18 60 17 60 17 50 || 17 20 19 10 18 40 18 50. | 18 40 20 70 19 40 19 40 } 19 +40 | Although the foregoing figures represent the usual daily conditions, they do not by any means represent the actual daily consumption. As will be seen in Table II, there was no such degree of constancy as is represented by these averages. Taking the 10 days at the middle of each month, it is possible to represent prevailing conditions for that month. Thus the data of Table II are a fair representation of the actual variations as they occurred during the winter. It will be seen in this table that the daily variation in weight is all the way from a loss of 130 grams in some cases to no loss whatever or even an in- crease of 40 grams. Therefore it is hardly possible to assume that the weights of the entire hive will throw any lght on the amount of honey consumed in a single day. This increase in the weight of the hive during bad weather is a fact which, so far as the author is able to learn, has not heretofore THE TEMPERATURE OF THE BEE COLONY. 9 attracted attention. It can not be said in any wise that this 1s an increase in the amount of stores. The phenomenon usually accom- panied wet weather or fog and must be attributed to condensation of moisture. In the check hive moisture was frequently seen col- lected on the glass top and even on the frames and bees, but there the conditions were perhaps less normal than in the experimental colony. Root* says that he has seen confined moisture cause , 2#s0 2550 + icicles to form in the hive. The ‘ ned Nl condensation may become so § ereat in extreme cases as to 4 cause the bees to freeze together s in asolid block when chilled down N by severe cold. (Root, pp. 332— ont \ | 334.) Honey is well known to be hygroscopic, and if put into an ice chest or a damp cellar, it takes up moisture. Extracted 749? honey hs also nen observed to, "SCs re afm accumulate enough moisture to dilute it considerably. In the present case the hygroscopic property of the honey can not be held wholly responsible for the increased weight, although it may have contributed. Following an increase of this kind, as has been mentioned, there was a marked decrease with the coming of fine weather and dry: CLLAR ANNO WIND ie ness. For illustra- 6 | tion, the increase of ; 40 grams on Febru- Gres ES Neen VN ary 1 (fig. 5) occurred S hit thas! during the early part 8 of the day, when it N was raining. That S600 afternoon and the Fig. 6.—Curve showing changes in weight of the bee colony from Nov. following da there 20 to Nov. 23. ny y were fair weather and wind. Then there came a marked decrease in weight, which not only compensated for the increase during the storm, but also showed that stores had been consumed constantly, although the weights 1A B Cand X Y Z of Bee Culture, 1908 ed. 38957°—Bull. 96—14—2 10 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. failed to demonstrate 1t at the time. This same point is illustrated by the figures presented in figure 6. Such conditions suggest the complications which arise in attempting to correlate the colony tem- perature with the consumption of honey. GENERAL PHENOMENA OF THE CLUSTER IN WINTER. During the winter the bees are relatively quiet; the cluster expands and the bees fly only in the warmth of the warmest days. The heat maintained in the cluster has a general relation to the prevailing temperature of the air. This relation of the cluster temperature to air temperature is especially evident in a comparison of the maximum and minimum temperatures of the several thermometers of the hive with the tem- perature at the outside thermometer, 0. The daily maxima and minima were practically synchronous for all of the thermometers with the exception of c, which usually had its maximum when the temperatures registered by the other thermometers were lowest. Conversely, the minimum of ¢ occurred when the outside thermometer and the others in the hive were at their highest points. This will be explained in detail under a following caption. With the exception of c, then, and for the particular conditions under which this colony was kept, the minima occurred daily some time between 6 a. m. and 12 m., but usually about 8 or 9 o’clock. The maxima occurred daily in the afternoon, usually between 2 and 4 o’clock. While ¢ registered the highest in cold periods, the temperature recorded by the other thermometers showed a similarity with the prevailing temperature of the air. Thus, in periods of cold, as for example in December, the thermometers in the hive as a whole registered lower than they did in warm periods. In warm periods, when the bees are able to expand the cluster and move about, the maximum cluster temperature lacked but a few degrees of the maximum summer temperature. This is repeatedly shown in figure 7; and in March, on a warm day, the temperature reached the extreme of 33.2° C. (91.76° F.). The temperature of the cluster did not fall below 17° C. (62.6° F.), and usually the bees did not permit the temperature of the cluster to fall below 20° C. (68° F-.). The amplitude of the fluctuations between the maximum and minimum temperatures showed a close relationship to the external conditions. In the center of the cluster, for instance, ¢ registered much more constantly than the thermometers in the outside layer of the cluster. The daily oscillations of c were usually not greater than 1 to 5 or 6 degrees Centigrade. On the contrary, in the case of the other thermometers in the hive which were more affected by the rise and fall of the temperature out of doors, the amplitude of the oscilla- tions was as great as 3 to 20 degrees Centigrade. The center of the cluster, therefore, shows more clearly the activities of the bees. The THE TEMPERATURE OF THE BEE COLONY. 11 active portion of the cluster has a higher and more uniform tempera- ture than the other parts, while the outside layers are subject more directly to the fluctuations of the winter weather. Most of the fol- lowing study of the winter conditions of the beehive will be based on the records of the center of the cluster. It would naturally be expected that the heat radiating from the bees would tend to delay the effects of the penetration of the cold of the outside air on the cluster. In other words, it might readily be expected that the cluster thermometers would reach their maxima and minima later than the outside thermometer. However, this occurred seldom and only in severe weather, when the changes were rapid and considerable. Even then there was a delay of only an hour or two at the most. This again suggests the sensitiveness and the responses of the ‘cluster to the changes in the ex- ternal air. The ad- aptation of the bees to changes in the atmospheric condi- tions will be more apparent when de- tails are considered. As has been sug- gested above, there was a tendency for the cluster gradu- ally to maintain a Fic. 7.—Schematic curve showing cluster temperatures of the bees dur- higher temperature ing the winter and after brood rearing began. as the season a d- vanced toward spring and the beginning of egg laying. The schematic curve, figure 7, presents graphically the conditions of temperature at thermometer c throughout the winter. It will be noticed that dur- ing the month of November, when the bees were less definitely and. constantly clustered, the amplitude of the daily variation and the general temperature of the cluster were higher than in the succeeding months. ‘This is also evident in the fact that the curve of the ther- mometer c at this time of the winter tended to follow the curve of the outside thermometer o to some extent. In December, however, there was a change in the course of the temperatures at c, in response to the change in outside conditions. The conditions remained more nearly constant from this time until egg laying commenced in the spring, except that as the weather tended to warm up at the approach NOEITELR 9 DLOGSIEELR 4 CLOERLARY / STAIR CC? BROOD KEARING . : Q DEGREES = CLW7/ GRADE 12 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. of spring the mean of the cluster temperature also raised. Finally when the days had considerably lengthened and were relatively warm, the amplitude of the cluster variations increased, as is shown in the schematic curve (fig. 7). When the summer season for the bees began, accompanied by the beginning of incubation, the tem- perature of the center of the cluster rose to 34° C. (93.2° F.) or 35° C. (95° F.) and continued practically at this level. For the winter, then, it might be said in a general way that the temperature prevail- ing for several days is in a measure an index of the temperature of the cluster. TEMPERATURE BELOW FRAMES IN RELATION TO OUTSIDE AIR. The thermometer f, situated below the bottom of the frames and cluster, as is shown in the general views of the apparatus (figs. 1 and 2), registered the temperature of the air at the bottom of the frames. It should have shown, if they were present, the effects of the cluster on the temperature of the air below the frames. It might be expected that the presence of the bees would have raised the temperature of the air in this part of the hive. For comparison with the other tem- peratures, thermometer 0 was hung in the shed in which the experi- ments were conducted, and registered the temperature of the air which enveloped the hive. Comparison of the readings of thermome- ters f and o reveal some significant facts not altogether in accord with the general belief of beekeepers. During the winter as a whole these thermometers registered almost identically. Shght variations occurred, but only for a few hours at a time, and may be attributed to minor influences of the cluster, to peculiar atmospheric conditions, to drafts, and to the agitation of the bees. It should also be noted that the air which came in the entrance entered from outside the shed and the temperature of this air may not have been exactly that recorded by the thermometer o. During the period of most protracted cold, from January 23 to Feb- ruary 1, when the outside air ranged about 0° C. (32° F.), thermometer f followed the outside temperature closely, and the course of the two curves is practically the same. In some cases, as for instance on January 26, thermometer f was slightly lower than the record of the outside air, which may possibly be explained by lack of ventilation or stagnation of the air of the hive. The lowest recorded outside tem- perature was —10° C. (14° F.). Since it was impossible to read these low temperatures on instrument f, and since the two curves are parallel so far as records were possible, it may be assumed that ther- mometer f would have registered almost the same as thermometer o. During the warmest days and nights the recorded temperatures were the same. The maximum for the winter period came on March THE TEMPERATURE OF THE BEE COLONY. 13 15, when the outside thermometer reached 22.6° C. (72.68° F.). In all the other winter months there were days when the thermometers registered only 2 or 4 degrees less. In conclusion it may be said that throughout the season the tem- perature below the frame was practically the same as that of the out- side air. Of special significance is the fact that the daily extremes, the maxima and minima, no matter what were the variations at other periods of the day, were usually identical. From these observations [ay 8 8 DECKLES CLNW7/GRADE Fic. 8.—Curves showing relation of temperature of center of bee cluster to outer temperature, Feb. 1 to 10. it would appear that the contraction of the entrance and the tight bottom board were not of much service in protecting the colony from. cold. Colonies without bottom boards have frequently been known to survive extreme winter cold. It may be, however, an advantage to a colony to be protected from the sweep of violent winds; but there is no evidence that this colony appreciably warmed the lower part of the hive in which it was wintering. Under such conditions the bottom of the cluster is bathed in an atmosphere of the same temperature as the outside. 14 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. COMPARISONS OF TEMPERATURES OF THE CENTER OF THE CLUSTER AND OF THE OUTSIDE AIR. The curves have revealed no more striking results than the relation observed between the temperature in the center of the cluster, c, as compared with the temperature of the outside air, 0. These curves (fig. 8) at times show a peculiar inverse relation; for instance, when the thermometer out of doors registered low, below zero, the thermometer in the center of the cluster registered high, and vice versa. It should be observed that the maximum within the cluster occurs practically simultaneously with the minimum outside, and vice versa. Even minor changes outside are accompanied by cor- responding inverse fluctuations in the cluster. The responses of the cluster to the outside temperature were shown particularly by the thermometer which recorded the temperature of the center of the cluster, ¢. Up to the day of the first egg laying in the spring, March 9, the general courses of ¢ and o continued relatively constant. But with the commencement of egg laying c changed its trend. The temperature of the brood cluster then became more and more constant, as may be seen in the results of the summer observations. At first glance these curves might be interpreted. as independent of each other, that the outside atmosphere has no effect on the center of the cluster, that 1t does not penetrate and modify the readings of ¢ as it appears to have done in the case of the temperatures in the margin of the cluster. Im all probability c more nearly represents the activities of the bees than do the other temperatures; but there is a relation of c to 0. It might be supposed that the reaction registered by cis deferred for a period of hours and consequently appears at a time when o has changed. For instance, corresponding to the minimum of o on the 4th of February, the minimum of c came nine hours later. If this is due to a delay or ‘‘lag,”” maxima and minima in some cases are delayed for 24 hours or more. But this can not be; there are many minor variations which appear on the curves, and which are synchronous. Were there no relation of c to o these minor variations would either not have appeared in ¢, or, more especially, they would not have occurred simultaneously with a minor fluctua- tion in the outside temperature. It is therefore impossible to explain the phenomena on the ground of retardation (lag), for in that case it would be far more constant than is evident. Related to the assumed explanation by delay or ‘‘lag,’’ humidity or condensation, convection, radiation, and conduction might be assumed to be factors involved. The experimental colony furnishes no data for a consideration of humidity or condensation. The factors of convection, radiation, and conduction can not be conceived as slow enough to retard c from 9 to 24 hours nor would it account for its minor, THE TEMPERATURE OF THE BEE COLONY. 15 synchronous variation. Without doubt of these three factors the loss of heat from the cluster by convection is sufficient to counteract the hypothesis of the lag. Coupled with this the other factors would be expected to participate. The convection is also modified by the generally known contraction and relaxation of the cluster, referred to elsewhere. These physical phenomena are evidently unsatisfactory as an inter- pretation from this standpoint of the lag. Thorough comparison of the charts fails to provide suitable material for conclusions as to the cause. Table III shows the relative increase of temperature in the cluster corresponding to the progress of the winter season, while Table IV shows the monthly maximum and minimum temperature of the center of the cluster during the period from November 9 to March 9. Taste III.—Relative increase of temperature in the bee cluster corresponding to the progress of the winter season. Month. Range of temperature. °@, °F. November, beginning of winter conditions. ....................--------- 20 to 24 68.0 to 75.2 IDEQOMINEE 2 LS aebe cnt GoeSe nec acee CAOnO oe eee eRe inn a4 Son MP EE Teeer re 20 to 22 68.0 to 71.6 Jeri, Wi@ I). Ss eqeteees dessa Ses Ok ets aeons eee 4 eee 22 to 25 71.6 to 77.0 davai, 1) 1) Ol. ogo do seose aodese do out neo Sete ean ANE SA} SS Ceareed ane as 23 to 28 73.4 to 82.4 EDU Ap gprs cease wiser eee te time cc cnn 2 5 seems Soci eie Mele ate 24 to 30 75.2 to 86.0 Mie, TL TO Os oh ees o en One ea aoe ar O CeCe ae Ae a APES c © 5 Scenes See aera 27 to 32 80.6 to 89.6 When brood rearing is established........--...--..-------+--------------- 34 to 35 93.2 to 95.0 TaBLE 1V.— Monthly maximum and minimum temperature of the center of the bee cluster during the winter period, Nov. 9 to Mar. 9. Temperature of cluster. Month. - | Maximum. Minimum. INIGKV HM OOP. oo + Aone Nees Bese ae CBee SE See eee reer 2 Tigh © ge aha nee a 17° to 18.2° C. SOSGOR SH e ee ee eae 62.60° to 64.76° F. ID ECE NN CL Ae MAE re ee aioe ame es Be a 8 Zo 18.5° and 31.3° C.1_.._. 18.1° C. 65.30° and 88.34° F....| 64.58° F. AINA Aaya eo oe ates se eee tae eee os eee S028 C 21 ee se eee 19° SGte Oct ae ee ser eres 66.20° F He PRU aI yAR ees Aeilytosebeiawc cela sam hee edsees oss bab ee DLAC ae a ea Pa ee Ril? SORGO CMH eye earestne cee 69.80° F Witke, 1) AS ae Scie OBER ODS See Be eRe SE CEI ee eae Sandy One Bie Sh Wee Te Dien, Oe On Micaela 80.60° F 1 Ona very warm day, Dec. 28. 2This occurred on two occasions, Jan. 14 and 30, at 8 a. m., when the outside temperature was 4° C. or more below freezing. 3 Approximated several times when outside temperature was below freezing. £ Occurred after a warm day; approaches summer conditions EFFECTS OF MANIPULATION ON THE CLUSTER. Good beekeepers know that it is not well to open a hive in winter, but perhaps few realize the resulting effects on the colony. In Washington there are days in every winter month which are suf- ficiently warm to permit opening a hive without chilling the bees. It was necessary, partially in order to observe the effects on the 16 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. colony and partially to know their condition, to open the hive under experimentation. The results recorded by the thermometers on all of these occasions are pronounced. In the course of the observations on this colony it was found impossible to disturb the colony in the slightest degree, even to remove and replace a thermometer, to jar the colony, or to puff smoke in at the entrance, without notice- ably affecting the temperature. These effects, as in the case of open- ing the hive, were not always temporary, but sometimes lasted for hours. Any disturbance resulted in an almost immediate rise in the temperature, and was appreciable throughout the cluster. On March 12 the colony was opened for 15 minutes at 1 o’clock in the afternoon. The thermometers throughout the hive and even the one below the frames to some extent registered an immediate rise in temperature. When the hive was closed the cluster was soon reestablished but it was several hours before the temperature in the margins of the cluster became normal. On the interior of the cluster, however, the excitement and its effects were not so soon overcome. The curve for ¢ shows that not until the next day did conditions ap- proximate normal; the effects were appreciable even the day following the opening of the hive. These results agree with the experience of many practical bee- keepers, who consider it unadvisable to open their hives during the winter. BEHAVIOR OF THE CLUSTER IN WINTER: OBSERVATIONS ON THE CHECK COLONY. By means of the check colony with glass top and bottom, described on pages 5-6, 1t was possible to watch the movements of the bees throughout the winter at any time of day or night. Various theories have been advanced by beekeepers to account for the behavior of bees in winter, but the writer is not aware that they are based on continuous and close observation. For instance, it has been maintained by some that bees semihibernate; by others it is affirmed that there is at intervals a general warming up of the colony in order that it may feed. The theory is that at stated periods bees generate enough heat to enable them to brave the cold and to expand the cluster sufficiently to enable them to reach fresh stores. It is not necessary to multiply theories on the condition and activities of bees in winter. In a previous portion of the text the relation of the temperatures of the cluster to the temperature of the outside air has been suffi- ciently considered. It remains now to describe the activity of the bees as seen in the glass check hive. In some respects the move- ments or the reaction of the bees, and more particularly of the cluster as a whole, to the stimuli of changes in the atmospheric conditions was rather pronounced. THE TEMPERATURE OF THE BEE COLONY. 1 In watching this colony it was found that the density, and conse- quently the shape of the cluster, varied from day today. When the air outdoors was warm, the cluster expanded; with cold, it contracted. The expansion usually did not cause the bees to cover more frames, but caused them to Gover more completely those frames which they were occupying. Thus the expansion was usually downward toward the bottoms of the frames and in the direction of the entrance. With cold, the bees receded from the bottoms of the frames and from the top bars. At all times the colony was sensitive to the slightest jar. The bees were also especially sensitive to the hght which burst in upon them whenever the covering of the glass top was removed. If the hand were passed over the glass, bees would fly toward it as if to sting. This was noticed no matter how cold the day and shows that the colony, and particularly the outside of the cluster, is far from torpid, inactive, or semiquiescent. At practically all times there were bees moving on the outside of the cluster or on the top bars of the frames. Whenever the hive warmed up in the sun, although there were no bees flying, this was evident. There can be no question, therefore, of the alertness and activity of a colony in winter. One of the most surprising observations was the apparent inter- change of bees from the inside of the cluster with those on the outside of the cluster. As the writer watched the cluster, the head of a bee would gradually appear from below the bees forming the shell of the cluster. Finally this bee emerged and took her place with the others on the outside. Similarly, bees were frequently seen to disappear into the mass. The behavior was in no way general, but apparently was going on constantly and gradually. The phenomenon was repeatedly observed under all manner of conditions and at different times of day and night. By carefully arranging the covers, so that it was unnecessary to remove them, and thus cause a jar, it was proven that this behavior is normal and not the result of a disturbance of the bees. It must be concluded, therefore, that in this way the same bees may not be exposed to the outside cold for a long period. So long as they are able to keep up their own body temperature they remain outside, but when chilled they pass into the interior. Thus there must be a continual interchange of bees from the outside to the inside. Were it possible of observation, there would doubtless be found a relation of the interchange to the meteorological conditions. In cold weather the interchange may be expected to be greater. In severe weather the bees were especially compact and _ their - arrangement definite and constant. They were arranged side by side between the tops of the frames, with their heads downward. At the lower part of the cluster they were also arranged head down but with a little less regularity. It is difficult to see just what this means. 18 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE, As further evidence that the colony is not torpid in cold weather, some of the other activities observed will be of interest. During the day, particularly, the bees were seen grooming and combing one another, feeding, and fanning at the outside of the cluster; and when the light was admitted to the top, they sometimes flew up as if to sting. It should also be stated that on nights of the most severe weather the bees in both this check colony and in the experimental colony were heard faintly and intermittently buzzing. This buzzing was even more noticeable on cold nights than on warmer ones. A peculiar trembling of the bee such as is seen in summer was not infrequently noticed. All of these activities are commonly observed in summer, but heretofore have not been thought to occur in winter and spring before the colony is able to fly forth. It is probable that the heat of the sun has no slight influence on the cluster. At least in the check colony under observation it was evident that the cluster sought the sunny side of the hive, the front above the entrance, where from 10 or 11 o’clock in the morning until ‘sundown the sun shone on the hive. TEMPERATURE ACCOMPANYING THE LAYING OF THE FIRST EGGS. With the laying of the first eggs in the spring, which marks the beginning of summer activity, striking changes occur in the behavior and temperature of the cluster. The central thermometers 0 and ¢ were particularly affected. Upon opening the hive March 12 eggs less than three days old were discovered. Up to March 9 ¢ had usually continued its winter course inversely to 0, as is described and ulustrated above by figure 8. But after March 9, when the first eggs were seen, the course of ¢ changed and the inverse relationship was no longer apparent. In order to explain the change in the course of ¢ in relation to 0, the behavior of the bees at egg-laying time must be considered. During the winter, while fresh air is necessary, there is no such need of it as when the eggs, or more particularly the brood, appear. Moreover, for incubation and for brood rearing a much higher and more constant temperature is needed. The effects of drops in the temperature of the outside air must be overcome. In preparing room for the laying of the queen, the zone for the brood nest is established, which is an important factor in the change in the course of curve c. All of these things appear immediately in the curve at the time of incubation. Formerly, when the bees went forth on a warm day there was a drop in ¢c; now the trend of cis slightly upward during the warmth of the day corresponding somewhat with the’ warmth outside. Flight occurs nearly every day. It is the belief of many beekeepers who winter their bees in cellars that too high a temperature is likely to cause uneasiness and brood THE TEMPERATURE OF THE BEE COLONY. 19 rearing. Root (1908) calls attention to the necessity of maintaining a temperature of not more than 45° F. (7.22° C.) at the approach of spring. The writer is not aware that any systematic study of the temperatures of bees in cellars has ever been made, so that it is impossible to say how the temperature of the cluster would compare with that of the colony under experimentation. The prevailing outside temperature, however, in the present experiment was found to be about 45° F. (7.22° C.) for several days previous to the laying of the first eggs, March 9. At any rate in this experiment it appears that a temperature of 45° F. (7.22 C.), with an occasional maximum outer temperature of 8° to 11° C., is closely associated with the beginning of egg laying. But there are probably other factors of importance, particularly the matter of food. In establishing the experimental colony late in the fall, it was impossible for the bees to store any pollen. In the spring, however, for a week previous to egg laying they were seen gathering it. This might be expected to be an important stimulus to egg laying, and the bees could not rear brood until some could be gathered. While there appears to be a close relation between stimuli, tempera- ture out of doors, and pollen gathering to the laying of eggs, details of the phenomena can be worked out only on a larger number of colonies under experimental conditions. Another noticeable phenomenon which occurred at this time was the equalization of the temperature throughout the cluster. This might occur earlier in colonies protected from the winds and in sunny locations and later in colonies less favorably situated. If, however, upon experimentation this should be found to be one of the funda- mental stimuli to egg laying, it would in a measure explain the fact that eggs do not always appear at the same time in all of the colonies of a bee yard. Another factor would be the strength of the colony and the resulting heat which it could produce and conserve. These results of the present investigation suggest great. possibilities for dis- covering the stimuli which regulate the beginning of egg laying in the spring and which might influence the periodicity of brood rearing during the summer. So far the consideration has been largely of the period in which egos were laid and which preceded directly the beginning of incubation or brood rearing. It will beseen, therefore, that this time is in a sense transitional from the winter condition to the summer season, the topic which will next be considered. TRANSITION FROM WINTER TO SUMMER CONDITIONS. The phenomena mentioned in the preceding caption which accom- panied the laying of the first eggs marked the beginning of the transi- tion from winter to summer conditions, but this transition was not 20 BULLETIN 96, U. §. DEPARTMENT OF AGRICULTURE. completed until brood rearing was well established. With the estab- lishment of brood rearing, the changes which manifested themselves with the first eggs became intensified. The course of the temperature recorded at ¢ became unlike that which was observed in the winter and was influenced more directly by the outside temperature. The influence of the outside temperature became less and less marked, as is shown from the fact that the oscillation of ¢ became less and less, the temperature in the center of the cluster became more constant, and the temperature throughout the hive became more equalized. As was stated, the turning point came on the 9th of March, but it was a little more than two weeks, about the 24th or 25th of March, before the colony really assumed normal summer temperature condition. Once this was gained, the temperature, particularly of the center of the cluster, remained relatively constant until fall. This transition period of two weeks was characterized by several features. There was an increase of temperature both in the colony and out of doors. Out of doors the maximum ranged between 12° and 18° C. (53.6° to 64.4° F.), but even more favorable weather followed the establishment of brood rearing and the maximum ranged from 18° to 25°C. (64.4° to 73.4° F.). To acertain extent the temperature of the colony was raised like that of the outside temperature. The increase was general throughout the colony and must be attributed to the need of more heat for brood rearing, more ventilation, and the general increased activity of the bees. At this time } and ¢ ranged constantly between 33° and 35° C. (91.4° to 95° F.), which will be seen to be prac- tically the range throughout the summer. In a word, the transition from winter to summer conditions was accomplished in a surprisingly short time. Accompanying incuba- tion and brood rearing the temperature was gradually raised and became equalized through the hive, and once well established was maintained during the summer. . Although the transition was rela- tively abrupt, it would be expected to vary with the colony and perhaps be prolonged in unfavorable weather. GENERAL PHENOMENA OF THE SUMMER TEMPERATURE. The constancy and equalization of the temperature and the range of 33° to 35° C. (91.4° to 95° F.), which characterized the close of the transition from winter to summer conditions, characterize equally well the prevailing summer phenomena. So constant were the tem- peratures in summer that their peculiarities may be briefly sum- marized. Few external factors influenced the hive temperature, and these affected it but slightly. In the original plan of the experiment it was hoped that it would be possible to discover whether there is any correlation between honey flows and temperatures; but inasmuch as the season was excessively dry and the flowers secreted no nectar Zi | wl] THE TEMPERATURE OF THE BEE COLONY. for weeks at a time, this phase of the experiment could not be carried out. RELATION OF C TO THE OUTSIDE TEMPERATURE. Whatever is said of ¢ in the following paragraphs apples equally to . b, and practically as well to all the thermometers in the hive. Although the temperature at ¢ coursed constantly in the sursauie direction to o during the winter, there is no appreciable correlation between the temperatures in the summer. It might be said of the hive that the temperature as a whole was independent of external conditions. A few exceptions to this will follow, however. During a period of stormy and cooler weather, for instance, although there were slight changes which will be discussed later, the temperatures were largely unaffected. Moreover, since the oscillation of ¢ was slight, as will be explained, there was little relationship between the temperature of the center of the cluster and o. THE MAXIMA AND MINIMA OF C IN RELATION TO O. The daily oscillation between the maximum and minimum of c was usually less than 1° C. (1.8° F.), and in many instances it was but one or two tenths of a degree. On the whole the temperature in the brood nest is remarkably constant, ranging between 34° and 35° C- 32290 95> i.) Even with this slight fluctuation there was perceptible on many days a maximum and minimum for ¢, and particularly for the other hive thermometers which perhaps were the most influenced by ex- ternal conditions. It may be said that, roughly, the maxima and minima occurred within two hours of the maxima and minima of 0, but since in some instances this happened previous to the maximum and minimum out of doors, the warming up of the colony due to the increasing activity of the bees must have had its effect. To show how closely the maxima of the thermometers in the outer parts of the cluster ultimately approached the readings of the central thermometers, it may be said that while in April the maximum of the outer thermometers in the hive was 19° C. (66.2 F.), in the fol- lowing months it rarely fell below 34° C. (93.2° F.). In September, however, with the general cooling of the atmosphere, it fell to 28° C. (82.4° F.). This showed the tendency at the close of the experiment for the colony to approach winter conditions. The facts show again the unity or equalization of the temperature throughout the cluster, which in the brood-rearing season ranges between 34° and 35° C. (93.2° to 95° F.). The maxima and minima are shown in Table V. The range of the oscillation shows the constancy of the temperature during the height of the season and the greater fluctuations in spring and fall. 22 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. TaBLe V.— Maximum and minimum temperatures of the center of the cluster during - summer. Thermometer C. ae asd Approximate Month. Meximum. Minimum, range. Gh oF es CRO OUR: are Duyae SATUS Sacer eee vemos camino wemen ameasce Ce) ceowen ieee 35.4 95.7 31.6 88.9 4 Whee DV estate sea pea ed om ena Sate Phe lass ean eeee Ace ice 36.0 96.8 33.8 92.9 2 3.6 UTA ee ee a ee ee ene oe ety eet oe 35.5 95.9 33.6 92.5 2 3.6 DULY iia ofa ar ne re ee ee ee tis © cys a Se ER elec 35.0 95.0 OBee 91.8 2 3.6 CANIS TIS Es See Ree eS tN ee Ea ae ek me) 35.8 96.4 33.8 92.9 2 3.6 Septemiber soreness, eee eee eta. cae atsrs eens oe 34.8 94.6 28.0 82.4 7 12.6 FLUCTUATIONS IN THE HIVE TEMPERATURE AND THE CAUSES. It has already been said that the fluctuations in the hive tempera- ture were slight and that hot days and winds had very slight effect on the cluster temperature. There are some minor fluctuations due to internal and external disturbances which caused decrease or increase in the hive temperature. THE EFFECT OF “ORIENTATION” OR “PLAY FLIGHTS.” Every beekeeper is familiar with the “‘play flights” of young bees about noon on warm sunny days. These are generally believed to be ‘orientation flights,’ in which the young bees fly forth in circles and with head toward the hive in order to learn its location. During the period of resumed brood rearing in August these flights occurred every few days in the experimental colony. At such times ther- mometer readings were taken at short intervals. Instead of causing the heat of the hive to increase these flights first caused a decrease, then aslightincrease. Table VI presents figures for a typical observa- tion, made after the bees had been confined to the hive by inclement weather for three days. TasLe VI.—E fects of ‘‘orientation flights” of bees on the temperature of the hive. Thermometer. Aug. 28 a b } c d. € if 0 aia OFA adaey as ek Oe) nea AN na OA Vay ial a Oe Nay eM Oe Oak NW Choe i jal lS (Op i) Ouat 6a.m.! 34.0) 93.2 | 34.4) 98.92) 34.4) 93.92) 34.4! 93.92) 33.6] 92.48) 34.6] 94.28] 15.6! 60.08 eyaeMM i ots =) ore 34.0] 93.2 | 34.4) 93.92} 34.4! 93.92) 34.0) 93.2] 33.4) 92.12) 34.4] 93.92) 16.4) 61.52 Ridemieege ss Sion 34.0] 93.2 | 34.2] 93.56} 34.2) 93.56) 34.0) 93.2] 33.4] 92.12} 34.6] 94.28) 16.8] 62.24 ee 0 34.0] 93.2 | 34.0} 93.2 | 34.3) 93.74) 34.0} 93.2} 33.2! 91.76) 34.6] 94.28) 17.4] 63.32 (ihe eee 34.0} 93.2 34.2) 93.56) 34.3) 93.7 34.0) 93.2 33.2) 91.76] 34.8) 94.64) 18.0} 64.40 Lagrmnee sean 33.8] 92.84] 33.8) 92.84) 33.8] 92.84] 33.8] 92.84) 33.2! 91.76] 34.2) 93.56] 19.4! 66.92 11.30 a.m.4....| 33.8] 92.84) 34.0) 93.2] 34.0] 93.2 | 384.0) 98.2] 83.8) 92.84) 34.4) 98.92] 20.0] 68.0 12 oe eee 34.0) 93.2 | 34.0) 93.2] 34.0) 93.2] 34.0] 93.2] 33.6) 92.48! 34.4] 93.92) 19.6] 67.28 1B sp aleb le ee 34.0) 93.2 | 34.2) 93.56] 34.2) 93.56) 34.0} 93.2] 33.6] 92.48) 34.8) 94.64) 20.2) 68.36 PASS MY eee 33.8] 92.84! 34.0) 93.2 34.0} 93.2 33.8] 92.84) 33.6) 92.48] 34.4] 93.92) 20.2) 68,36 ZAS Daler etos 34. 0] “93.2 34.0) 93.2 34.0} 93.2 34.0} 93.2 33.6} 92.48) 34.4) 93.92) 20,4! 68.72 2.30 p. m.6 34.0} 93.2 34.0) 93.2 34.2] 93.56) 34.0) 93.2 33.6] 92.48) 34.6} 94.28) 20.0} 68.0 245). M2... 34.0} 93.2 34.2) 93.56) 34.2) 93.56] 34.0) 93.2 33.8] 92.84) 34.8] 94.64) 20.4] 68.72 Osby ae eee 34.0} 93.2 34.2) 93.56) 34.2) 93.56] 34.0) 93.2 33.8] 92.84) 34.8] 94.64) 20.8] 69.44 4p.m. 34.0] 93.2 34.4) 93.92) 34.4) 93.92) 34.2] 93.56) 33.8) 92.84) 34.8) 94.64] 20.2) 68.36 1 Cloudy. 4 Quieted flight. 2 Bees fly slightly. 5 Bees fly freely again. 3 First good fly for three days. 6 Quiet again. THE TEMPERATURE OF THE BEE COLONY, 23 It will be noticed that short flights were taken at 8 o’clock in the morning when the thermometer c fell 0.2° C. At 11 o’clock the first flight of importance occurred. Then there was another shght drop in the temperature followed by a rise. At 2 o’clock there was a similar fight and change in the thermometer. In all cases within 15 to 30 minutes the thermometer had regained its normal tempera- ture. While the drop was actually slight, when it is remembered that the daily fluctuation in the temperature was frequently but a fraction of a degree, the decrease was relatively considerable. The same effect was noticed in the spring and in the early part of the season, when the bees first commenced to take field trips. This cooling effect must be attributed to the rushing forth of the bees from the cluster; in so doing they liberate the confined heat of the cluster. Another factor is probably the excessive fanning at the entrance which usually accompanies these “play” flights. When the activities wane and the bees commence to return to the hive, the temperature resumes its normal condition. A similar decrease in temperature was common in the early morn- ing when the bees commenced to leave the hive for the field. For comparison with the foregoing, the readings taken in the early morn- ing of August 3 and 4 are presented in Table VII. TaBLeE VII.—LH fects of early morning flight of bees on temperature of the hive. Thermometer. Date. a b c d é 0 Aug. 3. me ele eC: O17, Ce: OUR °¢, OTR, “Cr, O10, °C. nee SAM So. 35 3 34.0 | 93.2 34.2 | 93.56 | 34.6 | 94.28 | 34.2 | 93.56 | 34.0 | 93.2 22.6} 72.68 DlaremMsos. 5.2 2)2 2 33.8 | 92.84 | 34.2 | 93.56] 34.4 | 93.92 | 34.2] 93.56 | 33.8] 92.84 | 26.0] 78.80 10!a. mM. ...-.-.- 33.9 | 93.02 | 34.4 | 93.92 | 34.8 | 94.64 | 34.2 | 93.56 | 34.0 | 93.2 26.8 | 80.24 Ul fars Mes Loe a= 2 34.0 | 93.2 34.4 | 93.92 | 34.8 | 94.64 | 34.6] 94.28 | 34.0 | 93.2 27.4) 81.32 Ian aes Ses oes: 34.0 | 93.2 34.6 | 94.28 | 34.8 | 94.64 | 34.6 | 94.28 | 34.0 | 93.2 28.0] 82.40 Aug. 4. 5a.m1_____....| 34.4 | 93.92] 34.6 | 94.28 | 34.8 | 94.64 | 34.6 | 94.28] 34.2 | 93.56 | 21.2] 70.16 Gilat misses Sees: 34.4 | 93.92 | 34.6 | 94.28 | 34.6 | 94.28 | 34.6 | 94.28 | 34.4 | 93.92 |} 21.0] 69.80 OB te sonaoce||. Bile || By 34.4 | 93.92 | 34.6 | 94.28 | 34.2 | 93.56 | 34.0 | 93.2 22.6 | 72.68 Siam eee. se. 34.0 | 93.2 34.4 | 93.92 | 34.8 | 94.64] 34.4 | 93.92 | 34.0 | 93.2 25.0} 77.00 ORS tty coenoescas 34.0 | 93.2 34.8 | 94.64 | 34.8 | 94.64 | 34.4 | 93.92 | 34.0 | 93.2 27.0 | 80.60 1 Fanning entrance. 2 Bees begin to fly freely. EFFECTS OF CLUSTER HEAT ON THE TEMPERATURE BELOW THE FRAMES. It was found that the heat from the cluster had no perceptible influence on the temperature of the air below the frames during the winter. Practically the air was at the outside temperature. But in summer totally different conditions prevail; the temperature within the hive becomes equalized. Furthermore, the crowding of the bees at certain seasons tends to force them to hang down from the bot- 24 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. toms of the frames or even out at the entrance. Consequently that space which was outside the frames assumes cluster conditions. ; Early in the season f averaged 3° C. higher than o at all times; at the end of the season, September, it averaged from 5° to 6° C. higher. By the middle of May f stood only 1° or 2° C. lower than the thermometers in the cluster, although the thermometer in the outside air was much lower. Throughout the summer there was practically no difference between ¢ and f. During the storm period, as will be seen in Table IX, which is discussed farther on, f ranged even higher than the prevailing cluster temperature. This was undoubt- edly due to the massing of the bees below the frames as they were crowded in from the alighting board. THE EFFECTS OF STORM. Since the summer of 1908 was remarkably dry and free from storms, it is not possible to draw any definite conclusions upon the effects of storms, cold waves, and winds upon the cluster temperature. The only severe storm of the summer occurred in the latter part of August. The outside thermometer went as low as 14° C. (57.2° F.), while before and after this period there were frequent readings ranging from 20° to 30° C. (68° to 86° F.). During the storm there ‘were several high winds. These, however, did not blow directly in at the entrance. The bees were thus confined for three days, and at times showed much evidence of shifting and massing at different parts of the hive. In a glass observatory hive the bees were actually seen to cluster now in one part of the hive and then in another. The wind and rain also drove the bees in off of the alighting board and forced them to hang from the bottoms of the frames. If the readings of the thermometers nearest the outside of the hive are rightly interpreted, the cluster withdrew from the walls of the hive, and this caused a decrease in the temperature at these points. While there is some evidence in the figures that the cold outside the hive had its effects on the center of the cluster, the temperature was not permitted to remain below 34° C. (93.2° F.). No fall was recorded lower than 33.8° C. (92.84° F.). Thus the bees appear to be able to control and conserve the temperature with remarkable constancy, even though there be high wind and relatively low temperature. Table IX, in comparison with the figures for a bright day in Table VIII, reveal these facts. THE TEMPERATURE OF THE BEE COLONY. TasLe VIII.— Temperatures of a bee colony on a normal day. Time. Thermometer. Saar. Hour a b. c d. é. 0. | SIGN | CRE n en hel am nestle.) s Reem Be seLtce ||) Sel amelie carte | eis” CUA aro) si Bie Aug.15| 6a.m.1..... 34.4 | 93.92 | 34.4 | 93.92 | 35.0 | 95.00 | 34.8 | 94.64 | 34.8 | 94.64 | 24.4 | 75.92 (ERNE Sara 34.4 | 93.92 | 34.4 | 93.92 | 34.8 | 94.64 | 34.8 | 94.64 | 34.6 | 94.28 | 26.0 | 78.80 (rEg ltl epee 34.2 | 93.56 | 34.4 | 93.92 | 34.8 | 94.64 | 34.8 | 94.64] 34.8 | 94.64 | 24.6 | 76.28 Slay. S ..). 34.2 | 93.56 | 34.4 | 93.92 | 34.8] 94.64 | 34.8 | 94.64 | 34.8 | 94.64 | 25.8 | 78.44 LO} asa 34.6 | 94.28 | 34.6 | 94.28 | 34.8 | 94.64 | 34.6 | 94.28 | 34.6 | 94.28 | 27.6 | 81.68 arse se ene 34.8 | 94.64 | 34.8 | 94.64 | 35.0] 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 28.8 | 83.84 PQerrne ss 8 = 34.8 | 94.64 | 34.8 | 94.64 | 35.0} 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 29.0 | 84.20 LSD Te ats ores =, - 34.8 | 94.64 | 35.0 | 95.00 | 35.0} 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 29.6 | 85. 28 7410) dt egos 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 35.2 | 95.36 | 35.2 | 95.36 | 30.4 | 86.72 ANTS TIN crea 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 35.2 | 95.36 | 35.2 | 95.36 | 29.2 | 84.56 (p]Ou de Sec mcle 35.0 | 95.00 | 35.0 | 95.00 | 35.2 | 95.36 | 35.2 | 95.36 | 35.2 | 95.36 | 28.2 | 82.76 7703 MOeeo0 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.2 | 95.36 | 35.0 | 95.00 | 27.6 | 81.68 Sipe taeet se 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0) 95.00 | 35.0 | 95.00 | 26.6 | 79.88 AIS 8), Ga. 0. 532-2 34.0 ; 93.2 | 34.2 | 93.56 | 34.0} 93.2 | 34.0 |] 93.2 | 34.2 | 93.56 | 21.8 | 71.24 ein TVS ye cays 34.2 | 93.56 | 34.2 | 93.56 | 34.4 | 93.92 | 34.4 | 93.92 | 34.2 | 93.56 | 22.0] 71.60 Orbe TL. sere, < aie 34.2 | 93.56 | 34.2 | 93.56 | 34.4 | 93.92 | 34.4 | 93.92 | 34.2 | 93.56 | 22.4 | 72.32 9a.m.1.._...| 34.4 | 93.92 | 34.4 | 93.92 | 34.6 | 94.28 | 34.6 | 94.28 | 34.4 | 93.92 | 25.0 | 77.00 10 a.m.5.._.| 34.4 | 93.92 | 34.6 | 94.28 | 34.6 | 94.28 | 34.8 | 94.64 | 34.6 | 94.28 | 26.0] 78.80 ih) exe aa 34.6 | 94.28 | 34.8 | 94.64 | 34.8 | 94.64 | 34.8 | 94.64 | 34.8 | 94.64 | 26.5] 79.70 1701 Sees 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 27.4 | 81.32 fp mee 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0] 95.00 | 35.0 | 95.00 | 28.6 | 83.48 WO s te Gaaa- 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 29.0 | 84. 20 ShJ0y HME eeaoe 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0] 95.00 | 28.0} 82.40 Asp lamers. =a 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.2 | 95.36 | 35.2 | 95.36 | 28.0] 82.40 Qos i eeedoue 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.2 | 95.36 | 27.4 | 81.32 Une ie edone 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 26.2 | 79.60 Shp diese ses 34.8 | 94.64 | 34.8 | 94.64 | 35.0 | 95.00 | 35.0 | 95.00 | 35.0 | 95.00 | 25.6 | 78.08 1 Cloudy and calm. 4 Clearing and calm. 2 Clearing, calm and close. 5 Clear. 3 Cloudy. TABLE IX .—The effects of storm and wind on the temperatures of the bee colony. Thermometer. Time. = a. b. Cc. d. é. iff Month ° ° ° ° ° ° ° iro on” ° ° ° ° ° andday. Hour (C4) Gua @ JD Wann ernie || OL APOE OLN V aN OLS Ree aol Keo. Aug. 25 | 8a. m1_..../34.2 |93. 56 |34.4 |93.92 |34.2 |93.56 |34.2 93.56 |34.0 |93.20 [34.6 |94.28 |20.4 | 68.72 8.30 a. m 34.2 |93. 56 |34.2 |93.56 |34.2 |93. 56 |34.2 93.56 |34.0 |93. 20 |34. 6 |94. 28 |19.8 | 67. 64 9a.m.2..... 34.4 |93.92 |34. 4 |93.92 |34.2 93. 56 |34.2 |93. 56 [33.8 |92. 84 |34.6 |94. 28 |19. 8 | 67. 64 10a.m.. 34.0 |93. 20 [34.2 |93. 56 |34. 2 |93. 56 |34. 2 |93. 56 |34.0 |93. 20 [34.6 |94. 28 |20. 8 | 69. 44 11 a. m.3.._./34.2 |93. 56 |34. 4 |93. 92 |34. 4 193. 92 134.2 (93.56 134.0 |93. 20 |34. 6 |94. 28 |20.2 | 68.36 UZ Teo aah 34.0 |93. 20 |34. 8 |94. 64 |24. 2 |93. 56 /34. 4 |93.92 [34.0 |93. 20 |34. 6 |94. 28 |20.6 | 69.08 1p.m.4..../34.2 |93. 56 |34. 4 |93. 92 |34.2 |93. 56 [34.2 |93. 56 |34. 0 93. 20 |34. 6 |94. 28 |18.4 | 65.12 2p.m......|34.0 |93. 20 |34. 6 |94. 28 |34.0 |93. 20 [34.0 |93. 20 134. 4 |93. 92 134.6 |94. 28 |17.8 | 64.04 3p.m....../34.0 |93. 20 |34. 4 |93.92 |34.2 |93. 56 134. 2 |93. 56 134.0 |93. 20 |34. 6 |94. 28 |17.6 | 63. 68 4p.m...... 34.0 |93. 20 |34. 8 |94. 64 |34. 2 193. 56 134.0 |93. 20 |34. 0 |93. 20 |34. 6 |94. 28 |17.0 | 62.60 5 p.m....../34.0 |93. 20 |34.0 |93. 20 |34. 2 |93. 56 |34.0 |93. 20 |34.0 |93. 20 |34. 6 |94. 28 16.2 | 61.16 6 p.m... ../34.0 |93. 20 |34. 2 |93. 56 |34.0 |93. 20 |34.0 |93. 20 133.6 |92. 48 |34. 6 |94. 28 18.2 | 64.76 Wop Mesee 34.0 |93. 20 134. 4 |93. 92 134.2 |93. 56 [34.2 |93. 56 |33. 6 |92. 48 |34. 6 94. 28 |16. 4 | 61.52 8 p.m......|383. 8 |92. 84 |34. 2 |93. 56 134. 2 |93. 56 |34.0 |93. 20 |33. 4 |92.12 |34. 6 |94. 28 |16.2 | 61.16 9p.m....../34.0 !93. 20 |34. 2 193. 56 134.2 |93. 56 134.0 !93. 20 |33. 6 192. 48 |34. 6 |94. 28 15.0 | 59.00 UO To. Woke 34. 0 |93. 20 |34. 4 |93. 92 134. 4 |93. 92 |34. 4 193. 92 |33.0 191. 40 |34.6 |94. 28 ]15.0 ] 59.00 Hips meses. 34. 0 193. 20 |34. 2 |93. 56 134. 4 193. 92 |34.2 93. 56 |33. 2 |91. 76 134. 6 194. 28 {14.6 | 58. 28 12 p.m.. __|33. 8 |92. 84 |34. 0 |93. 20 |34. 2 |93. 56 34.0 |93. 20 |33. 4 192.12 134.6 194. 28 |15.4 | 59.72 Aug. 26 | la.m...... 33. 8 |92. 84 134. 2 193. 56 134.0 |93. 20 134.0 |93. 20 133. 4 |92.12 |34. 6 |94. 28 |15. 6 | 60.08 2) PT Scie 33. 6 |92. 48 |34. 0 193. 20 |34. 0 193. 20 |34. 2 193. 56 133. 0 [91. 40 34. 6 |94. 28 114.8 | 58. 64 3 a.m.o...../33. 6 |92. 48 |34. 2 193. 56 (34. 2 193. 56 /34.0 193. 20 (33. 4 |92.12 |34.6 |94. 28 |17. 4 | 63.32 4a.m.6_.... 33. 6 192. 48 |34. 2 |93. 56 134. 2 193. 56 34.0 93. 20 (33. 4 |92.12 134. 6 |94. 28 {16.2 | 61.16 5 a. M.6.....| 33. 6 192. 48 {34.0 193. 20 134. 2 193. 56 (34.0 |93. 20 |33. 2 |91. 76 |34. 6 |94. 28 |17.0 | 62.60 Grasse ase |33. 6 192. 48 |34. 2 193. 56 |34.2 193. 56 [34.0 |93. 20 |33. 2 |91. 76 [34.6 |94. 28 |16.6 | 61.88 7a. .6.._..|33.6 |92. 48 fie 4 193.92 134.2 |93. 56 |33.6 |92. 48 |33.4 |92.12 |34.6 94.28 |17.0 | 62.60 1 Cloudy. 4 Rain. 2 Breeze from north. 3 Raining a little. 5 High wind from east. 6 High wind from east, no rain. 26 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. Another fact to which reference has been made under the caption, “Effects of cluster heat on the temperature below the frames,’’ should be mentioned here. During this period of storm, f frequently recorded a higher temperature than the thermometers above it. This was undoubtedly due to the crowding of the bees in off of the alighting board, forming a curtain below the frames. This is an advantage in helping to conserve the heat and in preventing the cold, inward draft through the entrance from striking directly on the brood. THE EFFECTS OF TRANSPORTATION ON THE TEMPERATURE OF THE COLONY. Not infrequently beekeepers sustain heavy losses in moving their bees, although it is not usually done in extremely hot weather. Since the moving of the experimental colony to College Park, Md., a distance of about 11 miles, was unavoidable, the writer decided to make the most of the necessity and determine in so far as possible the effects of transportation on the colony. Even with precautions, strong and populous colonies sometimes smother. Brood is often killed, supposedly from excessive heat. With these points in mind every precaution was taken to protect the colony from harm; and since no damage resulted, the experiment reveals the temperature conditions in a successful transportation of a strong colony under most adverse circumstances—extreme heat and humidity and bad roads. The trip was commenced at 10.30 a. m. on July 2. The day was humid, with intermittent sunshine and clouds, and no breeze. In Washington the mercury rose to 32.33° C. (90° F.) at 2 o’clock. The road was through the city of Washington over asphalt and stone pavements for several miles and then over rough country roads, which had scarcely any shade. The colony was moved on a spring express wagon with cover, the curtains of which were kept down on the sunny side so as to prevent the sun from striking directly on the hive. The other curtains were rolled up in order to allow all the ventilation possible, but since there was no breeze all the draft which the bees got must have been procured by fanning and by the movement of the wagon. The colony was crowded into a 10-frame Langstroth hive and the entrance was screened the night previous. All of the thermometers remained in position. This, of course, prevented giving ventilation through the top of the hive, which is the common practice in moving bees. In order to give room for expansion of the cluster and to con- fine the air as little as possible, the hive was set over an empty body, on the bottom of which wire cloth was tacked. In order to allow the air to circulate freely beneath the hive, it was supported above the THE TEMPERATURE OF THE BEE COLONY. 27 bottom of the wagon on {-inch strips of wood, the spring of which relieved to some extent the jolt of the wagon. In the morning, before the colony was disturbed and just after it was loaded, thermometer readings were taken. On the road readings were also made at short intervals. In this way the result of every successive event in the trip was known. The first disturbance, carrying the hive downstairs and loading, was immediately responded to by the bees. The first 15 minutes on the road were but slightly more disturbing. Gradually, however, the temperature increased until 1.30 o’clock in the afternoon and an hour previous to releasing, when practically the maximum was reached, 36.0° C. (96.8° F.). It should be mentioned, however, that during the next few hours and even after the bees had their liberty the ther- mometers in the distant parts of the hive, a and e, registered 36.2° C. (97.16° F.). But it is probable that the bees clustered more densely at these points than they did in the center of the hive. This tempera- ture can not be considered particularly abnormal, although it is higher than any temperature registered immediately before or after the transportation. On several occasions during the summer and even in May, practically the same degree was reached; but since in normal circumstances it never went higher than 36° C. (96.8° F.), the temperature observed is probably nearly as high as can be reached by bees without damage. It would not have taken many degrees more than this to have softened the combs and to have caused them to sag and break. The melting point of pure wax is 62° to 64° C. (143° to 145° F.), but the difference between the melting point and the point at which combs become soft enough to sag must be con- siderable, perhaps 20° C. (36° F.). It can not be said that the temperature was higher at any one part of the hive than at another, unless possibly there was a slight tend- ency for the brood cluster to be maintained cooler. This would naturally be expected, but under such trying circumstances the phe- nomenon could not be measured satisfactorily. At no time on the trip did the bees hang down from their combs into the lower body, and upon releasing them there was no evidence of condensation. At all times, as would have been expected, there was considerable fanning. Furthermore, the bees were not made cross by their con- finement, as was the case when the rest of the colonies of the apiary were moved, which was done under much more favorable circum- stances except for ventilation. That no brood died in the experi- mental colony is further evidence that 36° C. (96.8° F.) is not abnormal. The colony was placed in its new position at 2.30 o’clock and the bees liberated. The effects of their liberty on the temperatures were not apparent, however, as will be seen in Table XI, for more than an 28 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. hour, when the temperatures began gradually to fall. Finally, when the bees had orientated themselves and had commenced to return to the hive, there was a noticeable quieting and a perceptible drop in the mercury. At 7.30 o’clock, after all the bees had returned to the hive, conditions were practically normal. In conclusion it may be said that the conditions under which the bees were moved, although trying and about as adverse as possibly could be encountered, did not produce abnormal heat in the hive. The temperature increased only 2°, from 34° to 36°+C. (93.2 to 96.8° F.). While it is generally admitted that ventilation from the top is preferable in moving bees, on the hypothesis that warm air rises, ventilation from the bottom was a success in the case under dis- cussion. In moving the rest of the department apiary to College Park earlier in the season, when the weather was more favorable, the day being cloudy with showers, three colonies suffered severely from overheating and condensation. These colonies were screened at the entrance and over the top of the hive; but apparently the screening of the top was not sufficient, because when the bees became excited and expanded as a result of the heat, they packed so tightly against the top screen as to shut out all ventilation. The tendency of bees is upward and toward the ight. On the contrary, if ventilation is given from below, there is less tendency for them to pack against the screen. While it is generally maintained that for moving colonies top ventila- tion is preferable, the present experiment would indicate that bottom ventilation is practical and advantageous. For comparison, figures taken the day previous (Table X) and the day after the transportation (Table XII), as well as on that day (Table XI), are presented. TaBLE X.—Readings of thermometers, July 1, on day previous to transportation of bee colony. Thermometer. | i | Hour. a. b. c. d e. 0. | ns 2G Rs 8. °F AG. oF ae oF: es pif 20, ma QR occaee ses 33.4 | 92.12 | 34.0] 93.20] 34.0] 93.20] 33.8] 92.84] 33.8] 92.84] 25.8] 78.44 LU: 5 0 eee er 33.6 | 92.48 | 34.0 | 93.20] 34.2 | 93.56] 33.6] 92.48 | 33.6 | 92.48] 27.0] 80.60 WAT ie eo eee 33.8 | 92.84} 34.2] 93.56] 34.2] 93.56] 33.8] 92.84 | 33.6] 92.48] 28.5] 83.30 DE ere eek 33.9 | 93.02 | 34.5 | 94.10] 34.5] 94.10] 33.9 | 93.02] 33.9 | 93.02] 29.0] 84.20 1 iy oi 11 eee re 34.0 | 93.20] 34.5 | 94.10] 34.5] 94.10] 34.0] 93.20] 34.0] 93.20] 29.8] 85.64 P| Up 0s Pee ee ge 34.4 | 93.92} 34.8 | 94.64 34.8 | 94.64 34.0 | 93.20 | 34.0] 93.20] 31.5] 88.70 Ji) Opa | See apie 34.4 | 93.92 | 34.8 | 94.64 34.8 | 94.64 34.0 | 93.20} 34.0 | 93.20] 31.5] 88.70 Cs ct pes ee 34.6 | 94.28 34.8 | 94.64 34.8 | 94.64 34.2 | 93. 56 34.2 | 93.56 32.2 89.96 Spr Messses ees 34.8 | 94.64 34.8 | 94.64 35.0 | 95.00 | 34.8 | 94.64 35.0 | 95.00 | 29.0] 84.20 J THE TEMPERATURE OF THE BEE COLONY. 29 TasLe XI.—Readings of thermometers during transportation of bees, July 2. Day extremely warm and sultry. Thermometer. . Hour. c Observations. SUAS aC. mer SH: PxGP Ue a0 eee 93. 92 34.4 | 93.92 20 | 34.0 Hive closed but un- moved. 10.15 a. m. 95. 00 35.0 | 95.00 64 | 34.8 Hive loaded on wagon. 10.30 a. m. 95. 00 35.0 | 95.00 64 | 34.8 Drive to College Park started. 10.45 a.m : 95. 36 - 35.1 | 95.18 82 | 35.0 jl a.m. .4 Nz || doe 35.2 | 95.36 00 | 35.0 11.15 a. m .4 72 | 35.0 35.1 | 95.18 00 | 35.0 Sun and clouds. 11.30 a. m- 6 08 | 35.2 35.2 | 95.36 00 | 35.0 Do. 11.45a.m .8 44 | 35.4 35.6 | 96.08 18 | 35.2 Do. 175 0 eee .8 44 | 35.6 35.6 | 96.08 54 | 35.4 Do. 12.15 p.m. 8 44 .8 35.6 | 96.08 72 | 35.6 Do. 12.45 p.m.| 35.8 44 6 35.6 | 96.08 72 | 35.6 Stopped 30 minutes for lunch. iipamtec--- .8 44 .6 35.6 | 96.08 08 | 35.6 1.15 p.m--.} 36.0 80 .8 35.8 | 96. 44 44 | 35.8 1.30 p.m.. .0 80 .0 35.9 | 96.62 44 | 36.0 PI) ye Was eee -0 80 -0 36.0 | 96.80 62 | 36.0 2.30 p.m. .2 16 .0 36.0 | 96.80 80 | 36.1 Hive set on stand and opened. BipemMeace- ne, 16 .0 36.0 | 96.80 80 | 36.2 3.30 p.m Bed 16 | 35.8 35.8 | 96.44 80 | 36.0 4p. me... - pl 98 | 35.4 35.8 | 96. 44 80 | 36.0 4.30 p.m..} 35.4 12) \\ evcal 34.8 | 94.64 18 | 35.4 GUase eee .0 00 | 34.0 34.6 | 94.28 82 | 35.0 6.30 p. m-. .6 28 «2 34.2 | 93.56 92 | 34.4 Bees all returned to hive. Cel stlae -4 | 93.92 | 34.2 34.2 | 93.56 56 | 34.2 7.30 p. m.. -4 | 93.92 -0 34.0 | 93.20 56 | 34.2 Quiet and normal. TaBLE XI11.—Readings of thermometers, July 3. Day after transportation of bees. Thermometer. Hour. c d Observations. OTA. °F. “Ge O70! 28 2185 7.30 a.m.. 92. 84 .0 -20 | 34.0} 93.20 .6 | 92.48 91. 40 8.30 a. m 92. 84 .8 84 34.0 | 93.20 -4 | 92.12 91.40 | Cloudy. 10‘a.m-.... 92. 84 -0 20 | 34.0 | 93.20 .4 | 92.12 92.48 | Breeze. Mikasiee sae 93. 20 .0 20 | 34.0 | 93.20 -4 | 92.12 92.12 Pim eee 93. 20 2 56 | 34.2 | 93.56 -6 | 92.48 92.12 CIOs tS oanse 94. 64 -8 -64 | 34.6 | 94.28 .2 | 93.56 93.20 | Bees returned. Sip: Wee: 2. .6 . 28 34.6 | 94.28 -0 | 93.20 93. 20 94. 64 WASHINGTON : GOVERNMENT PRINTING OFFICE: 1914 BULLETIN OF THE USDEPARTNENT OFAGRICULTURE A No. 97 M) Contribution from the Bureau of Soils, Milton Whitney, Chief. | June 12, 1914. (PROFESSIONAL PAPER.) IDENTIFICATION OF COMMERCIAL FERTILIZER MATERIALS. By Wriu1am H. Fry, Scientist in Soil Laboratory Investigations. INTRODUCTION. In working with commercia: fertilizers it is often desirable to know not only the percentages of the various ingredients as given by chemi- cal analysis but also the compounds in which these occur in the fer- tilizer, i. e., the carriers of these ingredients. The calculation of the rational composition from the ultimate analysis in the case of salts gives results which are open to doubt and requires a much more com- plete analysis than is usually made. In the case of organic materials such a, calculation is practically impossible. It, therefore, becomes necessary to identify a great number of the substances occurring in commercial fertilizers by means which give the compounds as dis- tinguished from the chemical ingredients of these compounds. The following substances were chosen for examination: Potassium chloride. Basic slag. Potassium sulphate. Ground rocks and minerals. Ammonium sulphate. Cottonseed meal. Kainite. Raw bone meal. Sodium nitrate. Steamed bone meal. Superphosphate. Peat, humus, muck, etc. Calcium nitrate. Dried blood. Lime. Slaughterhouse tankage. Apatite. Garbage tankage. Phesphate rock. Fish scrap. Gypsum. Dissolved bone black. Limestone. ‘ Shells. Calcium cyanamid. Note.—This bulletin gives methods for identifying the carriers of the various fertilizing ingredients, and is intended to serve as a laboratory guide to those studying this phase of the fertilizer question. 33791°—14 2 BULLETIN 97, U. S.. DEPARTMENT OF AGRICULTURE. It was found that potassium chloride, potassium sulphate, ammo- nium sulphate, kainite, sodium nitrate, calcium nitrate, apatite, gypsum, limestone, and other ground rocks and minerals could be identified definitely by microscopic-petrographie methods. For the equipment and modus operandi of determining substances by their optical characters reference is made to the literature of the subject. A brief outline only is here given. EQUIPMENT. For the determination of the optical constants of the various salts and consequently for the identification of the salts themselves, a petrographical microscope is practically a necessity. Ordinary microscopes converted into petrographic microscopes by the addi- tion of various adjuncts are clumsy at best and are far from being satisfactory. Petrographic microscopes, as at present manufactured, have reached a high degree of perfection and, considering the quality of the workmanship and their all-round usefulness, the price is not exorbitant. For a full description of these instruments, reference is made to the trade catalogues. A few words concerning them, how- ever, are necessary in order to render intelligible the description of the manipulations used in determining the optic constants. The petrographic microscope is, in general make-up, similar to ordinary microscopes. It has both coarse and fine adjustments for focusing; the stage is constructed so as to revolve around the axis of the instrument and is graduated into 360°, so that the angle of any revolution may be read off directly. Just below the stage is a con- denser lens so fitted that it may be readily thrown in or out at pleasure. Below the condenser lens is a nicol prism which acts as a polarizer, and below the polarizer is the mirror. The objectives are attached to the tube of the microscope by a clamp device which admits of their ready insertion or removal. The objective is centered by two screws acting at right angles to each other. In the tube of the microscope is another nicol prism, the analyzer, which may be thrown in or out of the line of vision and which may be rotated from a position parallel to the polarizer to a position at right angles to it. Between the objective and the analyzer is a slit at an angle of 45° to the planes of the nicols through which various adjuncts are inserted as needed. Above the analyzer is another slit through which another accessory, Bertrand lens, is inserted as needed. The oculars have cross hairs at right angles to each other and parallel to the planes of the nicols. 1 Bul.91, Bureau of Soils, U.S. Dept. Agr. Iddings, Rock Minerals. Johannsen, Determination of Rock- Forming Minerals. Rosenbusch and Wiilfing, Mikroskopische Physiographie der petrographisch wichti- gen Mineralien, 2 vols. ade IDENTIFICATION OF FERTILIZER MATERIALS. 3 The accessories are a quartz wedge, a quarter undulation mica plate, a gypsum plate, a Bertrand lens, a Bertrand ocular, an eyepiece micrometer, mainly, with others, a description of which, with their uses, will be found in the standard texts. In examining substances with a view to obtaining their optical constants a series of oils of definite refractive indices are used as embedding mediums. Johannsen? gives the following series, which contains oils suitable for practically all purposes: Refractive indices of various liquids used as embedding mediums. Liquid. Index. | Liquid. Index. UBT NSS Heed Pte ds sek oh Lo he? | paleeieeT aes Gerla secre! ee We aes Carhombisnlphiders.t3 22455 42 ae 1.768 |) Hthylene bromide.:.--..+:.::-------2-2- 1.536 Nodosme tiivlene esses joes soa Se cece 1.749 || Monochlor benzene................--.-.- 1.527 a—Monobrom naphthalene..........--.- H658. i Ceclamloies a3 tances ts el ae ese 1.516 a—Monochlor naphthalene.............. 15639: | BeWzeMesess a eae Oh) 17 ue he Bete 1.501 Mono-iodo benzene..........------------ SUG 211i | eens kay Eimear eee a eer 1. 495 @assiaqOmatalcsc. Se ou. cee saiajcin)= Selle 1600) |IPBeeckinj Ouse so sek eee = ss eta. es 1.477 Cimamonroule see Ue ee UsColabs yale A ltewovorawal oy ee ee oe el ee 1. 469 PBTOLIGIO EIN AS a. eee Bee ee eases 1.588 || Carbon tetrachloride...-...-...-.-------- 1. 466 Monobrom benzene........--.---------- IS SoMa (ClhrGeinbalys = SoobosSacunesdesaoe-veesecos 1. 460 ING) DEAR OS per eR See aEanoe pee sees 1554: | Paani alcoholecse sass eran se es tees aee 1.4075 Wlovieroule Shier cies ooh otto e ee ces 1.544 Various mixtures of almond oil and cassia oil can be made with refractive indices running from 1.474 to 1.562. The indices of these liquids vary somewhat on standing, and they should be checked up to at least the second decimal place at occasional periods. Any good refractometer will serve the purpose, or mineral grains of known refractive indices may be used as will be presently explained. The substance to be examined is mounted on a slide in one of the oils, preferably one’ of medium index, and covered with a cover glass. It is then ready for observation. If the indices of the liquid and the substance are fairly different the outlines of the particles show up distinctly, and the crystal habit, cleavage angles, color, and so forth, should be noted. Ceeinlianne and cleavage sages may pe approximately measured by aid cf the cross hairs and the rotating stage. Efforts should be made to determine whether the color of colored grains is that of the substance itself or of inclusions. High- power lenses will usually accomplish this. However, the majority of the salts are colorless, and consequently color is only rarely of importance. These preliminary observations made, the optic proper- ties of the substance are determined as outlined below. ISOTROPIC SUBSTANCES. All substances are either amorphous or crystalline; and all crystal- line substances are either isotropic or anisotropic, i. e., they transmit light with equal velocity in all directions or they transmit light with 1 Rock-Forming Minerals in Thin Sections, pp. 16-18 (1908). 4 BULLETIN 97, U. S, DEPARTMENT OF AGRICULTURE. different velocity in different directions. Amorphous substances and substances crystallizing in the isometric system are isotropic. All others are anisotropic. Whether a given substance is isotropic or anisotropic can be readily determined by crossing the nicols; that is, by putting the analyzer in at right angles to the polarizer, and rotating the stage. Isotropic substances remain dark during a complete rotation, whereas anisotropic substances alternately light up and become dark four times during a complete rotation. It should be noted here that sections of anisotropic uniaxial substances cut at right angles to the principal axis remain dark during rotation; but this case can be easily determined by means of interference figures, as will be seen later. Should the substance be isotropic, there remains only the refractive index to be determined. REFRACTIVE INDEX. By focusing sharply on an edge of the grain, analyzer out, and then raising the tube of the microscope shghtly by means of the fine adjust- ment, a line of light will be seen to move into orout of the grain. Ifthe refractive index of the grain is higher than that of the oil, the line will move in; if the index of the oil is the higher, the line will move out. In other words, the line of light moves into the medium of higher index on raising the tube. Tbe reverse phenomena takes place on lowering the tube. Another method is to use an objective of medium power with the condenser in and raised. A shadow is thrown across half the field by placing the finger between the reflecting mirror and the polarizer. The grains with an index higher than that of the oil appear dark with a bright band on the side toward the shadow. Should the index of the oil be higher, the bright band is on the side from the shadow. It being known whether the index of the grain or of the oil is the higher, by trial an oi! can be found in which the substance com- pletely disappears. The indices of the grain and of the oil are then the same; and since the index of the oil is known, the index of the substance is also known. As a supplementary test, a shadow can be again thrown across the field. Then, the indices of the substance and of the oil being the same, one side of the grain is colored blue and the other red. The isotropic nature of the substance in conjunction with the index of refraction is sufficient to identity it. ANISOTROPIC SUBSTANCES. Should the substance be anisotropic, the extinction angles are first measured. This is done by noting the position of the grain when it is completely dark and then rotating it until a crystallographic or a cleavage face is parallel to one of the cross hairs. The angle of rota- tion read off from the stage is the angle of extinction. A more exact method is that of the Bertrand ocular. This ocular consists of two IDENTIFICATION OF FERTILIZER MATERIALS. 5 right and two left handed quartzes of the same thickness cut perpen- dicular to the axis. The lines of contact between the four parts are parallel to the principal sections of the nicols. This ocular is inserted in the tube of the microscope in place of the ordinary ocular and a cap nicol placed over it in such a position as to cross the polarizer. The analyzer is out. When a double refracting substance is placed under the microscope with this arrangement, the adjacent quadrants appear dissimilarly colored and the diagonal quadrants similarly colored. Upon rotating the stage a position is reached at which the four quad- rants are uniformly colored. Then the principal sections of the grain are parallel to those of the nicols. The angles can be read off as above. In tetragonal, hexagonal, and orthorhombic substances the extinction is always parallel to a crystallographic direction, and con- sequently the angle of extinction is zero. In monoclinic substances the extinction is parallel or symmetrical only in the zone parallel to the b-axis. The extinction is oblique in all cther sections. In triclinic substances the extinction directions are all inclined. PLEOCHROISM. Some anisotropic substances possess the property cf changing their color or the intensity of their color when rotated under the microscope with the analyzer out. This phenomenon is due to differ- ent degrees of absorption in different directions in the crystal. For example, in one direction one color constituent of white light may be absorbed more than another color. The degree of absorption in one direction is expressed as greater, less, or equal to the degree of absorp- tion in another direction; and the absorption axes are assumed to coincide with the axes of vibration of the light. REFRACTIVE INDICES. Anisotropic substances belonging to the tetragonal and hexagonal systems have two indices of refraction; and those belonging to the orthorhombic, monoclinic, and triclinic systems have three. These indices may be determined substantially as given for the indices of isotropic substances. One index may be observed in one position of the crystal. The stage is then rotated and another index determined Except in cases cf strongly double refracting substances, the deter- mination of the mean index is sufficient for practical purposes. BIREFRINGENCE. When the refractive indices are known accurately, the maximum birefringence is obtained directly from them by subtracting the lowest index from the highest. Since, however, it is not always practicable to determine the indices with the required degree of accuracy, other methods are used. The table of Michel-Lévy is here very useful. A copy of it will be found in most textbooks of optical 6 BULLETIN 97, U. S. DEPARTMENT OF AGRICULTURE. mineralogy. In its use it is necessary to know the thickness of the grain. To determine this a sharp focus is first made with the fine adjustment of the microscope on the upper surface of the grain and then on the lower surface. The fine adjustment of course must be first calibrated. The value thus obtained is multiplied by the refrac- tive index of the substance, which gives the real thickness. The thickness line is then followed across the table to the color given by the grain between crossed nicols. The nearest oblique line is then followed to the edge of the table, where the birefringence will be found. It should be remembered that this table gives only the maximum birefringence, and consequently it is necessary to try several orientations of the grain in order to be sure that the bire- fringence obtained is the maximum. Other more elaborate methods for determining birefringence will be found in the standard texts. OPTICAL CHARACTER OF ELONGATION. To determine this, the grain is first rotated to extinction between crossed nicols. It is then rotated 45°, thus bringing the interference color to amaximum. For thin plates or weakly refracting crystals a mica plate, for thick sections or strongly refracting crystals a gypsum plate, or quartz wedge, is inserted between the crossed nicols. The vibration directions of these plates must, of course, be known. The colors of the grain will rise to higher orders when similar axes in the grain and plate have the same direction, and will fall when different axes are superimposed. Knowing the directions of vibration in the plate, the directions of vibration in the grain are also known. When the direction of elongation of the crystal is practically the same with the axis of least ease of vibration, the grain has positive elongation. When the direction of elongation of the crystal is practically the same as the axis of greatest ease of vibration, the grain has negative elongation. UNIAXIAL SUBSTANCES. All anisotropic substances may be divided, by means of interfer- ence figures, into two great classes, uniaxial and biaxial substances. Interference figures are obtained, with good illumination, by using a high-power objective, putting in and raising the condenser lens, cross- ing the nicols, and removing the ocular. The figure is rendered more distinct by placing over the top of the microscope tube a small black- ened disk with a very small aperture through its center. Thus prac- tically all light except that coming from the grain under examination is excluded from the range of vision. The figure may also be seen enlarged by leaving the ocular in and placing a Bertrand lens between it and the analyzer. In the case of uniaxial crystals lying perpen- dicular to the optic axis, the figure has the form of a dark cross, gen- erally with colored rings around the intersection of the arms of the IDENTIFICATION OF FERTILIZER MATERIALS. 7 eross. When the crystal is so oriented that the section viewed is perfectly perpendicular to the optic axis the center of the cross re- mains stationary during a complete rotation of the stage. Should the section be slightly inclined, the center will revolve around the inter- section of the cross hairs. It may happen that the section is so much inclined that the center of the cross does not appear in the field at all. In this case, a dark bar is seen moying across the field, as the stage is rotated, occupying successive positions parallel one to another and the principal sections of the nicols, followed on further rotation of the stage by a bar perpendicular to the first and also occupying suc- cessive parallel positions. In cases where the section viewed is par- allel to the optic axis, hyperbole are shown which are somewhat similar to those of biaxial figures. However, they do not appear until the stage is nearly in the 90° position. Then they move in, form an indistinct cross, and move out again very rapidly. The hyperbole leave the field in the direction of the principal axis. OPTICAL CHARACTER. The optical character of uniaxial substances, that is, whether they are optically positive or negative, may be determined by means of the quarter undulation mica plate, the gypsum plate giving red. of the first order, quartz or mica wedge, etc. In general the quartz or mica wedge or plate serve the purpose when the center of the interference figure is seen in the field. The interference figure is first obtained and then one of these accessories placed between the objective and the analyzer in the 45° position. In optically positive crystals the colored rings in the NE. and SW. quadrants contract while those in the NW. and SH. quadrants expand. With negative crystals the reverse takes place. It is of course necessary to know the directions of vibration of the plates used. This can always be determined by the same means as those given for crystals by using the plate as an object to be examined. Should the center of the cross be beyond the field of the microscope, a gypsum plate giving red of the first order with the a direction parallel to the elongation of the plate is used. Positive crystals show blue in the NE. and SW. quadrants and yellow in the NW. and SE. quadrants, The phenomena are reversed in the case of negative crystals. BIAXIAL SUBSTANCES. Biaxial interference figures in sections lying perpendicular to the acute bisectrix, Bx,, provided the axial angle is less than the field of the microscope, show, when the plane of the axes and the cross hairs coincide, a black cross and a series of coiored curves. The points of emergence of the optic axes are indicated by dark spots with colored lemniscates surrounding them and joining at 8 BULLETIN 97, U. 8. DEPARTMENT OF AGRICULTURE. the center. Upon rotating the stage, the cross dissolves into two hyperbole. The convex sides of the hyperbole are always toward the acute bisectrix. The smaller the axial angle, the nearer together are the loci of the optic axes; and finally, for very small angles, the interference figure approaches the form of a uniaxial interference figure. When the axial angle is so large that neither of the loci of the optic axes show, the biaxial character is indicated by the movement of the bars. Sections lying perpendicular to the obtuse bisectrix, Bx,, show similar figures to those of sections lying perpendicular to the acute bisectrix, provided the axial angle is not too large. Should the section be inclined to the bisectrix, one of the dark spots may be completely outside of the field of the microscope. The other spot, however, will show, and this is sufficient to determine the biaxial character. Sections at right angles to an optic axis show a single straight dark bar surrounded by almost circular concentric curves whenever the bar is parallel to the principal planes of the nicols. This bar changes to a hyperbola on rotating the stage, and the convex side is toward the acute bisectrix. In sections parallel to the plane of the optic axes the interference figure is similar to that of uniaxial crystals parallel to the optic axis. In this case it is advisable to apply a slight pressure with the finger upon one side of the cover glass which causes the erystal to move about into some other orientation which will show one of the interference figures described above. OPTICAL CHARACTER. The optical character of biaxial crystals may be determined by means of the mica plate, gypsum plate, and quartz or mica wedge. To use the mica plate, the interference figure is first obtained and the stage rotated until the hyperbole form a cross. Upon the insertion of the quarter undulation mica plate, the phenomena are then the same as in uniaxial substances. Sections perpendicular to the acute bisectrix, the interference fig- ure of which shows no colored curves, are rotated until the hyperbole form across. The gypsum plate is inserted; and, if its a direction is parallel to the elongation of the plate, the center of the field is red and the NE. and SW. quadrants are colored blue while the NW. and SE. quadrants are yellow in positive crystals. The reverse phenomena take place in negative crystals. If the stage is so rotated that the hyperbole form a cross, the phenomena presented on the insertion of a quartz or mica wedge are similar to those of a uniaxial crystal. By remembering that the convex sides of the hyperbole are always toward the acute bisectrix, IDENTIFICATION OF FERTILIZER MATERIALS, 9 the optical character of a biaxial crystal can be determined when only one hyperbola appears in the field. The phenomena are similar to those presented when both hyperbole appear. OPTIC AXIAL ANGLES. In the interference figure of sections cut normal to the acute bisectrix and rotated into the 45° position, the distance between the hyperbole, i. e., between the two dark spots, represents the angle between the two optic axes. The observed angle, 2K, however, is not identical with the actual angle, 2V. The symbol 2H is some- times used to represent the angle when it is measured in an oil. The distance between the points of emergence of the axes, in the 45° position, can be measured by a micrometer eyepiece. Let this dis- tance be 2d. Then E is half the axial angle in air, d is half the distance between the points of emergence of the optic axes as measured with the eyepiece micrometer, and C is a constant which must be determined for each lens combination. It may be determined by using a mica plate, whose axial angle is known, as an object and substituting in the formula. Ifn is the mean index of refraction of the mineral, then Sin H Sin — aes 2V can thus be readily found. In a large number of cases the simple designation of the angle as “‘large”’ or ‘‘small”’ will serve all purposes; and this relative size may be observed by a glance at the interference figure. DISPERSION. Here p is used to indicate red light, and v violet light. Observa- tions are made on the interference figures. In the orthorhombic system the dispersion is least, ov, for the color within the cirele which is nearest the bisectrix and which touches the concave side of the hyperbola when the crystal is in the 45° position. The colors are symmetrical to the bisectrix. In the monoclinic system there are three kinds of dispersion, inclined, horizontal, and crossed. -In inclined dispersion the colors are arranged symmetrically to the line joining the loci of the hyper- bole, but are not symmetrical in the other direction. One locus is oval shaped, larger, and less intense; and the other is round, intense, and smaller. In horizontal dispersion, the colors are not arranged symmetrically to the line joining the loci of the hyporbole. They are symmetrical, however, to a line at right angles to this line. In crossed dispersion there is only a point of symmetry. 10 BULLETIN 97, U. S. DEPARTMENT OF AGRICULTURE. In the triclinic system the arrangement of colors in the inter- ference figure is unsymmetrical. In actual determinative work it will seldom be found necessary to - determine all of the foregoing optical properties of crystals. But in doubtful cases, the more data available the better; and even in seem- ingly clear cut cases it is sometimes advisable to make as thorough a study of the substance as possible. The methods described herein are, in general, those of the simplest and most accessible nature, but with their aid and a little practice anyone should soon be able to determine many of the materials ordinarily used in the manufacture of fertilizers. However, it should be remarked that problems contin- ually arise for the solution of which wide experience and a compre- hensive knowledge of all theoretical questions involved are none too much. OPTICAL CONSTANTS OF FERTILIZER MATERIALS. The diagnostic optical constants of the substances mentioned on page 2 were taken mainty from. Dana and Groth* and are as follows: Potassium chloride. Sylvite. KCl.—Isometric. Habit cubic. Cleavage cubic perfect. Refractive index, 1.4903. Sometimes ex- hibits anomalous double refraction. Potassium sulphate. Arcanite. K,SO,—Orthorhombice. Twinning yields pseudchexagonal forms. Optically positive (+). Ax. pl. |.a Bxte. Dispersion feeble, 9 >v oil, o< Vin air. Refractive indices, «7 =1.4920, B=1.4935, 7 =1.4970. 2V =66° 30’, 2E=109° 57’. Ammonium sulphate. Mascagnite. (NH,),SO,—\Orthorhombic. Pseudohexagonal. Optically positive (+). Ax. pl. |b. Bx 1 a. Dispersion weak, o / P t eh” s ‘ Ato AE, RD ater fbi ‘ bby DBA Leer WA TAMU DD Sar cede)! Wa OneA MRE y ra BULLETIN OF THE Eo) ener eA No. 98. Contribution from the Bureau of Animal Industry, A. D. Melvin, Chief. August 14, 1914. (PROFESSIONAL PAPER.) THE APPLICATION OF REFRIGERATION TO THE HANDLING OF MILK. By Joun T. Bowen, Technologist, Dairy Division. INTRODUCTION. In the following pages an attempt has been made to discuss briefly the various applications of refrigeration, both when employing ice and refrigerating machinery, in the operation of the modern milk plant, creamery, or dairy, and to discuss in each instance the methods most commonly used in the latest and best equipped plants. While refrigeration has made considerable advancement in dairy- ing in the last few years, even more progress could have been made had more owners and operators of milk plants, creameries, and dairies been fully aware of the many advantages to be derived from the use of proper refrigeration. It is further believed that the manufacturers of refrigerating machinery are not familiar with the special conditions existing in this industry. Therefore the object of this bulletin is to be of service to the manufacturer of refrigerating machinery as well as to those employed in the dairy industry. It is not intended to give in detail the size and arrangement of refrigerating equipment necessary in plants of various capacities, as the conditions vary to such an extent that to do so would be impossi- ble, but to state briefly the elementary principles of refrigeration and refrigerating machinery and to describe what is recognized as the best and most modern practice in the industry and to leave the details in each case to those on the premises, who are better able to judge and to modify the suggestions given herein to suit the existing conditions. It is a well-known fact that heat and cold perform very impor- tant duties in handling milk and milk products. In pasteurizing milk Nove .—Discusses the application of refrigeration in the operation of the modern milk plant and describes the various forms of mechanical and other systems of cooling. Of interest to procucers, shippers, dealers, and consumers of milk generally, and also to manufacturers of refrigerating machinery and appliances. 40083°—Bull. 98—14——_1 9 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. heat is used to destroy the bacteria, or at least to reduce their num- ber to such an extent as to prevent their producing disease; but pas-_ teurized milk as well as unpasteurized market milk should be cooled to a temperature of 50° F. or below and held at this lower tempera- ture until used. At a temperature below 50° F. bacteria multiply less rapidly, but between 50° and 100° F. the increase is very fast; hence the necessity for thorough cooling and the maintenance of low temperatures until used. DEFINITIONS OF TERMS. A knowledge of the terms used in refrigeration is necessary in order to better understand the matter given in the following pages. There- fore definitions of the principal terms and units employed are given for the benefit of those not already familiar with them. British thermal unit.—A British thermal unit (B. T. U.) is the quan- tity of heat required to raise 1 pound of pure water 1 degree Fahren- heit, at or near its maximum density, 39.1° F. Some authorities consider a British thermal unit as the heat required to raise 1 pound of pure water from 61° to 62° F.- For practical purposes, however, it may be considered the heat required to raise the temperature of i pound of water 1 degree Fahrenheit. Sensible heat.—Sensible heat is the heat that may be felt by the hand or measured by a thermometer. Latent heat.—Latent or “‘hidden”’ heat is the heat which is expended in molecular work of separating the molecules of the substance and can not be measured by a thermometer. Every substance has a latent heat of fusion, required to convert it from a solid to a liquid, and another, latent heat of vaporization, required to convert it from a liquid to a gas or vapor. Thus, if heat is applied to a pound of ice at 32° F. it will begin to melt, and no matter how much heat is applied the ice will not get any hotter. After every particle of ice has melted, we will have 1 pound of water at 32° F., the same temperature as the ice before heat was applied. Experiments have shown that it requires 144 British thermal units to melt 1 pound of ice at 32° F. into water at 32° F.; hence the latent heat of fusion of ice is said to be 144. If heat is applied to 1 pound of water at 212° F., the water will remain at 212° F. under atmospheric pressure until all of it has been evaporated into steam at 212° F. This has been found to require 970.4 British thermal units; hence the latent heat of vaporization of steam at atmospheric pressure is said to be 970.4 B. T. U. Specific heat.—The specific heat of a substance may be defined as the ability of that substance to absorb heat compared to that of water. Water being one of the hardest of all substances to heat, its specific heat is taken at unity. Therefore the specific heat of other substances is usually less than unity. A better understanding of latent and spe- APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 3 cific heat may be had by studying the diagram in figure 9, on page 24, which shows graphically the relation of heat to temperature. Ton refrigeration.—Refrigeration, or ice-melting capacity, is a term applied to represent the cold produced, and is measured by the latent heat of fusion of ice, which is 144.B.T.U.perpound. In other words, it is the heat required to melt 1 pound of ice at 32° F. into water at the same temperature. The capacity of a machine in tons of ‘“‘ice melting” or “refrigeration”? does not mean that the machine would make that amount of ice, but that the cold produced is equivalent to the melting of the weight of ice at 32° into water at the same tem- perature. Therefore 1-ton refrigeration is equal to 144 x 2,000, or 288,000 B.T.U. A 1-ton refrigerating machine is a machine that has a capacity sufficient to extract from an insulated bath of brine 200 B. T. U. per minute, 12,000 B. T. U. per hour, or 288,000 B. T. U. per 24 hours. Absolute pressure.—Absolute pressure is pressure reckoned from a vacuum. Pressure gauges in general use are arranged to indicate pressure in pounds per square inch above atmospheric. To convert gauge pressure to absolute pressure, 14.7 pounds, the weight per square inch of air pressure at sea level, must be added. CHANGES IN MILK CAUSED BY TEMPERATURE AND TIME. PHYSICAL CHANGES IN MILK AT LOW TEMPERATURES. During the last decade the progress made in the physical, chemical, and bacteriological studies of milk and its products has greatly mod- ified the various dairy operations and has led to improved methods of treating and handling dairy products, based mainly on the appli- cation of the two extremes, heat and cold. The preservation of milk and its products depends almost entirely on the use made of these two factors. In this bulletin, however, we will discuss only the use of refrigeration as a means of preserving dairy products. Before dis- cussing the practical application of refrigeration to the dairy industry it is advisable to make a short summary of the data at hand relating to the physical, chemical, and bacteriological changes and modifica- tions which the action of cold produces in milk. SPECIFIC HBAT. In view of the wide variations in the specific heat of milk and cream, as found in the limited amount of literature on the subject, the United States Bureau of Standards was requested to make determinations of the specific heat of whole milk and single and double cream. Sam- ples of milk and cream, approximating average conditions, were pre- pared by the Dairy Division laboratories and forwarded to the Bureau of Standards in the afternoon, placed in the calorimeter and packed 4 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. in ice until the next morning when observations were begun. The chemical analyses of the samples were as follows: 34 per cent milk: 12.68 per cent total solids, 9.18 per cent solids not fat, 87.32 per cent water; 20 per cent cream: 27.27 per cent total solids, 7.27 per cent solids not fat, 72.73 per cent water; 40 per cent cream: 44.30 per cent total solids, 4.30 per cent solids not fat, 55.70 per cent water. In view of the fact that only a single test on one sample of the material was made the results can be considered only as tentative and not final. Taste I.—Specific heat of milk and creain. 20 40 20 - 40 Temperature. Milk. per cent | per cent Temperature. Milk. | per cent | per cent cream. | cream. - cream. | cream. ele aC °F. EE 35. 6 QAO} es eocas te OS eoH Ie Beaseesas 95.9 35. 5 0. 93 0. 89 0. 86 37.4 3.0 OVOP | eee aiciterete 0. 83 100. 4 BSHO Ii its a sae AS eee cd 80 43.7 6.5 92 91 90 105. 8 41.0 92 SUn eves at aac 48, 2 ONO i spencer CPEB oaaee toe 109. 4 ASS Ole saeictsl es ahcns hee 2 78 51.8 11.0 OB al Re eemcemes - 96 114.8 AG JONG ora cose SY Pu SS See eae 55. 4 IS SOM eats oes CE aces aS 118. 4 48. 0 Cacao aaa 78 59. 0 15.0 94 95 1. 02 123.8 DOM ee se aca SON Mee ae tae 66. 2 19.0 95 1.01 1.07 127.4 BO NOH ce MN estat ek 77 71.6 22.0 94 1 Bee 131.0 55. 0 93 Orbis ehete conics 75. 2 24.0) Sarasa false abeeee 93 136. 4 5850) nce ces | Pee aoe 76 78. 8 26. 0 OB ieee since 88 141.8 61.0 93 S| Pacem scar 82.4 2850) He ee aoe oe Ot Ses a2 tases 145. 4 GBNOM) See ears cea athe ener 72 86. 0 30.0 99) |oceeius mere .88 150.8 66. 0 ai Nim yea ne oo 89.6 S200) Re eee eee CIN Renate ser The curves, figure 1, show the specific heat of 34 per cent milk and 20 and 40 per cent cream at different temperatures between 35.6° F. and 150.8° F. COHESION AND VISCOSITY OF MILK. Milk upon cooling assumes a denser semiliquid aspect and sticks more closely to the walls of the vessel than when warm. Conse- quently it is harder to clean, by means of water, a vessel that has contained cold milk than one that has contained warm milk. On the other hand, for the same reason, it is more difficult to cleanse vessels that have contained milk by the use of cold water than by the use of warm water. Milk is more liable to foam when cold than when hot, and the foam will keep longer. The foam, however, will disappear if the milk is heated. With the lowering of the temperature of milk the cohesion increases in proportion to its viscosity. At 86° F. the viscosity is about 1.7 times as great in milk as it is in water, while at 32° F. its viscosity is about 2.4 times that of water. At 32° ¥. the viscosity of milk is about 2.6 times as great as it is at 86° F. 4 APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 5 Freshly drawn milk shows a smaller viscosity than it does after being allowed to stand for some time. It is a well-known fact that the viscosity plays an important part in the formation of cream and in the skimming of milk. COEFFICIENT OF EXPANSION OF MILK AND CREAM. In Table II is given the change in the volume of milk and cream with varying percentages of fat and degrees of temperature. The ey S i a Leu) a saan nts a a See 7 a eee ellen ESieeles| Eee Palesiescrice et a i ie Tani aan eee eae Dae andi aa Sane a AO rec Ss pa eas EERE SoSeC oe El rN L| ES Hy: # i ty ING i | 41 ea a aaa ea Hey eee ES He be es Bez ee Esl SPECIFIC HEAT o Es LE 2 a Al f) Ls 5 Ee sles Ee SS Ss ee a ae ee hs REE EEE + singe Seer et cosue eT eee a ee yer Ty ee “32 42 52 Lali 72 32 Bee Hal Leal hai ey Ee 452 TEMPERATURE -— DEGREES FAHRENHEIT. Fig. 1.—Curves showing the specific heat of milk, 20 per cent and 40 per cent cream at different tem- peratures. percentage of fat varies in steps of 1 per cent from skimmed milk to double cream, and determination of change in volume has been made in steps of 2° F. from 50 to 140° F. A temperature of 68° F. (20° C.) has been taken as the basis and the change in volume reckoned from this temperature. These tentative determinations and those on spe- cific gravity were made by the Division of Weights and Measures of the United States Bureau of Standards. 6 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE, TABLE II.— Volume | of milk and cream at various temperatures occupied by unit volume at 68° F. (20° C.). 0. 025 OMIM RWNre Temperature (° F.). 50 | 52 | 54 | 56 | 58 | 60 | 62 | 64 | 66 | 68 | 70 | 72 Volume. 0.9980 | 0.9980 | 0.9985 | 0.9985 | 0.9990 | 0.9990 |0.9990 | 0.9995 | 0.9995 | 1.0000 | 1.0000 | 1.0005 . 9980 . 9980 - 9985 - 9985 . 9990 - 9990 | .9990 | .9995 . 9995 | 1.0000 | 1.0000 | 1. 0005 9975 .9975 | .9980} .9980 . 9985 . 9990 | . 9990 - 9995 . 9995 | 1.0000 | 1.0000 | 1.0005 -9975 | .9975 .9980 | .9980]) .9985 - 9990 | . 9990 -9995 | .9995 | 1.0000 | 1.0000 | 1.0005 -9975 | .9975 -9980 | .9980 . 9985 - 9985 | . 9990 - 9995 - 9995 | 1.0000 | 1.0000 | 1.0005 -9975 | .9975 | .9980 - 9980 . 9985 -9985 | .9990 |} .9995 - 9995 | 1.0000 | 1.0000 | 1. 0005 -9970 | .9975 . 9975 . 9980 . 9980 -9985 | .9990 |} .9995 - 9995 | 1.0000 |} 1.0000 | 1.0005 . 9970 . 9970 . 9975 . 9975 . 9980 - 9985 | . 9985 . 9990 - 9995 } 1.0000 | 1.0000 | 1.0010 . 9970 -9970 | .9975 . 9975 -9980 | .9985 | . 9985 -9990 | .9995 |} 1.0000 | 1.0005 | 1.0010 . 9965 . 9965 -9970 | .9975 - 9980 . 9985 | . 9985 . 9990 - 9995 | 1.0000 | 1.0005 | 1.0010 . 9965 . 9965 - 9970 -9975 | .9980 | .9985] .9985 | .9990] .9995 | 1.0000 } 1.0005 | 1.0010 . 9965 . 9965 -9970 | .9975} .9980 - 9985 | .9985 | .9990 - 9995 | 1.0000 | 1.0005 | 1.0010 . 9955 -9960 | .9965 -9970 | .9975 - 9980 } .9985 | .9990] .9990 | 1.0000 |} 1.0005 | 1.0010 . 9955 .9960 | .9965 . 9970 - 9975 . 9980 | . 9985 . 9990 - 9990 | 1.0000 | 1.0005 | 1.0010 . 9950 . 9955 . 9960 . 9970 . 9975 - 9980 | .9985 | .9990 - 9990 | 1.0000 | 1.0005 | 1.0010 . 9950 - 9955 -9960 | . 9970 . 9975 . 9980 | . 9985 - 9990 - 9990 | 1.0000 | 1.0005 | 1.0010 . 9950 . 9955 - 9955 . 9965 . 9970 - 9980 | .9985 | .9990} .9990 | 1.0000 | 1.0005 | 1.0010 . 9945 9950 | .9955 . 9965 .9970 | .9980 |] .9985 | .9990 | .9990 | 1.0000 | 1.0005 | 1.0010 - 9940 | .9945 . 9950 - 9960 | .9970 9980 | .9980 | .9985 - 9990 } 1.0000 | 1.0005 | 1. 0010 .9940 | .9945 | .9950 -9960 | .9970| .9975 | .9980}) .9985} .9990 | 1.0000 | 1.0005 | 1.0010 .9930 | .9940} .9945 |) .9955] .9965 | .9975 | .9980}) .9985 | .9990 |} 1.0000 | 1.0005 | 1.0010 -9930 | .9940) .9945 . 9955 . 9955 -9975 | .9980 | .9985 - 9990 } 1.0000 | 1.0005 | 1.0010 . 9930 . 9940 . 9945 - 9955 . 9965 -9975 | .9980 | .9985} .9990 | 1.0000 | 1.0010 | 1.0015 .9930 | .9940 .9940 | .9955 . 9965 .9975 | .9980 | .9985 1! .9990 | 1.0000 | 1.0010 | 1.0015 - 9925 | .9930 .9940} .9950 | .9960 | .9975} .9975] .9985 - 9990 | 1.0000 } 1.0010 | 1.0015 . 9925 . 9930 . 9940 - 9950 . 9960 .9970 | .9975 | .9985 . 9990 | 1.0000 | 1.0010 | 1.0015 . 9925 9930 | .9940 -9950 | .9960 .9970 | .9975 | .9985 - 9990 |} 1.0000 | 1.0010 | 1.0015 - 9925 - 9930 | .9940 9950 | .9960 .9970 | . 9975 . 9985 - 9990 | 1.0000 } 1.0010 | 1.0015 -9915 | .9925 . 9935 . 9945 -9955 | .9965 | .9975 | .9980] .9990 | 1.0000 | 1.0010 | 1.0015 -9915 | .9925 . 9935 .9945 | .9955 - 9965 | .9975 . 9980 - 9990 | 1.0000 | 1.0010 | 1.0015 - 9915 . 9925 . 9935 9945 | .9955 9965 | .9970 |} .9980 | .9990 | 1.0000 | 1.0010 | 1.0020 9915 | .9925 - 9935 . 9945 . 9955 9965 | .9970 | .9980 - 9990 | 1.0000 | 1.0010 | 1.0020 -9910 | .9920) .9930 . 9940 . 9950 9960 | .9970 | .9980 . 9990 | 1.0000 | 1.0010 | 1.0020 -9910 | .9920} .9930 .9940 | .9950 9960 | . 9970 -9980 | .9990 | 1.0000 } 1.0010 | 1.0020 . 9910 9915 | .9925 .9940 | .9950 9960 | . 9970 . 9980 - 9990 | 1.0000 | 1.0010 | 1.0020 . 9900 9915 | .9925 .9940 |} .9940 | .9960] .9970} .9980 . 9990 | 1.0000 | 1.0010 | 1.0020 .9900 | .9910] .9920} .9930|] .9940] .9955] .9965| .9980} .9990 | 1.0000 | 1.0010 | 1.0025 - 9890 - 9910 . 9920 - 9930 . 9940 9955 | . 9965 . 9980 . 9990 | 1.0000 | 1.0010 | 1.0025 -9890 | .9910 9920} .9930 | .9940 9955 | .9965 | .9980] .9990} 1.0000 | 1.0010 | 1.0025 - 9890} .9900) .9915 - 9925 . 9940 9955 | . 9965 -9975 | .9990 | 1.0000 } 1.0010 | 1.0025 . 9890 | .9900 . 9915 . 9925 .9940 | .9950 | .9960 | .9975 | .9990 | 1.0000 | 1.0010 | 1.0025 1 The tabulated values are given to the nearest 0.0005. i APPLICATION OF REFRIGERATION TO HANDLING OF MILK. ‘ Taste I1.— Volume of milk and cream at various temperatures occupied by unit volume at 68° F. (20° C.)—Continued. 2 Per Temperature (° F.). cent- age of 74 | 76 78 | 80 | 82 | 84 | 86 | 88 | 90 | 92 | 94 | 96 but- ter fat. Volume 0.025 | 1.0005 | 1.0010 | 1.0010 | 1.0015 | 1.0020 | 1.0025 | 1.0030 |1.0030 | 1.0035 | 1.0040 | 1.0045 | 1.0050 1 | 1.0005 | 1.0010 | 1.0010 | 1.0015 | 1.0020 } 1.0025 | 1.0030 |1.0030 | 1.0035 | 1.0040 | 1.0045 | 1.0050 2 | 1.0010 | 1.0010 | 1.0015 | 1.0020 | 1.0020 | 1.0025 | 1.0030 |1.0035 | 1.0040 | 1.0040 | 1.0045 | 1. 0050 3 | 1.0010 | 1.0010 | 1.0015 | 1.0020 | 1.0020 | 1.0025 | 1.0030 |1.0035 | 1.0040 | 1.0045 | 1.0045 | 1. 0055 4 | 1.0010 | 1.0010 | 1.0015 | 1.0020 | 1.0020 | 1.0025 | 1.0030 |1.0035 | 1.0040 | 1.0045 | 1.0050 | 1. 0055 5 | 1.0010 | 1.0015 | 1.0020 | 1.0020 | 1.0025 | 1.0030 | 1.0035 |1. 0035 | 1.0045 | 1.0045 | 1.0050 | 1. 0055 6 | 1.0010 | 1.0015 | 1.0020 | 1.0020 | 1.0025 | 1.0030 | 1.0035 |1. 0040 | 1.0045 | 1.0050 | 1.0050 | 1. 0060 7 | 1.0010 | 1.0015 | 1.0020 | 1.0025 | 1.0025 | 1.0030 | 1.0035 |1. 0040 | 1.0045 | 1.0050 | 1.0055 | 1.0060 8 | 1.0010 | 1.0015 | 1.0020 | 1.0025 | 1.0030 | 1.0030 | 1.0035 |1. 0040 } 1.0045 | 1.0050 | 1.0055 | 1. 0060 9 | 1.0010 | 1.0015 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0040 |1.0045 | 1.0050 | 1.0055 | 1.0060 | 1.0065 10 | 1.0015 | 1.0020 | 1.0025 | 1.0025 | 1.0030 | 1.0035 | 1.0040 |1. 0045 | 1.0050 | 1.0055 | 1.0060 | 1. 0065 11 | 1.0015 | 1.0020 | 1.0025 | 1.0025 | 1.0030 | 1.0035 | 1.0040 |1. 0045 | 1.0055 | 1.0055 | 1.0065 | 1.0070 12 | 1.0015 | 1.0020 | 1.0025 | 1.0030 | 1.0030 | 1.0035 | 1.0040 |1.0050 | 1.0055 | 1.0060 | 1.0085 | 1.0070 13 | 1.0015 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0040 | 1.0045 {1.0050 | 1.0055 | 1.0060 | 1.0065 | 1.0070 14 | 1.0015 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0040 | 1.0045 |1.0050 | 1.0055 | 1.0065 | 1.0070.] 1. 0075 15 | 1.0015 | 1.0025 | 1.0030 | 1.0030 | 1.0035 | 1.0040 | 1.0045 |1.0055 | 1.0060 | 1.0065 | 1.0070 | 1.0075 ° 16 | 1.0015 | 1.0025 | 1.0030 | 1.0035 | 1.0040 | 1.0045 | 1.0050 |1. 0055 | 1.0060 | 1.0070 | 1.0075 | 1.0080 17 | 1.0015 | 1.0025 | 1.0030 | 1.0035 | 1.0040 | 1.0045 |_ 1.0050 |1. 0060 | 1.0060 | 1.0070 | 1.0075 | 1.0080 18 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0040 | 1.0045 | 1.0055 |1.0060 | 1.0065 | 1.0075 | 1.0080°} 1. 0085 19 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0045 | 1.0045 | 1.0055 |1.0060 | 1.0065 | 1.0075 | 1.0080 | 1.0085 20 | 1.0020 | 1.0025 | 1.0030 | 1.0035 | 1.0045 | 1.0050 | 1.0055 |1.0060 | 1.0070 | 1.0075 | 1.0085 | 1.0090 21 | 1.0020 | 1.0025 | 1.0030 | 1.0040 | 1.0045 | 1.0050 | 1.0060 |1.0065 | 1.0070 | 1.0080 | 1.0085 | 1.0090 22 | 1.0020 | 1.0030 | 1.00385 | 1.0040 | 1.0050 | 1.0055 | 1.0060 }1. 0065 | 1.0075 | 1.0080 | 1.0090 | 1.0095 23 | 1.0020 | 1.0030 | 1.0035 | 1.0040 | 1.0050 | 1.0055 | 1.0065 |1.0070 | 1.0075 | 1.0085 | 1.0090 | 1.0095 24 | 1.0020 | 1.0030 } 1.0035 | 1.0040 | 1.0050 | 1.0060 | 1.0065 |1.0070 | 1.0080 | 1.0085 | 1.0095 | 1.0100 25 | 1.0020 | 1.0030 | 1.0035 | 1.0045 | 1.0055 | 1.0060 | 1.0070 1.0075 | 1.0080 | 1.0090 | 1.0095 | 1.0105 26 | 1.0025 | 1.0030 | 1.0040 | 1.0045 | 1.0055 | 1.0060 | 1.0070 |1.0080 | 1.0085 | 1.0090 | 1.6100 | 1.0110 27 | 1.0025 | 1.0030 | 1.0040 | 1.0045 | 1.0055 | 1.0060 | 1.0070 |1.0080 | 1.0085 | 1.0095 | 1.0100 | 1.0110 28 | 1.0025 | 1.0030 | 1.0040 | 1.0045 | 1.0055 | 1.0065 | 1.0075 |1. 0080 | 1.0090 | 1.0095 | 1.0105 | 1.0115 29 | 1.0025 | 1..0030+} 1.0040 | 1.0050 | 1.0060 | 1.0065 | 1.0075 |1.0080 | 1.0090 | 1.0095 | 1.0105 | 1.0115 30 | 1.0025 | 1.0035 | 1.0045 | 1.0050 | 1.0060 | 1.0065 | 1.0080 |1. 0085 | 1.0095 | 1.0100 | 1.0110 | 1.0120 31 | 1.0025 | 1.0035 | 1.0045 | 1.0050 | 1.0060 | 1.0065 | 1.0080 |1.0085 | 1.0095 | 1.0100 | 1.0110 | 1.0120 32 | 1.0030 | 1.0035 | 1.0045 | 1.0055 | 1.0065 | 1.0070 | 1.0085 |1.6090 | 1.0100 | 1.0105 | 1.0115 | 1.0125 33 | 1.0030 | 1.0035 | 1.0045 | 1.0055 | 1.0065 | 1.0070 | 1.0085 |1.0090 | 1.0100 | 1.0105 | 1.0115 | 1.0125 34 | 1.0030 | 1.0040 | 1.0050 } 1.0055 | 1.0065 | 1.0075 | 1.0085 |1.0095 | 1.0105 | 1.0110 | 1.0120 | 1.0130 35 | 1.0030 | 1.0040 | 1.0050 | 1.0060 } 1.0070 | 1.0075 | 1.0090 |1. 0095 | 1.0105 | 1.0110 | 1.0120 | 1.0130 36 | 1.0035 | 1.0045 | 1.0055 | 1.0060 | 1.0070 | 1.0080 | 1.0090 |1.0100 | 1.0110 | 1.0115 | 1.0125 | 1.0135 37 | 1.0035 | 1.0045 | 1.0055 | 1.0060 | 1.0070 | 1.0080 | 1.0095 1.0100 | 1.0110 | 1.0115 | 1.0125 | 1.0135 38 | 1.0035 | 1.0045 | 1.0055 | 1.0065 | 1.0075 | 1.0085 | 1.0095 |1.0100 | 1.0115 | 1.0120 | 1.0130 | 1.0140 39 | 1.0035 | 1.0045 | 1.0055 | 1.0065 } 1.0075 | 1.0085 | 1.0095 |1.0105 | 1.0115 | 1.0120 | 1.0130 | 1.0140 40 | 1.0035 | 1.0045 | 1.0055 | 1.0065 } 1.0075 | 1.0085 | 1.0095 {1.0105 | 1.0115 | 1.0125 | 1.0130 | 1.0145 8 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. TaBLeE II.—Volume of milk and cream at various temperatures occupied by unit volume at 68° F. (20° C.)—Continued. Temperature (° F.). Percentage of butter fat. 98 . | 100 | 102 | 104 | 106 | 108 | 110 | 112 | 114 116 | 118 Volume. 0.025 | 1.0055 | 1.0060 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100] 1.0105 1} 1.0055 | 1.0060 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 2 | 1.0055 | 1.0060 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0110 3 | 1.0060 | 1.0065 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100} 1.0110 4 1.0060 | 1.0065 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100} 1.0110 5 | 1.0060 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0085 | 1.0090 | 1.0095 | 1.0100} 1.0110 6 | 1.0060 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0090 | 1.0095 | 1.0100} 1.0110 7 | 1.0065 | 1.0070 | 1.0075 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105} 1.0115 8 | 1.0065 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110} 1.0115 9 | 1.0065 | 1.0070 | 1.0080 |} 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110} 1.0115 10 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0090 } 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 11 | 1.0070 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 12 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0095 | 1.0105 | 1.0110 | 1.0115 | 1.0120} 1.0125 13 | 1.0075 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 | 1.0120} 1.0125 14 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0100 | 1.0110 | 1.0115 | 1.0120 | 1.0125] 1.0130 15 | 1.0080 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 | 1.0120 | 1.0125} 1.0130 16 | 1.0085 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 | 1.0120 | 1.0125 | 1.0130] 1.0135 17 | 1.0085 | 1.0090 | 1.0095 | 1.0105 | 1.0105 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0135] 1.0140 ~ 18 | 1.0090 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140] 1.0145 19 | 1.0090 | 1.0095 | 1.0100 | 1.0110 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140] 1.0145 20 | 1.0095 | 1.0100 | 1.0105 | 1.0110 | 1.0115 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 21 | 1.0095 | 1.0100 | 1.0105 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0145 | 1.0150} 1.0155 22 | 1.0100 | 1.0105 | 1.0110 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0150 } 1.0155 | 1.0160 23 | 1.0105 | 1.0105 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 24 | 1.0105 | 1.0110 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 25 | 1.0110 | 1.0115 | 1.0120 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0160 | 1.0165} 1.0170 26 | 1.0115 | 1.0120 | 1.0125 | 1.0135 | 1.0140 |} 1.0145 | 1.0155 | 1.0160 | 1.0165 | 1.0170} 1.0180 27 | 1.0115 | 1.0120 | 1.0130 | 1.0135 | 1.0140 | 1.0150 | 1.0155 | 1.0160 | 1.0170 | 1.0170} 1.0180 28 | 1.0120 | 1.0125 | 1.0130 | 1.0140 | 1.0145 | 1.0150 | 1.0160 | 1.0165 | 1.0175 | 1.0175 | 1.0185 29 | 1.0120 | 1.0130 | 1.0135 | 1.0140 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0175 | 1.0180] 1.0185 30 | 1.0125 | 1.0130 | 1.0135 | 1.0145 | 1.0155 | 1.0155 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0190 31 | 1.0125 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 | 1.0175 | 1.0180 | 1.0185 | 1.0190 32 | 1.0130 | 1.0135 | 1.0140 | 1.0150 | 1.0160 | 1.0165 | 1.0170 | 1.0180 | 1.0185 | 1.0190 | 1.0195 33 | 1.0130 | 1.0140 | 1.0145 | 1.0155 | 1.0160 } 1.0165 | 1.0170 | 1.0180 | 1.0185 | 1.0190] 1.0195 34 | 1.0135 | 1.0140 | 1.0150 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0185 | 1.0190 | 1.0195 | 1.0200 35 | 1.0135 | 1.0145 | 1.0150 | 1.0160 | 1.0165 | 1.0170 | 1.0180 | 1.0190 | 1.0195 | 1.0200} 1.0205 36 | 1.0140 | 1.0145 | 1.0155 | 1.0165 | 1.0170 | 1.0175 | 1.0185 | 1.0195 | 1.0200 | 1.0205} 1.0210 37 | 1.0145 | 1.0150 | 1.0160 | 1.0165 | 1.0175 | 1.0180 | 1.0185 | 1.0195 | 1.0200 | 1.0205} 1.0210 38 | 1.0150 | 1.0155 | 1.0165 | 1.0170 | 1.0175 | 1.0185 | 1.0190 | 1.0200 | 1.0210 | 1.0215] 1.0215 39 | 1.0150 | 1.0160 | 1.0165 | 1.0170 | 1.0180 | 1.0185 | 1.0195 | 1.0205 | 1.0210 | 1.0215 | 1.0220 40 | 1.0155 | 1.0165 | 1.0170 | 1.0175 | 1.0185 | 1.0190 | 1.0200 | 1.0210 | 1.0215 | 1.0220} 1.0280 APPLICATION OF REFRIGERATION TO HANDLING OF MILK. g Taste I1.— Volume of milk and cream at various temperatures occupied by unit volume at 68° F. (20° C.)—Continued. (Temperature (° F.). Percentage 9 of butter tat. 120 | 122 | 124 | 126 | 128 | 130 132 134 136 138 140 Volum 0.025 | 1.0110 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 1.0175 1 | 1.0110 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 1. 0175 2 | 1.0115 | 1.0120 | 1.0125 | 1.01380 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 1.0175 3 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170] 1.0175 4 | 1.0115 | 1.0120 |) 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 | 1.0175 5 | 1.0115 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 | 1.0160 | 1.0170 1.0175 6 | 1.0115 | 1.0120 |} 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0155 |} 1.0160 | t.0170 | 1.0175 7 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0170 | 1.0175 8 | 1.0120 | 1.0125 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0165 | 1.0170 | 1.0175 9 | 1.0120 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 1.0180 10 | 1.0120 } 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 1. 0180 11 | 1.0120 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0180 12 | 1.0130 | 1.0185 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 1. 0180 13 | 1.0130 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 1. 0180 14 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 15 | 1.0135 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 16 | 1.0140 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 1.0190 17 | 1.0145 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0175 | 1.0180 | 1.0185 | 1.0190 18 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0189 | 1.0185 | 1.0185 | 1.0190} 1.0195 19 | 1.0150 | 1.0155 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 | 1.0185 | 1.0190 1. 0195 20 | 1.0155 | 1.0160 | 1.0165 |} 1.0170 | 1.0175 | 1.0180 |} 1.0185 | 1.0190 | 1.0195 | 1.0200 1. 0205 21 | 1.0160 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 | 1.0190 | 1.0190 | 1.0195 | 1.0200 1. 0205 22 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 | 1.0190 | 1.0190 | 1.0195 | 1.0200 | 1.0205 1. 0210 23 | 1.0165 | 1.0170 | 1.0175 | 1.0180 | 1.0185 | 1.0190 | 1.0195 | 1.0195 | 1.0200 | 1.0205 | 1.0210 24 | 1.0170 | 1.0180 | 1.0185 | 1.0190 | 1.0195 | 1.0200 | 1.0205 | 1.0205 | 1.0210 | 1.0215 1. 0220 25 | 1.0175 | 1.0180 | 1.0185 | 1.0190 | 1.0195 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 1. 0225 26 | 1.0185 | 1.0190 | 1.0195 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230] 1.0235 27 | 1.0185 | 1.0190 | 1.0195 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 1. 0235 28 | 1.0190 | 1.0200 | 1.0205 | 1.0210 } 1.0215 | 1.0220 | 1.0225 | 1.0280 | 1.0235 | 1.0240] 1.0245 29 | 1.0195 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0235 | 1.0240 1. 0245 30 | 1.0195 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0235 | 1.0240 | 1.0245} 1.0250 31 | 1.0200 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0235 | 1.0240 | 1.0245 1.0250 32 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0235 | 1.0240 | 1.0245 | 1.0250} 1.0255 33 | 1.0205 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0235 } 1.0240 | 1.0245 | 1.0250] 1.0255 34 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0240 | 1.0245 | 1.0245 | 1.0250 | 1.0255] 1.0260 35 | 1.0210 | 1.0215 | 1.0220 | 1.0225 | 1.0230 | 1.0240 | 1.0245 | 1.0250 | 1.0250 | 1.0255 | 1.0260 36 | 1.0215 | 1.0225 | 1.0230 | 1.0235 | 1.0240 | 1.0245 | 1.0250 | 1.0255 | 1.0260 | 1.0265} 1.0270 37 | 1.0215 | 1.0225 | 1.0230 | 1.0235 | 1.0240 | 1.0245 | 1.0250 | 1.0255 | 1.0260 | 1.0265 | 1.0270 38 | 1.0220 | 1.0230 | 1.0235 | 1.0240 | 1.0245 | 1.0250 | 1.0255 | 1.0260 | 1.0265 | 1.0270 1. 0280 39 | 1.0225 | 1.0235 | 1.0240 | 1.0245 | 1.0250 | 1.0255 | 1.0260 | 1.0265 | 1.0270 | 1.0275 1. 0280 40 | 1.0235 | 1.0240 | 1.0245 | 1.0255 | 1.0260 | 1.0265 | 1.0270 | 1.0275 | 1.0280 | 1.0285 1. 0290 10 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. SPECIFIC GRAVITY OF MILK AND CREAM, Table IIT covers the specific gravity of milk and cream determined at 68° F. (20° C.) in terms of water at the same temperature as unity. TasiLe III.—Specific gravity of milk and cream corresponding to various percentages of butter fat at 68° F. Per- . Per- . A . Specific Specific Specific Specific n = 5 = 4 Be pegs gravity. ‘of fat. | gravity ae gravity. || © ese gravity 0.025 1.037 11 | 1.024 21 1.012 31 1.003 1 1.036 12 1.022 22 1.011 32 1. 002 2 1.035 |) 13 1.020 23 1.010 33 1.001 3 1.034 14 1.019 24 1.009 34 1.000 4 1.032 15 1.018 25 1.008 35 - 999 5 1.031 16 1.017 26 1.008 36 . 999 6 1.030 17 1.016 27 1.007 37 - 998 7 1.029 18 1.015 28 1.006 38 . 997 8 1.027 19 1.014 29 1.005 39 . 996 9 1.026 |) 20 1.013 30 1.004 40 . 995 10 1.025 FREEZING POINT OF MILK. The freezing point of milk depends upon its composition, but is always lower than that of water. The freezing point of market milk generally varies from 31° to 29° F. The addition of water to milk serves to raise the freezing point toward that of pure water, 32° F., while, on the other hand, the addition of fats, solids, ete., tends to lower the freezing point, as does also the increase in acidity. Upon these varlations in the freezing point is based the cryoscopical method of determining the addition of water to milk. EFFFECT OF FREEZING ON MILK. While the action of cold on milk at a temperature above the freezing point has no other effect than that of varying the density and vis- cosity, at a temperature below the freezing point it changes the chemical and physical composition. According to Kasdorf,! when raw milk which was partly frozen at a temperature of 10.5° F., in the ordinary container, during trans- portation, it was found that ice first formed around the sides and at the bottom of the can; the central core contained most of the casein, sugar, and other mineral ingredients, while most of the fat was found in the top layer of the liquid portion. f When milk has been frozen gradually, without agitation, and thawed out clots will be found floating in the liquid, composed mostly of albumen and fat, which may be dissolved by cooking; on the other hand, if the milk is preserved in a frozen condition for three or four weeks these clots will be very hard to dissolve, and the difficulty experienced in dissolving them increases as the length of time the 1Kasdorf, Otto. Eis und Kilte in Molkereibetrieb. Leipzig, 1904, p. 20. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. idl milk is preserved in a frozen state. For this reason the freezing of milk, for the purpose of transportation, has hitherto been little used. If the milk is held at 32° F. for a few days, some types of bacteria may grow and multiply slowly. With a good quality of milk, i. e., that containing few bacteria, it may take weeks or even months for them to gain great headway. What few bacteria develop at low tem- peratures are of different species from those ordinarily found at the higher temperatures, and they may produce marked changes in the chemical composition of the milk without especially changing its ap- pearance. Consequently, it is unsafe to assume that milk which has been held for several days at a low temperature is in good condition. According to Pennington' milk exposed continually to a temperature of 29° to 32° F. causes, after a lapse of from 7 to 21 days, the formation of small ice crystals which gradually increase until the milk is filled with them, and there may be an adherent layer on the walls of the vessel. The milk does not freeze solid. In spite of the fact that the milk was a semisolid mass of ice crystals, an enormous increase in bacterial content took place. Though the bacterial content was numerically in the hundreds of millions per cubic centimeter, there was neither taste nor odor to indicate that such was the case. Neither did the milk curdle when heated, and the unfitness of the milk for household purposes would not ordinarily be detected until the lactic acid bacteria decreased in numbers and the putrefactive bacteria began to develop. THE INFLUENCE OF TEMPERATURE ON THE BACTERIOLOGICAL FLORA OF MILK. Each species of bacterium found in milk and each particular variety has an, upper and lower temperature limit beyond which it does not grow, and a certain temperature, called the optimum, at which it grows best. The optimum temperature of most forms occurring in milk is between 70° and 100° F. As the temperature of milk is lowered the rate of growth is diminished until at 40° F. the multiplication is very slow and at a temperature just above the freezing point the develop- ment practically ceases; in fact, there is an apparent decrease in the number, at least for a short time. The action of cold at this tem- perature, however, does not totally destroy life in the bacteria, but causes them to lie dormant. When the temperature of the milk is raised they again begin to multiply. As an illustration of the relative variation in the growth of bacteria in milk held at different temper- atures, one writer gives the data found in Table IV, in which 1 is assumed to represent the number of bacteria in the fresh milk, and the relative numbers which will be found at the end of 6, 12, 24, and 48 hours, at the two temperatures, are shown in the succeeding col- 1 Pennington, Mary E. Bacterial growth and chemical changes in milk kept at low temperatures. Journal of Biological Chemistry, vol. 4. nos. 4 and 5, pp. 353-393. Baltimore, 1908. i eg ee 12 BULLETIN 98, U. 8S. DEPARTMENT OF AGRICULTURE. umns. These figures are based on a number of actual counts and illustrate the effect of a difference of 18° on the multiplication of bacteria. If the milk had contained at the beginning 1,000 bacteria, the part held at the lower temperature would have contained at the end of 24 hours only 4,100 bacteria, while the other would have con- tained at the same stage 6,128,000. Table V, from Bulletin 133 (Extension Bulletin 8) of the agricultural experiment station of Nebraska, illustrates the importance of holding cream at low tem- peratures. TaBLe [V.— Multiplication of bacteria in milk held at different temperatures." Relative number of bacteria held at— Milk held at— a 0 hours. | 6 hours, | 12 hours. | 24 hours. | 48 hours. f(t) gl ee ee Loe oe ae me rer See ee ae ore oC ee 1 1.2 15) 4.1 6.2 (Seyi Des See pie ees all av ese yeah sesh eM Mtg a ac 1 ia 7 24.2 | 6,128 357, 499 1 Rogers, Lore A. Bacteria in milk. U. S. Department of Agriculture, Farmers’ Bulletin 490. Washington, D. C? TaBLe V.—The effect of temperature on the growth of bacteria in cream. “ Number of : Number of Temperature of cream. ae bacteria Temperature of cream. Tine bacteria 3 per ¢. ¢. . per ¢. c. ois Hours. CIR, Hours. SE CES RO Sei tet Une acs 10 3, 8005 (Oke. ss cee Meee eee eee 11 188, 000 LY AR A esis es ciane sae aie St ie os 10 U1 '580.1| ‘SOR... . case seee Soe aera 11 2, 631, 000 BON Ren eee ee 104 15,120 || 90..... "2 3c Ee ee 113] 4,426, 000 THE INFLUENCE OF TIME ON THE BACTERIOLOGICAL FLORA OF MILK. The influence of temperature and time bear certain definite rela- tions to each other; hence, a study of one necessarily includes a study of the other. Table VI serves to illustrate the effect of time as well as temperature on the keeping qualities of milk. If the table is read downward we note the effect of temperature and if read across the effect of time. When milk is first drawn from the cow it usually contains bacteria, even though it is produced under sanitary conditions, and if held at the ordinary temperature of the surrounding air in a short while the bacteria will grow and increase in numbers so rapidly that when such milk reaches the consumer it will contain many thousand bacteria per cubic centimeter. Conn furnishes an example of milk giving ns following results: Bacteria per ¢. ¢. Milkidyswnat 59° Fame. 2 A v3 ee 153, 000 Atieem Hours). 2000F.. 42. SSL) SE 616, 000 2 hours: 5) - 4H Sh sede es ee eee 539, 000 Avhotirg = 2.3255 ot8 =). ots, ee. Sr ee 680, 000 MOUTH gcc aia Seite nie = dbp a pak eee es oe. Se 1, 020, 000 DP OUUS = «cone Gee = ry tian ae tain e eC a oe 2, 040, 000 POUT S sobs bt Gis ate ua ae eM eee 85, 000, 000 , — a — ee eG APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 138 According to Park,’ two samples of milk maintained at different temperatures for 24, 48, 96, and 168 hours, respectively, showed the development of bacteria as indicated in Table VI. The first sample was obtained under the best possible conditions, while the second sample was obtained in the usual way. (The figures of the second sample are heavy face in the table.) When received the first sample contained 3,000 bacteria and the second 30,000 per cubic centimeter. TaBLE VI.—L fect of time and temperature on the growth of bacteria in milk. Temperature. 24 hours. 48 hours. 96 hours. 168 hours. SP VIS ORCA) tk ey ee oe ea 2, 400 2, 100 1, 850 1, 400 30, 000 27, 000 24, 000 19, 000 Spel (AoC n awake Se. Aes 2, 500 3, 600 218, 000 4, 200, 000 38, 000 56, 000 4,300, 000 38, 000, 000 ADAH (unl) seins sae O eee eis Snel oe 2, 600 3, 600 400% OOOR EAaeeeeoeesaee 43,000 210, 000 BGO 3000) | eas ape GPT GO De Soe ee ee 3, 100 12,000 TAS OM OOO) |e eee 42,000 360, 000 1252005000) see see eee GOP IM \((lOF (Ce) Seseeseoeaneee et eae a 11, 600 DAOKOOOM ese ree esata seater AVA 89, 000 9400000 Me eee eae ee GP 19: (IBY CR eee Sei ee ae e Sees aes 18, 800 Dp AWOS OOO ererccrer eae rocco ee areas 187, 000 SSS000K000N | eae eae hl agee eee GUpe hen (One Cs) ee see cae. seh esses ee 180, 000 2S SOOOTOOO™ |e ate sees ae ee | ee a ee gee $00, 000 GSSO00 O00 yas se eee es rs GSgnHa(20cdC 3) se ce -wisk 2 s/4- 2) ete sees 450, 000 ZO OOOSOOOSO00 Resear se epee eer 4° O00 0008 ete 5400040005000) knee emeea nmin: Remnelnaaei ase SOs (BOqt Ca) ienists seewe eoctere ewer see HAND: OCOROOON =r Ae eee reise ie =| ees ie he ae ee EEEOO0: OOO OOO pre Sa ee ee NOR RAL ele SE a a a GACH (GEM Ch) etree in oak cronies se 254000: OOOMODOM Meester mae ces emp eee en lA ee 25/000, COOS OOD see es cee ne a as [boeing In Table VI it will be noted that at 32° F. there is an actual decrease in the number of bacteria in both samples of milk during the 168 hours, while at all other temperatures there is an increase in the number of bacteria. Ordinarily the consumer receives milk when it is from 24 to 48 hours old; hence it becomes an easy matter to deliver the milk in good condition, providing the milk is produced under sanitary conditions and is properly cooled and held at a tem- perature of 50° F. or below. An examination of the tables and fig- ure will show how intimately the two mfluences of time and tem- perature act and interact in relation to the multiplication of bacteria in milk. Fieure 2 is a graphical representation of the relation of temperature to bacterial giowth in milk, taken from Bulletin 26 of the Storrs (Conn.) Agricultural Experiment Station.? At @ is represented a single bacterium; at 6 is shown the progeny resulting from the growth of a single bacterium in 24 hours in milk kept at a temperature of 50° F.; at ¢ is represented the progeny from a single bacterium in 24 hours in milk kept at 70° F. At 50° the multiplication was fivefold, at 70° the multiplication was seven 1 Park, William Hallock. The great bacterial contamination of the milk of cities. Can it be lessened by the action of health authorities? Journal of Hygiene, vol. 1, no. 3, pp. 391-406. Cambridge, July, 1901. 2Conn, Herbert William. The relation of temperature to the keeping property of milk. Connecticut (Storrs) Agricultural Experiment Station Bul. 26. Storrs, 1903. 14 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. hundred and fifty fold. The figure shows graphically what a decided influence the dairyman can exert upon the keeping of his milk by a lowering of temperature only 20°. From the foregoing it is obvious that proper refrigeration is of the utmost importance in the preservation of milk. In fact, without thorough cool- Guy e Sora, ing it is impracticable to keep milk for cor ES RRR any considerable length of time in a con- o b Ea BA We dition that would justify its use for house- ra ee age hold purposes. It should be cooled to CoN RS pl 50° F. or below as quickly as possible Fie. 2.—Graphical eames Td of after it is drawn from the cow, as such the relation of temperature to bac- cooling will at once check the increase in terial growth in milk. bacteria. COOLING BY MEANS OF SALT AND ICE MIXTURES. Where asmall amount of refrigeration is required it is often produced by a mixture of common salt and ice. The action of the mixture in lowering the temperature below 32° F. is as follows: When two solid bodies, as salt and ice, mix to form a liquid a cer- tain amount of heat be- comes latent, called the latent heat of solution. Since this latent heat is taken from the mixture itself the temperature falls correspondingly. The tem- perature obtained by a salt and ice mixture depends principally on the relative proportions of the mixture, and to a less extent on the rate at which the heat is supplied from the outside, the size of the ice lumps and salt particles, and the amount and density of the resulting brine. Hence it is impracticable to give Re AD tal oa) 2) Le) o NE Ee Boe A MBE aie APPROXIMATE TEMPRATURE °F Fic. 3.—Approximate temperatures obtained with different proportions of salt. other than approximate temperatures with fixed ratios of salt and ice. From the curve in figure 3 the approximate temperature resulting from different proportions, by weight, of salt and ice may be obtained. If, for example, we desire to know what tempera- ture may be obtained by using a mixture of salt and ice containing 15 per cent of salt, follow the vertical line marked ‘15 per cent of APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 15 salt’? upward until it cuts the curve, then read opposite on the ver- tical line marked “ Approximate temperature ° F., 11°.”? The curve in figure 3 was plotted from the figures in Table VII, which gives the approximate temperatures obtained with different proportions of salt and ice. Taste VII.—Approximate temperatures obtained with different proportions of salt and ice. Per cent of | Tempera- || Per cent of | Tempera- salt in ture of salt in ture of mixture. mixture. mixture. mixture. “a a “FF, 0 32 15 11 5 27 20 1.5 10 20 25 —10 One pound of ice, in melting, absorbs 144 B. T. U. This is known as the latent heat of fusion of ice. Salt in dissolving also absorbs heat, called the latent heat of solution, which varies in amount, depending on the density and temperature of the resulting brine. The heat of solution of salt in water at 32° F. varies from 58 to 16 B. T. U., depending on the final strength of the brine obtained. Table VIII gives the heat of solution of 1 pound of salt dissolved in water at 32° F. up to the concentration given by the numbers of pounds of salt dissolved in 100 pounds of water. Taste VIII.—Refrigeration available with different proportions of ice and salt. Heat re- Heat re- binge per Heat of Total heat quired per Salt per Heat of Total heat quired per pounds luti of resulting d 100 pounds luti of resulting water Soreas icoliorn eo” water solution. | solution. | Pound of = mixture i mixture. Pounds Bait T. 13 NE OF Pounds TES IE WE A) BG Ye T U: 1 58.0 14, 458 143.0 27.0 14, 940 124.5 5 49.7 14, 668 139.5 25 22.5 14, 962 119.5 10 40.5 14, 806 134.5 30 19.1 14, 973 115.0 15 33.0 14, 895 129.5 35 16.4 14, 974 111.0 The curve in figure 4, based on the percentage of salt, shows the amount of refrigeration available per pounds of ice and salt mixture. This curve was plotted from the figures given in Table VIII corrected to a percentage basis, which were calculated from the melting of ice at 32° F. into a liquid at the same temperature. If, however, the salt is added to the ice at a temperature varying from 32° F. or, if the resulting brine is allowed to escape at a temperature other than 32° F., the amount of available refrigeration must be corrected accordingly. These corrections are determined by multiplying weights, in pounds of salt and brine, by their respective specific heats and by their dif- ference in temperature from 32° F. The specific heat of dry salt may be taken as 0.214, and as the specific heat of salt brine varies with its density, it may be obtained from Table [LX or from curve figure 5, which is plotted from the figures contained in the table, 16 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. Taste IX.—Specific heat of brine with different percentages of salt. Specific Per cent heat of of salt. princes 0 1.000 1 . 992 5 - 960 10 . 892 Per cent Speaihe of salt. panes 15 0. 855 20 829 25 . 783 Usually salt when added to ice is of a higher temperature than that of the ice; consequently the correction for its heat above 32° F. TOTAL AVAILABLE REFRIGERATION B.TU. PER POUND OF PIIATURE PERCENTAGE OF SALT IN A(X TURE Fig. 4 SENS SEIOE available with different percentages of salt. must be subtracted from the available refrigeration shown by the curve, figure 4; and if the brine is al- lowed to escape at a tem-— perature below 32° F. the refrigeration lost in the dis- charge brine must be sub- tracted, while, on the other hand,if the discharge brine is at a temperature higher than 32° F. the correction must be added. If given amounts of ice and salt, at a temperature of 32° F. are mixed together and the mixture supplied with suffi- cient heat to melt the ice and dissolve the salt and raise the tem- perature of the resulting brine to the original temperature of 32° F., then the total amount of heat absorbed by the reaction will be the sum of the latent heat of the ice and the heat of solution of the salt to form the resulting brine of the density which will result from the particular proportion of salt and ice chosen. As an example, under the foregoing conditions, if 100 pounds of dry salt is added to 900 pounds of ice the total available refrigeration is 1,000,54133:— 183,000. B.. T. .U. The available refrigeration per pound of mixture, SPECIFIC HEAT: PERCENTAGE OF SALT. es Fig. 5.—Specific heat of common salt brine, with different percentages of salt. 133 B.'T. U., is taken from curve-in figure 4. If the salt added is at a higher temperature than 32° F., say 60° APPLICATION OF REFRIGERATION TO HANDLING OF MILK. hy F., then the available refrigeration will be 133,000—[100x*0.214 (60-32)]=132,401 B. T. U., or 132.4 B. T. U. per pound of mix- ture. If the resulting brine is allowed to escape at 25° F., the available refrigeration is 133,000—[1,000 0.892 (32—25)]=126,756 B. T. U., or 126.7 B. T. U per pound of mixture. Or, in other words, there is lost in the first case 100 x 0.214 (60-32) =599 B. T. U., and in the second case, 1,C00 x 0.892 (32-25) =6,244 B. T. U., or a total loss, if the salt is added at 60° F. and the brine allowed to escape at 25° F., of 599+6,244=6,843 B. T. U. Under these conditions the available refrigeration is 133,000-6,843=126,157 B. T. U., or 126 B. T. U.-per pound of mixture. REFRIGERATION AS APPLIED TO MILK PLANTS, CREAMERIES, AND DAIRIES. The function of refrigerating apparatus, whether it is a refrigerating machine or a bunker filled with ice, is to provide a heat-absorbing medium which, after absorbing heat in the cold-storage room, may be removed. After it has been removed from the coolers it may be divested of its heat and allowed to return to the cooler for the pur- pose of absorbing more heat, as is the case when some volatile liquid is used, or it may be allowed to go to waste and a new supply introduced, as in the case of cooling with ice. ICK BUNKERS. OVERHEAD BUNKERS. One of the simplest methods of cooling a cold-storage room is that of an ice bunker, the principle of which is shown in figure 6 and consists of a water-tight floor located over the compartments to be cooled. The ice is piled on the floor through an opening at or near the top of the room and the cooling is effected by the natural circu- lation of air up and over the ice and down into the compartment in which the goods to be cooled are stored. The movement of air is naturally slow, as the power available is the difference between the weights of the ascending column of warm air and the descending column of cold air. As the air in contact with the ice is cooled it flows down into the room below, where it comes in contact with the warm goods in storage and absorbs heat from them, and as it becomes warmer is forced up to the bunker, where it is gradually cooled, thus producing a circulation. The movement of air may be increased and lower temperatures obtained by employing a fan driven by an outside source of power, or a mixture of salt and ice may be used in the bunker, in which case a lower temperature may be obtained, but in either case at the expense of a greater consumption of ice, 40083°—Bull. 98—14——2 18 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. for, as previously stated, the use of a mixture of salt and ice in a refrigerator does not increase the cooling capacity of a given amount of ice, but the effect is to cause the ice to melt more rapidly and thus absorb heat more quickly. In, other words, the melting point of ice is lowered when mixed with salt. One pound of ice in melting absorbs 144 heat units, either with or without salt. With salt the absorption is quickened, hence a lower temperature for a shorter time. Therefore there is no gain bese in efficiency by employing a mix- — ture of salt and ice; in fact, there WML O03] . is a loss in efficiency due to the SANT OASIS IDEAS A Lik PLDC HL NGI? DEES Sales a % heat of solution. Ice bunkers for cooling pur- poses, when located over the compartment to be cooled, should be made in the form of a box with one side removed, as shown, in figure 6, in order to assist the air currents. With this form of construction the air, as it is gradually cooled, flows to the left down over the ice, while the warm air rises on _ the right to take its place. It is obvious that if the bunkers RASA YPREELL IAT EOE QX|E MK III SS LNW BE Hs 0) -_— he | , 7} ———— s-¥ & t] ) 4 8 Hf ' So Ho hes = 9 : hy HA 1: | cs a A ‘we AK a ho Y ( ie t : x | cis 8 : AH) Bat a by a 4 Bk GN 4 by ly Bi J Ai a fj Ky ft <4 ox} We ey ie Pal Pa KY 4 Ny ware tan) Reb aac tena Oe aR STADE CATO ISLES MS A, STORAGE Frooar Ss EESTI AIF SND CASER ES PI IR ASSLT ER \ WHOS CER IPD AN CASAL UREN L.A OH EES TVR ALIS END SPL? \ SS Ie Le UN ESPN ITY ETP N ELIA DE SEI EI 1 = iN LL Tic. 6.—Overhead ice bunker. should be made in the form of a rectangular box the air would have a tendency to flow off in all directions and give rise to con- flicting currents which would re- tard the circulation and for the same rate of circulation, a greater difference in, temperature between, the air in the bunker and that in the compartment below would be required. Ample spaces for air ducts should be provided between the sides of the bunker and the walls of the cold-storage compartment in order to permit the air to circulate freely. The cross-sectional area of the ducts should be from 10 to 15 per cent of the area of the ceiling. The floor of the bunker and the walls of the air ducts should be well insulated to prevent the too rapid cooling of the relatively warmer ascending air as well as that lying next the floor of the bunker. Rapid cooling of the air at these points tends to check the circula- tion by reducing the difference in temperature between the warm APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 19 air in the ducts and that in the bunker. With properly insulated bunkers and liberal-sized ducts the circulation. should be sufficiently rapid to carry any air saturated with moisture to the ice bunker before its moisture can be precipitated by coming in contact with the cold walls of the storage room. With properly proportioned ducts and insulated walls the excess moisture will be precipitated in the ice bunkers and run off with the melted ice. If the air ducts and bunker walls and floor are not sufficiently insulated the excess of moisture will be condensed on them and will drip down, on the goods in storage. Provision should be made for thorough drainage and the drain- pipe should be effectively trapped or sealed to prevent the outside air from entering the cold-storage room. An efficient water seal may be had by allowing the outer end of the drainpipe to extend below the surface of the water in a cooling tank outside the room, and as the water from the melted ice is approximately 32° F. it may be utilized for further refrigerating purposes. As the melting point of ice is 32° F., it is obvious that, in a room cooled by ice, the temperature must necessarily be somewhat higher. In practice the temperatures obtained are rarely below 40° to 45° F. during warm weather. In addition to the disadvantage of the com- paratively high temperatures obtained by using ice as the cooling medium in cold storage, the excessive moisture present in the air, together with the slop incident to its use, makes it undesirable. Ths nearer the temperature of the air in a room cooled by ice approaches that of the melting ice the more sluggish becomes the circulation and the higher the percentage of moisture contained in the air. Mois- ture in a cold-storage room favors the growth of molds and bacteria, which rot the floors and walls of the room, as well as the goods stored; consequently sensitive goods like dairy products are liable to be damaged by such conditions, especially if kept in storage for a con- siderable length of time. However, in small plants or on the farm, where goods are stored for a short period only and where ice may be had at a nominal cost, either natural or artificial, this method of cooling is employed to advantage. Great care should be exercised to prevent any cross currents of air in the cooling room, for when such currents are present there is danger of the cold air and warm air coming in contact with each other, in which case condensation will be sure to take place on the cool surfaces of the walls and ducts, thereby preventing the displace- ment of the impure gases to be condensed on the surface of the ice in the bunker and removed with the drip. It is very important that a positively guided circulation of air be maintained. In order for the cold air to be most effective it should 20 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE, be admitted into the storage room at a low level, as indicated in figures 6 and 7. The cold air will then pass over the goods in storage, and as it becomes warmer will gradually rise to the bunker, where it is recooled. As natural circulation is brought about by the difference in temperature between the warm air and cold air, which is only a degree or two, advantage must be taken of the difference in height of the respective columns. The simplest and most effective way to accomplish this is to extend the cold-air duct to within about 2 feet of the floor. The inner side of this duct should be insulated to pre- vent condensation. The uptake duct should be similarly insulated and should extend from the bunker floor i ae to near the ceiling of VM VYj,, the vo0m, leaving an j ie area equal to the : cross-sectional area ; of the warm-air duct. The warm-air duct should be located on the warmest wall of the room in order to take advantage of the natural air circula- tion, and for the same reason the cold-air duct should be on the coldest wall. SIDE BUNKERS. Ice bunkers are often constructed as " shown in figure 7, and the same care in con- struction and insulation should be observed as in the overhead type of bunker. i SN ry Wa WAI svi WOK SS... NCAP Te IS OTORN ETRE TP OD Bord CVE SAIT 2R WSS SS SS Ce PARP ACPA EIS E= TRENT PO ONE AAS EAU AE SUE YEN 1 ;S Ma“ elect il -gaims Mare Ane webs t etniorn Pans SS Fic. 7.—Side ice bunker. N AN GRAVITY BRINE SYSTEM. The system illustrated in figure 8 has made it possible to obtain temperatures considerably lower than can be obtained with the bunker system. It consists of a tank filled with ice and salt, in the proportions required to produce the desired temperatures, and an endless-pipe circuit. The pipe is completely filled with a brine solution of the proper density to insure against freezing. It is customary to use a solution of calcium chlorid, as lower temperatures are obtained without danger of freezing and the corrosive action is less than that of com- APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 21 mon salt. The solution should not be stronger than the temperature to be maintained requires, as the specific heat.of brine decreases as the strength of the solution increases. A part of the pipe coils are placed in the tank containing the mixture of salt and ice, and a part are led down into the cooling room below. The coils of pipe . that are in the cooling room absorb heat from the stored goods WL 1) ses tre ANY YLLLL 1 IEE ANO SALT TANK Wl Liddd Vy Hl i q PRE FRE LMU LR RUPEE MED IE LLL LLL LLL LZ, rH i NALLY TOP RRS PNG SERA TW NOON YL N S is PEATE pS fi Si Sarat ee A SI ER EAB UPC 275M CASE ND PALER NS EEE SERRE Bas Aa XX Q__E NI ES BSTIRAGE Foow “iy ECW ANTEFAS AT SN Sees ee ee 77 WLLL LLL Fig. 8.—Gravity brine system. and those in the tank give up heat to the freezing mixture of salt and ice. The operation of this system is as follows: The brine in that part of the pipe circuit in the tank becomes heavier as it is cooled and flows down into the storage room, forcing the warmer and there- fore lighter brine up into the coils in the tank. The heat ab- sorbed in the storage room is transferred to the mixture in the tank by the natural circulation of the medium. This system is to a certain extent automatic in its operation, as an abnormal rise in temperature of the storage compartment from any cause increases the velocity of the brine circulation and therefore increases the re- 2°, BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. frigerating capacity of the system. With this system it is possible to prevent the air in the cold-storage compartment from becoming contaminated by contact with the melted ice and insanitary bunkers, as is the case when ice is used. In addition, a drier, purer air is maintained in the storage room. In milk plants, creameries, and dairies, where the cooling is done in a comparatively short time, it is necessary to have a large stor- age tank for brme, which may be cooled in the afternoon or over- night and held for quick action when needed. As the temperature of the brine in the storage tank will gradually rise as the work of cooling the milk goes on, the volume required will depend on the amount of milk to be handled and the range of temperature through which it is to be cooled. For example, if there are 1,000 pounds of milk to be cooled from an initial temperature of 90° F. to a final temperature of 35° F., the heat that must be removed is 1,000X0.95 (90-35) =52,250 B. T. U. Then, if the initial temperature of the brine is 25° F., the allowable rise in temperature will be 10°, and if the specific heat of the brine is 0.83, neglecting radiation, the amount necessary will be 52,250 0.85 X10 that the brine is pumped from a brine tank through some form of tubular cooler. =6,292 pounds, or 87.5 cubic feet. It is assumed above CONSTRUCTION AND LOCATION OF COLD-STORAGE ROOMS. In the construction of cold-storage rooms consideration should be given to the relations that the lateral dimensions bear to the cubical space of the room. This is an important factor in the construction of refrigerators and is one to which but little attention is given. It is important that the shape of the room should be given first con- sideration, and unless there are some local conditions that compel a different arrangement it should be built, as nearly as possible, in the form of a cube. This will present the smallest exterior surface for a given cubical space for any practical form of construction. For very small rooms, however, of less than 1,000 cubic feet capacity, it is impracticable to build them in the form of a cube, as the height should be 10 or 12 feet. This height affords a better circulation of air, and consequently a more uniform temperature, a purer, drier air, and more satisfactory refrigeration. Where mechanical refrigeration is employed this height is neces- sary in order to provide space for the coil bunkers unless wall coils are used, in which case the height may be less. The circulation of air, however, is not so good with wall coils as with a bunker loft. If very cold temperatures are not required, as in the case of ordinary ice | APPLICATION OF REFRIGERATION TO HANDLING OF MILK. a boxes, a lower room may answer the purpose. As an illustration of the saving of material in construction and in refrigeration, let us consider two cold-storage rooms, each of 1,000 cubic feet capacity; one room to bein the form of a perfect cube, 10 by 10 by 10 feet= 1,000 cubic feet; the other room to be 10 by 6 feet by 16 feet 8 inches = 1,000 cubic feet. The total square feet of surface in the first room is 600; the total square feet of surface in the second room is 653; therefore, for the same cubical contents, the second room has 8.8 per cent more radiating surface and will require 8.8 per cent more material in construction. The cold-storage room should be where it is protected as much as possible from the direct rays of the sun. Unless some natural pro- tection is afforded, such as trees or buildings, the cold-storage room should be in the northeast corner of the building. In the construction of a new plant advantage should be taken of the actua! condition surrounding the proposed building site. Very often considerable may be gained by proper location of the building and arrangement of machinery. For insulation of cold-storage rooms the reader is referred to the matter under the heading “ Insulation.” PRINCIPLES OF MECHANICAL REFRIGERATION. When a solid or a liquid changes its state or condition, as when a solid is converted into a liquid or a liquid into a gas or vapor, the change of state or condition is in each case accompanied by the absorption of heat. This absorption of heat, as previously explained, is called “latent heat;”’ that is, heat that can not be measured by a thermometer; and in order to transfer a substance from one state to another it is only necessary to supply or extract heat. For instance, if we take 1 pound of ice at zero temperature, Fahrenheit scale, and apply heat, the temperature will rise until it reaches 32°. If we continue the application of heat the ice will begin to melt, and after we have supplied sufficient heat the 1 pound of ice will have changed to water at 32° F., the same temperature at which the ice commenced to melt. If the application of heat is continued the water will grow warmer, but at a slower rate. It now takes about double the amount of heat to raise the 1 pound 1 degree as water that it did to raise the 1 pound 1 degree asice. In other words, the speci- fic heat of water is approximately double that of ice. When sufficient heat has been added to raise the 1 pound of water to a temperature of 212° F’., another critical point is reached at which further application of heat to the water, under atmospheric pressure, will not increase its temperature, but changes it into steam at a temperature of 212°. Figure 9 shows graphically the relation of heat to temperature. 24 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE. It will be noted from figure 9 that to raise the temperature of the 1 pound of ice from zero to the melting point (32° F.) 16 B. T. U were expended; in melting the ice, 144 B. T. U.; in raising the water to the boiling point, 180 B. T. U.; and to evaporate the water, 970.4 B. T. U. If the operation is reversed, the heat being extracted instead of being added, the curve will follow backward on itself to the starting point. The latent heat of fusion and the latent heat of vaporization are represented on the diagram by the two lines parallel to the horizontal base line, the length of the lines representing to scale the amount of heat expended in molecular work in separating the molecules of the substances. Starting from the left, the rising lines represent the heat CSRS Baas ao ee seer Pe SSS eee SL). Ae ce SHIGE ABs 200 300 400 500 600 700 800 900 /000 /100 1200 /300 /400 QUANTITY OF HEAT IN B.TU. Fic. 9.—Diagram showing the relation of heat to temperature. required to raise the temperature of the ice, water, steam at constant volume, and steam at constant pressure, respectively. The same law applies to liquified anhydrous ammonia, carbon dioxid, and sulphur dioxid, which are the substances most com- monly used in commercial refrigerating machines. These liquids are extremely volatile, their change of state takes place very rapidly, and their latent heat is absorbed at a corresponding rate. Their boiling point is sufficiently low under atmospheric or other con- veniently produced pressure to give the temperature desired. AI- though the same principles underlie the use of all such fluids, their physical properties vary, and consequently demand different treat- ment in order to produce the best results. The theoretical requirements of a good refrigerant are: A low boiling point at ordinary pressure, a large latent heat of vaporiza- APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 25 tion, and a small specific volume. A low boiling point is desirable, because it makes operation possible with comparatively low pressure in all parts of the system; therefore, the machines and accessories may be of lighter construction, with smaller loss of gas by leakage. As the latent heat of vaporization is, to a certain extent, a direct measure of the cooling effect, it is obvious that the greater the heat of vaporization the better the refrigerant. The specific volume of the refrigerating agent determines the volume of the cylinders of the compressor, consequently the size and weight of the machine. In comparing the three refrigerating agents which are considered applicable to the dairying industry, viz, ammonia, carbon dioxid, and sulphur dioxid, it will be noted by referring to tables giving the main characteristics of the agents that, assuming the limits of operation are between 5° F. and 85° F., the absolute pressures are: Ammonia from 27 to 175 pounds, carbon dioxid from 290 to 1,000 pounds, and sulphur dioxid from 9 to 65 pounds. Taking the boil- ing points of the liquids at the temperature at which the liquid boils under atmospheric pressure, it will be noted that there is a wide difference in their boiling points as well as their latent heats of vaporization. Ammonia boils at 28.5° F. below zero and has a latent heat of vaporization of 572.8 B.T.U. Carbon dioxid boils at 110° F. below zero and has a latent heat of vaporization of 140 B. T. U. at a pressure of 182 pounds per square inch absolute. The latent heat at atmospheric pressure is not definitely known. Sulphur dioxid boils at a temperature of 14° F. and has a latent heat of vaporization O1G2.27B.)T.. U: For practical purposes the value of a refrigerant depends upon its boiling point, its latent heat of vaporization, and upon the pressure at which it can be used. To maintain a zero temperature with ammonia as the refrigerant an absolute pressure of 30 pounds per square inch is required in the evaporating coils; with carbon dioxid, 310 pounds absolute; and for sulphur dioxid, 10 pounds. Ammonia has a much greater latent heat of vaporization and the working pressures are not excessive, but it has the disadvantage that it corrodes brass or any other copper alloy; consequently only iron or steel can be used in the construction of those parts of the machine with which the agent comes in contact. The pressures of carbon dioxid are so high as to cause trouble in keeping the stuffing box and joints tight. A relief valve is often placed in the high- pressure side of the system in order to protect it from excessive high pressures. It is noncorrosive, nonexplosive, and is not dan- gerous to life when diluted with air. The high pressures necessary, combined with the small specific volume of the gas, make it suitable for use with a very compact machine. As the lower pressure of 26 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. sulphur dioxid is below the atmospheric, any leakage of air will be into the system and will cause corrosion of the metal by forming sulphurous acid. The low pressures required in using sulphur di- oxid as a refrigerant in connection with its large specific volume makes a large and cumbersome machine necessary. The ratios of the volumes of the cylinders necessary for a given capacity of ma- chine, taking that of carbon dioxid as one, are approximately as follows: Carbon dioxid 1, ammonia 4.4, sulphur dioxid 13. If either liquid ammonia, carbon dioxid, or sulphur dioxid is placed in a test tube, as shown in figure 10, it will boil under atmospheric pressure below the ordi- nary temperature of the surrounding air, and the heat of evaporation will pass from the surround- ing air directly into the refrigerant. The air, therefore, will be refrig- erated or cooled, due to the fact that its heat is taken up by the boiling liquid. In other words, the heat required for the evaporation of the liquid is extracted from the air. At the boiling point the refrigerant will absorb a definite amount of heat from the air to effect the vaporization of a definite amount of the liquid, the heat being absorbed directly through the walls of the test tube from the outside air. There will be a circulation of air around the test tube, as indicated by the arrows in the figure, due to the greater weight of the cooled film of air lying next the surface of the tube which flows down and away from the bottom of the vessel, allowing the warmer and therefore lighter air to rise and take its place at the top. Figure 10 embodies the principle of the direct- expansion system of refrigeration explained in detail later. If the test tube containing the refrigerant is immersed in a second vessel containing a solution of brine, as shown in figure 11, the evaporating liquid will absorb heat from the surrounding medium just as in the preceding case, but in this case the surrounding medium is brine instead of air and the heat required to effect the vaporization APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 27 of the liquid is absorbed from the brine, which in turn is absorbed from the air by the brine. In this case there is a double transfer of heat, viz, from the air to the brine and from the brine to the evaporating liquid in the test tube. The cooling effect is assisted by the circulation within the brine itself, due to the difference in weight of the colder liquid in contact with the surface of the test tube, and that at a distance from it. The colder brine sinks to the bottom of the vessel and its place is taken by the warmer brine, thus producing a circulation as indicated by the arrows, whereas in the preceding case the heat from the surrounding air was absorbed directly by the re- frigerant. In view of the fact that it is 1m- practicable to lower the temperature of the brine to that of the refrigerant, the absorption of heat from the surround- ing air by the brine is not so rapid as when the air is in direct contact with the walls of the ves- sel as in the preced- ing case. Figure 11 embodies the prin-. ciples of the commer- cial brine-storage system of refrigera- tion, which will be discussed later. Going one step fur- ther toward the practical application of artificial refrigeration, imagine an arrange- ment as shown in figure 12, where the test tube in the foregoing illustration is replaced by a steel cask or drum, such as is commonly used for shipping ammonia, carbon dioxid, and other liquid gases, the tank corresponding to the beaker containing the brine. The liquid in the drum is under pressure, and if allowed to escape in a small stream through the throttling or expansion valve against atmospheric pres- sure it will evaporate in the coils located in the brine tank and the heat required for vaporization will be taken from the brine. If a pump were attached to the free end of the pipe the suction of the pump would tend to produce a vacuum, which action would accelerate 28 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. the evaporation of the liquid and the absorption of latent heat would go on faster than ever. If it were not for the initial cost of the refrigerating medium this elementary form of refrigerating system, in which the refrigerant is allowed to escape to the atmosphere after evaporation, might find some commercial application, but as the refrigerants are expen- sive, such a system would be very costly to operate. Therefore, as the volatile liquids are valuable and can not be thrown away, if the reverse action takes place, that is, if the volatile gas is again converted into a liquid, it may be carried through the same cycle, over and over again indefinitely, and if it were possible to have no leakage one charge would be sufficient for all time. REFRIGERATING MACHINES. COMPRESSION SYSTEM. In order to make the system illustrated in figure 12 commercially practical, it is necessary to provide some means for converting the S Me, PRESENT RA etn aH bs OREN TS | i} mu SRV PI EP APRS CS AO ES i Veco YL ZL” Volati! Lreawd Drum Brine Tarik Fig. 12. gasified refrigerant back into the liquid state in order that it may be again used for the purpose of absorbing heat. In other words, after the refrigerant has evaporated in the expansion coils and absorbed its fill of heat, much as a sponge sucks up its fill of water, the heat and water with which therefrigerating gas andsponge arerespectively filled must be extracted before they can again perform the function of absorption. The water is forced out of the sponge by the simple application of pressure, but in the case of the refrigerating gas it becomes necessary not only to supply pressure, thereby raising the temperature of the gas by converting mechanical work into heat, but since the heat can be made to ‘‘flow” only from a rela- tively warmer to a relatively cooler substance, there must also be provided some cooling medium which will absorb the heat from the gas. Water being the cheapest and most convenient natural cooling medium, it is used almost entirely for this purpose. Since the pressure and consequent temperature of the cold refrig- erating gas returning from the expansion pipes must be raised before APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 29 the transfer of heat can be made to take place between it and the cooling water at ordinary temperatures, a compressor or a suitable gas pump must be used with a compression system of refrigeration. There must also be furnished a suitable cooling chamber or con- denser in which the cooling water may be brought sufficiently near the refrigerating medium to allow the necessary heat to flow from the hot refrigerant to the cool water. Therefore the essential parts of a compression refrigerating system and their functions are: A. compressor, which is nothing more than a speciaily designed pump, which takes the gas from the evaporator coils and com- presses it into the coils of the condenser, reducing the volume of the eas and increasing its temperature by changing work into heat. A condenser, which consists of coils of pipe over which water is allowed to flow, or in some constructions the cooling water passes through an inner tube and the gas is discharged by the compressor into the annular space between the inner and the outer pipes. The heat imparted to the gas is given up to the cooling water, thereby liquefying the gas. An evaporator, in which the liquid is allowed to bail and absorb heat from the surrounding media, again changing into the gaseous state. In other words, the process of refrigeration by means of the compression system is divided into three distinct stages, namely, compression, condensation, and expansion.’ Compression.—The gaseous refrigerant is drawn into the com- pressor or pump and there compressed to a pressure dependent upon the refrigerant and the temperature and quantity of cooling water used in the condenser. The latent heat of the vapor, that is, the quantity of heat imparted to it to effect its vaporization from aliquid — to a vapor is converted into active or sensible heat during this compression. Condensation.—The vapor is forced into the condenser coils under high pressure by the compressor, where the nonactive and sensible heat developed during compression is absorbed by the cooling water, thus removing from the vapor the heat required to keep it in the gaseous state, and thereby reconverting it into a liquid at the tem- perature and pressure existing in the condenser. Expansion.—The refrigerant, after being liquefied in the coils of the condenser, is passed first to a liquid receiver and then into pipe coils through a throttling or expansion valve which is capable of being adjusted to allow the liquid to pass in small quantities. As there is a materially lower pressure maintained in these pipe coils by the com- 1Tm order to make the compression system perfectly reversible there is, in addition to the three stages mentioned above, a fourth, which consists in the reduction of the temperature of the liquid from the con- denser temperature to that of the refrigerator, by the vaporization of a part of the liquid and by doing work by moving a piston. 30 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. pressor or pump, the liquefied refrigerant again expands into a vapor after passing into the coils, taking up from, whatever substance sur- rounds it an amount of heat exactly equal to that which was given up during condensation. The vapor is again drawn back into the compressor, compressed, condensed, and expanded, the cycle of op- eration being repeated indefinitely with the same refrigerant. Figure 13 presents diagrammatically the essential members of a compression-refrigerating system, in which A represents the direct expansion coils, in which the refrigerant is expanded after leaving the expansion valve 2; B, the compressor or pump, which takes the warm gas or vapor from the expansion coils A and compresses them into the condenser C; C, the condenser for cooling and liquefying the gasi- fied refrigerant; A, the receiver, into which the liquefied refrigerant flows from the condenser; H, the expansion or throttling valve, which controls the flow of the liquid refrigerant from the receiver R to the YZ g LOW PRESSURE HIGH PRESSURE GAUGE QAVEE Y LLL RAIN PSR COSTE Au SS EXPANS/ON SOUS fy ha NUE EA See meet LEU LIN QAM ait Bina w as ay OW Us ata TROVAN PMA SC od iv etes Ce As As” ESO Ue SOON TE CORI POE PED EMAL BRS Ie CEN Fe: IN NS SS SEA MATL NAN ERY ESED AON BD SITES aay igs a Yin REFRIGERATOR. Fia. 13.—Elementary diagram of direct expansion system. expansion coils A, where a materially lower pressure is maintained by the compressor, which causes the liquid to boil at a temperature sufficiently low to absorb heat from and therefore refrigerate the surrounding air. In practice, however, the system is more elaborate, as will be noted by referring to figure 14, which shows a complete compression- refrigerating plant with all the accessories necessary for its opera- tion. DIRECTIONS FOR INSTALLING, CHARGING, AND OPERATING ee TYPE OF AMMONIA COMPRESSION MACHINES. INSTALLING. The compressor, condensor, and receiver should be located in a dry and well-lighted place where they will be accessible at all times for inspection and repairs. The liquid receiver and connections APPLICATION OF REFRIGHRATION TO HANDLING OF MILK. 31 should not be placed in the engine or boiler room, as the heat will evaporate part of the liquid and drive gas back into the condenser to be recondensed. Such an arrangement makes it necessary to install a larger condenser and to use more condensing water, and, in addi- tion, the liquid goes into the evaporating system carrying its full quota of heat, thereby reducing its value. The machine should be set on a well-built brick or concrete founda- tion, care being taken to have the machine perfectly level. Before making the pipe connections all dirt and scale should be removed from the inside of the pipe and a pipe die run lightly over all threads exposed during shipment, after which they should be thoroughly washed with gasoline or benzine. The pipe fittings should be cleaned’ in the same way before connections are made. After the pipe and fittings have been thoroughly cleaned, apply a paste of litharge and glycerin to the threads and screw the pipe fittings up tight. Where soldered joints are required the threads on the pipe ends and fittings should be heated and thinned with solder before they are made up. When the machine is in place and all pipe connections properly made, remove the cover of the crank case and fill with ammonia oil to the level of the crank shaft, or to the line on the frame of the com- pressor indicating the proper amount of oil required. Disconnect the by-pass piping and close the main suction and discharge valves. Run the machine under no-load conditions for two hours to smooth up the bearmgs and make any adjustments that may be found necessary; then connect the by-pass on the discharge side. (Some manufacturers provide plugs in the by-pass piping, in which case it is not necessary to disconnect the piping.) Open the main discharge valve and all other valves on the ammonia system except the main suction valve and the by-pass valves, which should be closed. Now start the machine again and pump air on the entire system to a pressure of about 150 pounds on the low-pressure gage. This should not be done, however, in one operation, on account of the possibility of melting the joints, due to the heat contained in the air. During the operation the machine should be stopped from time to time and ali the apparatus examined in order to see that no undue heating occurs. Should parts of the apparatus be found unduly hot, the machine should remain at rest until the heated part is sufficiently cooled. Stop the machine and examine all piping and connections for leaks. ‘This can best be done by applying soapsuds with a brush to all connections, and if there are any leaks they will be indicated by bubbles. If there is an ice-freezing tank in connection with the system, run water into the tank, completely submerging the coils, 32 BULLETIN 958, U. S. DEPARTMENT OF AGRICULTURE, and if there are any leaks they may be detected by air bubbles rising from the joints. If the ammonia system has been found to be tight at the pressure of 150 pounds, close all expansion valves and again start the machine and pump air to a gage pressure of about 275 pounds, unless the discharge pipe gets very hot. As the low-pressure gage will not register so high a pressure as 275 pounds, it should be cut off when it has reached the limit of its scale. Allow the system to remain under this pressure for several hours and if the loss in pressure as shown by the gage, does not exceed 5 pounds, the system may be considered satisfactory so far as leakage is concerned. Remove the short pieces of pipe between the suction valve and the machine and allow the air under pressure to escape quickly through the suction valve. Any dirt and scale that may be in the piping and which would otherwise be drawn into the machine with the suction gas will be blown out. Before the system is charged with the refrigerant it is necessary to remove all air and moisture; otherwise the efficient operation of the machine will be seriously interfered with. Manufacturers usually provide special valves for discharging the air from the system, which is accomplished by starting up the machine and pumping the air out, the operation being just the reverse of that when working under service conditions. When a vacuum of about 26 inches has been obtained, stop the machine again and allow it to stand for several hours in order to determine if the system will maintain a vacuum. If the vacuum is maintained, the system is ready to be charged with the ammonia. It is impossible in some cases to remove all the air from the system by means of the compressor, in which case it is desirable to insert the proper amount of refrigerant gradually. Often from 60 to 70 per cent of the full charge is inserted, and the air remaining in the system is allowed to escape through the purgecocks on the condenser until the ammonia shows, which will be detected by the very strong odor, and the escaping vapor will have the appearance of steam. An additional quantity of ammonia should then be inserted. This should be re- peated once or twice a day until all the air has been displaced and the complete charge has been introduced. CHARGING. To charge the machine, a drum of anhydrous ammonia is connected by a suitable pipe to the charging valve on the liquid receiver. Allow ammonia to enter the system through the charging valve until a pressure of about 15 pounds is recorded on the gage and then turn on the condensing water and start up the machine slowly at first. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 33 The suction and discharge valves should be wide open while the machine is being charged. When one tank is emptied the charging valve should be closed and another tank placed in position, this being repeated until the system is sufficiently charged for work, when the charging valve should be closed and the main expansion valve adjusted. The ammonia drums should be weighed before and after being emptied or partially emptied, and a record kept of the amount necessary for charging. The glass gage on the liquid receiver will show the amount of liquid contained, and the pressure gages, as well as the gradual cooling of the brine in the refrigerator and the frost collecting on the expansion pipe, will indicate when a sufficient amount of the refrigerant has been inserted to start working. OPERATING. After the machine has been started and the expansion valve ad- justed, the temperature of the delivery pipe should be carefully noted, and should a tendency to heat be observed, the expansion valve should be opened wider, while, on the other hand, if it should become cold, the valve should be slightly closed, the adjustment being continued until the temperature of the pipe is the same as that of the cooling water leaving the condenser. If there is an insufficient ‘charge of the refrigerant, the delivery pipe will become heated, even though the expansion valve is wide open. Some of the signs which indicate the proper working of the plant, other than the fact that it is satisfactorily performing its refrigerating functions, are: The vibrations of the pointers on the high and low pressure gages; the frost on the exterior surface of the refrigerating pipes; the liquid refrigerant can be plainly heard passing through the expansion valve; and the difference in temperature between the liquid leaving the condenser and the final temperature of the cooling water, and between the refrigerator and the brine. Should it become necessary to disconnect any part of the ammonia system for any reason, the ammonia must be pumped out of that part and stored in another part of the system. After making repairs, all the air must be exhausted from that part of the system before the ammonia is again allowed to enter. To pump ammonia out of the condenser.—Close valves in the liquid pipe, the main suction, and discharge valves, and open the by-pass valves after draining the water from the condenser to prevent freezing and bursting of the pipes. Start the machine and pump out the ammo- nia until a partial vacuum is indicated by the high-pressure gage; then stop the machine and allow it to stand for two or three hours in order that any liquid ammonia lying in the pipes may have time to evaporate. Start up the machine again and pump down to a 25-inch 40083°—Bull. 98—14——3 34 BULLETIN $8, U. S. DEPARTMENT OF AGRICULTURE. vacuum. After all ammonia has been exhausted from the system, close the valve in the ammonia discharge pipe and the condenser may then be disassembled. To pump the air out of condenser.—The main suction and ecnnnes sila should remain closed. The by-pass valve on the Beeianss side must be open and the one on the suction side closed. Manufac- turers provide some means of opening the by-pass piping, either by a pipe tee or some form of cock; this should be opened and the machine run until all air is exhausted from the condenser. After all air has been exhausted the opening in the discharge by-pass must be closed and all valves set as they were originally. Ammonia may now be allowed to reenter the condenser, and after turning on the cooling water the plant is again ready for operation. To pump ammoma out of cold-storage room or cooler coils —Al expansion valves must be closed, also the suction stop valves, except the suction stop valve on the coil which it is desired to pump out. This valve must be left open and the machine run until a 10 or 15 inch vacuum is obtained, when the machine should be stopped for two hours in order to allow any remaining liquid in the coils to evapo- rate. After the evaporation of the remaining liquid, start the machine again and pump down to a 25-inch vacuum. If all liquid has evapo- rated and the ammonia valves are tight, the coils should maintain’ the 25-inch vacuum until broken. The suction and discharge valves on the machine may now be closed and the part of the system which has been pumped out may be opened with safety. To pump air out of storage rooms or cooling coils.—See that the main discharge stop valve is closed and remove the plug from tee or open cock, as the case may be, in the by-pass just below the discharge stop valve. The machine should be started slowly and run until all the air is exhausted from the coils, then stop machine and replace plug in tee or close cock in the by-pass. To pump out compressor.—The same method as above is followed, except that the suction stop valve only is closed, as no part of the system except the compressor is to be pumped out. CARE OF REFRIGERATING MACHINERY. In caring for machinery of any kind, one of the most important things is cleanliness, and especially is this true of refrigerating appa- ratus. If the cooling and condensing surfaces are allowed to become coated even slightly their heat-transferring efficiency will be lowered materially. Where atmospheric condensers are used it is an easy matter when the surfaces become coated to clean them with a brush, provided the coating is not of the nature of a scale. If the substance is hard, it will be necessary to employ files or steel scrapers in removing the APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 35 scale. In double-pipe condensers and coolers it is not such an easy matter to clean them as it is necessary to take off a return bend from the end of the condenser or cooler in order to ex- amine or clean them. This should be done frequently, and if the inner pipe is found to be coated with a soft substance it can be re- moved by the aid of an ordinary flue brush. If, however, the coating is in the form of scale, it will be necessary to bore it out on a lathe or tube- boring machine. The life and satisfac- tory operation, of all me- chanical apparatus are dependent on proper care as well as on the original design. It is therefore necessary that such apparatus should receive frequent and careful inspection and prompt correction of all defectsfound. Asclean- liness is essential for the satisfactory operation of machinery of all kinds, the wearing parts of the machine should be kept free from dirt and grit and the oilways open, well lubricated, and ad- justed. The clearance of the pistons should be adjusted to a minimum, both in the steam and compressor cylinders. AMIMOMIA SUCTION PAIN. he gages should be carefully In operating an ammonia plant t watched, as they are the indicators of the work being done. STORAGE FOOT BDNAH'O PIASSIGS MOP FMD IWNSS AIS WD/H COMPRESSOR Fig. 14.—General arrangement of compression refrigerating system. The 36 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. suction or low-pressure gage is controlled to a great extent by the expansion valve in the liquid line; consequently opening it will in- crease the low pressure, as the more the valve is opened the more gas will be pumped, providing the machine is run at a constant speed. If the speed of the compressor is increased, the amount of work will be proportionately increased provided the valves are large enough to handle the additional amount of gas, and vice versa. If the ex- pansion valve is opened too wide for the speed at which the machine is running, the suction pipe will frost back to the machine and even the top of the compressor may become covered with frost. For satisfactory operation in a refrigerating plant a slight frost should cover the suction pipe close to the machine. If the temperature of the brine in the cooling room is high, a cor- responding high back pressure should be carried, and, on the other hand, a low brine temperature requires a low back pressure. Should a very low brine temperature be required, in addition to a low back pressure, the machine should be run at a faster speed, depending upon the relative capacity of the machine and the work to bedone. It is necessary in the maintenance of low temperatures to keep the sys- tem free from air and deleterious gases, and plenty of cooling water should be supplied to the condenser while the plant is in operation. For small plants the receiver should be of suitable size to hold all the refrigerating medium in a liquid form. It is usually located just below the condenser, or as near to it as local conditions will allow, so that the liquefied gas may return to the receiver by gravity. In order that the amount of refrigerant contained in the system may be seen at a glance, the receiver should be provided with a glass gage similar to that placed on steam boilers to show the amount of water. This is especially true in small plants, where the attend- ant may not have had the necessary experience to enable him to judge of the amount of refrigerant in the system, and by observing the line of the liquid in the glass gage each time before starting up the compressor he will be able to note any loss of the refrigerant which he might not be able to do by other methods. Some manufacturers, however, object to placing a gage of this kind on the receiver, as they contend that there is a possibility of loss of refrigerant by the breaking of the glass, and perhaps some danger should anhydrous ammonia be the refrigerant used. There is little danger, however, as the pressure and temperature is nearly constant and automatic ball stop valves may be used that will shut off the flow should the glass break. It should be distinctly understood, however, that the foregoing refers to new plants and not to old ones. Under no circumstances should air at high pressure be pumped directly into an old system after repairing, or into one that has been standing idle for some time, a as an explosion is likely to occur, due to the vaporization of oil which may have lodged in the coils. The temperature of the air, when pumped into the system at a high pressure, is liable to exceed the flash point of the oil, resulting in an explosion. For the same reason it is also dangerous, especially in the case of small, fast-running machines, to allow too much air to enter when pumping out the compressor in case it becomes necessary to pack the stuffing box; for should the attendant neglect to purge the condenser after the operation, the air in the system will be car- ried along with the ammonia gas, necessitating a higher pressure and a consequent higher temperature than would otherwise be attained; and should the temperature in the system get too great, there is danger of the oil which may be deposited in the coils reaching a point where flash- ing will take place, which will result in an explosion. In small installa- tions usually found in milk plants, cream- eries, and dairies the condensers are of small dimensions; consequently, they can not hold large quantities of excess air. Hence great care should be taken to thoroughly purge the system of air when starting up after pumping out the compressor by blowing the air from the system. Manufacturers provide cocks for this purpose. In cleansing old plants or those that have been shut down for some time from deposits of oil, it is a good plan to pump hot ammonia gas into the system. The gas should be taken from the line just before it enters the condenser. If taken from the top of the con- denser, the gas will probably contain air and other impurities which would be liable to cause an explosion. Referring to the conventional diagram, figure 15, the method of operation should be as follows: Connect a temporary pipe line with valve from the lowest part of the condenser or to the pipe line just before entering the condenser. Close the expansion valve and pump hot ammonia gas into the coils. Have the suction valve opened slightly and occasionally open it wide quickly to allow the oil to be carried out and deposited in the oil trap, from which it can be drawn off. Before starting up the “ean care should be taken to see that all oil cups are filled and the oil ways open, in order that all wearing surfaces may be well lubricated before the machine is started. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. aot SUCTION VALVE EXPANSION VALVE REFRIGERATOR COILS Fig. 15.—Conventional diagram. 88 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. To start.—(1) Turn the water on the condenser and water jacket, and open the discharge valve on the compressor; (2) start the machine slowly at first and after the machine is in motion and the pressures are at proper point open the suction valve on the com- pressor gradually; (3) open the expansion valve sufficiently to give the required back pressure and the machine is in full operation. To stop.—(1) Close the king valve which is between the receiver and the expansion valve and pump the low pressure to zero. This is considered better practice than closing the expansion valve each time the machine is stopped, thereby necessitating readjustment of the expansion valve upon starting up again; (2) open all drips and CONDENSER EX ExPansion valve COOLING WATER INLET = T] GENERATOR. REGENERATOR ABSORBER TIL iM EXABVOST STEMP Coola WATER ¥ PIP ovr.er Fic. 16.—Elementary diagram of absorption system. drains and shut down the machine; (3) close the suction and dis- charge valves, and all oil cups and water valves; (4) clean the ma- chine thoroughly and examine all bolts and nuts to see that they are tight and see that the bearings are properly adjusted. VAPOR ABSORPTION SYSTEM. The absorption and expulsion of ammonia gas by water forms the basic principle of the absorption process of refrigeration. By referring to the elementary diagram, figure 16, the principles of this system of refrigeration will be understood. The generator G is an inclosed vessel which is partly filled with a solution of ammonia gas in water, under high pressure. Heat is applied to the generator, \ \ APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 39 usually by allowing low-pressure steam to flow through coils of pipe located in the generator, as indicated in the diagram, and the ammonia gas is driven off under pressure through the pipe into the condenser (, where it is condensed to a lquid when cooled by the condensing water. The ammonia, now in aliquid state, flows through the expan- sion valve H into the vaporizer V, where it is evaporated, the heat required forits evaporation being absorbed from the brine surrounding the coils. The vaporization of the liquid ammonia is made possible by the low pressure which is maintained in the evaporator due to the rapid absorption of the anhydrous ammonia by the weak aqua ammonia in the absorber. The brine is circulated about the coils of the vaporizer and from thence through the coolers, where it in turn absorbs heat from the goods in storage. The vaporizer coils may, however, be located directly in the compartment whose tem- perature it is desired to lower, in which case it is termed a direct expansion system. From the vaporizer the ammonia, now in the gaseous state, flows through the pipe P into the absorber A, which contains a weak solution of ammonia. The absorption of the ammo- nia gas by the weak solution in the absorber generates heat, which is carried off by the cooling water which is circulated through coils located in the absorber. The strong liquor thus formed in the absorber is delivered to the generator by a pump through the outer space in the regenerator coil R. The weak liquor from the generator is transferred to the absorber through the inner coil of the regenerator; consequently the liquid entering the generator is thus heated while that entering the absorber is cooled. The function of the regenerator is, therefore, to economize heat by transferring the heat from the weak to the strong liquor. The weak liquor coming from the gener- ator, where it has been subjected to heat, goes into the absorber, where it is cooled by means of water circulation. The reverse is true in the case of the strong liquor; that is, the strong liquor comes from the absorber, where it has been cooled by water circulation, and goes into the generator, where it is heated. It is obvious that any heat transferred from the weak to the strong liquor represents just so much gain in economy. As the only power required by the absorption system is that necessary to circulate the various liquids, it is inconsiderable when compared with that required by the compression system. Usually the exhaust steam from the pumps furnishes sufficient heat from the operation of the plant. The amount of cooling water, however, required by this system is greatly in excess of that required by a com- pression plant of the same capacity. In practice, however, the vapor-absorption system of refrigeration is more complicated than shown in the elementary diagram. Figure 40 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. 17 illustrates a general arrangement of a plant of this character with all the necessary accessories. OPERATING ABSORPTION MACHINE. To start.—(1) Start water circulating through machine; (2) start brine pump, making sure that the brine is circulating through cooler; (3) turn steam on gradually (steam should never be shut off entirely) ; (4) open gas line between cooler and absorber; (5) open weak-liquor valve, setting it at the usual running position; (6) start ammonia pump; (7) when generator pressure is about that usually carried, open valve in the dry gas line slowly, allowing the gas to enter the con- denser; (8) open and set expansion valve. To stop.—(1) Close steam valve on generator almost entirely (steam should never be shut off entirely); (2) close expansion valve; (3) shut down ammonia pump; (4) close weak-liquor valve; (5) shut Fic. 17.—General arrangement of absorption refrigerating machine. off cooler and absorber gas line; (6) close valve in dry gas line to con- denser; (7) shut down brine pump; (8) shut off water supply. The foregoing suggestions are of a general nature only and should be considered as such. The purpose for which a plant is used and the character of the trade supplied have considerable bearing on its operation and management; consequently the engineer in charge must determine on the best methods to employ in order to get the best results. Figure 18 is intended to show, diagrammatically, the apparatus which is common to both the compression and absorption systems of refrigeration, As amatter of fact there are a number of accessories required in both systems for their successful operation which are not shown in the elementary diagram, as will be noted by referring to fig- ures 14 and 17, which show the complete equipment of the two systems, APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 41 METHODS OF UTILIZING REFRIGERATION. There are two distinct methods of utilizing refrigeration, namely, the direct expansion system and the brine system. DIRECT-EXPANSION SYSTEM. The coils of pipe in which the refrigerant is evaporated or expanded are placed directly in the room to be cooled; the heat necessary for the evaporation of the liquid refrigerant is, therefore, absorbed directly from the air, or whatever substances surround the tubes. The diagrammatic arrangement in figure 19 shows, in an elementary form, the commercial direct-expansion system. With a system of this kind the work of refrigeration practically ceases as soon as the plant isshut down; consequently it becomes necessary, in Fig. 18.—Diagrammatic arrangement showing equipment common to both the compression and absorption systems of refrigeration. most cases, to run the plant continually or take the risk of losing the goods in storage. For economical operation the suction pressure and evaporating temperature should be as high as possible. The suction pressure is governed by the temperature desired in the refrigerator. In milk plants, creameries, and dairies the suction pressure with an ammonia system should be about 15.67 pounds gage and a consequent gas temperature of 0° F. Take, for example, a creamery cold-storage room 10 by 10 by 10 feet inside dimensions, which is of sufficient capacity to hold a week’s output of butter from a creamery making 2,000 pounds daily. For the sake of simplicity, only the storage of butter is considered. It is assumed that the average outside temperature of the room is 75° F. and the inside temperature is to be maintained at 32° F. while the 492 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. machine is in operation. It is further assumed that the walls, floor, and ceiling are insulated for a heat transmission of 2 B. T. U. in 24 hours per square foot per degree difference of outside and inside temperature of room. The butter will come from the churn at about 58° F. B. T.U. The heat that will come through the insulation is 600 2(75—32)=51,600 The heat to be removed from butter is 2,000X0.5494(58—32)=28,574 80,174 Allowing 25 per cent to cover the additional work required for opening doors, lights, ete., we have a total of, say, 100,000 B. T. U. in 24 hours. Assuming a back pressure of 15.67 pounds, which is equivalent to zero temperature ammonia, and a difference of temperature between ADR) eS TT ET yam OY OI AOA AL LAST RR) Gon Yuals J Gaia Gaenl QO, OY HST TLIC y EXPANSION COILS pera l/ (Gay Ly i (OMEN ENA ABE TRIER AN AUS SAY CPN RAS VC SY TROUGH CONPENSER 4/QU/D FREF RIGERATOR Fig. 19.—Elementary diagram of direct expansion system. the refrigerant inside the piping and the layer of air surrounding the same of 10° F., and that 1 square foot of pipe surface will absorb about 10 B. T. U. per hour for each degree of difference between the inside and outside temperature of the pipe, the number of linear feet of 14-inch direct-expansion piping required for the room, is 100,000 X 2.3 241010 foot of piping. With the direct-expansion system the work of refrigeration practically ceases with the shutting down of the machine. The frost which has collected on the piping itself will tend to keep the room temperature down for a short time, but this is so small that it may be disregarded; consequently, it is necessary to run the direct-expansion plant continuously in order to maintain low temperatures. =96, or 10.4 cubic feet of room space for each linear APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 43 BRINE-CIRCULATING SYSTEM. In this system the coils of pipe in which the refrigerant is expanded are located in a tank or specially designed brine cooler containing a solution of common salt, or calcium chlorid, of sufficient density to insure a low freezing pomt. After the brine has been reduced to a low temperature by the transfer of its heat to the expanding refriger- ant, itis pumped through coils of pipe located in the room to be cooled, absorbing from the atmosphere a good part of its heat. It is then returned to the brine tank, or brine cooler, where it is recooled and again circulated through the rooms. While the direct-expansion system is simple to operate, less expen- sive to install, and more efficient from the standpoint of heat transfer, nevertheless in the operation of small plants, applicable to the dairy industry where the plant proper is operated perhaps six or eight hours per day, it is more economical to install a brine system, in order Bow PRESSURE $1/aN PRESSURE GAUGE AORUGE SS bat ka iA PrN OR DENS TEA SS BRINE CONS QM YAAAG A tf i) y fl Be ones | SS PRN te } & CONGCENSER IRSSTixxvxxn WW BS REFRIGERATOR NS Fig. 20.—Elementary diagram of brine circulating system. that some work of refrigeration may go on after the plant is shut down for the day, or in case of accident to the machinery. It is only necessary in the brine-cireculating system to operate the brine pump for forcing the brine through the coils. The principles of this system are illustrated in figure 20. In addition to the usual members shown in the direct-expansion system, this system employs a brine tank, a series of brine coils, and a brine pump for circulating the brine through the cous. The cooling effect of. the evaporating refrigerant is expended in the brine in this case, instead of directly in the cooling room, as indicated in the direct-expansion system, and the brine is circulated by the pump through the brine coils located in the cooling room. It should be borne in mind, however, that there is a double transfer of heat which cuts down the efficiency of the system to a certain extent, namely, from the air in the cooling room to the brine and from the brine to the expansion coils. The initial 44 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE. cost of installing the brine-circulating system is more than that of - the direct expansion, as it includes, in addition to the members of the direct-expansion system, a brine tank, brine coils, and a brine pump. The power necessary to operate the brine pump must also be con- sidered. The excess power required for the operation of the brine- circulating system over that of the direct expansion of the same capacity is that necessary for pumping the brine from the tank through the cooling coils back to the tank; that required to overcome the friction of the brine in the pipes in traversing the above cycle; the additional refrigeration necessary to make up for the heating effect produced mechanically by circulating the brine, and the heat absorbed through the brine tank and through the brine piping; that required to make up for the reduced efficiency by having to operate the plant at a back pressure sufficiently low to obtain a correspond- ingly low temperature in the evaporator coils to compensate for the second heat transfer encountered between the air in the cold-storage room and the refrigerant. The average difference in temperature between the circulating brine inside the piping and the surrounding air is, of course, much less than is the case when the refrigerant is expanded directly in the piping located in the cooling room, assuming the back pressure on the machine is the same in both cases. The difference in temperature between the refrigerant and brine depends on the insulation of the brine tank, piping outside of the rooms, etc., and as this varies between wide limits it is impracticable to calculate the amount of brine piping very closely on the basis of heat transfer, as was done in the case of direct expansion; consequently it is the common practice to install from one-half to twice as much brine piping in the brine- circulating system as would be used if direct expansion were employed. This allowance, however, is very liberal and is made to cover unfavor- able cases where the insulation is poor; and further, any surplus pip- ing serves to increase the efficiency of the plant. Allowing 50 per cent more brine than direct expansion piping we have 96 X1.50=144 linear feet of 14-inch piping required to do the same work as the direct expansion, or 7 cubic feet of storage space per linear foot of pipe. This amount of piping, when filled with brine, will contain 1.5 cubic feet. During the night the average difference in temperature between the inside and outside air will be about 43° F., therefore the heat that will come through the 600 square feet of surface of the room during 16 hours’ shut-down COO KEKE XT 84,400 B. T. U. If the initial temperature of the brine during the shut-down period is 16° while the final is 32°, giving a rise of 16 degrees, the heat that will be absorbed by the 1.5 cubic feet of brine contained period will be APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 45 in the piping will be 1.5 x52x16=1,248 B.T. U. Consequently the hold-over period due to the brine in the piping is “7571 0.58 d hour. If there are 2,000 pounds of butter stored in the room, it will also assist in increasing the time of shut down for a 3-degree rise in room and contents. The rise in temperature of the butter for a 34,400 2,000 x 0.5494 degrees in 1.53 hours. Therefore, the total time the plant can be shut down for a 3-degree rise in temperature of room and contents is 0.58+1.53=2.1 hours. Consequently it becomes necessary with this system to circulate the brine continuously. If, however, a sufficient volume of low-temperature brine is available for circulating through the coils, the refrigerating machine may be shut down for 16-hour shut down will be =31.3 degrees, or 3 tow PRESSURE Hii Mert PRES TOne anu Se os t WERK Et) SSS I NPR CnC RET Pe Peat SS SS NS iti: OEY, LLL eh re tiie LLL Fic. 21.—Elementary diagram of brine storage system. a time, depending on the volume and temperature of the brine, by continuing the action of the pump. BRINE-STORAGE SYSTEM. In place of the continuous brine coils employed in the brine-circu- lating system there is a modified brine system designed to give practically the same results (fig. 21). This is known as the brine- storage system and consists in replacing the main tank by several smaller ones located in the various compartments of the cold-storage plant. With an equipment of this kind the initial cost of the brine pump, the main brine tank, the necessary piping for brine circulation, and the brine-tank insulation are eliminated, as well as the power to operate the brine pump and the radiation losses through the brine tank and pipe insulation. The heat-absorbing surfaces of the various small tanks entirely replace those of the brine coils. In practice, however, from one third to two-thirds of the direct expansion coils are placed outside of the brine, in direct contact with the air in the cold-storage room, in 46 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. order that the room may be cooled more quickly when the plant is started after being shut down for several hours, the remaining one-third or two-thirds, as the case may be, being submerged in the solution of brine. Allowing a 3° rise in temperature of the air inside the room (32° to 35°) and a rise of calcium chlorid brine of 16° (6° to 22°), and as a cubic foot of brine will absorb about 52 B. T. U. per degree rise in temperature, the heat absorbed by the brine per cubic foot will be 52 (22-6) =832 B. T. U. The volume of brine necessary to hold over temperature under the foregoing conditions will then be 34,400 832 feet of room space. In other words, the heat that will be absorbed by the 41.3 cubic feet of brine for a 16-degree rise will be 41.3 x 52 x 16=34,362 B.T.U. Therefore, the hold-over period due to the brine 34,362 X16 34,400 hold the temperature for 2.1 hours for a 3-degree rise in the room temperature. Consequently the total hold-over period due to both the brine and the butter will be 16+2.1=18.1 hours, or for a 16-hour shutdown the rise in room temperature will be 2.6°. During the hold-over period the average temperature difference between the air.and the brine is about 19° F., and with a coefficient of heat trans- mission through the walls of the brine tanks of 1.5 B. T. U. per square foot per hour per degree difference in temperature of the brine and air, the effective square-foot surface of the tanks should not 34,400 160,198 157), wide, and 24 feet deep. One linear foot of 14-inch pipe when submerged in still brine will absorb about 4 B. T. U. per hour per degree difference in temperature between the inside and outside of pipe, and as this difference is about 13.5°, the amount of 14-inch submerged piping required is 51,600 8X13.5 x4 This method, however, is only a compromise between the brine- circulating and the direct-expansion systems, but has been found satisfactory and compares very favorably with the brine-circulating system of the same capacity. When used for holding over tempera- tures when the plant is shut down, either in case of breakdown of machinery or to avoid keeping an experienced attendant on duty continuously, the tank system for small plants possesses advantages over either the direct-expansion or brine-circulating systems. =41.3 cubic feet, or 1 cubic foot of brine for each 24.2 cubic is =16 hours. The 2,000 pounds of butter in storage will be less than 75; say two tanks 8 feet long, 1 foot =117 linear feet, or 58.5 feet per tank. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 47 CONGEALING-TANK SYSTEM. There is in use a modification of the brine-storage system known commercially as the ‘‘congealing-tank system.” The principal advantage of this system is that by using a weak solution of brine a greater amount of refrigeration per cubic foot of brine is obtained by freezing a portion of the brine on the direct-expansion coils. This method, however, is not so efficient as the brine-storage system, due to the fact that the ice formed around the coils acts as an insula- tion. But the advantage gained in being able to store a greater amount of refrigeration in a small space often makes it advisable to install this system. In the operation of the congealing-tank system care should be taken not to let the volume of brine in the tanks freeze solid, for during the hold-over period some of the brine ice will melt, leaving a space between the ice and the sides and bottom of the tanks, and when starting up the refrigerating machine the smaller space between the ice and sides of the tanks will freeze first; con- _sequently when the larger volume of brine at the bottom freezes the sides of the tank will be bulged out, due to the expansive force of the freezing brine. Therefore, ample space between the coils and sides of the tanks should be provided in order to allow the requisite amount ‘of brine ice to form around the pipe coils at a safe distance from the sides. When a part of the brine solution is to be frozen, the volume of brine required is necessarily less than that required for a brine- storage tank system of the same capacity. In practice about one- half the volume of the brine storage is allowed for the congealing- tank system. Therefore the case under consideration will require two tanks 8 feet long, 24 feet deep, and 6 inches wide. The effective surface of the two tanks is 93 square feet. The heat absorbed by each square foot of surface per hour during shutdown period is eam B. T. U. Taking the coefficient of heat transmission in B. T. U. per degree difference in temperature as 1.5 per square foot per hour, the temperature difference necessary between the brine and Shona i ar 1s 7 = fied Aig With a 15 per cent solution, by weight, of common salt the freezing point is 12.2° F. Then the temperature of brine at the time the plant is shut down will be 12.2°, and at the time of starting up 27.6°. One cubic foot of the brine will absorb 59.2 B. T. U. per degree rise in temperature, and for a 15.4° rise 59.2 *15.4=911 B. T. U. The vol- ume of the two tanks is 20 cubic feet, consequently the heat absorbed by the brine will be 911 x20=18,220 B. T. U., leaving 34,400— 18,220=16,180 B. T. U., to be absorbed by brine ice. Taking the latent heat of the brine ice as 122, the amount of brine to be frozen on the coils will be ee aa 132 pounds. With 117 feet of submerged 48 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. 14-inch pipe, this is equivalent to a uniform coating of ice 2% inch thick. In raising the temperature of 1 pound of a 15 per cent solution of common salt from the freezing temperature of 12.2° to 27.6°, 13 B. T. U. are required. For the same range in temperature of 1 pound of brine ice, approximately 135 B. T. U. are required. In other words, under the above conditions there is about 10 times more re- frigeration available in the 1 pound of brine ice than there is in the 1 pound of brine. Consequently, by freezing a portion of the brine on the coils the hold-over period can be greatly increased. AIR-CIRCULATING SYSTEM. There is a further modification of both the direct-expansion and brine-circulating systems, known as the indirect air-circulating sys- tem. This system is seldom used, except in connection with ice- cream hardening, where low temperatures must be obtained in a short time. It requires, in addition to the necessary members of the di- rect-expansion or brine systems, a fan, located in the cooling room over the coil bunkers and driven fe without the room. The air is simply the circulating medium for producing the desired refrigera- tion and is forced by the fan over the cooling coils and down into the room below, where it comes in contact with and absorbs heat from the goods in storage. This results in a pure dry atmosphere, as the moisture content of the air is deposited on the surface of the coils in the form of ice and the greater portion of the microorganisms which were originally contained in the air are inclosed and rendered innoc- uous. If the initial and final temperatures of the air, together with the corresponding moisture contents, are known, the refrigeration re- quired for the simultaneous cooling and drying of the air can be ascer- tained. To cool the air alone necessitates the withdrawal, for every pound of air, of a number of B. T. U. equal to the product of the difference of temperature and the specific heat of ai at constant pressure. As it is common practice to measure air by volume, it is most con- venient to express its specific heat in a unit of volume instead of weight. Since, however, the density of air varies with its tempera- ture, it is impossible to obtain a value that will apply other than ap- proximately to more than one condition. Taking, for example, air under standard conditions, density at 70° F., and a relative humidity of 70 per cent, a cubic foot weighs 0.07465 nous and its specific heat is 0.0177. If the initial temperature of the air in the room is 70° F. and it is cooled to, say, 20° F., the refrigeration to cool 1,000 cubic feet of air, neglecting the moisture, is 1,000 x 0.0177 (70—20) =885 B. T. U. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 49 Considering the moisture in the air, the moisture content at 70° F. and 70 per cent relative humidity would be 5.596 grains per cubic foot, and at 20° F. for saturation there would be 1.235 grains. There- fore, there is eliminated per cubic foot 5.596 — 1.235 =4.361 grains, or for the 1,000 cubic feet, 1,000 x 4.361 =4,361 grains or 0.623 pound. Consequently the refrigeration required is: B.T.U. Waren heater liquetaction, 0.623 X970.4.... 282. -->-.----2-.-55--22---2- 22 605 Soommeninant. 70°%to 32° F., 0.623 (70— 32) 0% ee take S20 PL 24 Pine meen OCA Arte) 0h Life ties. oes See oe cee). ey ek 90 Sopolnemee irom:32” to 20° H.,.0.623X0.5(82 520). Jose 22 25 - docibae eet nae ede 4 723 The total heat, therefore, that must be removed in cooling the 1,000 cubic feet of air under the above conditions is 885 +723 =1,608 B.T.U. In the case of cold storage the total amount of refrigeration required for air cooling depends, of course, on the number of times the air in the room is renewed in a given time. With the indirect-air system usually employed in the dairy industry the same air is kept in circulation to a great extent. In all cold-storage work the air in the rooms must, of course, be cooled, but as the refrigeration required is generally swell compared with that necessary for cooling the goods and in taking care of the heat that comes through the walls, floors, and ceiling, it is usually ignored and a liberal allowance made to cover this as well as lighting, presence of workman, poor workmanship, and other factors. INSULATION. The word “insulate” is derived from the Latin word “insula,” meaning “‘island.’”’ Therefore the significance of the definition of insulate is: To place alone or in a detached situation; separated by a nonconductor from other conducting bodies; having no communi- cation with surrounding objects. Hence insulation in a cold-storage room is applied on the interior surface of the outside walls, under the roof, and under the lowest floor, to prevent, as far as possible, the transfer of heat from exterior heat-conducting bodies like the air and the ground. With the increased application of refrigeration the problem of properly insulating the walls, floors, and ceilings of the cold-storage rooms is of the greatest importance and should be considered in the light of a permanent investment along with the building and equip- ment, the returns on which should be based on the saving effected by the lower operating cost. It is evident that after the goods 1 in storage have once been cooled to the desired temperature, it is then merely a question of supplying 40083°—Bull. 98—14—_4 Pat | 50 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE. sufficient refrigeration to take care of the heat which finds its way through the insulation of the walls, floors, and ceilings of the cold- storage rooms. The greater the efficiency of the insulation the less heat will get through from without. There is a limit, however, to the amount of insulation that should be installed, which is the point where the interest on the money invested in insulation, the repairs and depreciation on same, balances the saving in operating expenses. There is no material known that will entirely prevent the passage of heat. However, there are some which offer a very high resistance, and are therefore termed nonconductors or insulators. The best heat insulators appear to be those that contain the greatest amount of entrapped air confined in the smallest possible air space. The function of cold-storage insulation, then, is to prevent the outside heat from passing through the walls, floors, and ceiling into the interior of the cold room. Therefore the problem is to minimize the passage of heat by interposing in the walls, floors, and ceiling a material or construction which will resist the transfer of heat from the outer to the inner side of the room. The materialsmost commonly used for this purpose are the different varieties of cork products, mineral wool, hair felt, rock wool, vegetable fiber, sawdust, mill shavings, etc., used in combination with wood, cement, masonry, and air spaces. At one time it was common practice in the construction of buildings for cold-storage purposes to provide a series of air spaces in the walls, some of which were as much as 12 inches wide, the supposition being that they were dead-air spaces. As a matter of fact they were not. As the air in contact with the warmer surface became heated it rose, while that in contact with the cooler surface fell, thus producing a circulation tending to equalize the temperature of the sides of the airspace. Dead air, however, is a good nonconduc- tor, but unless the air spaces are properly proportioned, the above- mentioned air currents will be set up. Therefore, it is the present practice to fillin the spaces with some porous substance to break up the space into an indefinite number of small dead-air spaces which will effectually prevent circulation of the entrapped air. On the other hand, there is danger of packing the insulating material too closely, which will result in favoring the conduction of heat through the walls. Sawdust and mill shavings are mentioned in the above partial list of insulating materials, but they are not to be considered among the best. They can be had in any part of the country, and often without cost, and if kept dry are good insulators. Itis a very difficult problem, however, to keep them dry, and when used, great care should be exercised in the construction and vO of the walls in order to keep out the moisture. j APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 51 Planing-mill shavings are better for insulating purposes than sawdust. They are elastic, do not settle rapidly, and will not absorb moisture as readily as sawdust, and, most important, can usually be had in very dry condition. They should be odorless, free from dirt, bark, and chips, and should be well packed into place to prevent future settling. About 9 pounds per cubic foot is considered the proper density to which they should be packed. Sawdust has in the past been used to a great extent in rural dis- tricts for insulating the walls of small cold-storage buildings, due to the fact that it is available in most country districts, and generally may be had without cost. It is not a satisfactory material, however, for insulating purposes, as itis always more orlessdamp. The damp- ness not only destroys its insulating value, but it favors the growth of molds and bacteria, first in the sawdust itself and then in the walls of the building. The rotting and the consequent heating causes the sawdust to settle and leaves open spaces, which further weaken the insulation. It also furnishes an ideal nesting place for rats and mice, and the tendency of these rodents to carry matches into their nests and to start fires is well known. When sawdust or mill shavings are to be used they should be thoroughly drted before being put into the walls. Furthermore, if air is allowed to circulate in the shavings or sawdust moisture will be deposited in warm weather, and then, again, in cold weather it will dry out. This being repeated for several years will cause the boarding and shavings to rot. If, however, the shavings or sawdust is surrounded by waterproof paper and boarded, the con- densation will not occur and deterioration will be prevented. In deciding upon an insulating material for cold-storage purposes the following points should be carefully considered: Efficiency as a heat insulator; whether or not it will retain its efficiency indefi- nitely; structural strength; the effect of moisture; uniformity of insu- lating value; whether fireproof or not; space occupied; first cost; cost of installing, etc. The greater portion of the refrigeration required for cooling cold- storage rooms is done to remove the heat that leaks through the walls, floors, and ceilings, and only a small part is required to cool the goods in storage. As previously stated, it is necessary to pump out, so to speak, the heat that enters from the outside after the goods are once cooled to the desired temperature. Take for example a creamery cold-storage room 10 by 10 by 10 feet, inside dimensions, which is of sufficient capacity to hold a week’s output of butter from a creamery making 2,000 pounds daily. The butter will come from the churn at approximately 58° F. The average outside temperature of room is assumed to be 75° F., and the inside temperature 32° F. It is further assumed that the walls, floors, and ceiling are insulated for a heat transmission of 3 B. T. U. 52 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. in 24 hours per square foot per degree difference of outside and inside temperatures of the room. The total surface of the room is 600 square feet. Then; Bo eae), The heat that will leak through mto the room in 24 hours is 6003 (75-32)... 77,400 The heat to be removed from the butter is 2,000 0.5494 1 (58-32). ......... 28, 574 Total heat that will have to be removed................---------0-- 105, 974 From the above figures it will be noted that practically three- fourths of the refrigeration required in the average cooling room is done to remove the heat that leaks in through the insulation. Hence the necessity for good insulation. It would seem from the foregoing that the more insulation put into the walls, floor, and ceiling the better, which is true when viewed from the standpoint of the refrigerating machine, as the more and better insulation used the less work the machine will have to do. But as insulation is expensive, a point is soon reached where the interest on the money invested, repairs, and depreciation on the insu- lating material balances the saving in reduced machine capacity and operating expenses. By installing more and better insulation, the saving in the capacity of the refrigerating machine is an item of considerable importance and one that has not been given the atten- tion that it justifies. From the data at hand, it appears that the most economical point to insulate for is a transmission in 24 hours of 2 B. T. U. per square foot per degree difference of outside and inside temperature of room, when the average outside temperature is 70° F. and the inside tem- perature of the room is 32° F. With an average outside temperature of 70° F. and an inside temperature of 0° F., the economical point is about14B.T.U. In view of the fact that dairy products are extremely perishable when held at a temperature of 60° F. or above, the added security which the lowest heat transmission affords in order to hold over temperatures in case of the machinery breaking down, or where the plant is operated during the day only, makes the increased invest- ment in insulation desirable. Good insulation not only permits operating the plant with the least refrigeration, power, time, and cost, but also helps to reduce fluctuations in room temperature. After shutting down the refrigerating plant the inflow of heat con- tinues, but at a constantly decreasing rate. With a properly insu- lated room it will be several days before the inner air temperature will be near that of the outside temperature. As an example of the saving effected by good insulation, take two cold-storage rooms of the same size and construction, say 10 by 10 by 10 feet. The walls are assumed to be built of brick 13 inches 10. 5494 specific heat of butter. : APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 53 thick, the floors and ceiling of concrete slabs 5 inches thick, the floors resting directly on the ground in both cases. The inside temperature of the two rooms is held at 30° F. by refrigeration and the average outside temperature is assumed to be 70° F. for 90 days. Suppose one building is not insulated at all and the other is insulated for a heat transmission of 2 B. T. U. per square foot of surface per 24 hours for each degree difference between inside and outside temperature. The heat transmission through the 13-inch insulated brick walls is taken as 11.3 B. T. U. per square foot per degree difference of inside and outside temperature in 24 hours, and that for the 5-inch con- crete slabs forming the floor and ceiling 28.8 B.T. U. In view of the earth offering a certain amount of protection to the floor slabs, which were assumed to rest on the ground in both cases, only half of the temperature difference between the outside and inside air is taken in computing the heat transfer through the floor in the uninsulated room. Then, for the uninsulated room the transmission will be: B.T.U. Brtclewalis, 4005113 (70230) 90520 2). eae es eee Se! 16, 272, 000 elmney O0>< 28:87 (702380) X908 et os. ok AL dete dt Eee 10, 368, 000 RaOTABIO> 28-5) (O00 D905 a. teh oie es RL Si ali 5, 184, 000 Total heat transmitted through the walls, floor, and ceiling........ 31, 824, 000 This is equivalent to 10.5 tons. Therefore there will be 110.5 tons refrigeration required to remove the heat which comes through the walls, floor, and ceiling, and assum- ing that it cost $1 per ton to produce the refrigeration, it will amount to, in 90 days, 110.5 x 1=$110.50. Now, in the case of the insulated building we have: Erick wells e4005<2 (10030) 908 ol he 2, 880, 000 Geilnne met GOOS » BACARO mB WRPAPER : S"SHEET GORA thet NAPAPER %, Boarg 10 Z Boarvs W.RPAPER 4GRAnuLATED CoRK, 1.70 % 80aros WPPAPER 58 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE, supply curve is based on the monthly percentage of the average supply. The temperature curve is the average of the mean 24-hour temperatures. Referring to the curve showing the variation in the supply of milk from month to month, it will be noted that there is practically a fixed relation between the temperature of the air and the supply of milk. The average of the milk supply, which is taken as 100 per cent, is available durmg April and September, while the maximum occurs during June. The highest summer temperature occurs the latter part of July and the first of August, and the maxi- mum amount of work to be done by the refrigerating plant is durmg July. Therefore the condi- }azs tions existing at this time should be taken as a basis for determining the size of the re- 225 irigerating plant required. If the capacity of the refrigerat- an ing plant is sufficient to han- dle the maximum load run- ais ning eight hours a day, it will handle the average load run- azs ning four hours a day. The time of running the machine will decrease from a maximum of eight hours during July until it can be shut down entirely in the Northern States during December, January, and Feb- ruary. In the South it will aoa be necessary to operate the Y S2oancsemrrans|., refrigerating plant to some extent during the entire year. The curve marked ‘‘compres- Fic. 25.—B. T. U. transmitted per square foot per 24 sor curve 7 shows the approx- hours per degree difference in temperature. imate daily hours the compres- sor will have to be operated to produce sufficient refrigeration to take care of the milk during the different months of the year. This curve, however, is based on the milk supply and weather conditions existing in the Northern States, where the dairying industry is prin- cipally located at the present time. In the Southern States the daily hours of operation will have to be increased. However, the flush period is not so marked as in the North, as the seasons are longer ; consequently the refrigerating load is more uniform and the peak load is not so great. A simple and fairly accurate estimate on the size of refrigerating machine required to do the work of a given amount of ice may be made as follows: %: BOARD, 0.« mt, % BOARDS, Bem WPPAPER WP PAPER Y S0ARDS, Drm. SS SS eS eS, 2’ ae a ad a le WPPAPER a ZSOaRPS, Dem. ital PPAPER “AIR SPACE. Ww PPAPER % BOARDS, D.t/4. YZ BOARDS, D.+re r HPPAPER a a5 AIR SPACES _— SS o SS eee eC SOARDS, DM. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 59 Suppose the ice required to cool a certain size box during the hot- test weather is 500 pounds per 24 hours. The refrigeration accom- plished by this amount of ice melting is 500 Xx 144=72,000 B. T. U. Assuming that the conditions existing in operation of the ma- chine eight hours per day, then the capacity of the ma- chine must be suffi- cient to extract 72,000 B. T. U. in eight. hours, or in one-third of the time that it takes to melt the ice. Therefore the capac- ity of the refriger- ating machine must 72,000 3 be 388,000 = (1.75 ton. Usually lower temperatures than can be maintained by the use of ice are desired, consequent- ly a 1-ton machine, although slightly larger than the re- quirements, should be installed. the plant will justify the ZB BOARD Dyn. WPPAPER 2'MPS.CORK 420 VAIR SPACE % BOARDS, DAE WRPAPER Ya BOARDS, D. vi. a WPPAPER ZA MAS CORK tpeany 2 NPS.CORK AIR SPACE 78 S0ARDS, BrP + MePAPER 170 Reo See, % BOARD 2YMtWA PAPER jz) ZNV.PS.CORK VAIR.SPACE 7g 8O0ARPS, D.YM1.tW.PPAPER 210 p 7g BOARDS, 2414, CWEPAPER R.20 4°7INERAL Wook 8370 Goa Fr —————— LS0ARDS, BYMTW.PPAPER. ° % BOARDS, BR tlt YAPPAPER LZ GRANULATED CORK ahr Cue. Fr; 3g BOARDS, 2-411 tWPPAPER " = 7a e0arvs,2 VV WPPAPER LAIR SPACE Vg BOAROS, D+I.+ WP PAPER $"GRANULATED CORK Lis 4 o 7p BOARDS,D.tM.tW.PPAPER 2°AIR SPACE 7g BOARDS, D.tM, tW.PRPAPER A FNPS.CORK = MAIR SPACE Jy BOARD. D.1P7, tW.P PAPER 170 —S- 7% BOARDS. O.4/.+WP PAPER Fic. 26.—B. T. U. transmitted per square foot per 24 hours per degree difference in temperature. In figure 29 (p. 62) are given the maximum and average tempera- tures for the different States. APPROXIMATE COST OF PRODUCING MECHANICAL REFRIGERATION IN SMALL PLANTS. The cost of producing a ton of refrigeration mechanically depends upon so many variables, especially in small plants, that it is impos- sible to give more than approximate costs. The average plant used in creameries and diaries is operated about eight hours daily during the summer months when the work required of the refrigeration machineryisatitsmaximum. ‘Then the total time of operation dimin- ishes until the machine is shut down entirely or run very little during the winter months. 60 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE, In most small creameries the engine is ordinarily run for only two or three hours while the churning, working the butter, and pasteuriz- ing is being done. The balance of the day the fire in the boiler is banked and only 10 to 15 pounds’ pressure is kept on the boiler. If, in order to operate a refrigerating plant, it is necessary to keep a greater pressure on the boiler and to operate an- engine which is a great deal larger than is required for the compressor, the cost per ton of refrigeration will, of course, be greatly in excess of what it would 0.70 SSCRATCHED HOLLOW THe FMINER AL WOOL SSSCRATCHED HOLLOW TILE. BS CEMENT PLASTER WALL CONSTRUCTION FIREPROOF CONCRETE FLOOR BS Booxrine 6 ofr CInDERS s1arstss SARA, y 4h Ny DOUBLESPACE HOLLOWY - TILE ARCHES CEMENT PLASTER 174 = lAIR sPAC — UBoancs DaeWRPArER 4° MINERAL Woot 17 BIR-SPAC Za Soaapso4m. +tMPPAPER 13, ‘PLANK FLOORING = B BOARD tW#LRPAPAR Ni =P" MIERAL WOOL 4 z AL Te TW.RPAPER L972 12° CINDERS FLOOR CONSTRUCTION. Fic. 27.—B. T. U. transmitted per square foot per 24 hours per degree difference in temperature. be if the engine was of suit- able size for operating the compressor only. Again, the refrigerating machines are often operated intermit- tently, thereby increasing the cost per ton of refriger- ation above what it would be if run continuously. In view of the above, it is im- practical to arrive very closely at the actual cost per ton of refrigeration when the compressor is operated by a steam engine which is also used for driving other machinery. The curves in figure 30 (p.63), showing the approx- imate cost of producing re- frigeration in creameries with belted, steam-driven equip ment, has been aver- aged from reports on a.large number of creameries, and in view of the fact that the engines were used for pur- poses other than driving the refrigerating machines, it should be borne in mind that the results are only approximate and should not be considered as positive. The cooling water supplied to the condenser and the wages of an attendant have not been taken into consideration in averaging the cost of producing the refrigeration. The water in most cases costs little or nothing, and it can be used for feeding the boiler, wash- ing utensils, and for other purposes after it has passed through the condenser, as it is only raised a few degrees in temperature. In op- erating small-machines of the size commonly used in milk plants, a | APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 61 creameries, and dairies, it is unnecessary to employ a regular attend- ant, as some persons regularly employed in other work on the premises can find time to start and stop the machine and to keep it oiled. The curve marked ‘‘Total cost per ton of refrigeration” has been calculated from the estimated cost of the plant, repairs, depreciation, and miscellaneous items, such as oil, waste, packing, ete. The in- terest on the money invested is figured at 6 per cent and the repairs and depreciation at 10 per cent. While the above curves representing the cost of producing refrig- eration in the smaller-sized creameries are believed to represent a fair average, it is lso believed that th anes ea hie oe ally | fifo) lessenedifmoreatten- a0" v4 Ee aea cea ke tion is paid to the aR ae anne fe Cie |e SS ee economic operation of the compressor. In a great many in- 6s" ae stances the engine drove long lines of shafting that were not in the best of condi- tion and a number of idle pulleys in addi- tion to the refrigera- ting machine. In many instances — where electricity is available motors may be installed at anad- ae ad vantage for operating wv a 8 CoE a aunea 2/ AOS 4 & un ~ HOURS NECESSARY TO OPERATE COMPRESSOR. MEAN TEMPERATURE OF AIR. 8, PER CENT VARIATION IN MILK SUPPLY 7) Cy the refrigerating ma- chine as well as other apparatus. Motors of MONTHS Fig. 28.—Curves showing the relation between the milk supply and the temperature of the air, averaged from the most important dairying States, and the hours necessary to operate the com- pressor based on the maximum amount of work being done in comparatively slow- eight hours. speed type can be readily connected by belt to the compressor. With the present price of electric power the cost of operating small units with electricity is slightly greater than when operated by steam power, provided the steam plant is run at or about normal load. But when the engine and boiler are operated at only a fraction of their capacity they become very inefficient and the cost of power is greatly increased. In view of the fact that with electricity the consumption of power starts and stops with the opening and closing of the switch it is often more economical to install electric motors for operating small refrig- 62 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. erating machines, even though the creamery is already equipped with a steam engine. This will depend, however, on the arrange- ment and efficiency of the steam plant and on the cost of electric power and must be determined in each individual case by those on the premises. The cost of power per ton of refrigeration as averaged from steam-driven plants in operation will compare with Bao drive at about 3 cents per kilowatt-hour. There are other advantages in employing electric drive over steam, the value of which can not be estimated in dollars and cents, viz, cleanliness, less space required, and that the power required can be determined accurately at any time. “32-2 MIss.! rare . Fic. 29.—Maximum and average summer temperatures in different States. Cleanliness in milk plants, creameries, and dairies is of special advantage, and with electrical drive practically all the dirt arising from smoke, coal dust, and ashes is eliminated. It is possible to install electric motors in out-of-the-way places where engines could not be located. This feature makes it practical to locate the refrigerating machine close to the cooling rooms, thereby eliminating long leads of refrigerating piping located outside the rooms to be cooled. The fact that the power required to operate the compressor can be determined accurately at any time is of great importance. This feature, however, may not seem of very great value at first thought, but it has been proved in many instances to produce higher economy. That the cost of production can be determined accurately is due to the fact that the cost of power is given in each monthly bill or, for that matter, can be calculated each day from the meter readings. With exact figures at his command the operator is able to detect d APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 63 leaks occurring in production due either to careless operation or to deterioration of the apparatus and is able to judge of the exact value of every movement in the process. REQUIREMENTS OF REFRIGERATING PLANTS FOR DAIRY PURPOSES. A refrigerating plant suitable for use in milk plants, creameries, and dairies should comply with the following requirements: (1) It should be reasonable in cost. (2) Economical to operate. (3) Reasonably sure against breakdown. (4) Should produce cool and dry air in storage room. (5) Should produce lower temperatures than ice. A00; & 3 nN) BBGSniseEnoe Pee eae fel ile ce bed be a i = S 8 AHH se COST PER TON OF FEFRIGERATION = S | ars (aa FRA va cc Loe One REFRIC. ae” 8 Fig. 30.—Approximate cost of producing refrigeration in the average creamery with belt-driven compressors. (6) Should give perfect control of temperatures. (7) Should be simple in construction and operation as to require little attention and be successfully operated by any careful person without any special mechanical or engineering skill. (8) Should occupy little space. The initial cost of a refrigerating plant should of course be as ‘small as possible consistent with high-grade apparatus. It is believed that no class of machinery depends more for satisfactory and economical operation on the original design, material of con- struction, and workmanship than refrigerating machinery. An inferior grade of refrigerating apparatus is an expensive investment at any price and should never be installed. With high-grade machin- — 64 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. ery and properly arranged and proportioned accessories the cost of repairs and operation is reduced to a minimum. In the summer months the refrigerating plant is often required to operate continuously in order to handle the increased amount of milk during the flush season, and, furthermore, there is a greater amount of refrigeration required on account of the higher summer temperature. A breakdown at this time would result in the prob- able loss of the stored products; besides, the daily supply of milk and cream which arrives in the plant at a temperature that will cause the rapid development of bacteria if held even for a short period. During the summer months the temperature of the con- densing water will be higher, and consequently a greater quantity will be required for satisfactory operation. With properly proportioned pipe coils, brine tanks or congealing tanks, and good air circulation within the cold-storage room, cool and dry air will be obtained and a lower temperature and purer atmos- phere than is possible with ice. The temperature obtained in the average refrigerator cooled with ice is seldom below 45° or 40° F., and the air always contains more moisture than it should for the best results. When employing a properly designed mechanical refrigerating plant the temperatures are under perfect control of the operator, regardless of weather conditions; consequently the result is a higher grade and more uniform product. It is absolutely necessary in manufacturing the highest grade dairy products to be able to control the temperatures at will. As the refrigerating plant is generally operated by persons unskilled in the management of machinery of this type, it should be as simple as possible in its construction and operation, especially in the smaller plants. In the larger plants, however, where an experienced attend- ant is employed, the equipment may be more elaborate. The appa- ratus should be designed to occupy as small a space as possible con- sistent with strength and efficiency, and as it is to be operated by unskilled persons, nothing but the very best material and workman- ship should be used in its construction. In order to keep the size of the refrigerating plant as small as pos- sible, it is advisable to provide storage tanks of ample capacity. The brine should be cooled and a large quantity held for quick action when needed, as when a supply of warm milk is received into the plant and it is necessary that it should be cooled in the shortest possible time. And, further, the cold brine in the storage room can be depended upon to hold the temperatures in case of a temporary shutdown of the refrigerating machine. In view of the fact that the quantity of milk or cream is liable to vary greatly from day to day, depending upon the supply from the APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 65 farms and upon the amount sold, it is necessary to have a consider- able margin of safety in the capacity of the brine-storage tank. The application of refrigeration for dairy purposes depends upon so many variables that it is practically impossible to treat the sub- ject other than in a very general way. Each particular case demands special study in order to obtain the best results, as there are many methods of application according to the character of the business and its particular phases. Generally speaking, however, the brine- storage or congealing-tank system seems to be the one best adapted for most plants, but the medium surrounding the evaporating coils may be either a brine solution of sufficient strength not to freeze at the ordinary working temperature, or it may be confined air, or it may be milk brought in direct contact with the cooling surface of pipes in which the refrigerant is evaporated. In many instances it may be advisable to employ a combination of the different methods in order to obtain the most satisfactory and efficient arrangement. As there are many methods of application of refrigeration to milk and milk products, we will endeavor to differentiate as far as prac- ticable between the various applications and discuss in a general way what seems to be the one best suited for the purpose, and for this reason the following classifications are made: (1) Cooling milk on the farm. (2) Maintaining temperatures during transportation. (3) Receiving stations. (4) Cooling milk in bottling plants: (a) pasteurizing plants; (0) raw-milk plants. (5) Refrigeration in creameries, general. (6) Local creameries. (7) Centralized creameries. (8) Auxiliary creameries. (9) Cream-buying stations. (10) Market cream plants. COOLING MILK ON THE FARM. As the influence of both time and temperature combine to hasten the development of bacteria in milk, it is obvious that it should be cooled just as soon as possible after being drawn from the cow. As has been previously pointed out, the cooling of fresh milk retards the development of the bacteria, which produces fermentation in milk, thereby in turn destroying the milk by causing it to sour. The indications are that at 32° F. the development of bacteria is not only retarded, but there is apparently an actual decrease in their number when held at this temperature. The bacteria referred to, however, are those found in milk, even though produced under favor- 40083°—Bull. 98—14——5 66 BULLETIN 98, U. 8. DEPARTMENT OF AGRICULTURE. able hygienic conditions, and not to pathogenic (that is, disease- producing) bacteria. It is impracticable to reduce the temperature of milk much below 50° F. in summer without employing a refrig- erating machine or ice, and as the former is too expensive for the ordinary farmer, we are limited to the use of ice or well water. Where ice is plentiful and may be had at a nominal cost it is an easy matter to reduce the temperature to, say, 40° F., and by referring to Tables IV, V, and VI under ‘“‘Influence of temperature and time on the development of bacteria in milk” it will be noted that the multiplication of bacteria at this temperature is very small. In those locations where natural ice is available it is compara- tively an easy matter to cool milk or cream on the farm before carry- ing it to the receiving station or creamery. This may be done by running the milk or cream over some form of cooler in which cracked ice or a mixture of ice and salt is placed, or through which cold “water is circulated. Where the milk or cream is placed in cans and set in cool water, or even in a tank filled with ice and water, the cooling goes on very slowly, especially if the cans are large. The outside portion, how- ever, may be cooled in a comparatively short time, but unless it is stirred repeatedly it will take considerable time before the interior is cooled down to a point where the development of bacteria is re- tarded to such an extent that the milk or cream may be safely car- ried to the receiving station or creamery, as the case may be. It is often the case that a can of milk is set into a cooling vat in which the cooling medium is lower in level than the milk in the can, in which case the milkin the lower part of the can may be cooled down to approximately the temperature of the cooling medium, while that above the level will remain at the higher temperature of the atmos- phere; consequently, when the milk is stirred the whole will turn sour and spoil. The cold milk, bemg heavier than the warm, will naturally remain at the bottom of the can, while the warmer and therefore lighter portion will remain at the top, and practically no circulation will take place and the transfer of heat by conduction in this case is very slow. If proper care is exercised, however, milk and cream may be cooled down to a temperature sufficiently low to get to the receiving sta- tion or central creamery in good condition by running spring or well water through the cooler. In the winter months the lower atmos- pheric temperatures assist in the cooling, but in the hot summer months the higher temperatures of the atmosphere retard the cool- ing; consequently, during the hot weather the milk or cream should be run over the cooler very slowly, and if its temperature is not sufficiently lowered it should be run over the second time. In this APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 67 way it is possible to get the temperature down to within 2° or 4° of the cooling medium. As the development of bacteria begins as soon as the milk is drawn from the cow, it is of the utmost importance that the cooling be done as quickly as possible after milking, in order to keep the in- itial number of organisms down toa minimum. The rapidity at which the development of bacteria goes on in milk at a given tem- perature depends, of course, on the initial count, hence the impor- tance of keeping the initial count as low as possible. Tests were made to determine the time required to cool milk by placing a 10-gallon can in a box and running cooling water around the can, as shown in figure 31 (p.68). The average temperature of the water was 62.6° F. and the flow of water was regulated so that there -was practically no difference between the inlet and outlet water. Thermometers were placed in the can, as shown in the attached sketch, and readings were taken every 15 minutes until the tem- perature of the milk was approximately that of the cooling water. The results of these readings are plotted in the form of curves, which are numbered from 1 to 7, inclusive. Curve No. 8 is plotted from thermometer readings taken in the milk at top of can and shows that that part of the milk above the water level remains from 5° to 6° warmer than the portion below the water level; consequently, bacteria will develop at a higher rate in that portion of the milk above the water level and when mixed will hasten the souring of the milk, both by raising the temperature of the whole and by the in- creased number of bacteria contained in the warmer portion. The curve showing the comparatively rapid decrease in tempera- ture when the milk was thoroughly stirred at intervals of 15 minutes demonstrates the advantage of agitating the milk while cooling. The time taken to cool the milk in either case, however, is too great for good results, and the tests serve best to demonstrate the necessity of employing some efficient form of milk cooler suitable for farm use. Figure 32 (p. 69) shows the method of cooling milk employed on the United States experimental dairy farm located at Beltsville, Md. The equipment consists of a one-fifth ton refrigerating machine operated by a one-half horsepower motor, a small rotary circulating pump driven from the shaft of the refrigerating machine, and a corru- gated milk cooler. Water, instead of brine, is used for circulating through the cooler as the night’s milk is cooled, placed in cans, and set into the tank until the next morning; if brine were used {it would corrode the cans. The tank holds about 120 gallons of water, which is cooled down to approximately 35° F. and held at this tem- perature until time for cooling the milk, when it is pumped through BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE, 68 "AS FL HOS LN UATONY ANS “AID SO SOL NILNIWEYL DNIPGYSY PILIWOWAIMAL LUCHA AILLO TS G'ON JAHND "SOMIVIY SILIWOWNSIHL DMAINIOASBTHHOD WOOF AFL407a LOLS SIAHND SoGSLP Wo0oy a “ JoP AP AALOM DQAIIO0D SWIL JSOVWYIAY “SILANIA S{ABTIAZT CIBWLS WLS Soe2L19 woow ” ” JoP LP YILYM YNIT00S HUFL IOUNTAY “DOIN ILS LOM Tle WILLIE LLL f RSSSSSNSSNSSSR SESSA *Jo}JeM SUMMON YIM YUL Sujoo9— TE “OLE SSAN \] — By J Ss i IN | S| | a | a ie a BA BA [| Ee EY | “AIHA LS LOM HAMA Y SIINYIIO IAYNLGYIAWIL —— *SPILINILS St AHFAZ ABNNLS HTIW APPLICATION OF REFRIGHRATION TO HANDLING OF MILK. 69 the cooler by the small rotary pump. The water is allowed to pour back into the tank, consequently the temperature of the volume of water gradually rises. During the warmest weather it was necessary to run the refrigerating machine from 8 to 10 hours a day in order to cool the water down to 35° F. and hold it at this temperature until used. The volume of milk handled was that from 15 cows and it was cooled entirely by the refrigerating water from a temperature of about 98° to 35° F. Had well water been used in one section of the cooler at least half of the refrigerating duty would have been taken off the machine and the time of operating the machine would have been reduced one half, or, for the same number of hours of operation the FIACHINE AND COLD WATER TANK, #3 Fig. 32.—20-cow farm milk house equipped with refrigerating machine. machine would have taken care of the milk of double the number of cows. The cost of electric current at the experimental farm is 6 cents per kilowatt-hour, and as the input to the motor is about 0.55 horse- power, the cost of power for operating the machine is 24 cents per hour, or 20 cents for an 8-hour day. The amount of cooling water required is about 25 gallons an hour. MAINTAINING LOW TEMPERATURES DURING TRANSPORTATION. A great deal of the milk consumed in the cities at the present time is transported in wagons, or in the ordinary baggage car in use on the steam railroads or on the interurban electric railways, with no provi- sion for holding the milk at low temperatures. 70 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. ~ If, however, milk is thoroughly cooled on the farm and placed in large cans properly jacketed it will arrive at the city plant in good condition under ordinary weather conditions providing the time required for transportation is not over four hours. The transfer of heat through milk is principally by convection, and when in large volumes the transfer is very slow unless the milk is agitated. The time taken in the transportation of milk from. one point to another, together with the facilities available for holding it at low temperatures, determine, to a great extent, the initial temperature to which it should be cooled. For short distances, or short preserva- tion of a few hours only, it is believed that a temperature of less than 50° F. should be maintained. Some lactic acid bacteria will multiply even at this temperature and will cause a souring of the milk, but the increase is slow and for a few hours no serious results will occur. At temperatures below 50° F., however, the rate of bacterial growth is materially decreased. If, on the other hand, milk is to be shipped long distances, the initial temperature must be lower, assuming that no provision is made for maintaining temperatures during transportation. For com- paratively long-distance shipments, where the milk is in transit for several hours, it is necessary to cool it down near the freezing point. The point to which milk should be cooled, therefore, depends on the time taken in transportation and must be determined for each par- ticular case. | Tn order to maintain a low temperature as long as possible, the cans should be well jacketed. The curves in figure 33 (p. 71) show the result of jacketing the cans. The cans were set in an open truck with no covering to shield them from the direct rays of the sun. Long- stemmed thermometers were inserted through holes drilled in the covers of the cans. Thermometer readings were taken every 15 minutes and the results plotted in the form of curves. The milk was hauled a distance of 13 miles through the country and the average air temperature during the trip was 82.65°. It will be noted by refer- ring to the curves that the total rise in temperature of the milk con- tained in the hair-quilt-jacketed can was 54°, while that in the can wrapped in wet burlap was about 84°, and the unjacketed can showed a rise in temperature of 284°. It is obvious from the curves that it pays to jacket the cans in order to maintain a low temperature during transportation. There are at the present time two types of refrigerator cars de- signed especially for the transportation of milk. One is an ordi- narily constructed car of the baggage type, in which the milk cans are set and crushed ice packed around them. These cars are only good for comparatively short hauls, as they are poorly insulated or in most cases not insulated at all. The water from the melted ice APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 171 is allowed to run out at the doors, or through cracks in the floors. The other type of car is provided with ice bunkers or brine tanks. In these cars the bunkers are located in the ends of the car and have a ratio of ice to loading capacity of about 1 to 11 cubic feet. In some of the more recent designs of milk cars a mixture of salt and emma sa ee] Pee De STi Ts Eo Mee OD |) LTA Tes) live ofa fh La {tf ls, boa Dems ae : Sear ale MNS | i ie iad mabe alee ie SHAS gee eo gee BEARER EEE [4 AE Abe fool | 5 ellis [ot Fea SEAR E EE -HHH HH + Heels | DEGREES RISE IN TEMPRATURE nN S iia mcm cc). LA ik yeOce | | me eae SUE | ae Lich Ie rae Fic. 33.—Curves showing the relative rise in temperature of milk contained in insulated and uninsu- lated cans. Average air temperature, 82.65° F. ice is used to obtain lower temperatures than can be had with ice alone. One of the latest designs of refrigerator cars for use in trans- porting milk, employing a mixture of brine and ice, is constructed with two refrigerator compartments, each having a floor capacity of 160 46-quart cans, 13 inches in diameter. The volume of the refrigerating compartment is 1,468 cubic feet. The design of brine 72 BULLETIN 98, U. S, DEPARTMENT OF AGRICULTURE, tanks consists of two tanks having a radiating surface of 226 square feet and a volume of 77.25 cubic feet. The screened portion above the tanks has a volume of 9.42 cubic feet, making a total capacity of 86.67 cubic feet, or a total of 3,814 pounds crushed ice, weighing 44 pounds per cubic foot. The ratio of tank radiating surface to loading volume is 1 square foot to 7.48 cubic feet, and the ratio of ice to milk is 2 pounds of ice to 1 gallon of milk. The tanks have a 2-inch free-air space around them and are 15 inches above the floor. They are separated from the storage rooms by a partition open at top and bottom and screened, thus creating a circulation. Any moisture from tanks is carried off from drip pan through drain pipes and traps. The tanks are connected by 14-inch pipe, creating to some extent a circulation. This pipe also regulates the brine to a uniform height in both tanks, the height of the pipe above the bottom of the tank being so arranged that a certain amount of brine remains. A riser connection to the pipe forms an overflow. When refilling the tanks, the valve in the pipe connecting the tanks is opened and all water or brine above the horizontal pipe is drained off. Before refilling the tanks with crushed ice and salt the valve is again closed, causing the warm water to rise to a height equal to the top of the pipe. Any surplus water runs off through overflow pipe and outside trap without egress of air. The valve is manipulated by a rod and universal joints from the roof of the car by removing the plug door. When it is necessary to clean the tanks, the round plugs at the bot- tom are unscrewed about one-fourth inch, when they will release the brine, and after it has drained off the plug can be entirely unscrewed and the settlings removed. In order that the car can be kept in a sanitary condition the floor is covered with galvanized sheet iron, all crevices being soldered, and after each trip or shipment of milk the floors are scrubbed. - It is practicable with this type of car to maintain a temperature of about 35° or 40° F. The milk must be precooled, however, to about this temperature before it is placed in the car, as the refrigerat- ing apparatus is not intended to receive warm milk from the shipper and reduce its temperature to any great extent during transit. 450 cubic feet, providing the refrigerating machine is not operated at the time, but as a 74-ton machine is capable of extracting 12,000 x 7.5=90,000 B. T. U. an hour, or during the two hours taken to cool the milk the machine will extract 90,000 x 2=180,000 B. T. U., 351,310 — 180,000 780 =24tons. Butasthe consequently the actual cubic feet of brine required is = 219.6. Another method of calculating the amount of brine storage required to cool a given amount of milk, based on the capacity of the com- pressor used for cooling milk, is as follows: TT. (WRm) — (12,000 CHm) 60 Rb Where T=cubic feet of brine in tank. W =weighing of milk in pounds. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. mt Rm=temperature range of milk. (@=capacity of compressor used for cooling milk. Hm =hours required for cooling milk. Rb=temperature range of brine. Taking the values in the case under consideration and substituting in the above formula and solving for the number of cubic feet of brine, we have: T= (8,600 x 43) — (12,000 x 7.5 X 2) oT Sabie rent 60X15 During the 16-hour shutdown period the heat that will come per). 126,336 X16 through the walls, floor, and ceiling will be Fal Boba alee B. T. U., then 219.6 cubic.feet of brine will absorb in rising 1 degree 219.6 X52 = 11,419 B. T. U., or the temperature of the brine will rise during the 16-hour shutdown period, disregarding the milk in 84,224 11,419 A cubic foot of milk in rising 1 degree will absorb about 61 B. T. U. Therefore the milk in storage, disregarding the brine, would rise 84,224 8,052 Considering both the brine and milk, a cubic foot will absorb 132 X61+219.6 x 52 132+ 219.6 » 84224 351.6 X 55.4 Had the refrigerating machine been of sufficient capacity to have cooled the milk through the required range of temperature in the two hours it took to pasteurize, the size of the machine necessary 351,310 x 24 2X 288,000 would, therefore, be idle most of the time, and as the initial cost of the larger machine and equipment would be a great deal more than the smaller one, it would be poor economy to install the larger machine. When either the ‘‘flash” or ‘‘holder’’ process of pasteurization is employed, the temperature of the milk is generally first lowered to approximately 75° F. by water from the city mains or from wells; con- sequently the refrigerating machine has only to lower the tempera- ture of the milk from the temperature at which it leaves the water section of the cooler to the temperature attained in the storage room. storage =7.4 degrees. only =10.5 degrees. =55.4 B.T.U., and the rise in temperature will b =4.3 degrees during the 16-hour shutdown period. would have been =14.6 tons. A machine of this size RAW-MILK PLANTS. In raw-milk plants it is only necessary to cool the milk from the ~ temperature at which it is received, say 60° F., to a final tempera- ture of approximately 32° F. It is usually pumped directly from the 78 BULLETIN 98, U. 8. DEPARTMENT OF AGRICULTURE. receiving tank through some form of cooler to the bottler, where it arrives at about 45° F., after which it goes to the storage room. The refrigeration in the storage room is obviously the same as in the pasteurizing plants. The refrigeration necessary to reduce the temperature of the milk from 60° to 32° F. is 1,000 <8.6 x0.95 (60—32) =228,760 B. T. U. The heat coming through the floors, walls, and ceiling is the same as before. Therefore the total amount of refrigeration required in 24 hours, allowing 50 per cent for opening doors, presence of workman, 532,644 288,000 eight hours the size of the machine required is 1.85 X 3=5.55 tons. The volume of brine required to cool the 1,000 gallons of milk with ee cubic feet. The heat poor workmanship, etc., is =1.85 tons, or to do the work in machine running is 126,336 X16 == 84,224 B. T. U. The rise in temperature of brine and milk will be $4,224 go 254, 5X6007 2 KL In figure 35 (p. 79) are shown curves of the approximate size and cost of belt-driven refrigerating equipment for various sized milk plants. that will come through the walls, floor, and ceiling is REFRIGERATION IN CREAMERIES. GENERAL. In the application of mechanical refrigeration to creameries the first method employed “or cooling cream was to allow it to run over a cream cooler on the way from the separator to the cream vat. This method allowed the cream to be exposed to the air and its con- taminating influences; besides, there was no way provided for hold- ing the cream at a constant temperature after it had reached the vat. The next step was to place the brine piping in an open cream vat. This caused unequal temperatures in the cream and prevented the ripening process from going on at a uniform rate, as that portion of the cream in close proximity to the cooling pipes was chilled down considerably below that at some distance from the pipes. The cream was still exposed to the atmosphere, however. Consequently this method was finally discarded. Then followed the method of locating the brine or ammonia piping in the water space surrounding the vat, but with this arrangement, as in the foregoing, it was necessary to stir the cream occasionally in order to equalize the temperature of the mass. This method was an improvement, however, as the piping submerged in the jacket water became coated with ice and after the circulation of brine or ammonia had been discontinued the ice would melt and maintain a APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 79 fairly low temperature until the cream was ready to churn. This method also had the additional advantage of allowing the brine to be circulated through the coils in the lining of the cream vat after the plant proper had been shut down. The latest ripening apparatus is arranged for brine circulation through a spiral immersed in the cream and which is rotated at a constant speed, thereby maintaining a constant temperature. By varying the flow of brine any desired temperature may be obtained. The vats are closed and insulated. Consequently contamination x . Ua wa qf g¥ a nS cll an 98 (EAI a FE ee 3 _ Deen eae a eae opel see eee fe ee of SESE a Sie eg sa LT fa Z a, mmm | Laer | ae ay eV EASED ca Pa a is} ET 12 TRESS coe | Ea ‘JL ee One ake oe eee eee ge i Vane Ane ee eee eee SST a SS 2 PP a ) Fasc aa oe SERESETEGECEaEGEEETEE {e) aS: ee mavine Sena as Pues Fic. 35.—Curves showing the approximate size and cost of belt-driven refrigerating equipment for various size milk plants. from the surrounding atmosphere and changein the temperature of the cream are prevented. In no business is temperature control of more importance than in the handling of milk and its products. The perishable nature of milk and the rapidity with which it deteriorates when exposed to ordinary temperatures make thorough cooling facilities a necessity. In the production of the highest grade of butter it is absolutely necessary that the temperature of the cream during the ripening process be under perfect control in order to check any further fer- mentation when the proper degree of acidity is reached. As the control of temperatures is very important in the manufacture of high-grade butter, it can best be accomplished by means of mechani- cal refrigeration, as it enables the buttermaker to control the tempera- 80 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. tures of the cream at will, and furthermore mechanical refrigeration does away almost entirely with the mold and slop that must neces- sarily follow the use of ice. A creamery equipped with a mechanical refrigerating plant can at all times, provided the cream is of good quality, turn out a uniform grade of butter, regardless of weather and temperature changes. In the modern creamery refrigeration is employed in connection with the processes of pasteurizing, ripening; churning, in the prepa- ration of starters, cooling water for washing butter, in cooling storage for the finished products, and frequently the raw products. In the pasteurization of cream the same methods are employed as inthe pasteurization of milk, viz, the “flash”? and “holder”’ processes. In the ‘“flash’’ or continuous process of pasteurization the cream is heated to a temperature of 160° F. in about 30 seconds and is then run over some form of cooler where the temperature is lowered to about 65°. From the cooler it is run into the ripening vats, where the proper temperature is maintained for 18 to 20 hours, at which time the cream has ripened sufficiently for churning. Asa temperature of 65° is entirely too high for churning,it is lowered by running cold water or brine through the coils in the vat or through the coils of the cooler, should a cooler be used, and the temperature lowered to that necessary for churning. In practice, however, the ripening temperature of cream varies within wide limits. A ripening temperature that will give good results under certain given conditions would, perhaps, give poor results under different conditions. Consequently the existing con- ditions will to a great extent govern the ripening temperatures. When the cream is ripened, cooled, and churned on the same day, a higher ripening temperature is of course necessary, while, on the other hand, if the cream is ripened overnight, a comparatively low temperature is employed. The range of ripening temperatures varies from 60° to 80°, but it is believed that between 60° and 70°, with an average of 65°, the best results are obtained, as cream held at these temperatures does not ripen very rapidly. Consequently the desired degree of ripening is approached very slowly and the fermentation may be checked quickly when the desired degree of acidity is reached, thereby reducing to a minimum the chances of getting overripe cream. If, however, the cream is ripened at a high temperature there is a great danger of getting overripe cream. During the ripening process extreme and rapid changes of tempera- ture in the cream should be avoided as much as possible, as the more uniform the temperatures are kept the better the results. It is believed that the tendency is toward the ‘‘holder” process of pasteurization for cream and also toward pasteurizing directly in the ripening vats. Some types of modern ripening vats are provided with spiral coils or disks through which low-temperature water or APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 81 brine is circulated, and the temperature is controlled by regulating the flow. The coils are rotated at a constant speed, thereby insuring even, temperature throughout the mass of cream. With an arrange- ment of this kind the temperature of the cream is raised to 140° and allowed to stand for 30 minutes, when it is cooled quickly to about 65° by circulating cold water through the coils. The cream is allowed to stand at this temperature until it is ripened. The temperature must again be reduced to 52° to 60° before the ripened cream is run into the churn. This latter reduction of temperature of about 10° is accomplished by low-temperature brine or ice water. The proper churning temperatures also vary, but in summer from 52° to 54° is considered to be an average, while in the winter, the churning temperature rises to about 56° to 60°. The term ‘‘starter’”’ is used to designate a quantity of milk in which lactic acid-forming bacteria have been cultivated until it contains large quantities. This starter is added and seeds the cream with great numbers of these cultivated bacteria, which by their growth cause the acid formation to progress rapidly and in a more definite manner than without the addition of the starter. In the preparation of the starter a quantity of good skimmed milk is taken and heated to a temperature of 185° to 190° and allowed to stand for 30 minutes, after which it is cooled down to 70° or 80°. To this milk is added the mother starter, which is a pure culture of the desired bacteria, in sufficient quantity to sour the skimmed milk in about the desired time. In order to develop the proper flavor, the perfect control of the temperature of the starter milk is necessary. Where the starter is made every other day it is pre- served by holding at a temperature of 50° or below. The amount of starter usually required is one gallon for every 10 or 15 gallons of cream. ‘The cooling of the starter from the pasteurizing temperature, 185° to 190°, is usually done by circulating well water through the jacketed space surrounding the starter can; consequently, mechanical refrigeration is only required to preserve the starter in storage. An ample supply of pure cold water for working the butter is very desirable. The average temperature of well water, especially in the South, is too high for washing butter; consequently it becomes necessary to cool the water to a temperature sufficiently low for this work. The temperature of the water used in washing the butter depends to a certain extent upon the character of the butter. In summer weather, wash water at a temperature of about 52° to 56° is considered satisfactory, while in winter, the temperature may be as high as 60° to 62°. It may be generally stated that the tempera- ture of wash water should not vary more than from one to three degrees below the temperature of the buttermilk. 40083°—Bull. 98—14——6 82 BULLETIN 98, U. 8S. DEPARTMENT OF AGRICULTURE. The cooling of wash water is done in tanks which should be located at an elevation sufficiently great to command the butter worker and churn. The cooling is done either by direct expansion or brine coils submerged in the tank. The capacity of the tank necessary will vary with the size of creamery, but tanks holding from 100 to 500 gallons are of sufficient capacity for the majority of creameries. In the medium and smaller sized creameries a cold storage is pro- vided of sufficient capacity to hold at least a week’s output of butter, as it is not always convenient to make shipment as soon as made. The question of the proper temperature at which butter should be stored is an open one. It is at its best, however, when freshly made, and its fine quality will last only a few days if kept at the ordinary summer temperatures. Experiments show that the changes which take place in butter and cause rancidity and other disagreeable flavors diminish as its temperature is reduced. Consequently its quality is determined by the temperature at which it is held rather than the time. The quality and flavor of butter will eventually deteriorate under any storage temperature that has so far been tried. There- fore, the effect of storing at different temperatures is only a matter of degree and not of absolute stoppage of all changes. It is believed that in the individual creamery where not over a week’s output is in storage at one time, that a temperature of 32° F. is satisfactory where mechanical refrigeration is available. Where refrigeration is accomplished by using ice, it is impracticable to get so low a temperature, 50° to 45° F. being about the temperature main- tained in the best ice refrigerators. LOCAL CREAMERIES. Local creameries are either cooperative or privately owned, and receive milk or cream, or both, from the immediate vicinity or from their auxiliary creameries located near by. Their equipment usually consists of pasteurizers, coolers, churns, etc., with the necessary motive power apparatus, and often separators for handling the whole milk, which may be delivered direct to the creamery instead of to the auxiliary creamery. Often the local creamery is not supplied by auxiliary creameries but depends on the farmers of the immediate vicinity who deliver the whole milk directly to the creamery, in which case the local creamery does all the separating. Probably the majority of local creameries are supplied with cream separated on the farm and delivered by the patrons to the creamery, or col- lected by cream haulers. In a local creamery making, say, 2,000 pounds of butter daily the method of operation is as follows: In the morning the cream which has been allowed to stand and ripen overnight in the ripening vats is emptied into the churns and the churns started. About three-quarters of an hour is required APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 83 to do the actual churning, and about 20 minutes more to work the butter. During this time the cream ripeners are washed. The arriving cream from the auxiliary creameries or farms is weighed, sampled, and pasteurized. The pasteurizing may be done either in the ripening vats or in a separate pasteurizing machine. When the cream is pasteurized in the ripening vats it is cooled by running cold water through the coils and the jacket surrounding the vat. When a separate machine is used, the cream is run over a cooler on its way to the ripening vats, where it is held at the proper temperature for ripening from 18 to 20 hours. After the churning is finished and the butter packed in tubs or boxes and stored in the refrigerator, the churns and other apparatus are washed as well as the floors of the buildmg. The afternoons are usually given up to office work, making repairs, etc. The machinery is, therefore, operated only about eight hours a day; consequently, the refrigerating machine should be of sufficient capacity to do the work in about eight hours’ time. The size of the room necessary to accommodate a creamery making 2,000 pounds of butter daily is about 10 by 10 by 10 feet, giving 600 square feet surface. Assuming that the walls, floors, and ceiling are insulated for a heat transmission of 2 B. T. U. per square foot per 24 hours for each degree of difference between the inside and outside temperature, then with an average outside temperature of 80° F. the refrigeration necessary is: Beak. U, Removing heat coming through walls, floors, and ceiling, 600 2(80°-32°)... 57, 600 CantnogereamaO00><. 9010 00g). 5525222 See eho ete ence ce eke 123, 750 Coolime butter, 2.000 .5494(58°-32°). 2.2 sie to eee e et ceek ee 28, 568 209, 918 In view of the fact that the greater part of the refrigeration is required for cooling the cream, an increase of 25 per cent to com- pensate for losses of various kinds should be ample.. Therefore, the total amount of refrigeration necessary in 24 hours is 262,398 B. T. U. But as the work is to be accomplished in 8 hours, the capacity of the 262,398 3 388,000 The cooling of the cream will take about one hour and the amount of brine necessary, allowing a 10° rise in brine temperature, is 238 cubic feet, without the aid of the machine at the time. machine necessary is: = 2.73 tons, say, 3-ton machine. With the machine running during the time the cooling takes place, 123,750 — 36,000 520 the cream is cooled and run into the vats for ripening, the brine is cooled down for holding over the room temperature during the the cubic feet of brine necessary is =168. After 84 BULLETIN 98, U., S. DEPARTMENT OF AGRICULTURE. night. The heat that will come through the walls, floor, and ceiling | 57,600 x 16 during the shutdown period is 54 38,400 B. T. U. and the | peo 10 apse ene temperature of the brine will rise 16g x5a 744 2 The curves in figure 36 show the approximate size and cost of belt- driven refrigerating plants for various sized creameries. The curves are estimates under average conditions of operation and were checked by a large number of such plants now in operation. In the construction of the cold-storage room great care should be exercised in selecting and installing the insulation. It has been shown under the section on insulation that three-fourths of the work Bey genes APACE Ye J00000LBS. BUTTER 2 ol PRS RE RE USS BeBe >/ SRE eee soeecy icf #aan LNW IO ALIDVAYD PAVLYYIDINIIN SNOL b/ Fic. 36.—Curves showing the approximate size and cost of belt-driven compressors for various size creameries, of refrigeration required for cold storage is utilized in ‘‘pumping out,’’ so to speak, the heat that comes through the walls, floor, and ceiling of the room. In addition to the insulating value of modern insulation, it serves as a protection to the goods in storage in case of fire, due to its slow burning qualities. It is often advantageous in creamery cold storage to ural extra rooms for the purpose of storing eggs and poultry. They should never, however, be stored in the same compartment with the dairy products, as they will impart a taint to these goods. CENTRALIZED CREAMERIES. Centralized creameries, as the name implies, are established for the purpose of handling and manufacturing into butter the cream received from many outlying stations, or from direct shippers. The outlying stations are usually termed ‘‘cream-buying stations” and often located at a distance of 100 miles or more from the main creamery. APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 85 The centralized, or main, creamery is usually located on a rail- road or, better still, at the intersection of two or more railroads. The cream-buying stations are distributed along the lines of the railroads in the most favorable locations for collecting cream. The collected cream is shipped to the centralized creamery, the time of arrival, of course, depending upon train schedules. In some instances cream arrives at practically all hours, both day and night. As soon as received at the creamery, the cream is sampled, weighed, and pas- teurized. After pasteurization the cream is cooled and run into vats where it is held until the following morning, when it is churned. Generally the churning and the working of the butter take place in the forenoon, although in some instances this work is done at any time that happens to be the most convenient. Usually the cream is ripe when received, and if churning is to be delayed the temperature of the cream is lowered to a point where the development of acid bacteria practically stops, at which tempera- ture it is held until ready to churn. In case a force is kept on duty continuously, the refrigerating plant may be operated 24 hours a day; hence, the size of the plant is ma- terially reduced from that required if the plant were operated only 8 hours. Generally speaking the methods of operation employed in the centralized creameries are very similar to those of the local creamery, except they are on a more extensive scale and only cream is handled. CREAM-BUYING STATIONS. Cream-buying stations are established for the purpose of supplying the centralized creameries with cream by collecting the cream directly from the farmers and shipping to the main creamery. These stations are located at suitable points along the railroads in close proximity to a large number of farms. The cream is brought to the buying stations by the farmers, where it is received by the agent of the main creamery and held until a sufficient quantity is on hand to justify shipping. Generally no provision is made for cooling the cream at the buying stations. In figure 37 are given the weights of a gallon of cream containing varying percentages of fat. COOLING CREAM IN AUXILIARY CREAMERIES. The auxiliary creameries, commonly known as skimming stations, are erected for the purpose of furnishing cream to the main creamery without the inconvenience of having to haul the raw milk a long dis- tance. Byseparating the cream from the milk in the auxiliary cream- ery and hauling only the cream to the main creamery a great saving in time and labor is effected, as it is necessary to haul only about an average of 13 per cent of the total weight of the whole milk. 86 BULLETIN 98, U. 8S. DEPARTMENT OF AGRICULTURE. The auxiliary creameries are located at suitable points in the country surrounding the main creamery, where they are in close proximity to a number of farms. Where a creamery draws its sup- ply of milk from a large and scattered area, the auxiliary creameries are essential to its peeaarnical operation. The milk is brought to the auxiliary creamery by the farmers early in the morning and it is immediately sampled, weighed, and sepa- rated. The skimmed milk is returned to the farmers, who haul it home for feeding to stock, and the cream is run from the separator over a cooler, caught in cans, and carried to the main creamery, where it is ripened and made into butter. In some States the skimmed milk is heated before being delivered to the farmers to a temperature of 180° F. in order to destroy any disease-bearing bacteria that might be transmitted to stock by feeding on the milk. Se) al es Toile | Tee ai va gps el TTS STS TESTE TST Tc TTS Te STD aT a a FO is Oe (Pe le SIE Es PER CENT FAT: Chesed tees ate uel eal dhacbatet ees eel esl WEIGHT IN POUNDS FER GALLON OF CREAM. Vi SSe Eases eSessiae! 62 Fig. 37.—Weight of a gallon of cream at 68° F. with varying percentages of fat. Before separating the whole milk its temperature is raised to 90°. It is then run through the separator, coming out at a slightly lower temperature than that at which it entered. It should be immediately run over some form of cooler and its temperature reduced to an aver- age of about 40°, at which temperature it should be run into insulated cans and carried to the main creamery, where it is ripened and made into butter. It is practicable to reduce the temperature of the cream by the water section of the cooler to about 60° in the Northern States, but in the Southern States a temperature of 70° is about as low as it is practicable to lower the temperature by well water. From the temperature at which the cream leaves the water section of the cooler to a final average temperature of 40° the cooling is done in the more modern creameries by circulating low-temperature brine or water through the coils. In those localities where natural ice is available at a small cost the cooling is generally done by employing a mixture of salt and ice, In the Southern States, however, where natural ice APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 87 is not available and the cost of manufactured ice is too great for economical use, mechanical refrigeration is desirable in order to reduce the temperature of the cream to a point where it can safely be carried to the main creamery. Due to the development of the hand separator, by the use of which the farmer is enabled to separate his milk on the farm, the auxiliary creamery is fast being done away with. This arrangement, however, places the responsibility of properly cooling the cream upon the farmers before it is hauled or shipped to the creamery. What has been said on the subject of cooling milk on the farm is, of course, applicable to the cooling of cream, and as the weight of cream is only about 13 per cent of that of the whole milk, the coolmg is a com- paratively easy matter. Where the separating is, done at the auxiliary creamery the milk is first heated to about 90° before being run through the separator. The temperature of the cream is first reduced by the well-water section of the cooler to approximately 60°. Assuming that the auxiliary creamery handles 1,500 pounds of cream daily through the summer months, and the temperature of the cream when received is 60°, and that it is cooled to an average tem- perature of 40°, the refrigeration necessary to cool the cream is 1,500 x .90(60-40) =27,000 B. T. U. But there is the loss in cooling brine, radiation, etc., that must be taken into consideration. Owing to the variation due to poor workmanship, the arrangement of the apparatus, etc., it is impracticable to calculate very closely on the amount of refrigeration that will be lost. Therefore it is cus- tomary to allow a certain amount to cover this loss, which usually varies from 25 to 50 percent. Jn the case under consideration 25 pet cent would be ample. During the summer months the machine would be run about 6 hours per day; therefore the size of machine PUNO K125 X40 ge 288,000 Be A cubic foot of calcium-chlorid brine will absorb about 52 B. T. U. in rising 1° F., and allowing a 10-degree rise in brine, 30 to 40 degrees, each cubic foot will absorb 52(40—30) =520 B.T.U. Therefore the 27,000 520 feet, providing the machine is not running during the cooling process. But with the machine in operation the volume of brine will be con- siderably less. A half-ton machine is capable of extracting 6,000 B. T. U. per hour. Consequently as the machine is run during the two hours of cooling it will extract 12,000 B. T. U. and the volume (27,000 x 1.25) —12,060 7 520 _ As the amount of heat that will come through the walls of the brine tank is directly proportional to the exposed outside surface, and as necessary would be =52 cubic volume of brine required for cooling the cream is of brine necessary will be =41.8 cubic feet. 88 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. the cost of insulation also varies in the same proportion, it is obvious that the brine tank should be constructed in the form of a cube which gives the least exposed surface for a given volume of any form of rectangular tank. The brine tank should be in the form of a cube with 3-foot 8-inch sides, giving a surface of 80 square feet. The tank should be insu- lated for a heat transmission of not over 2 B. T. U. per square foot, per 24 hours per degree difference between the inside and outside temperature. MARKET CREAM PLANT. The market cream plant, as the name implies, handles only sweet cream for the market. The plant is usually provided with churns in order to make butter from any soured cream that may accumulate, otherwise the equipment consists of that: necessary for pasteurizing and cooling. The method of operating a plant of this kind is essentially the same as that employed in operating a regular local creamery; that is, the plant is located on a railroad where good connections are had with the markets. The milk or cream is received from the producers or auxiliary creameries, usually early in the morning, and is pasteurized and refrigerated immediately. In a market cream plant it is impera- tive that the work be done quickly and thoroughly in order to get the cream on the market in perfect condition. In this type of plant refrigeration is of the utmost importance, as the safe handling of the cream depends more on the proper cooling than any other one feature of the business. The amount of refrigeration required in the market cream plant is of course considerably more than that for a creamery handling the same amount of cream for butter making, as the temperature main- tained for market cream is considerably lower. In ripening cream for butter making it is seldom that its temperature is allowed to go below 50° F., about 65° F. being the usual ripening temperature. With cream intended for the market, however, a temperature of just above the freezing point is desired. Shipping facilities often require the holding over of one day’s supply of cream to the morning of the following day, consequently suitable provision for.cold storing must be provided. What has already been said on the cooling, storing, and shipping of milk is of course applicable to cream. ADDITIONAL COPIES O¥ THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. A T 10 CENTS PER COPY Vv WASHINGTON ; GOVERNMENT PRINTING OFFICE ; 1914 BUtdikeh TIN’ OF; THE USDEPARTMENT OFAGRICULTURE No. 99 { ely 4 \ Foe Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. June 8, 1914. TESTS OF SELECTIONS FROM HYBRIDS AND COMMERCIAL VARIETIES OF OATS. By ©. W. Warsurton, Agronomist in Charge of Oat Investigations, and L. C. BURNETT and H. H. Love, Collaborators, Office of Cereal Investigations (in cooperation with the Iowa and Cornell University Agricultural Experiment Stations).? INTRODUCTION. The breeding of oats was begun by the Bureau of Plant Industry in 1902. In that year Mr. Jesse B. Norton, then of the Plant-Breeding Laboratory, grew a collection of varieties at the Arlington Experi- mental Farm, near Washington, D. C., and made a large number of crosses. The resulting seed was planted in the spring of 1903 at Willey, Il. The following year the work was transferred to the vicinity of Bloomington, IIl., where it was conducted from 1904 to 1908.2. Field-plat tests of a number of commercial varieties were also made at Willey in 1903 and during the earlier years of the work near Bloomington. The experiments were confined to nursery tests in 1907 and 1908. Pure-line selections were made from these plats of commercial varieties, and material for crossing was also taken from them. The first selections were made from the hybrids in 1904, and reselections were made from time to time as further breaking up was apparent. All these selections were first grown in head rows, and those which appeared to be most desirable were grown in suc- ceeding years in nursery rows of uniform length for comparative tests. In 1907 considerable numbers of the selections were sent to the Kentucky, Iowa, and Cornell University (New York) agricultural 1 This bulletin is intended for the use of farmers, agronomists, and cereal breeders, to whom the com- parative data on selections from hybrids and commercial varieties should be of interest. It is adapted to the northern part of the United States as far west as the Missouri River. 2The work in cooperation with the Iowa Agricultural Experiment Station has been under the direct chargeof Mr. L.C. Burnett, while that in cooperation with the Cornell University Agricultural Experiment Station has been under the direction of Dr. H. H. Love. The results of the work at these stations have been prepared for publication by Messrs. Burnett and Love, respectively. ‘The remainder of the bulletin has been prepared by Mr. C. W. Warburton. 3 Mr. Norton and the writer desire to acknowledge their indebtedness to Messrs. Deane N. and J. F. Funk for facilities furnished and for their hearty cooperation in the work near Bloomington, 40361°—14——_1 2 BULLETIN 99, U. S. DEPARTMENT OF AGRICULTURE. experiment stations for testing. In that year, on the resignation of Mr. Norton from the United States Department of Agriculture to accept a position in Cornell University, the writer was placed in charge of the oat-breeding experiments in connection with his other work with oats in the Office of Cereal Investigations. In 1909, the work in Illinois having been discontinued, the Iowa station was made the headquarters for the testing of the oat selections. Since that time the more extensive tests have been made at the Iowa and Cornell University experiment stations, while smaller numbers of the selections have been tested at several of the other State stations, as detailed in the pages which follow. It. is the purpose of this bulletin to present the results of these preliminary tests, as indicative of the varieties and varietal combina- tions which are most likely to prove of value in the various sections where the tests have been conducted. PARENTAGE OF THE SELECTIONS. Three lots of hybrids were made by Mr. Norton, the first at the Arlington Experimental Farm in 1902, the second on the Funk brothers’ farms at McLean, IIl., in 1905, and the third at the latter place in 1906., The hybrids resulting from the first lot of crosses have been quite widely tested. Those of the second and third lots have been grown only at the Iowa station and have not yet been tested long enough to report results. A considerable number of combina- tions were made in each of the years, but only those which are rep- resented in the nursery tests reported in this bulletin are given here. HYBRIDS. Of the 52 varietal crosses made in 1902 only 19 are represented in the records after 1906, the others either having failed or having been discarded because of evident inferiority. The varietal combinations which are still represented in the nursery tests, with the series num- bers by which they are designated, are as follows: 3. Golden Giant X Asia Minor Rust- { 34. Burt & Sixty-Day. proof. 38. Burt < Clydesdale. 8. Danish Island & Asia Minor Rust- | 41. Asia Minor Rustproof Clydesdale. proof. . 42, Asia Minor Rustproof & Clydesdale. 25. European Hull-less X Garton Tartar | 44. Asia Minor Rustproof X Garton Tartar King. King. 27. Garton Tartar King & Clydesdale. 45. Asia Minor Rustproof & Silvermine. 28. Silvermine * Danish Island. 48. North Finnish Black & Burt. 30. Burt Clydesdale. 49. Sixty-Day * Clydesdale. 31. Burt * Red Rustproof. 50. Sixty-Day & Probsteier. 32. Burt X Early Champion. 51. Sixty-Day & European Hull-less. 33. Burt * Burt. TESTS OF SELECTIONS OF OATS. 3 COMMERCIAL VARIETIES. In 1904 pure strains from commercial varieties were started from heads selected from the field plats grown that year in cooperation with the Funk Bros. Seed Co., at Shirley, Ill. The series numbers of these pure-line selections are as follows: 62. Sixty-Day. 125. Silvermine (Great American). 63. Burt. 131. Pringle Progress. 115. Red Rustproof. 132. Sixty-Day. 117. Early Champion (Alaska). 137. Early Champion. 118. Silvermine (Musselshell). 138. Early Champion. 119. Probsteier. 142. Goldmine. 120. Silvermine (Great Dakota). 165. Sixty-Day. 123. Welcome. 5938. Sixty-Day. 124. Silvermine. THE SYSTEM OF NUMBERING. As shown in the preceding paragraphs, each combination of varieties which was made was given a series number. Thus, all hybrids in which Sixty-Day, S. P. I. No. 5938, was the female parent and Clydes- dale, P. B. No. 8, was the male parent were of series 49. Each combination of individuals was designated by a letter, as a, b, c, ete. For instance, if crosses were made on three plants of Sixty-Day oats, using the same or different plants of Clydesdale as the male parents, these individual combinations were numbered 49a, 49b, and 49c. Each plant produced in the F, generation was numbered consecutively for each combination of individuals, as 49a1, 49a2, 49a3, 49b1, ete. This number is always written as a unit. As individual plant selec- tions were made, these were given serial numbers, this number being separated from the hybrid plant number by a dash. As subsequent selections were made, these were also numbered serially. Thus, 49a2—20-7 is pure-line selection No. 7 from pure-line selection No. 20 from plant No. 2 of the hybrid combination No. 49a, Sixty-Day x Clydesdale. If a reselection was made after alapse of one or more years without selection, this lapse is indicated by xx, as 49a2-—20- xx-7. Ifa bulk selection was made, the selection number is written in Roman instead of in Arabic, as 51a1—15-I. The selections from commercial varieties were numbered in the same manner as those from the hybrids. Each stock was given a series number, but the numbers of pure-line selections from commer- cial varieties do not contain a letter followed by a numeral, as is the case in all hybrid numbers. Each individual selection bears the series number followed by a serial number within the series and separated from it by a dash, as 125-17. Bulk selections, as in the hybrids, are indicated by Roman numerals. Thus, 62-IIJ-18-1 is the progeny of plant No. 1, selected from the progeny of plant No. 18, which in turn was selected from Bulk Selection II from the original 4 BULLETIN 99, U. S. DEPARTMENT OF AGRICULTURE. Sixty-Day stock. By this system of numbering, the common par- entage of strains is shown at a glance. MAKING THE SELECTIONS. In both the hybrids and commercial varieties selections of indi- vidual heads were made, the selections being based on size of head, vigor of plant, size and color of grain, and other characters, as de- sired. The seed from each head was planted in a head row, usually a row 5 feet long. These rows were then numbered serially, to indicate their location in the nursery, while the selection number indicated the parentage of the selection. Only those rows which appeared to be of value were harvested. Usually not more than 10 per cent of the head selections which are made are retained after the first year’s test in head rows. No doubt some valuable strains are lost in this way, but the success of work of this kind depends very largely on the judgment of the breeder. Where space and funds are more or less limited it appears to be better to make a large number of head or plant selections, cull these carefully in the head rows, and put only those that appear to be best in the comparative- yield test, going back to the original stock or drawing on new sources for additional material for head rows as opportunity offers rather than to select a comparatively small number of individuals and retain all these in the test for several years. It is only by handling large numbers of individuals and by culling very carefully that one can hope to gain the desired ends in cereal breeding. The strains which were selected from the head rows were tested first at McLean, Il., on the farm of Mr. Deane M. Funk. Later, con- siderable numbers of them were tested at the Iowa and Cornell University stations, and less inclusive tests were made at a number of other experiment stations. The results of these tests are given in the following pages. TESTS AT M’LEAN. METHOD OF TESTING. The tests at McLean, IIl., were made in rod rows according to a method devised by Mr. Norton.t. Briefly, the strains included in the comparative test at McLean were planted in rows 17 feet long and 1 foot apart, with every twentieth row as a check row. A pure-line selection of Sixty-Day, 62-II-19, was used as a check in 1907; a selection of this strain, 62-[J-19-3, was used in 1908. The rows were 17 feet long, so that each row occupied 17/43560 or approxi- mately 1/2560 of an acre.? As there are 512 ounces in a bushel of 1 Norton, J. B. Notes on breeding oats. American Breeders’ Association, Report 3, pp. 280-285, 1907, The method is described somewhat more in detail by H. J. Webber in Plant-breeding for farmers (New York, Cornell Agricultural Experiment Station, Bulletin 251, pp. 318-319, 1908) and by C. W. Warburton in Improvement of the oat crop (U. 8S. Department of Agriculture, Bureau of Plant Industry, Circular 30, pp. 6-8, 1909). 2 The first fraction is equal to 0.00039027 acre, while the second is 0.00039063 acre, TESTS OF SELECTIONS OF OATS. 5 oats, a yield of 1 ounce from one of these rows is at the rate of 5 bushels to the acre. Similarly, the rate of seeding is easily calcu- lated; at the rate commonly in use in the corn belt, 2.5 bushels to the acre, one-half ounce of seed is required for each row. RESULTS OF THE TESTS. The tests at McLean in 1907 included 419 selections from hybrids and 82 pure-line selections from commercial varieties. In 1908, 378 hybrids and 69 pure-line selections were grown. Only 177 of the selections from hybrids and 51 of those from commercial varieties were grown both years. Table I summarizes the tests of these two years, the strains being grouped and averaged according to their parentage. This table shows the number of strains of each series which were grown each year and the number which were included in both years’ tests, with the average yields in bushels to the acre. TaBLe I.—Average yield per acre of each series of hybrids and commercial varieties of oats grown in nursery tests at McLean, Ill., in 1907 and 1908, showing also the number of strains of each series grown. Grown in 1907. Grown in 1908. |Grown both years. Series. = + Num- Average sae Average Num Average ber of “atl ber of natal ber of vata strains.| - | strains.) ¥ - | strains.| Y = Bushels Bushels. Bushels WOM Sa eee eetie wea cise eee sate eelnisiteercetincc sce - 5 43.96 3 32.70 3 38.00 INOSSe me eiierriecccec sestee eesti ccansseceesseeeu 21 49.47 18 40.77 10 48. 62 NOR ZO Me Ee cacao eens nndessacenenicet esiecs-|. casceeplepecnecces 2 V5YAR SERS os Soci eee. myers INOS26 Me Scio sce oie Seca cei ames ete acces 2 262000 bese. oe asc eeee los oe ees eae ING: Hl inca GBC B BENGE DOCOEE SOE eo e eee ee ee 5 34. 47 9 33.11 2 36.37 INIOs eo Se GRECO SE SEO ee a eae eae 1 35. 80 1 31.55 1 33. 67 INOnG OMe acca eae co eres sre wicca ams case = 63 44.32 36 36. 04 20 44. 65 ING 3) S566 SH Se BSE eB Cee CCR Seen eee eee 5 38. 27 8 40.09 2 44.58 IN On Sone eee ie eine enn tas sieee mee nse Seecalncwa 2 46.32 2 39.90 2 43.11 ING. B62 be oesOssor EROS ESCH Se Een esse meee 29 48.58 10 43.16 10 47.67 ING. Geis 6 eG HOR BEE OBE BU EEE a NESE eee 59 49.82 28 43.08 16 47.74 IN moe ease ee cece nem snl ce eiaeeee eens cous 1 BB Eh) eee ae [Se ares ar) earn eC Soopeadoc INO. evs CgueceHes BaP OE Se see tae ee 7 43.59 4 33. 21 4 38.57 ING: 4 ees gaese saeco eee Cecne cee ee nee eee 3 32. 20 3 BCG le tn Paes ar eee IN\O: 4s 6 be Caddo Cee ECE DEE CE tee SBE aeee aoe 12 39. 69 3 39. 63 2 41.13 ING) Gi SER BSE ee Nee ee ae ee ee eer a eee eee 4 37.09 4 33.46 1 35.77 ING, OSs oc debt ob een eeOESE SEO EE SEC aet Eee oEeaEEe 5 SCRUM Ee ts ee aS eed peeneecnue ING) (isc 2t 6e0b Ae OC ORC D OEE OEE EE Benne aan Seeee 7 37. 65 15 46.08 3 45.12 INGOs ree tenes Se SS SESS a Se oe 135 46.14 id: 38. 07 71 45.14 NIG: Gs 1c Se OR SE CSE SECO SEED E De DaBbEE BeOS oaee ne 47 50. 87 42 39. 42 26 46. 82 ING. ce Ande eee aS ee eee one aaa ee 6 40.10 13 26.33 4 37.34 ING@s G2. 2c CS EE cece ane IEEE eee eee eee ae 16 59. 41 17 44. 23 13 52.90 INN OSM ey oe ee pan Abs Lose checeooeeoae 6 56.55 5 48. 43 5 52. 83 SIN Gpap UD eso et ne ie ee ee 6 eh 1 ADS GON: 32 sass come eas Zee eceee lose eaceene WGy, UGS Pe SBCs Oe ee ae ee ee ee ee 4 48. 65 3 25.58 3 36.18 ING: LG. 3 cee SSRs Se ones Geet GIO S ERIE EE eae 3 37.55 1 28.15 1 34.15 Nig i@s sScok sae ees See eee ae ee eee eae 4 38. 32 1 29.55 1 32.27 NIG. LAD. 6 SSS SSeS e Ee aa oe ee oe SC 4 38590 BAee ear eee lee ele aaeeeeee INGE ene aoe Ae ees = ee ie te 1 42.95 1 32.25 1 37.60 ING, ee Ss Gabe e SEE Ree re ee are eee 2 41.70 2 25.25 2 33.47 ING. IPs Sete eS ae ees es ee ee ee 13 38. 66 8 33.66 8 35. 72 b a 49. 20 7 40. 74 5 47.30 3 61. 72 8 46. 42 3 56. 11 9 47.19 4 26.50 2 39.15 6 49.35 4 26. 42 4 38.50 1 51. 25 1 21.50 1 36.37 1 56. 40 1 36. 85 1 46.52 1 46. 30 il 28. 45 1 37.37 Be eA SI Soho vehe tet eae aiale eae aie Meena Sie ae eee ss tee eee ee 5 ALIGN ess toe el aceeee eee 5010 Seema GAA. Se 228M See ese AHS See ee ios aie A Aes ctl Sage See a as tae AG AD i pep O85 20 |S eae 45.04 BULLETIN 99, U. S. DEPARTMENT OF AGRICULTURE. THE MOST PROMISING SELECTIONS. The highest yielding selections were all from commercial varieties, as follows: 62—II-19-3 from Sixty-Day, 58.27 bushels to the acre; 63-I-4 from Burt, 57.7 bushels; 62-II-6-3 from Sixty-Day, 57.37 bushels; 132—3-1 from Sixty-Day, 57.2 bushels; and 62—IJ-19-1 and 132-2 from Sixty-Day, 56.57 bushels. Practically all of the 25 highest yielding strains in these tests were derived from the Sixty- Day or Burt or a combination of these two varieties. Of the selec- tions grown in both 1907 and 1908, 17 pure lines of Sixty-Day aver- aged 52.55 bushels, 15 strains of Burt averaged 49.39 bushels, and 16 strains of series 34 averaged 47.74 bushels. These yields were in excess of those of all other series except series 8, Danish Island x Asia Minor Rustproof, 10 strains of which averaged 48.62 bushels. The 25 strains which produced the highest average yields for the two years are shown in Table II. Taste I1.—Average yield per acre of 25 highest yielding oat selections grown in nursery tests at McLean, Ill., in 1907 and 1908. l Ss - J / - Rank. Selection | parentage. at Rank. | Sus | Parentage. aha z | Bushels Bushels. 1 | 62-II-19-3.| Sixty-Day ..-.....- 58. 27 15 | 132-3-2....| Sixty-Day......... 54. 55 2 | 63-I4..... Bua: ese 57.70 16 30a2-6-15. -| Burt X Clsdedaie: 54.35 3 | 62-I-6-3__| Sixty-Day ......-.- 57.37 17 | 62-II-19...| Sixty-Day.. A 53.95 A | 132-3-1...[2.--2 eS 5 ae A 57. 20 18 | 49a2-13....| Sixty - Day 53. 72 5 | 62-11-19-1.|._._. giis Sia ccae od 56. 57 Ciedesiainn iy ie ky. See asee TSS eee 56. 57 19 | 8a2-6-5....| Danish Island xX 53. 25 7 | 34a1-12-3..| Burt X Sixty-Day. 56. 50 Asia Minor Rust- 8 | 8a2-6-4....| Danish Island X 56. 35 proof. | Asia Minor Rust- 20 | 50a1-15-5..| Sixty-Day X Prob- 53.15 proof. steier. 9 | 6-L-1_.... CST ig Kase ae AS ee ee 56. 05 21 | 62-IT-18-1.| Sixty-Day......... 53.12 10 | 49a1-7....- Sixty - Day X 55. 97 22 | 50a1-20-7.. Sixty-Day Xx Prob- 53. 10 Clydesdale. steier. 34) ') 4981-19) 22 ee dole! Ses mh 55. 57 23 | 63-I-7..... Bite eee eee 53. 00 12 | 62-IL- 721 Sixty-Day -- 222-5. 55. 37 24 | 49a2-18.. Sixty - Day xX 52.95 13 | 34a1-13-1._| Burt X Sixty-Day- 54. 82 ‘i Clydesdale. 14 | 8a2-4-4....| Danish Island Xx 54. 60 25 | 62-II-6-1-1 Sixty-Day......... 52. 80 Asia Minor Rust- | proof. i ! i Five of the 10 strains which produced the highest yields for the two years were pure-line selections of Sixty-Day, 2 were pure-line selections of Burt, 1 was a selection from a hybrid of these two varieties, 1 was a selection from a hybrid of Danish Island x Asia Minor Rustproof, and 1 was a selection from a hybrid of Sixty- Day X Clydesdale. Thus, of these 10 strains, 7 were pure lines from Sixty-Day or were selections from hybrids in which that variety was a parent, 3 were selections from Burt or from hybrids in which Burt was a parent, and only 1 was unrelated to either of these varieties. These 10 strains averaged 56.85 bushels to the acre, as compared with an average of 45.04 bushels for the 228 strains tested. The 25 highest yielding strains averaged 55.07 bushels to the acre. Of these 25 strains 15 were selections of Sixty-Day or TESTS OF SELECTIONS OF OATS. 7 Burt or from a hybrid of these two varieties, 18 were pure lines of Sixty-Day or were selections from hybrids in which that variety was a parent, 6 were pure lines from Burt or selections from hybrids containing that variety, and only 3 represented neither variety. It is apparent, therefore, that Sixty-Day and Burt are valuable varieties for central Illinois, a conclusion which is in agreement with varietal tests at the Illinois experiment station. COMPARISON OF SELECTIONS FROM HYBRIDS AND COMMERCIAL VARIETIES. In 1907, 82 selections from commercial varieties exceeded 419 selec- tions from hybrids in average yield to the acre by 2.57 bushels, or 5.59 per cent. In 1908, 69 selections from commercial varieties aver- aged 0.07 bushel, or 0.18 per cent more than 378 selections from hybrids. In all the 948 tests made in the two years, 151 pure lines from commercial varieties averaged 1.56 bushels, or 2.69 per cent more than 797 selections from hybrids. Of the 228 strains which were tested both years, however, 51 pure lines from commercial varieties averaged 0.56 bushel, or 1.24 per cent, less than 177 selec- tions of hybrid parentage. Of the 10 highest yielding strains, 7 were selections from commercial varieties and 3 were from hybrids, while of the 25 highest, 13 were from commercial varieties and 12 from hybrids. ‘This slight superiority for the selections from commercial varieties over those from hybrids is probably due largely to the fact that a large proportion of the former were from two varieties par- ticularly suitable to central Illinois, Sixty-Day and Burt, while one or both parents of many of the hybrids were varieties not so fully adapted to the conditions. TESTS AT THE IOWA AGRICULTURAL EXPERIMENT STATION. INTRODUCTION. The cooperative investigations for the improvement of the oat crop by the lowa Agricultural Experiment Station and the Bureau of Plant Industry were begun in 1903. In the earlier years of the co- operation a study was made of the general conditions and methods of production. In 1907, 66 of the better strains from the oat nursery at McLean, Ill., were secured for testing. When the work at McLean was discontinued in 1909, the strains retained from the earlier trials at that place, 381 in all, were added to the nursery at Ames, Iowa. CONDITIONS OF THE TESTS. The plats used in all nursery tests at the Iowa station have each been confined to an area of 30 square feet. Each selection is planted in duplicate in rows 15 feet long and 1 foot apart. These rows are the unit of the nursery. Each is maintained as a separate plat until thrashing time, when the duplicates are united and yields and other 8 BULLETIN 99, U. S. DEPARTMENT OF AGRICULTURE. data on the grain are taken from the combined product. Figure 1 shows the method of harvesting the selections, while figure 2 is a view of the oat nursery when the harvest was about completed. The soil used in the nursery work has varied somewhat, but in general may be termed rolling prairie upland. In 1907, 1908, and 1911 the tests were made on a dark prairie-loam soil. In 1909, 1910, and 1912 the fields varied from dark prairie loam to a much lighter colored gravelly loam. The preceding crop each season except 1910 and 1911 was corn. In 1910 the nursery followed the oat varietal plats, while m 1911 it followed barley. When the nursery has followed corn the stalks have been removed and the land plowed in the fall. When following small Fic. 1.—Field of oats, showing the method of harvesting selections when grown in nursery rows. grain, it has been necessary to plow in the summer and to cultivate, in order to germinate all volunteer grain before seeding time the fol- lowing season. The climatic conditions have been far from uniform during the period covered by the tests reported in this publication. The years 1907 and 1908 were very wet. In 1909 the yields of all the early and medium selections were reduced, because they were blown down by a severe wind and rain storm before the grain filled. The 1910 crop was grown almost entirely from moisture that fell before May 1. The 1911 crop was grown under abnormally dry conditions and was badly damaged by a hot wind about July 1. The 1912 crop was produced under the most favorable conditions of any of the six, with the exception that two windstorms lodged many of the selections. TESTS OF SELECTIONS OF OATS, 9 THE HIGHEST YIELDING SELECTIONS. Of the 64 selections which have been tested at the Iowa station for six years, the five with the highest average yield to the acre follow: Welcome selection 123-5, 48.5 bushels; selection 50a1—24 from the hybrid Sixty-Day x Probsteier, 47.8 bushels; and Sixty-Day selections 62—II-6-3, 47.2 bushels, and 62-II-19 and 62-II-19-1, 46.5 bushels each. Of the 10 highest yielding strains four are selec- tions from Sixty-Day, two from Burt, two from a hybrid of two strains of Burt, one from Welcome, and one from the hybrid Sixty- Day X Probsteier. Only three of these 10 selections have been de- rived from hybrids. Eight of the 10 highest yielding selections are early in maturing, the average date of ripening for the six years being before July 15. The highest yield obtained in the 4-year test is Fig. 2.—Oat nursery at the lowa experiment station when harvesting was almost completed, showing the method of protecting the bundles from mixture and from injury. that of selection 34a1—-12-1-1 from the Burt x Sixty-Day hybrid, 72 bushels to the acre. This high average is due largely to the ex- tremely high yield of this selection in 1912, 117 bushels, while other selections from the same hybrid which yielded as well in previous years ranged from 60 to 80 bushels. This selection is not yet fixed, as it still shows considerable variation in some characters. This may explain, in part at least, its high yield. It will be further selected in the future. Six closely related selections from series 8, Danish Island x Asia Minor Rustproof, ranged from 59 to 64 bushels in average yield. The highest yield obtained from any selection from a commercial variety in this test was 58 bushels from the Welcome selection, 123-5. Of the 25 selections which averaged 54 bushels or more in yield for 40361°—14——2 10 BULLETIN 99, U. S. DEPARTMENT OF AGRICULTURE. the four years, 7 are from series 34, Burt x Sixty-Day; 9 are from series 8, Danish Island x Asia Minor Rustproof; 4 from series 33, Burt X Burt; and 1 each from series 3, Golden Giant < Asia Minor Rustproof; series 49, Sixty-Day x Clydesdale; series 50, Sixty-Day x Probsteier; series 123, Welcome; and series 131, Pringle Progress. AVERAGE YIELDS FOR THE VARIOUS SERIES. The most valuable hybrid combinations included in the tests at the Jowa station are series 3, Golden Giant x Asia Minor Rustproof; series 8, Danish Island x Asia Minor Rustproof; series 31, Burt x Red Rustproof; series 33, Burt x Burt; series 34, Burt X Sixty-Day; and series 44, Asia Minor Rustproof x Garton Tartar King. Among the commercial varieties the highest average yields were produced by selections from series 63, Burt; series 123, Welcome; series 125, Silvermine; series 131, Pringle Progress; and series 165, Sixty-Day. The annual and average yields of each series for the four years are shown in Table III. Taste II].—Annual and average yields of each series of oat selections grown at the Iowa station in a 4-year test, 1909 to 1912, inclusive. | Number Yield (bushels per acre), Series No. : OLS @] @ C= tions. 1909 1910 1911 1912 Average. Hybrids: SO CEA SOOO COD REAR COB CO ECHOES sB Eee 3 62. 00 66. 33 18. 67 63. 33 52. 33 Gens ouoa nina ckesshecesensepee ake eseente 16 59. 94 69. 50 16. 62 70. 62 54. 31 QO eae sat ee leeeee nae seine ounce cate 1 49, 00 52. 00 5. 00 39. 00 36. 00 SR SO SCORE DOS PE OOO OrS HOR ASE 20 47. 00 57. 20 12. 85 52. 80 42. 40 Ionita le alee nleleittn saipeten ems alee iene 1 37. 00 62. 00 20. 00 49. 00 42. 00 BO epee nice ook seca Sake ee vacle Sees 32 BYAe?) 59. 44 18. 28 43. 59 39. 22 0) lee Ae SACO e SCE eC eno pa GEES aS abs 7 47.71 61. 29 20. 57 59. 57 47. 43 Doves ices esate ade oe Hooper wee cae 2 50. 50 45. 50 21. 00 49. 50 41. 50 Oa ae aie tales Saleh a eiela ne aie BAe a ahorein ee eerS 10 48. 90 64. 90 18. 90 69. 80 50. 60 SANE eRe Sia aaie a erate om eioein aio seinen cieteieioes 2 47. 26 58. 19 19. 59 68. 52 48. 41 SOoe sericea cmeble hitch Mes seeee cee centre aele 2 35. 50 54. 00 7.50 54. 50 38. 00 AN ere aa se rto me Mera atalstao Goin Betas eee 2 35. 00 54. 00 7. 50 70. 00 42.00 ADE tS evesia te Siciw siete eines