GB Beth fle Yj Ye ty YE: tity Z tii tity Ye Z y yyy tits Yj tity ¥ Ye ys Sy YY My HEEL GSLs Cig “6s Ley, 7 Kn ( se \f 7 U A Le BULLETIN No. 36. W. B. No. 342. ice, $1.50. We mies Jib U.S: DEPARTMENT OF AGRICULTURE. WEATHER BUREAU. A HIRST REPORT Ad ON THE RELATIONS BETWEEN CLIMATES AND CROPS. BY CLEVELAND ABBE. PREPARED UNDER THE DIRECTION OF WILLIS L. MOORE, Chief United States Weather Bureau. WASELENG TON: GOVERNMENT PRINTING OFFICE, 1905, GERRIT S, MILLER JR, GIES ~+— Va LETTER OF TRANSMITTAL. Unitep States DEPARTMENT OF AGRICULTURE, WeaTHER Bureau, OFFICE OF THE CHIEF, Washington, D. C., August 1, 1905. Hon. James Writson, Secretary of Agriculture, Washington, D.C. Sir: I have the honor to submit the manuscript of a first report, by Prof. Cleveland Abbe, on the Relations Between Climates and Crops, and to recommend its publication as a bulletin of the Weather Bureau. This paper is not designed as an original investigation, but as a summary of the views of the best experimentalists and observers, so far as those had been published up to 1891. Hay July 18 6010 |W OLGO ses ene ase | Aug. 9 63.0 | 0.0 63 | 60 l4 81.5 MH iar si We gs 10 60. 0 x (al eee el (OR, 15 81.0 AO) | peated fe eae | ul 62.0 COW 2. alee ee 16 2.0) RO ty iis | oer | IR 74.0 10:4 ee 17 79.0 0 rte | Roe 13 79.0 0:4 ee eee ae 19 | 86.0 0 Da aca 14 75.0 )) fel eae 23 82.0 0 BAL sles fe 15 69.0 20 2 ed 24 83.0 0 Ror ilLer se 16 72.0 0 Tl) eee 25 82.5 0 ei tee ane 17 73.0 0 12) je ee 26 89.0 0 ian eens 18 | 82.0 0 ilies eet " 88.0 0 iT Nae BE 19 72.0 a (ae Pec 28 94.0 0 85 67 20 80.0 (OTe (| eames ene ne ee 29 89.0 0 q 70 21 79.0 | .0 {Oe ee ae 30 101.0 28 108 76 22 SLO | 4 78 78 31 73.0 0 87 65 23 EO Oe a ral Aug. | 77.0 0 tf 67 24 89:0) 1 20 1) Ky re) 2» 91.0 0 85 68 25> | hen f94/0P 1) GO alt eHe82 5 3 | 830] .0 GS ae 70 26 sBL:O8 ee &O'e a] senate eae 4 89.0 0 85 71 27 89,00)) 0 a) cS4bals ames 5 7950" || S07 # ee see eee 28 822050420 | = psn et aes Diffuse digit yee 2 sete ee De ea ae he oe coe cate 22 aia DOs eee ceeees Darknegs AG. 8 Seb sao ean ome 5 ea Naot ate 22 .O11 Barley, sik 2 2 SUNSHINE ee eee oe ee oe Ge ge ee eas ohalees 19 . 742 Doses: to Diffusedight 22-2 --- 22-2. - pasate Bo ae Se eS eee ees 16 . 180 ID@345t eee DarkNESss ase gre ict ee oe eR ee te oS Lae cane cooe 16 023 Wihestss- 0.2: Peel SUNSHINO 6 eee eee a See eee ce oe lay tes SSL 22 718 1D Yo)S ues aoe se Dankn Oss esses 2 soos ae eee eee ee ee nee So Anes 16 . 028 1X0) ee, ee ee SUMSHINGS sete ee eet ee Sees eee ee ker Nee Pe 28 . 703 Wows hes ase = te Diffusedichtes-) sa2 45. —55 52 See SSRs ae fe eS 22 . 060 Dose se Sse: BD) TENG SS Sees ede nes te a te en SE tee 22 007 The effect of sunshine in stimulating transpiration is very clearly seen by a study of these figures. The small transpiration from the leaf when kept in darkness is supposed to be, at least in part, due to a persistency of the stimulus given to the plant by the light; so that, as is well known, the growth of the plant goes on at its maximum rate in the late afternoons, sometimes even after sunset, and does not attain its minimum until early morning. 70 Deherain also arranged the following experiments showing the effect of temperature. Some living leaves of wheat were kept within a glass tube which lay in a water bath at a uniform temperature of 15° C. and the following measurements taken : In full sunshine the transpiration was 0.939 gram of water per hour per gram weight of leaf. In darkness the transpiration was 0.016 gram of water per hour per gram weight of leaf. The water bath was then reduced to a temperature of 0° C., and the temperature of the leaf within the tube must therefore have been at the freezing point. In this condition the transpiration in full sun- shine was 1.088 grams of water per hour per gram weight of leaf. Thus leaves in sunshine in free air'at 28° C. and leaves in the air at 15° C., and again in the water bath at 0° C., give us the tran- spiration under these conditions 0.882, 0.939, 1.088, respectively. It is evident that this transpiration is not due to evaporation alone, else it would be independent of sunshine and depend wholly on heat; the decided differences here shown must be attributed to the special excitement of the cell by the solar radiation. Marie Davy gives for July 24 and 25, 1877, the following record from a self-registering apparatus showing the diurnal periodicity of the transpiration from the leaves of four plants of haricot beans which were watered daily at 7 p. m.: Diurnal periodicity of transpiration. Riou [Beano gta, 7 ease | 9 ices ea eee WetorSepeamis me. seen cee AO 4scolora meee nee eerse S| | LEGO FA nye ee eee 120 8 to9 p. m__- E 2) ||hOsbO Grane sees reas Brin | ees ovis iq Oss AO 95 Oetoe Ola Bee ee 2) (6 toian maeesns ee 465) |t3 Cords pares 67 JOOS pam == soee 4a MigtOxSias Mae anes ee 99) || 45bodp am S22 2a 44 11 p.m. to1l2midnight- | NSxtO19 fan ee ee 86))|\-5toiGsp sams =e 25 12 midnight tola.m_-_ 4 | 9 ton Oaemis see 128 | 6itoWepsm: hos eee 10 ADR ORE Fah 0 eh eee ae 2) lO tor tases eee 153)||iGtO Sap sina eee 4 Pan Oy yelp 08 Ole, oe el eae ae 4 || 11 a. m. to 12 noon _-_- 179 Sto aia bth ae ee 4 || 12 noon tol p. m_---- 143 These same four plants showed the transpiration day by day, as given in the first column of the following table (Marie Davy, 1880, p. 239). The third and fourth columns, respectively, show the rela- tion of this transpiration.to the daily mean temperature and the daily mean radiation, as shown by the conjugate thermometers. (gp Insolation and transpiration for kidney beans at Montsouris. | Weight of tran- | | Weight of tran- spired water | spired water Weight divided by— Weight divided by— We oftran- |——— +; = . We of tran=| == (7- 1 Date, 1877. spired | yfean | Mean Date, 1877. spired | wean Mean water. | tamper- | actino- water. | tamper-| 2ctino- ree | metric | rere | metric | degrees. | * | degrees. | Grams. Grams. aly sl Gwe =e 8 Se 0. 686 4.1 1.16 Sully: 240) = so 2 2e=2: 0. 706 3.8 2.00 ikem ted 0. 422 2.6 1.36 Pal sea et sae 1.300 fiat 2.17 ioe eee ee 0.727 4.4 1.21 Phe eae eee 0.991 5.3 1.92 (Geese eeecont Ovb4s 2.9 1.23 Tipe ates 1, 255 6.7 2.46 ROLE aes Ce 0.577 3.3 - 1.56 CBee seas | 1.426 7.8 2. 64 rol [ts re oe ie beef 9.1 1.24 3 ee Bees 1.277 5.9 2.97 ee ee 1. 608 6.2 1.81 BU) ee oe 2.167 7.6 3.55 (3 )5 eee 1, 204 5.4 1.88 Bile Sete aes 2.710 8.4 3.15 The figures in the above table are influenced by the quantity of moisture in the soil; therefore Marie Davy occasionally omitted the evening watering, and the transpiration for the day after such omis- sion was smaller. In general, Marie Davy concludes that the relation between transpiration and temperature is very variable from day to day, while that between transpiration and radiation is very regular, x regularity that would very probably be heightened if the cloudiness and the evaporating power of the wind, as depending on its dryness and velocity, had been considered. The belief is that sunshine excites the contraction of the stomata of the leaves and thus stimulates tran- spiration; but the stomata can not exude water to a greater extent than as supplied by the roots; therefore the transpiration is limited by the humidity of the soil adjacent to the roots. Thus on the 30th the radiation averaged 45.5 actinometric degrees, and the plant tran- spired 2.167 grams of water; on the 31st the radiation was 64.1 and the transpiration correspondingly increased to 2.710 grams; but on this day the reserve moisture in the soil was drawn upon very heavily, and in the evening the leaves of the plant were flabby and drooping and evidently wilting for the want of moisture. The results by Deherain at temperatures of 15° C. and 0° C. and those by Marie Davy seem to demonstrate satisfactorily the slight influence of the temperature of the air as such upon transpiration. Daubeny (1836), Deherain, and Wiesner have studied the effect of radiation in different parts of the spectrum, and their work shows that the radiations that are absorbed by chlorophyl, the so-called chlorophyl-absorption bands, are those that are efficient in stimulat- ing transpiration; also that xanthophyl acts similarly, but weaker than chlorophyll; that the violet and ultraviolet have no appreciable influence; that the ultrared rays have an appreciable action, but feebler than the visible rays between the red and blue, notwithstand- 72 ing that their heating effect 1s usually greater than those of the visible spectrum. The laws of growth or StL are the laws of physics and mechan- ics and chemistry as applied to living cells. The changes that go on slowly in the plant are not the same as would go on rapidly in large masses of the same chemicals when treated as in the ordinary chemical laboratory. In the plant small masses are confined within the transparent walls of the cells until that subtile influence which we call radiation can do its work in bringing about new combinations of the atoms. It matters not whether we consider the radiation as an orthogonal vibration, as in light, or a.promiscuous interpenetration of the molecules, as in heat, or a radial vibration, as in the waves of sound; whatever view we take of it, or whatever the details may be, even if it be a rythmic breaking up and re-formation of the mole- cules, the general characteristic of radiation is an extremely rapid motion along the molecules and atoms of matter. Therefore, by radiation we understand energy or momentum in the minute atoms that go to make up the molecules and the masses that we deal with; this implies that work is done by one atom upon its neighbor, which work, according to its style, we call hght, heat, evaporation, ete. Assimilation and transpiration are among the forms of work in the growth of the plant that are due to the molecular energy contained in sunshine, and it is essential to progress in agriculture that there be kept a continuous register of the intensity and nature of the solar radiations that reach the plant. But this is a difficult problem, whose satisfactory solution has not yet been attained, although the work of Violle, Bunsen and Roscoe, Marie Davy, Marchand, Langley, Row- land, Hutchins, and many others have marked out the methods which seem most promising. ANNUAL DISTRIBUTION OF SUNSHINE. Humboldt (1845), in his chapter on “ Climate,” after comparing the climates and fruits of Europe, says: These comparisons demonstrate how important.is the diversity of the distribution of heat throughout the different seasons of the year for the same mean annual temperature, as far as concerns vegetation and the culture of the fields and orchards, and as well as regards our own well-being as a consequence of these conditions. The lines which I call isochimenal and isotheral (lines of equal tem- perature for winter and summer) are not parallel to the isothermal lines (lines of equal annual temperature) in those countries where— notwithstanding the myrtle grows wild in its natural state, and where no snow falls during the winter—the temperature of summer and fall scarcely suffices to bring apples to full maturity. If to give a potable wine the vine shuns the islands and nearly all sea coasts, even those of the west, the causé is not only in the moderate heat of summer upon the seashore, a circumstance which is shown by thermometers exposed 73 in the open air and in the shade, but it consists still more in the dif- ference between direct and diffused light, between a clear sky and one veiled with clouds, a difference which is still unappreciated, although its efficaciousness may be proved by other phenomena, as, for exam- ple, the union of a mixture of chlorine and hydrogen. Humboldt adds: I have endeavored for a long time to call the attention of scientists and physiologists to this difference; in other words, to the yet unmeasured heat which direct light develops locally in the cell of the living plant. (Cosmos, t. I, pp. 347-349.) TOTAL QUANTITY OF HEAT REQUIRED TO RIPEN GRAIN. Boussingault (1834), in his Rural Economy, computes the total quantity of heat required to ripen grain by multiplying the mean daily temperature of the air in the shade in centigrade degrees by the duration, in days, of the process of vegetation. This product is known as the number of “ day degrees” that the plant has experi- enced or has required for the development from sowing to maturity. (See Annual Report Chief Signal Officer for 1881, p. 1208.) Bous- singault’s results are given in the accompanying table: Day degrees required at different latitudes. | Dura- Mean air Product of Plant and place. Tatitades woe Cr ceredun| ee anys . Peay || als cul- | tempera- ture. ture. Autumn wheat: St Days. | a: | Day deg. PAUIBACOpS naa teen es ee oe ei ec i ce an es 48 48 137 15.0 2 055 INAV G ap be ee sas gos BOSSE Se EEO SS Seana 44% 146 14.4 2 092 SINS GON eres a ae ene a esa eee 41 50 122 17.2 2 098 Summer wheat: PAISA COM a8 22! so 2¢b ce. cette ete hi icts tess ee cs 48 48 131 15.8 2 069 Kain STON Wa = sos sree sae ees ae esse ee = st oe SEs = 41 50 106 20.0 2 120 (Oyie(G hikakeh Sle So Sae = es ee ee ees 39 «6 137 aay 2 151 Abgrb.gl keys Sa ee ee Pee Opes Se See a ae See a ee 9 00 100 22.3 2 208 @uinchuquies: 3-28 2 o-c ese 8ae- here poem aces ste cs O 14 181 14.0 2 230 Winter barley: r—ih PNISHCOR ROM (scree tee os ee eee ee eee ee 48 48 122 14.0 1 708 ING WT fo iy DSRS Pee ee eee eee Cee eee aes 447 137 13.1 1 795 REIN PSCOM Pena ans et see wa tee tates Sess has 41 50 92 19.0 1 738 Sani tanh Omer ores. cus yt a cease aes ee aoe 2 4 35 122 14.7 - 1 793 (Chrba a 67 |S Se eee ee eee 0 00 168 | 10.7 1 798 The above table shows that the total quantity of heat required increases as the latitude diminishes. THE SUNSHINE AND HEAT REQUIRED TO RIPEN GRAIN. Tisserand (1875) modifies Boussingault’s hypothesis that growth varies with heat and time, but adopts the rule that the work done by - a plant can be represented by the product of the mean temperature 74 by the number of hours of sunshine, only rejecting the useless night- time, Just as one would reject the useless low temperature. In the absence of sunshine records he uses the number of hours between sunrise and sunset, or the duration of diffuse sunshine, and obtains for spring wheat and barley the data given in the accompanying table, where the last column may be said to give “sunshine hour degrees.” Sunshine hour degrees. Sunshine . nour Plant and locality. Datitude Desible anheee: jpebrees ; : sunshine. | perature. | pine Soe shine). Spring wheat: . Dips hl (Of PNISR Ole tee eee ee bea a ns ee eee 48 30 1 996 15.0 29 900 Christiania ee. cae oe era eee ee eee 59 9 1 795 15.4 27 643 Halsnos See eet: hace ck ee es ek ee eee ee eee | 59 47 2 187 13.0 28 431 BOGOF ee oe ee ee fees ore Cee es aera ee 67 17 2 376 11.3 26 848 S Grr) Ce ae ee ee eee ee eee ee ee 68 46 2 472 10.9 26 244 Skibotten?sceesas sce oes eee ee meee ee eee 69 28 2 486 10.7 26 600 Barley: PAN SS. COlae see eee io hee a ee ern ee 48 30 1 416 19.0 26 900 Christiania sete) Se ee ee ee ea ae 59 9 1 620 15.5 25 125 IH BISNOs: - vee see eee ek eae eis a ot AE ee 59 47° 2 035 Tey 23 809 BOG Oba 22 seen eee Sener ee ee 67 17 2 138 11.0 23 000 Skibotten ___.__- Speco ere 2h Sena oe hoe me 69 28 2 138 10.7 23 000 1D Yo eenewe ees 2A Se eRe AA Sanh eye ee eee ae 69 28 1 824 12.7 22 876 We see that the sunshine hour degrees diminish as the latitude in- creases. This diminution ought to be rather more rapid in propor- tion as the actual state of the cloudy atmosphere approaches the theo- retical state of absolute clear sky. Thus Halsno and Bodo, localities which have very nearly the same soil, the same altitude, the same orientation, the same distance from the sea, but which are more or less under the influence of the aqueous vapor coming from the Gulf Stream, have a cloudiness during the evolution of wheat of 5.6 and 7; during that of oats, 5.4 and 7; where 0 represents perfect freedom from clouds and 10 completely covered. If records of cloudiness could have been used, the numbers in the last column would have been computed like those in the following table: [Possible] Gioudi-| Gear ery [dally | _Sun- ait, || essa 4 ree tempera-| shine. : ture. | Spring wheat: Hours. | Tenths. | Per cent.| Hours. | Degrees.| Hours. Haleniomee od f0: os see ee 2,187 5.6 | 44 982| 13.0] 12,506 (IBOGOE a ers ecb soos eee 2,376 7.0 | 30 713 11.3 7,865 Barley: Ep lsno ese mem hi ee aS Racers Witney 46 936 11.7] 10,951 Bodo? tay A Pils ee kn | 2,188 | 7.0 30 641 11.0 7,051 75 THE SUNSHINE AND HEAT REQUIRED TO FORM CHLOROPHYLL. After considering the preceding data Marié-Davy (1880, p. 221) presents the following as his views: It is the chlorophyll or green coloring matter in the cells of the green leaves that alone has the property of decomposing the carbonic acid of the air. It utilizes the sunlight, but also requires a certain temperature, which may be given to it either from the air or from the sunshine itself, so that. we may say that ordinarily in nature the sun- shine both warms the chlorophyll by means of the red rays and enables it to decompose carbonic acid by means of the yellow rays. The decomposing action of the chlorophyll only becomes appreciable at a certain minimum temperature, which is about 15° C. when the tem- perature is rising. It attains its maximum activity at about 30° C., and as the temperature cools it retains an appreciable activity at about 10° C. These figures are obtained by experiments of Cloéz and Gratiolet on water plants in the full sunshine. On the other hand, Boussingault obtains 1.5° and 3.5° C. as the lower limits of temperature for the ordinary Graminee, but these plants were in the sunshine, and if his temperature observations had been made in the shade they would have given lower figures than these, so that un- doubtedly the Graminez can assimilate and grow when the tem- perature of the air in the shade is below freezing. On the other hand, Sachs find that when the illumination is below a certain minimum, which varies with the plant and with the temperature, the color of the chlorophyll is a clearer yellow tint, and for temperatures below a cer- tain minimum which varies with the plant it remains colorless, not- withstanding the most brilliant sunshine. Thus in 1862 the excep- tionally low temperature of the month of June was sufficient to prevent the development of new leaves on the stems of maize, cucum- bers, and beans, so that all these remained yellow and only became green subsequently with warmer weather and better sunshine. The pale leaves of a sprouting bean became green in a few hours under a temperature of 30° to 33° C., but this happened only in the sunlight, for at the same temperature in the darkness they remained yellow. Ata temperature of from 17° to 20° C. the greening of the leaf went on much more slowly; at 8° and 10° C. there was only a trace at the end of seven hours; below 6° C. the leaves remained fifteen days without greening. Similarly the pale shoots of maize, even at a temperature of 24° to 35° C., did not become colored in the darkness, but in the feeble ight of the interior of a room a green effect was visible at the end of an hour and a half, and at the end of seven hours the leaves were all green and of normal appearance. At a temperature between 16° and 17° C. the first traces of color were visible at the end of five hours. 76 But at temperatures of 13° and 14° C. nothing was seen even at the end of seven hours. At a temperature below 6° the leaves remained uncolored for fifteen days in the diffuse hight of the room. Again, the pale shoots of cabbage placed in the window, and there- fore in full sunshine and at temperatures of 13° or 14° C., became green at the end of twenty-four hours; but under temperatures of 3° to 5° C. only traces of green color were seen at the end of three days, and the coloration was not complete until at the end of seven days. Herve Mangon, by employing the electric light in place of sun- light, has arrived at similar results for rye. Marié-Davy, by the use of a single gaslight, has obtained similar results for the strawberry plant. Similarly De Candolle caused mustard and other plants to become green by the hght of four argand lamps. Evidently a very feeble light suffices to produce the greening, for the feeble individual effects accumulate and add together; but when a bright light is used secondary reactions set in, transforming and util- izing the chlorophyll itself. The heht that determines the production of the chlorophyll and its green color also proceeds to destroy the chlorophyll. Thus the direct light of the sun rapidly decolors the alcoholic extract of chlorophyll, while diffuse hght acts more slowly; but in a living plant the action of light is different, since it may become so intense for a special plant that the destruction of the chlo- rophyll may go on faster than its formation. If a green plant is car- ried into a dark room the chlorophyll ceases to form and a gradual process of destruction, or rather of transformation and assimilation, goes on until the plant becomes pale yellow. This mutability of chlorophyll makes it the essential medium through which the plant is nourished. Draper, Desains, and others have shown that the chlorophyll absorbs certain rays of the spectrum; that is to say, that the work of forming and transforming chlorophyll is accomplished by means of radiations that have a certain velocity of vibration or a certain wave length, and that they are mostly those that form the red, orange, yellow, green, and blue portions of the spectrum. Awaiting a more detailed study of this phenomenon, we must at present adopt the general rule that the variation in efficiency of each of these agents is approximately proportional to the variation in the total energy of the solar radia- tion, although our present knowledge points to the conclusion that a radiant beam generally contains specific active wave lengths in proportions and intensities that have no necessary relation to each other. (as INFLUENCE OF ABSORBENT MEDIA ON CHLOROPHYLL. The action of sunlight on the chlorophyll within the cell is not materially modified if the light passes first through layers of cells that do not contain chlorophyll, such as those of the red colored cab- bage leaf, since in those cells, as in yellow cells and others, the radia- tion that is absorbed is not to any extent that special radiation which the chlorophyll absorbs. The absorption of light by the yellow cells of the yellow leaves of an alder bush was examined by T. W. Engelmann (Agr. Sci., Vol. II, p. 189), who found that these ab- sorbed most from the middle of the spectrum and least at either end, whereas the chlorophyll absorption is complementary to this. He also found that the green leaves of the alder bush, when expesed to the light side by side with the yellow leaves, set free far more oxygen than these, so that it seems probable that if the yellow cells con- tain only pure xanthopyll there assimilating power would be zero. INFLUENCE ON THE SUPPLY OF SAP. The action of sunshine in producing or altering the colors cf fruits, especially the black Hamburg grape, has been experimentally studied by Laurent. (Agr. Sci., Vol. IV, p. 147.) Bunches of immature grapes quite shielded from the sunlight ripened, colored, and flavored as usual, but bunches whose food supply had been cut off by ringing the base of the stock supporting the bunch, and then also kept in the dark, remained green, small, and sour. Bunches that had been sub- jected to the ringing process, but which were exposed to the sunlight, produced berries of normal size, some reddish and others green and of an acid flavor. He concludes that the coloring matter of grapes may be formed in the absence of sunshine, provided a suflicient. sup- ply of nourishment be at hand, but if this supply be arrested then the color remains imperfect. CLIMATE AND THE LOCATION OF CHLOROPHYLL CELLS. Guntz (1886) has studied the anatomical structure of the leaves of cereals and grasses in their relations to locality and climate. This connection is infinitely complex. Among other items brought out by him we note that the green assimilating organism consists of many cells of various shapes and in most cases fills the spaces between the nerves of the leaves; in tropical grasses the green cells occur most in the inclosing sheath, but in the grasses of the steppes it lies on either side of the grooves or ridges. The intercellular gaps, according as they are larger or smaller, indicate a moist or a dry soil and, equally so, a moist or dry atmosphere. The bast in the leaves of the erasses serves primarily to strengthen the whole structure, but the bast increases with the dryness of the locality, and its proportional distribution is an appropriate, indirect indication of the climate. 78 THE INFLUENCE OF CLOUD AND FOG. There are some parasitic plants, says Marié-Davy (1881 and 1882), that require only moisture and warmth in order to vegetate. They mature and propagate while entirely cut off from sunlight, but they derive this power from organic matter or cells that have been pre- viously formed by the action of sunshine upon the plant on which the parasite itself feeds. Similarly certain bulbous plants will flower and mature in dark- ness, but in doing so the bulb itself is wholly consumed and dies; the plant lives on organic matter that was elaborated and stored up by its parent and predecessor in preceding years when it had sunshine to do the work for it. Ifa new bulb is to be formed as a basis for the flowering of the next year then the present bulb and plant must be allowed the necessary sunlight. Similarly the seeds of the annuals sprout and nourish their little plants out of their own substance while still beneath the surface of the earth, but when the shoots reach up to the sunshine this furnishes the energy needed for the work of assimilation and the plant. begins to live on the soil and the air. The roots can only send up to the leaf an inorganic sap with possibly here and there an organic cell scattered through it which has penetrated into the roots, as it were, by accident; it is the sunshine that sets these organic cells into activity, causing them to grow and to multiply. If a plant in vigorous growth is removed from sunshine to darkness it draws upon its own reserves and lives upon itself as long as pos- sible. In darkness the plant transforms the organic products that are at its disposition, but it can not manufacture any new ones. On the contrary, it consumes itself and its dry weight steadily diminishes. The experiments of Boussingault on seeds. those of Sachs on plants and seeds, those of Pagnoul on the beet, and of Macagno on the grape- vine all confirm this general principle. The observations of the latter show that as between two sets of vines, one exposed to the sun and the other covered with a dark cloth, the growth of the latter, as measured by the amount of solid and gaseous material, was not 10 per cent of the growth of the vine in the sunshine. Other vines under a white cloth showed a growth of 80 per cent, thus apparently proving that the differences were not due to anything else except sunshine. Pagnoul experimented upon sugar beets, some of which were coy- ered by glass that had been blackened on the inside; this coating of lampblack is ordinarily said to absorb heat, but it would be more proper to say that it transforms all the short waves of the sunshine into long waves so that the plants beneath it receive neither ultra- violet nor visual rays, but only the ultra-red, or long, heat weves. Therefore beneath the black glass the temperature was somewhat warmer than beneath the transparent glass and the latter warmer nee aemmet ess (ic) than the free air. The results of analysis at the end of the experi- ments showed that under the transparent glass the weight of the roots was the same as in the free air, but the weight of the leaf was much more, the weight of the sugar much less, and the weight of the nitrous salts much greater. Under the black glass the weight of the roots was 4 per cent of that in the free air, and the weight of the leaves was about 25 per cent, the weight of sugar 2 per cent, and the weight of the salts 8 per cent, thus demonstrating an almost complete stop- page of the vital processes. Evidently the action of these artificial coverings on the experi- mental plants is perfectly analogous to the action of cloud and fog in nature. It is commonly said that on the seacoast the action of the salt brine blown by the wind up over the land is to stunt or prevent vegetable growth, but the same effect must be produced by the absence of sun- light in those regions where fog and cloud prevail. INFLUENCE OF SHADE ON DEVELOPMENT. According to Marchand (1875, p. 130), the influence of a dimi- nution of sunlight on the development of the plant is apparent in the relative growth of plants on sunny and cloudy days or in sunny and shady places, but the matter was brought to exact measurement by Hellriegel. His experiments on barley gave him these results: Weight of harvest of barley. Plants raised— Straw. Seed. Pounds.) Pounds. rigs openiair 222th e os s2te ee - 1h RASS ids ASAE SARL PSY Sey 2 SU TSE ae Mee | 11. 44 | 10:10 10.99 11.19 imaereenhouse in dinectisunshinelss-s--- 26854. <2 2-2 8 ee ee | 6.72 2.86 6. 32 3.26 Inia greenhouse in diffuse light only —-/-..- 2-_25_----. 022 22S sc.2 228... Utes | 3. 40 | poe og PATO) IS crepe ee We see here that plants living in the greenhouse, receiving sun- light that has traversed the glass, have experienced a considerable diminution in their development as compared with those in the free air which experienced the full chemical force of the sunshine. The plants living under glass and in the diffuse light developed only a small quantity of stalk and did not perfect the seed at all. INFLUENCE OF LONG AND SHORT WAVES OF LIGHT. Vochting (1887) investigated the formation of tubers as influenced especially by sunlight. Sachs had maintained that the germination was entirely prevented, or at least went on very slowly, if sunlight, 80 i. e., short waves, had access to the tubers. Vochting finds that, although the light does delay the growth and diminishes the distance between the tubers, still the supply of water is the important factor. (Wollny, X, p. 230.) Sachs (1887), as the result of experiments on the effect of ultra- violet radiation upon the formation of buds, states that these rays exert on the green leaves (in addition to the assimilation produced by the yellow and neighboring rays) still another effect that consists in the development of particles that contribute to the formation of blossoms. These bud-forming particles move from the leaves into those parts of the plant where they are to bring about their own development into buds. We therefore now know of three different portions of the solar spectrum having very different physiologicai influences: The yellow and neighboring rays, which bring about the transformation of carbonic acid or the formation of starch; the blue and visible violet, that act as stimulants to motion; the ultraviolet rays, that produce in the green leaves the material for the formation of buds. (Wollny, X, p. 230.) INFLUENCE OF DRYNESS AND SUNLIGHT ON DEVELOPMENT OF TUBERS. In the climate of Germany the flowering of different varieties of potatoes is very much restricted. Only a small number of varieties flower regularly and bear fruit, whereas in Chile the plant flowers abundantly, but the tubers are small; in other words, in the Tem- perate Zone the formation of tubers is favored at the expense of fertilization; the energy of the one process increases while the other diminishes. Knight and Langenthal have found that by detaching the young tubers they increase the blooming, and on the other hand, by cutting off the flowers they increase the development of the tubers, thereby largely increasing the harvest. Wollny, in 1886, experimented on four plats, each for many varieties of potatoes. He found that cut- ting off the flowers increased the crop of tubers as to number, size, and weight, but that something depended upon the time of cropping the flowers, which is best done a considerable time before they arrive at maturity. It seems probable that dryness and sun- light stimulate the formation of flowers, but humidity and cloudi- ness, at least up to a certain limit, stimulate the formation of tubers. This harmonizes with some recent results obtained by Sachs, who has shown that the ultraviolet rays stimulate the flowering. (Agr. Sci., Vols p.c2(3.) wc Chapter V. THE METHODS OF MEASURING DIRECT OR DIFFUSE SUNSHINE AS TO INTENSITY OR DURATION. Sunshine may be measured as to its quality or wave length, its intensity, or its duration. The methods used in measuring either of these must be understood in order to intelligently compare the pub- lished observations with phenological phenomena. The following section considers some’ of the methods of measuring or registering the duration or intensity of sunshine, or the intensity of the skylight, at least in so far as these have been used in agricultural studies. THEORETICAL RELATION OF DIRECT AND DIFFUSED SUNSHINE. The relative intensity of any radiation may be measured by its heat or light or chemical effect. The insolation received by a horizontal surface, whether directly from the sun or diffusely from the sky, is subject in a general way to calculation, but the irregularities intro- duced by haze and clouds can not be so calculated and must be ob- served daily. The following table gives, for a clear blue sky, the values obtained by Clausius for the radiation (S) that falls upon a horizontal surface directly from the sun, and in the third column the diffuse radiation (C) that falls from the whole sky upon that same surface; the total radiation (S+C) is the sum of these two. If, however, the surface is normal to the sunlight, instead of hori- zontal, it receives the quantity in the fifth column (1) directly from the sun, and (c) which is less than the quantity (C) from the sky, depending upon the altitude of the sun, the total being, as before, the sum of these (I+c). The study of these columns shows us the maximum and minimum amounts of sunshine that may fall upon a given leaf surface, since a leaf will in general be in some position to receive the full sunshine normally to its surface, while others will be horizontal, or vertical, or in the shade, and receive only a part of the diffuse light from the sky. It is assumed by Radau, in his actinometry (1877), as also by Marié-Davy, that the bright and black bulb thermometers in vacuo, or the so-called “ conjugate thermometers,” give us the total radiation (C-+1) as for the horizontal surface, and that this is the quantity in which vegetation is interested. 2667—05 M——6 (81) 82 Relative quantities of direct and diffused sunshine. Horizontal surface. Normal surface. | Sun’sal- SS ] = titude. | sun (8). |Sky (©).| (go) | Sun @.|Sky(c).| Fetal ; | | 10 0.03 | 0.07 0.10 0.19 0.04 0.23 | 15 09 | 09 .18 . 33 05 38 15 fr 26 43 | 06 | 49 25 21 13 | BA 51 08 59 | 30 .28 14 | 42 56 | 10 66 | 35 35 159) 50 61 agli 7 40 Al 16 | BT 64 12 76 50 58 ali 69 69 14 83 60 62 51851 Saeee60 We a iG 88 70 .69 18 | 87 4 | si 91 #0 74 18 92 1 ee See 90 15 19 | my 15 19 | 94 | TOTAL INSOLATION, DIRECT AND DIFFUSED. The value of the intensity of the direct solar rays incident nor- mally to any unit surface, as determined by the absolute actinometers of Pouillet, Violle, and others, is not so applicable to the study of the growth of plants as is the sum of the radiation from the sky and other surroundings of the plant, added to the direct solar radiation. Comparative measures made in 1866 by Roscoe, at Manchester ; Baker, at Kew; Wollkoff, on the summit of Koenigstuhl, near Hei- delberg (altitude, 550 meters), and Thorpe, at Para, have given the following values of relative intensity of radiation at certain moments when the sun’s altitude above the horizon was sensibly the same at all the stations. (See Marie Davy, 1882.) Relative intensity of radiation for equal altitudes of the sun. | \Latitude. ¥rom | soe pias Sun/sky. Manchester se: 222s se ees N.53.5 0.048 0. 140 0.188 0.31 CSW eee ate his welt eae N.5L.5 150] —-. 162 .312| 0.98 eGciahfes hall Me Ee N.49. 4 .263| 174 437 | 1.51 Pamigee eMail eos N. 48.8 (222) B01 12 0.44 Phare c en Glt Tre eke S.00.5) 136). 136 .272| 1.00 At Manchester and at Paris the light that comes from the sky is more than double that which comes directly from the sun. When the sun is hidden by clouds, or even partially veiled, it is the radiation from the sky that is of the most importance to agriculture, and im any case this radiation is far from being negligible. The Arago-Davy actinometer (believed to have been invented by Arago before 1844, but improved by Marié-Davy and used at the utente 83 observatory of Montsouris ever since 1873) is an apparatus that 1s intended to determine the total solar plus sky radiation that is needed in agricultural physics. A theory of the action of this instrument was devised by Marié-Davy, but the proper method of calculating its results was first developed with exactness by Ferrel, in Professional Papers of the Signal Service, No. XTIT (1884), and subsequently in his Recent Advances in Meteorology (Annual Report, Chief Signal Officer, p. 8373). His formula will be given on page 88. The Arago-Davy actinometer is composed of two mercurial ther- mometers with very fine tubes, and having spherical reservoirs of equal dimensions, one colorless and the other covered with lamp- black. In the empty space above the mercury in the thermometer tubes there is a small quantity of hydrogen or other inert gas. The small quantity of gas left in the tubes of these thermometers has no other object than to prevent the mercury from falling in the tube by the force of gravity when the bulb is turned upward toward the sky. Each thermometer is inclosed in a larger glass tube or cylinder, ter- minated by a spherical enlargement, in the center of which is placed the center of the bulb of the thermometer. This tube and enlarge- ment constitute the inclosure, and it is exhausted of air as perfectly as possible. The immovability of the thermometer, relative to the walls of its inclosure, is assured by a soldering at the upper extremity of the tube and, at the opposite end toward the reservoir, by two rings of cork held by friction between the interior tube and exterior cylinder. These thermometers, with their respective glass inclosures, are turned up with their bulbs toward the sky, and by means of double clamps fixed parallel to two metallic rods, arranged in the form of a V and turned, the one toward the east, the other toward the west. These metallic rods make an angle with each other of 60°—that is to say, of 30° with the vertical—and are fastened to a support of wood or iron 1.20 or 1.30 meters in height above the earth. The support is solidly planted in the ground in an open place, remote from buildings, plants, or any other obstacle capable of intercepting the direct radiation of the sun. The two thermometers, the envelopes of which are exposed near each other, have necessarily the same temperature and mark the same degree as long as they remain in perfect darkness; but hardly does day begin to break than the thermometer with the black bulb marks a higher temperature than that with a plain glass bulb. The difference in temperature of these two thermometers gives the * acti- nometric degree” for the moment of observation; that is to say, it serves to measure the intensity with which the radiation strikes the two thermometers and is absorbed by the black bulb; consequently, at least approximately, it serves to measure the intensity with which the 84 radiation strikes the ground and neighboring plants and accumulates therein. After three years’ use of this instrument, Marié-Davy selected the observations made on the days of perfect clearness of the sky, of which there were only nine, since many days that would be called cloudless showed shght traces of haze. For these days the difference between the readings of the black bulb and bright bulb is represented closely by the exponential formula bt ie 01S 15" where the exponent e represents the thickness of the layer of air through which the sun’s rays must pass in order to reach the observer ; this thickness, of course, increases as the sun approaches the horizon, being unity for the zenith and 10 for an altitude of 2°, as shown by the following table, which is an abstract of that used by Marié-Davy in his computations: Thickness of the layer of air traversed by the solar rays, as computed by Lam- bert’s formula. Altitude | Thick- || Altitude! Thick- of sun. | ness, e. of sun. | ness, e. — ] } 5 | 5 0 12.69 | 25 2.30 2 10.20 || 30 1.96 8.28 || 40 1.54 6.83 |) 50 1.30 5.75 } 60 1.15 10 4.92 || 70 1.06 15 3.58. || 80 1.02 20 2.80 | 90 1.00 As the formula of Lambert has been chosen by Marié-Davy for use in connection with his form of actinometer, we have therefore given its results in the preceding table; but as the more accurate formula, as given by Laplace, has been applied to other forms of actinometers, and may even be preferred for the Arago-Davy instrument, I there- fore give a table showing the thickness by the formula of Laplace as used by Violle and the value of the intensity (I) as given by Violle. : 85 Thickness of the layer of air traversed by the direct solar rays as computed by Laplace’s formula, and the corresponding value of I, the absolute intensity of direct sunshine in calories per minute per square centimeter which fall nor- mally on any surface through the purest air, as given by Voille. F Intensity | : Intensity Thickness . .| Thickness Zs |Altitude| (e),La- | of di | aitituae| (ce), La- | (of di of sun. place shine, || fsun. | _ place aniae formula. eaey ||| | formula. wien, Violle. Violle. 0 35.50 0.359 || 30 1.995 2.275 Ne 18. 90 0. 896 35 1.740 2. 306 4 12. 20 1.293 | 40 | 1.555 2.831 6 8. 60 1.540 45 1.420 2.349 8 6. 85 130) | 50 | 1.305 2. 364 10 5. 70 1. 868 60 1. 155 2.383 15 3.81 2.059 70 1. 065 2.395 20 2.90 2.164 80 1.016 2.401 25 2.425 2. 229 90 1.000 2.403 Observation shows that no two such Arago-Davy actinometers placed side by side will give exactly the same results; therefore the rule has been adopted of comparing all instruments with the stand- ard kept at Montsouris, and a standardizing factor is thereby obtained by which the observed difference between the bright and black bulb of any pair is to be multiplied in order to reduce it to a common standard. In addition to the standardizing factor of the preceding paragraph, Marié-Davy has also introduced the conception of an ideal standard actinometer, graduated in such a way that the first factor, 17° in the above-given formula as expressed in centigrade degrees, shall be represented by 100 ‘“ actinometric degrees” in his ideal instru- ment; that is to say, all the differences (¢-¢’) observed with any actinometer, after being multiplied by the standardizing factor, have still to be multiplied by the factor 5.88 in order to convert them into ideal actinometric degrees. For convenience both these factors may be replaced by one, and in this way the instrument and Marié-Davy’s methods have been extensively employed in studying the relation between sunshine and crops. In such study Marié-Davy and his pupils take the “sum of the total number of actinometric degrees” as the datum for comparison with crop reports, instead of the sum of the temperatures of the air observed in the shade, or the sum of the soil temperatures as used by other investigators. If we divide the actinometric degrees given in any case by the factor 5.88 we shall obtain the excess of the black bulb over the bright bulb as originally observed in centigrade degrees. From this we can obtain the true relative quantities of solar radiation by a modification of the method given by Ferrel (pp. 41-50 86 of his above-quoted work of 1884, on the Temperature of the Atmos- phere and the Earth’s Surface). Until such a method has been perfected (see an article by Ferrel in Am. Jour. Sci., May, 1891, 3, Vol. XLI, p. 378) we will for the present quote the actinometric degrees and other figures as ordinarily published by Marié-Davy and others; but the reader must bear in mind that these results from the hypothesis assumed by Marié-Davy that the observed difference between the bright and black bulb is pro- portional to and therefore a proper measure of the intensity of the radiant heat that falls upon these thermometers; a hypothesis which, as Ferrel has shown, is far from being true. The error of this hypoth- esis is of such a nature that for a given difference or a given actinometric degree the true intensity of radiation is greater at high temperatures than at low temperatures. Probably the recorded acti- nometric degrees therefore give a rather low value for the solar and sky radiation during the hottest portions of summer days. The accompanying table, as published by Marié-Davy, shows the actinometric degrees calculated for the clearest of skies at Paris at noon of each day. They are computed according to the preceding formula, viz, A=actinometric degrees=100X0.875°; in which, as before said, the coefficient, 0.875, represents the penetration or the total heat which penetrates to the observer, both from the sun and the surrounding sky, and includes even that small part that is directly reflected from the surrounding grassy lawn or other surface when the sun is in the zenith; if there were no atmosphere pres- ent the total amount received would be 100. It will be less confusing if the reader will consider these so-called “ actinometric degrees ” as “ percentages of what would be received in the absence of the atmosphere.” Columns 5, 6, and 7 of our table give the mean value of the five actinometric percentages observed on the clearest days at 6 a. m., 9 a. m., noon, 3 p. m., and 6 p. m.; in the absence of actual observa- tions these means may be employed in our study, provided we make a proper allowance for the influence of hazy and cloudy skies. It is, however, always desirable that, the actual observation of the acti- nometer should be available, and with it should be associated a simultaneous record of the cloud or haze as given by the sunshine recorder. es Me EE ee ee ee a 87 s Solar radiation plus sky radiation erpressed as actinometric percentages accord- ing to Marié-Davy, caleulated for skies as clear as at Montsouris and for various latitudes. Date. Noon observation, Mean of 5observations RIA Iy gle ae aes eae mes See et ek Seek semiieitavalleeee een een se co 4. ok eee ee oe * Lien OA Lk Sas ter ee ee ie eee een, alee age Goreaidy bas Sa cee SS ee ee ee eee eee Heleustsyuliten = totsetcee a 5 fess oP op ene ISO IEUaT Vas ete een Ae hegen e steerer a she UE TRH AY TL 6 eae Pape re ae Sin, ig Gti ee a Wie yrireh al FUL le sO eT al See Roe WR FAL Seo See ae 2 Seen eae Ee nee ee oe ee O CTO DET leer eae i bey Been ro ee INOVemiberwlewa teers yok Oh Oe ee Caos Bk yas November 11 IIOW Gr OGRA ee Se ee ee ees eee eee IDeaaisay ere al Sacer ee A Ries = eee es eee Se December 11 WMecemborie ieee eas a5. set UAV lene eon eee aaa eee i ed 34.6 THEORETICAL FORMULA FOR ACTINOMETER. latitude— daily, latitude— | 42° N.| 46°N.| 50° N.| 42° N.| 46° N. | 50° N. 73.6 | 69.9] 65.1 | 38.0) 34.6 30.2 74.5| 71.2| 66.7| 39.0] 35.9 31.9 75.9| 72.9] 69.0] 40.3] 37.7 34.2 OS NN) Be |e Si N 42; 08). 89,9 37.0 79.1| 77.0 | 74.4| 43.5| 41.8 39.6 80.6] 78.9) 76.7) 45.0] 436] 41.9 81.6] 80.1] 784] 46.2] 44.9 43°7 82.8| 81.6} 80.1] 49.6] 48.6 47.5 88.8| 82.8] 81.6) 55.7| 55.0] 542 84.7| 83.8] 82.9| 60.7] 60.6| 60.2 85.3} 84.6| 83.8] 65.0] 65.1 65.1 85.8] 85.2| 846] 68.4.) 68.7 68.9 96.2) 85.71}: 85.0] 71.0] 71.5 71.8 86.5 | 86.0] 85.5) 73.0] 73.4 73.8 86.7| 86.3| 85.8] 74.3] 74.9 75.3 86.8] 86.5] 86.0} 75.3) 75.9 76.3 86.9] 86.5] 86.2] 75.9) 76.3 76.8 87.0| 86.6) 86.2) 76.0) 76.6 77.0 86.9| 86.5) 862] %5.8| 76.3 76.8 86.8| 86.5] 86.0| 75.3 | 75.9) 76.3 86.7) 86.3) 85.8) 74.4) 75.0 75.4 86.5) 86.0) 85.5 13.0) 73.5 73.8 86:2 | 85.7] 85.11 71.0] 71.5 71.9 85.8 | 85.2| 84.5, 68.4) 68.8 69.0 8.31 84.5] 83.7| 64.7] 64.8 64.8 84.6| 83.8| 82.8| 60.5] 60.2) . 59.9 83.8) 82.8| 81.6} 55.9] 55.3 54.5 82.9] 81.7) 80.2) 49.4] 48.5 47.5 81.7| 80.3| 78.5) 46.1] 45.0 43.6 80.4 | 78.7] 76.4) 44.8) 43.4 41.6 78.8| 76.6] 73.9| 483] 41:5 39.1 7.2) TA) Ts 41.3) 39.0 36.0 Hoste 72-7, |te, 68.8.) en 40: 2, | corals 34.0 74.4| 71.0) 66.5| 38.8| 35.7%7| 931.7 73.5 | 69.8) 65.0] 87.9| $4.5] 930.1 73.2) 69:4] 644) 97.6/ 341 29.5 73.6) 69.9] 65.1| 38.0 30.2 In reply to some criticisms of Violle, Marié-Davy (1880, p. 245) gives the only statement that I have seen of his theory or explanation It is about as fol- of the working of his conjugate thermometers. lows: Let— a be the absorbing power of the bright bulb. / the absorbing power of the black bulb. ca numerical coefficient for converting degrees of temperature into a quantity of heat. 88 g the quantity of radiation or heat falling per minute on the black bulb and also on the bright bulb. aq the quantity of radiation absorbed by the bright bulb. l-q the quantity of radiation absorbed by the black bulb. e the emissive power of the black bulb. ’ the emissive power of the bright bulb. ¢and ¢’ the temperatures of the black and bright bulbs, respectively, when they come to the stationary temperature that indicates equilib- rium between absorption and emission. T the temperature of the glass envelopes within which the ther- mometers are inclosed in a space that 1s an approximate vacuum. On the assumption of the Newtonian law of radiation, viz, that the quantity of heat emitted is proportional to the excess of tem- perature, we have the following relations: g=ce (t—T) ag=ce’ (U—T) From these expressions we can, by elimination of 7, find the follow- ing expression for g—that is to say, the quantity of solar radiation per unit of time that is at that moment falling on the two thermome- ters, at least in so far as this radiation is capable of being trans- formed into heat by absorption into the bulbs of the thermometers: cee time =e gli?) Marié-Davy, in the absence of exact knowledge of these coefficients a, ¢, e, e’, prefers to attempt to determine only relative measures of the intensity of radiation. He therefore assumes that the expression cee! Ss oF is equal to 5.88 units, and the values for g thus obtained he calls actinometric degrees, since on the very clearest days in Paris they accord well with the assumption that the so-called solar constant of radiation is 100 actinometric degrees, and that the coefficient of transmission of sunshine through the atmosphere is 0.875. Ferrel (1884), in his memoir on the temperature of the atmosphere (p. 41), has improved upon Marié-Davy’s theory, in that he has applied to the conjugate thermometers the law of radiation, estab- lished by Dulong and Petit in 1817, which is applicable to a much larger range of temperatures than the Newtonian law adopted by Marié-Davy. Ferrel’s formula may be written: g=4.584 kh mt’ (m t—t’—1) where the notation is the same as before, except that m is the num- ber 1.0077, as determined by Dulong and Petit and &% is a factor that varies with the quality of the bright bulb, whose absolute value is 89 usually greater than 7, but whose relative value may by preference be determined by referring each pair of conjugate thermometers to an adopted standard pair. Ferrel’s formula is especially devised for thermometers having spherical bulbs, measures made by it at high and low temperatures give results that are comparable with each other; for absolute results the numerical coefficients may need some modification, but as it stands it gives the values of g approximately in calories per minute per square centimeter. Omitting for the present the factor / in Ferrel’s formula, which must be specially applied for each thermometer, we have the values of g in calories as given in the following table (see Ferrel, p. 37), which also presents the corresponding values given by the formula of Marié-Davy in actinometric degrees. In a critical study of observa- tions reduced by these two methods we have to recall that Marié- Davy’s actinometric degrees are really fractions of a calorie, or units of heat so small that 100 of them are equivalent to the absolute radia- tion of the sun received at the outside of an atmosphere whose coeffti- cient of transmission is 0.875; whereas Ferrel’s calories have been adopted without predicating anything as to the solar radiation or atmospheric absorption, concerning which his observations show that the solar radiation constant is between 2 and 2.25 calories per minute per square centimeter and the atmospheric coefficient of transmission to be used with the conjugate bulbs is 0.72. Solar radiation deduced from observations with the conjugate thermometers. Marie | Ferrel, calories per minute per square centimeter for the respective Davy, | bright-bulb temperatures. aul actino-| — —= * |metric | | de- —10° —5° | 0° +5°° |) 10° = -+-15° | +20° | +25° | +30° grees == es | _ eS Se eee OC; 5.....| 29.4| 0.166} 0.172] 0.179 | 0.186 | 0.194 | 0.201 | 0.209} 0.217 | 0.226 | | | 10_---| 58.8 | .339 | .352 .366 | .380 885 | .410 |. 426 .443 | .460 1a weee |r 18852 .518 | .538 559 581 . 604 | . 627 . 652 .678 | . 704 Pe Vercele EE 705 | . 132 761: | 791: . 822 .854 | .887 .922 | .958 25_---| 147.0 898 | . 933 .969 | 1.007 | 1.047 | 1.087 | 1.131 | 1.175 | 1.220 30_..-| 176.4] 1.099) 1.142) 1.187 | 1.284] 1.282) 1.332) 1.385] 1.4388 | 1.495 85_...| 205.8 | 1.309 | 1.360) 1.418 | 1.469] 1.526) 1.585 | 1.647 | 1.712 | 1.778 40.___| 235.2 | 1.525 | 1.585 | 1.646] 1.711] 1.778 | 1.848 | 1.920] 1.995 | 2.073 45.___| 264.6 | 1.750 | 1.820] 1.891 | 1.964] 2.042 | 2.121 | 2.204] 2.291 | 2.380 | INTENSITY AND DURATION OF SUNSHINE AT MONTSOURIS. In order to have at hand data that will enable one to approximately infer some of the relations between the temperature of the air and of the soil and of the solar radiation, one may consult the tables for the observations at Montsouris, given by Marié-Davy in his Annuaire for 1887. 90 As those who can not make use of the actinometric degrees deduced by Marié-Davy from his observations of his conjugate bulbs will necessarily have to use either the simple observations of clear sky and cloudy sky, as given by the sunshine recorder, or the equivalent personal observations of the clouds, I give the following tables, which show how nearly parallel these two phenomena may be. Evidently in our study of the influence of insolation on crops in America from year to year we may use the sunshine recorder or the ratio between the actual and the maximum possible duration of sunshine without much error, at least in the growing season. Mean of five daily actinometric observations at Montsouris, expressed in Maric- Davy’s actinometric degrees or percentages of maximum possible intensity. | | | | Month. | 1875. | 1876. | 1877. | 1878. | 1879. | 1880. | 1881. 1882. | 1883. | 1884. | 1885. = wt pues Bl SS Say a eve | scabised| Sere es | | | a (Mprile see 2 11T EA | 44.1} 40.1] 36.3] 35.4] 28.6} 38.9] 33.0] 39.7] 868) 845] 341 Maryse! Hsee footed 7.7) 45.8) 38.7) 41.5) 40.6) 50.3] 48.9] 47.4) 45.9] 46.3) 40.3 une ee see ee ae 46.0 | 48.8) 54.5] 47.7] 45.1] 41.2] 533] 47.0] 45.3] 43.2] 46.1 Taly pene eke 47.3} 521] 48.6] 50.6] 41.2] 50.0| 52.0] 46.6| 422] 43.4] 49.4 Auguste: arate 39.9 42.0| 43.2] 87.8] 42.3) 30.1] 40.3] 34.0] 39.0] 36.2] 36.4 September. _-....-_.- | 95.7 | 30.9] 31.4] 30:9] 82.7] 30.2] 28.3) 27.1 | 30.5) 308) 20a me eS | | Average ------- 43.5 | 43.5) 42.1] 40.7 | 38.0) 41.6) 42.7 |) 40.3/ 39.9) 30.1) 38.4 | Mean of five daily observations of the cloudiness at Montsouris expressed as ratio of the actual duration of sunshine to the maximum possible duration. Month. | 1875. | 1876. | 1877. | 1878. | 1879. | 1880. | 1881. | 1882. | 1883. | 1884. | 1885 | | | Pari oot ee ge 2 | 0.66) 0.60] 0.54] 0.53} 0.43] 0.58] 0.49| 0.60] 0.55] 0.52] 0.51 Mayes ae er Ne 6441 68:] =2ee'l< S86 > 555] 568° 266 |i 64 [see 62: mene? D4 Tne tees ser eae a .60| .64] .71| .62| .59| 154] .70| 61] .59 56 60 Til y eee ee GSE oe .63| .69| 64] .67| .55| .66| .69 62} .56] .57 BD Paste ees | .57| .60] .62 54/ .61| .56] .58| .50| .56] .52 52 September.---------- . 62 54 OD 54 67 .53 49 AT 53 54 42 Average -.-..-- | .e2| .62| .60| .58| .55] .59| .60| .57| .67| .55| 52 RELATIVE TOTAL HEAT RECEIVED FROM SUN AND SKY DURING ANY DAY, BY HORIZONTAL SURFACES. A more accurate way of considering the amount of insolation at any locality is to compute the total radiation (expressed by its equiva- lent heat in calories) received by a horizontal surface in the natural daytime of that day and latitude, taking account of the absorption by the atmosphere. (See Annales Agronomique, 1878, IV, pp. 270-296, or Ann. Report Chief Signal Officer for 1881, pp. 1200-1216.) This has been done by Aymonnet by a graphic method. He assumes that if the sun were in the zenith then the unit of horizontal earth’s sur- face would, because of atmospheric absorption, receive only 0.75 of 91 the heat that it would receive if it were outside the atmosphere. Of the remaining 25 per cent one-half reaches this horizontal unit by way of the diffuse reflection from the sky, so that with the sun in the zenith the unit receives 0.875 of the original solar heat. For a point on the equator during twelve hours this would amount to 0.875 x 126060 of the total possible if the sun were in the zenith. Using this as a basal datum, Aymonnet obtains the relative numbers given in the following table or the ratio of the heat actually received during one day to that which would have been received if the sun had stood for twelve hours in the zenith. Thus on June 20, at latitude 30°, the horizontal unit receives 0.347 of that corresponding to the ideal sun in the zenith all day, while at the north pole on the same day the horizontal unit received during twenty-four hours 0.328 of what it would had the sun stood in the zenith for twelve hours. In fact the amount of heat received by horizontal surfaces is nearly uniform for all latitudes for the days June 15-July 28. These relative numbers or ratios may be turned into absolute calories by multiplying them by the so-called “solar constant,’ whose value is probably between two and three calories per minute per square centimeter. Relative quantities of total heat received on specified days from the sun and sky at different latitudes by a unit surface of horizontal ground during one cloudless day, allowing for the absorption and diffuse reflection of ordinary clear air, as computed by Aymonnet. | Declin- Latitude— nation 7 = Mego: ofsun,| go | 10, | aoe. | so. | vo. | aoe. | om, Marcin a). sees ULE ee 007 | 0.301} 0.295 | 0.255] 0.175 | 0.075 0.029 0.000 Mam ChigS ta teens a Ses cence se 3 02 . 298 297 . 268 - 190 . 098 . 049 O17 Mri at MSS ARES 2 Fete 652| .295] .308| .284| .215| .127| .082| 058 Prmrilel ester (ibe bee, ge 948| .292] .306] .296| .235| .157| .115 100 Salt ae 1314} .288| .307] .310} .261] .191| .159| .151 MOM ne ee as 1617 | .284| .305| .322] 281] .226| .207 205 Marpineee Jot tii do Sis, 1854) .279| .304] 331] .208] .255| .249 250 Mapenbnbiee nN aut oF 1 | 2058| .274| .304| .337| 318] .282] 280 286 fins 5 2 eee 22 34] .272] .303| .342| .324] 304] 312 313 Homesinet es sete 2320| .268} .302] .346] .329| .314| .328 326 Tel to eae SEY a agar} .267| .301{ .347| .3390] .315] .325/ .328 Sriete [Pe Teena 22 36| .272| .303| .342| 324] .304] 312] 314 EjelbystoeeenOa vets Choa 7S _...| 2051] .274| .304| .3387| 313] .282/ 279 284 TTT as ol 9 ee AO | 1850] .279] .304| .381| .208| .255| .249] 251 ING aS AY Oe ge op el em | 1625] .284} .305] .822] .281| 226] .209 207 JSESYEG IS Be Es a ape ee 1306] .288{ .307| .310} .261] .191| .159 152 August 25 ___._- Set aig hee ae 1045| .200] 307} .301] .242] 164] .128 115 Bupienther site. att Sos Om 648] .295| .303] .284] .215| 127] .o82] .058 SentemiberIsi1/20 1222). isd! 300] .208| 207] .268] .190] .098| .049 O17 =) September 23.0 ek eee 006) .301 295 | .255) .175] .075| 029 000 92 RELATIVE TOTAL HEAT RECEIVED DURING CERTAIN MONTHS. By adding the amount for each day of any month in the following table we get the relative numbers for the total amount of heat received direct from the sun at various latitudes during certain months by a unit of horizontal surface under a clear sky, and after absorption by ordinary clear air, plus the amount received from the diffuse sky hight or the atmospheric reflection, all expressed in terms of the amount that unit surface would receive if the sun were constantly in the zenith during twelve hours. The coefficient of transmission through one atmosphere for zenithal sun is, as before, 0.75, and the added sky- light is 0.125, to accord with the Arago-Davy conjugate thermometers, since these are affected by the sum of the heat received by their sur- faces from the sun anda from the atmospheric particles in the visible celestial vault. ; Relative quantities of total heat received monthly at different latitudes in the northern hemisphere. Month. 0. 10. 30. 50. 70. | 80. 90. NUT RC TOO oleae! as ee ane ee a7 37| . 8538) = 2ai adel more 0.2 (eS adn ee AE AE) Nie Dee LG |} 100) 106] 101] 80| 54] 39 | 34 Ry rete heels he mes Sntenes 0. QU Snlee LON 7e pe eelleyalleecT Oa 9.0 8.6 | 8.7 DRS (s) ee oR eed et) ne ORE Qi2:| 1004) OaTS9N aaa 10599) 9 11907 eae STi yA 19 ee AR en is Ce eee 9.7 | AONT|)) QE We Tass 1083) )/ Ose eons | | | PTS be siee e Oen s aren separa Sree ioc | 10.1] 10.7] 10.9 9.2 6.8| 5.9] 5.8 September l toes: -.2-.- sas se eee eas eee As Oe) TG balleee nei Deena 2 ko dap as ae | 60.2 | 64.6] 67.1| 57.8] 460) 41.6] 40.3 | a PHOTO-CHEMICAL INTENSITY OF SUNSHINE. Bunsen and Roscoe, in a series of memoirs published in the Philosophical Transactions, London, 1857, 1859, and 1863, entitled, “ Photo-chemical researches,” discussed the methods of measuring the chemical action of light by help of photographic tints, and endeay- ored to improve upon the methods of Herschel, Jordan, Claudet, and Hankel. They adopted as a standard unit for measurement that intensity of the light which in one second of time produces the standard tint of blackness upon the standard paper. Their methods are too laborious for the ordinary meteorological observer, but have furnished some important data as to the chemical activity of diffuse sunlight and of total daylight. In his memoir of 1864, Roscoe states that he and Bunsen had developed a method of determining the chemical intensity of both direct sunlight and diffuse sunlight, or the total daylight, that is, based upon the law that the intensity of the hght multiphed by the duration of exposure of chloride of silver paper of uniform sensi- tiveness gives a series of numbers proportional to the shades of tints, _— a 93 so that hght of the intensity 50, acting during time ¢, produces the same blackening effect as light of intensity ¢ acting during the time 50. According to this method the chemical action of the total day- light was determined for Manchester, England, many times a day during 1864, and the total daily chemical intensity has been com- puted for the year August, 1863, to September, 1864. Very large changes in chemical intensity occur when the sky is cloudless and unchanged as far as the eye can perceive. The total intensity for an apparently cloudless day varies from 3.3 for December 21, 1863, to 119, June 22, 1864. This last number, compared with the figure 50.9 for June 20, and 26.6 for June 28, shows the enormous variations that take place in the chemical rays that reach the observer at Manchester on cloudless days. This variation is undoubtedly due in part to smoke and moisture, but possibly other unknown influences are also at work. In 1867 H. E. Roscoe communicated to the Royal Society the results of work done by his method at Kew, England, in 1865, 1866, and 1867; at Heidelberg, 1862 and 1863, and at Para, Brazil, 1866. The general results are that the chemical intensity attains its max- imum at noon and not, like the temperature, at some time after noon. Everywhere the intensity increases from hour to hour with the alti- tude of the sun, and is very closely proportional to it even when the sky is partially clouded, but of course the rate of increase varies with the season, the amount of cloud, and the degree of atmospheric opales- cence. The total chemical intensity for each month, as determined from numerous observations, 1s as follows for Kew: Total photochemical intensity of direct and diffuse light (Roscoe). ’ Month. | 1865. | 1866. | 1867. Month. 1865. | 1866. | 1867. | | Mammary tic. 222.802) ecu 15 Bt Ful eee 8 Te Pore eee Hepnuaryees..-. ker seke alesse. Jkce 24 93 tll Aaioust st te a a: 8 89 942 Bose 2 Rech ee pa yl sr 34| 81 || September. _......-.-.-- 108 | et eee sare labs ites Magis see 98 Foslcet | | Octaber_.--- Dayton) eee eae Niagra ets 2 ate Fes ee 118 | NO ee ee | November ]—) 2222.2 18 | Gil ees oe dibhe:) 2 eae a ee a 82 | 92 |, 24-) 52 | ecemiber 4752-2 4. (CS) ial el) yee ee Roscoe compares these figures with the cloudiness, and finds that the ratio between cloudiness, expressed on a scale of 10,and the chem- ical intensity is as 1 to 5 in some months and as | to $ in others. A similar irregularity of ratio is found when he considers the absolute moisture in the atmosphere; whence he concludes that the variations in chemical intensity, as between the spring and autumn, are not perfectly explained by either of these factors. He finds the high autumnal and low vernal intensity fairly well explained as due to the transparency or opalescence produced by finely divided solid particles or dust. 94 Passing from Kew to Para, it appears that the chemical action of total daylight during the month of April, 1866, at Para was 6.6 times as great as at Kew. In order to obtain data for a clearer atmosphere, Roscoe and Thorpe conducted observations in 1867 near Lisbon, Portugal, and published their results in a memoir of 1870, where they have given the relation between the sun’s altitude and the chemical intensity. The intensity is the same for hours that are equidistant from ap- parent noon. The relative intensity of direct sunlight, reflected sky light, and total insolation is shown for different altitudes at Lisbon by the following table: Intensity of insolation at Lisbon for clear skies. Menor ar een Observed a a inten- | titude of jof obser- Soe acne. | Sansa ein toil: : | 9.85 15 | 0.000 | 0.038 | 0.088 19.68 18 023 062 O85 31.28 22 | 052 100 | 152 42.22 22 | .100 Tab Als Pets 53.15 19 136 126 | 262 61.13 2% | 195 182 | 827 64.23. | u 221 138 | .359 | i} In general, the total intensity is directly proportional to the num- ber of degrees of altitude. For altitudes between 18° and 35° the intensity on a plane perpendicular to the incident rays is about the same as the intensity of total sky hight on a horizontal plane. The intensity of direct sunlight on a horizontal plane is equal to the intensity of total sky light on a horizontal plane when the sun’s alti- tude is about 45°. At all altitudes of the sun below 21° the chemical action of diffuse daylight exceeds that of direct sunlight. In their memoir of 1871 Roscoe and Thorpe determined the amount of chemical action for total sky light of a cloudy sky during totality of the solar eclipse, and found it much less than 0.003, and therefore not measurable. They found the total chemical action of the direct sunlight to be strictly proportional to the visible area of the portion of the solar disk up to a certain point in the obscuration, after which the influence of sky hght is inappreciable. For altitudes below 50° at Catania, Sicily, as elsewhere, the amount of chemical action effected by diffuse dayhght on a horizontal surface is greater than that exerted by the direct sunlight. At altitudes less than 10° direct sunlight is almost completely robbed of its chemically active rays. 95 PHOTOGRAPHIC INTENSITY OF SUNSHINE. A photographic method of determining the brightness of sunshine or sky light is very desirable as supplementing the thermometric methods. It is as erroneous to assume that all radiation that falls upon a black-bulb thermometer is absorbed by it and converted into heat and measured by the expansion of the mercury as it is to assume that all the radiation that falls on a photographic film is absorbed by it and is represented by the chemical changes that take place in the film. Equally erroneous would it be to assume that all the radiation that enters the eye is represented by the impression of brightness conveyed by the retina to the brain. In order to measure in absolute units the total energy radiated from the sun, we need a proper summation of the thermal, visual, and photographic work done by the radiation. If we wish to determine only the intensity of that part of the radiation that does the work in which agriculture 1s chiefly interested we should consider only the heating effects of the radiation and the special chemical effects manifested in the action of sunlight upon chlorophyll. The action of the sunlight upon the chlorides and bromides of silver, as in ordinary photographic processes, may not be an exact measure of its action upon the leaves of plants. Some other chemicals may be more appropriate for use at agricultural experiment stations, but the photographic methods perfected by Profs. H. W. Vogel and L. Weber are worthy of trial as a first step in the right direction. These processes give us the relative intensity ‘of the radiations that belong to the blue end of the spectrum, with only a small admixture of the influence of green and yellow rays. | During the year 1890, as the result of a numerous series of observa- tions at Kiel, Prof. L. Weber found that the reddish light of the spectrum on dark winter days has only about 500 times greater inten- sity than the quantity of light from a normal candle at a distance of 1 meter, when measured by their relative effects on a photographic plate, while at the same time the photographic intensity of the green light of the spectrum was four times as much. On bright summer days the intensity of the red ight was 50,000 times that of the candle at 1 meter, while the intensity of the green light was about 200,000, or about 4 times as much in summer as in winter. The intensity of the blue hight in the solar spectrum was about 25 times that of the red light, which ratio varied a little with the kind and amount of cloud. In all this photographic work a very sensitive silver bromide paper was used; so that these results, strictly speaking, relate only to the variations in the intensity of those special rays that affect this chemical. But these variations will be nearly parallel to the diurnal and annual variations of the rays that affect the growth of plants. 96 Further details of Weber’s results are given in the German periodical, Photographische Mitteilungen, edited by Professor Vogel, at Berlin. Tt is worth while to call attention to the fact that during the long twilights of northern latitudes in midsummer plants receive an appre- ciable quantity of the blue radiations from the sky, while receiving little or nothing of the red, or heat, rays. MARCHAND’S SELF-REGISTERING CHEMICAL ACTINOMETER. A convenient form of registering actinometer is that devised by Marchand (1875), which he at first called “ photantitupimeter,” but which name he afterwards contracted and modified to ‘“ phantupi- meter.” This consists of a vertical graduated tube, closed at the upper end, into which there can escape and be measured the carbonic acid gas given off by the decomposition of a mixture of solutions of perchloride of iron and oxalic acid. By the action of sunshine on this mixture, carbonic acid gas is slowly disengaged, and by its accumu- lation in the measuring tube gives us apparently a means of deter- mining the sum total of the influences of the sun during any period. This apparatus was diligently employed for many years by Marchand at Fecamp, near Havre, and has afforded him many interesting results. COMPARISON OF MARCHAND’S AND MARIE DAVY’S RESULTS. Radau (1877), in his work on Light and Climate, states that the results given by different methods of measurement of sunshine appear to differ largely among themselves, but yet there is a certain sim1- larity in the figures. The accompanying table shows the results of observations by Marchand’s chemical method and by Marié-Davy’s thermometric method, or conjugate thermometers, which latter, on account of jts convenience, has been widely adopted. Total daily’ 2) Total daily : chemical Moen deity chenaieal Moen daily ore chaln jactinomet- effect, in | actinomet- ? she ricde-. || cubic cen- |" ‘hic de- Month. timeters, mone Month. timeters, ee of car- AM ae of car- (Mont- ponte acid Saeeas homie acid wee (Fecamp, Pa we (Fecamp, f rn 1869-1872). | 1872-1876). | 1969-1872). | 1872-1876. januanyers i eees fe heawee 1.84 | 1DYOn| | PAtuguste sae ees 18.92 41.2 Mebruary; eas. s2-- --teeee- 3.93 1564||;September soss=- saeco = 13.65 31.8 Marche ome. Dee 6.44 | 26:0) lkOctober =a 6.86 20.1 | JXy 0) rt Se See ee eee eee Ser 14.10 | 3i20' || NOVem ber’ =--- 222-22 2--- 2.89 12.5 Maven snene fl eky sake B48 19. 46 | 46f2|| December 22.222 — ses--= 1.80 9.4 June --.----.--..------.-- 21.04 48.2 Annual average--_- 11.03 | 29.3 Ch ae ee ee eee 21.41 | 50.6 |) | Rolfe 1a] | If the atmosphere were not so very different at these two localities, we could have hoped to use the monthly ratios of these numbers for reducing similar series elsewhere to a common standard. a 97 VIOLLE’S CONJUGATE BULBS. The refined methods for measuring solar radiation adopted by Violle (1879) in his absolute actinometry can hardly be utilized in agricultural investigations owing to the labor of using the apparatus. But the continuous register obtained by him by means of thermo- electric apparatus is an important improvement in the methods avail- able for comparing climates. On the other hand, Violle has sug- gested a modification of the conjugate thermometers which he calls his “ conjugate bulbs,” which is worthy of consideration, although far from being as sensitive as Marié-Davy’s apparatus. These bulbs are made of thin copper, one of them blackened and the other gilded on the outside; the interiors are blackened, and the thermometer bulbs within them are also blackened. This apparatus has an appar- ent advantage over Marié-Davy’s, in that the sunlight is not required to pass through glass before striking the thermometer. It would appear likely that with smaller bulbs (Violle uses 1 decimeter in diameter) and with more sensitive thermometers Violle’s method might give better results and be worthy of recommendation to agri- cultural investigators. The results given by his apparatus have need to be reduced by some method based on the considerations indicated by Ferrel (1891). BELLANI’S RADIOMETER OR VAPORIZATION ACTINOMETER. Among the many devices invented for the purpose of obtaining, at least approximately, the sum total of the effect of sunshine received during any day by a given plant is one that has been used for a few years at the Montsouris Observatory, and is a modification of an apparatus originally devised by the Italian physicist, Angelo Bellani, which is thus described by Descroix (p. 128, Annuaire de Montsouris, 1887; see also the Annuaire for 1888, p. 206, where it is called the lucimeter, although it does not measure light properly so called). The vaporization actinometer or the Bellani radiometer as modi- fied at Montsouris consists of a bulb of blue glass A of about 60 mm. in diameter, inclosed within a larger bulb B of colorless glass. The space between the two bulbs is a vacuum. BIeT 7.05 September 26-12 5.4 2 ssa ee ce ee eee Peed ee Se 3.04 |. (6:82))| 81% |) = 6592 6.7 Sentem beret. s ai sees ae oe ee fee nee | 1.82] 5.89) 3.48) 8.51 3.48 Repbem Denes ee One, te coe cnee ees seas ieee lr es eee ae Dien eaead Bei | 5.58] 3.65] 2.58 3.04 Séptemberi29) 455. Be sce k Sane Sa Tee Me et Se ee | oe tel) Pare 2.96 1.86 2.61 September 0 psa. wc sae ie ele ey ee er ee ene (rae 2.48) 1.74] 1.76) 2.00 October ieee ste Fates ee ee ee ee feces ee 2.79) 5.55) 6.31) tz October lO ss ON le Me eee fesiees eso } 2.09| 2.89] 295 Totaltin':20\days=osos225=2 sss Sse ae oe eee 100. 43 | 99.69 | 100.09 | 85.02 | 67.98 68. 63 pa These experiments give us some idea as to what percentage of the rainfall remains in the soil for the use of the plant in the case of large and small rains, but do not quite answer the question how one and the same quantity of rain is utilized in moistening the earth when it is distributed through a larger or smaller number of rainy days. On this latter question Wollny has made the following experi- ment: A quantity of water corresponding to a rainfall of 60 muilli- meters was communicated to an experimental tub, No. 1, all at once, while in tub No. 2, 30 millimeters were given the first time and the remaining 30 after three days; in the third tub 20 millimeters were given at first and 20 millimeters every other day thereafter, and, finally, in the fourth tub, 10 millimeters were given every day, so that in six days all had received the same quantity of water. These experiments were repeated for different kinds of soil and the results show that in all cases the quantity of water lost by evaporation is larger the more frequently the water was communicated or the greater the number of rainy days. A fine illustration of the truth of this principle as apphed to practice is narrated by Haberlandt, who found that in 1874 the farmers at Postelberg got much better crops than those at Lobositz, which could only be attributed to the fact that during that year Postelberg had received 246 millimeters of rain- fall in forty days, or an average of 6, whereas Lobositz had received 309 millimeters in seventy-seven days, an average of 4, so that the usefulness of the greater quantity of rain in Lobositz did not equal that of the smaller quantity at Postelberg. Wollny shows that since the period of the heaviest rainfall occurs throughout central Europe at the time of the largest evaporation from the soil we must conclude that for the naked earth the wetting of the soil during the warmer season of the year is controlled much more largely by the rainfall than by the evaporation depending, on the temperature. His observations with the lysimeter show that the precipitation is principally concerned in the moistening of the naked soul during the warmer season, while the influence of the temperature and the resulting evaporation nearly disappears and is only observ- able in periods that are deficient in rain. In most cases the vegeta- tion is injured when the atmospheric precipitation during the coldest season of the year is insufficient. The precipitation at this time of the year is therefore quite as important for the success of the harvest as that which falls during the period of vegetation. (Wollny’s Forschungen, Vol. XIV, pp. 138-161.) A. Seignette has shown that the law of levels propounded by Royer is confirmed. This law states that for given plants and for other uniform conditions the reserve nutriment in the earth is always found at a constant distance below the surface; thus the bulbs of 112 a plant under given conditions are found at a given level, and if we change these conditions as to moisture, temperature, etc., we shall change the distance from the surface down to this level. (Wollny’s Forschungen, Vol. XIV, p. 132.) TRANSPIRATION. The quantity of water transpired by trees and plants depends upon the amount of water at their disposal, as well as on the temperature and dryness of the air, the velocity of the wind, the intensity of sunlight, the stage of development of the plant, the amount of its foliage, and the nature of its leaf. The following are some of the results of measurements at European experiment stations. (See Fernow, Report, 1889, p. 314.) KF. B. Hoehner found that the transpiration per day per 100 grams of dry weight of leaves is for conifers 4.778 to 4.990 grams, but for deciduous trees about ten times as much, 44.472 to 49.553. During the whole period of vegetation a unit weight of dry leaves corre- sponded to a total weight of evaporated water, as shown by the fol- lowing table, for three different years. Transpiration of water corresponding to growth of unit weight of dry leaves. Plant. 1878. | 1879. | 1880. || Plant. 1878. | 1879. | 1880. | | | Bireh and linden .::-3.<|7,.650)|'7'1,000)|| , 90), Oaks;<4 ees Aes 250 400 | 59 ING ees See 550 700 101 | Spruce and Scotch pine. 60 | 150 | 13 IBCCCH Banas eee ees 475 600 £2) Ul Vis) ota bea eo eS 3D | 100 9 Maple; ie oh. 2. eee 425| 550| 70|| Black pine __........-..- 35 75 4 7 | | The variability of transpiration is shown by the action of a birch in the open air, which transpired on a hot summer day from 700 to 900 pounds, while on other days it probably transpired not more than 18 to 20 pounds. A beech about 60 years old had 35,000 leaves, whose total dry weight was 9.86 pounds; hence its transpiration, at the rate of 400 pounds of water per pound of leaves, would be 22 pounds daily. An acre containing 500 trees would, during the total period of vegetation, transpire nearly 2,000,000 pounds of water, or about 50 pounds to the square foot. A younger beech, thirty-five years old, with 3,000 leaves and a dry weight of 0.79 pounds, would, under the same conditions, transpire 470 pounds per pound or 24 pounds per day from June to November. An acre containing 1,600 such trees would transpire about 600,000 pounds per acre or 15 pounds to the square foot from June to November. Of the entire mass of wood and foliage on an acre of forest from 56 to 60 per cent of the weight is water and 44 to 40 per cent dry sub- 113 stance. In agricultural crops the amounts of water are still larger, sometimes reaching 95 per cent of the whole weight. The amounts transpired by cereals, grasses, weeds, etc., are consid- erably larger than the preceding, as shown by the following table compiled from Wollny’s results: in- Water consump- Plant. Year. ning of a ssa acre = How: pen: Pounds. Inches. Vi Iai iSTO TEN) See Sa ee ee a ee 1879 | Apr. 20} Aug. 3 | 2,590,000 10 D3 TENN i Se Se a A a eR W8i9y |e2==do 222 -=-do-_-| 25,720; 000 11 IRB Dente Se Aaa hee Pee Be SOR oe ee een eee 1879) j=: -2do-:-|--..do___| 3,140,000: | 12 ieyeyel COWKAr LS ee Sy Se eee eee eee ae 18%9) |-.=-do_- | Oct. 11] 3,070,000 12 DEUITEMM OTIS, © Sete nen cae esa ee eee eee soe a ...--| 1880 |_...do___| Aug. 14 | 3,000,000 12 COTES era ce 1880 |_...do_--| Sept.14 | 3,420,000 14 IB Calis eae eee ee Sone os ee se SSIS. SHEE et OX 1880 |....do-_-| Sept. 10 | 3,140,000 | 12 1exaye! GONG)? 2S B= aS a ee ae eee ee 1880 |_...do_-_| Oct. 11] 4,110,000 | 16 The following table is given by Risler (1873) in his * Note on the diminution of the volume of water courses,” and shows the mean daily consumption of water by plants, expressed in millimeters of depth of water over the area of the field: Daily con- | Daily con- Plant. sumption of |) Plant. sumption of water. water. mm. | | mm. ihucernoerass! 2.7.2 020-2. 22255.- Sade oe (eOul |« Clover see Benc tose see ese es eee 2.9 THI OIT ASS —— ees ss ee oe 6 Fad Bey (a3 A 0 a ec Se EN ar 2.3 (CANES! poe Sia nae eee esate ees ae Pepe Wawgeesy: 130 al SS rb d= ee oe en aS eee ees a ee ee UE ee eed len) IBBANSE toa ee StS oe Sipe eo eee 3.0+ POLATOCS tp ee es een eee ee Ontee at ENV ATs See Ore oe ie eee ee 2S 524. Onl | PING LOLOS bes se cae a ae a sae eee le) Ofb sare Wali Ga beeen sae fae.” ime DES ON ses Sall Oalkf OLesbscce onan eee ene- aoe wel ee O25 0X3 These numbers have been deduced from the results of many years of experiments in the laboratory and from observations made in a drained field under conditions favorable to this kind of research. The crops have necessarily varied from one year to another, but unfortunately I am not acquainted with these details. The transpiration of the plant is only a means to an end. (See Marié-Davy, 1875, p. 209.) Its object is the introduction into the vegetable organism of the mineral elements necessary for the develop- ment of its tissues and that of the other principles united there. The experiments of Woodward and those of Lawes have already shown us that the same quantity of water is not always necessary in order to furnish the same amount of mineral substance and to produce in the plant all the elaboration and movements of organic products which should be produced there. It appears evident that in soils more or less fertile and which con- 2667—05 M 8 114 tain in unequal quantities soluble and nourishing principles the water absorbed by the roots may be more or less charged with these elements. We can understand, then, that the quantity of water necessary to enable a plant to furnish a given result is not the same for all soils, and that the richest soils may produce a greater yesult with a proportionably smaller consumption of water. By increasing the richness of the soil in soluble substances that can be assimilated, we should succeed in economically reducing the quantity of water consumed by the crops. In any case we might at the same time ask ourselves if all the water absorbed by the roots and introduced into the plant is utilized by it and at what limit the richness of the water should be arrested so as to be really profitable to the plant. In this connection Marié-Davy cites the following fact, mentioned by Perret in the Journal of Practical Agriculture for 1873: In Perret’s experiments a meadow having been covered with a suffi- cient quantity of nitrate of soda for a nitrogenous manuring of four years, the grass was magnificent in the spring. This grass was given green to the horses, who before long began to show strong diuretic symptoms accompanied by raging thirst. These animals seemed to be completely under the influence of the administration of a strong dose of nitrate. The following year there was a complete cessation of the beneficial effects of the nitrate on the meadow, which showed conclusively that the plants of the first year contained nitrate in a natural state and not decomposed by the assimilation. When nutritive substances are given to plants in abundané they can absorb a quantity of these elements besides what is necessary for their nourishment. This is particularly true when in the series of minerals which compose a normal nourishment, one of these sub- stances is in excess of the others. Besides, if we compare the chemical composition of a crop cut green with that of a similar crop after arriving at maturity, we find that in the latter there is a diminution in weight of several of the substances present in the former. It would, therefore, have been interesting to know if the trouble men- tioned by Perret was continued with the same intensity in the dry hay. RELATION OF PLANTS TO MOISTURE OF SOIL. E. Wollny (1887, Vol. X, p. 320) gives some results as to the influ- ence of plants and shade on the moisture of the soil, being a modifica- tion of a memoir published by him in 1877. His conclusions are as follows: (1) The water contained in the soil under a covering of living plants is, during the growing season, always less than in a similar layer of fallow, naked soil. ng or (2) The cause of the drying up of the soil by the plants is to be found in the very considerable transpiration of aqueous vapor by their leaves. (3) The plants deprive the soil of water in proportion as they stand closer together and have developed their tops more luxuriantly. (4) The influence of the vegetation on the moisture of the soil extends to the deeper layers of soil. (5) The moisture of the soil under a layer of inert objects, such as dead plants, manure, straw, pieces of wood, windfalls, etc., is always greater than that of the uncovered soil. (6) The retention of the moisture in the soil under a cover of dead matter is a consequence of the protection afforded by the latter against the influences that favor evaporation. (7) The quantity of moisture in the soil is, within certain limits and to a depth of about 5 centimeters, or 2 inches, greater in propor- tion as the covering of dead matter is thicker. (8) The soil shaded by living plants is, under otherwise similar conditions, driest during the growing period, but that covered by dead objects is the moistest, while that which is not cultivated, not covered with plants and naked, is midway between the two previous in reference to its relations to moisture. Wollny has also studied the influence of plants and shade upon the drainage of water from the soil. His conclusions are: (1) A notably smaller quantity of water drains through the soil supporting living plants from the same quantity of rainfall than through a naked soil during the growing season. (2) The quantity of drainage in cultivated fields is less in pro- portion as the plants stand more closely together and in proportion as they have developed themselves more luxuriantly. (3) The quantity of drain water from a soil covered by inert objects is increased in comparison with that from fallow land in proportion as the covering layer is thicker, up to a certain limit, up to about 5 centimeters, beyond which a further increase in the thick- ness of the covering steadily diminishes the quantity of drainage water. (4) For the same quantity of rain and under otherwise similar circumstances, the soil covered with dead leaves and similar objects furnishes the greatest quantity of drainage water up to a covering of about 5 centimeters thickness; the naked, fallow land furnishes the next smaller quantity of water; the soil covered with living plants furnishes the least quantity of drain water. 116 RELATION OF WATER TO CROPS. KE. Wollny has studied the relation of the irrigation and rainfall to the development and productive power of plants in cultivated fields, and the following summary is essentially as given by him in Volume X of his Forschungen for 1888, page 153. An early investigation of this subject was made by Tlionkoff, who filled five large tubs with soil and sowed buckwheat in each on the 15th of May; each tub was then watered regularly with a definite quantity of water, the total quantity used being given in the second column of the table following. The relative quantities of buckwheat harvested at the end of the season are given in the third column and the straw is given in the fourth column. The weight of the buck- wheat originally sown in each tub was the same, viz, 0.154 gram. Weight of green har- |Weight of dry| Ratio vest. harvest. pene of Total Pi | ber SAT TENG water |of ker- AyaGl 1 Sis tbea tol gam | nate terest Delonas plied. | Grain.) Straw. total, | Grain. Straw.) har- Pattie yeaa | |vested.| ocd Liters. \Grams.|Grams.| Gra ms. Grams. Pin) 22 25.008)) 1.8941" 26/1041" 27,90']). 1 68h| Barbet) cr ae 4s Pa eae Sets eb yen | 12.50 6.15 | 58.85 | 65.00 5.47 8.47 283 100 Pe te oe eer eel ae phe) 1.95 | 23.03 | 24.98 1.73 4.55 93 46 bE SA 2 ere 3.12 .58 | 9.42] 10.00 .52 1.41 | 37 14 Breese el ss 1.56 10 | 2:20) 0h 2530))25 1200 580: })t 4, Sap 3 These figures show plainly that the plants in tub No. 2 were most favorably situated. Probably No. 1 had too much water and Nos. 3, 4, and 5 too little. Haberlandt, in 1866, experimented on the quantity of water needed in the growth of plants in three plats of 14.41 square meters each; of these No. 1 received no artificial watering; No. 2 was watered once a week, except in great droughts twice a week; No. 3 received a double quantity once a week. These quantities corresponded to a rainfall of 6.46 millimeters for No. 2 and 13.92 millimeters for No. 3. The total quantities for the season were 96.96 and 193.92 millimeters. The natural rainfall was as follows: Month, 1886. Beiny Rainfall. nim, Maren. 5.2135 7c: pe ek. eb ee i oa Ae Se eee nee ee eee 17 40.98 INS apETTY [9 Ae NO ll ke eB ff Peak SS? SURE ES ee TESTI ee 15 | 35. 38 Ma yiee 2 sco cts cote oe ee ag ee ee eee ul | 52.20 UNC ere, SET. I ee ee ee oe 2 Re ei ee ee 13 46. 03 JU yt p2csc bo ct cc Set ot sched ee ee ee es SY 17 | 34. 40 POCA scott a ORS mee ea 73) 208.99 1 The number of rainy days was large, but the rainfall was small, and the plants in bed No. 1 suffered for want of water. The relative harvests for the different beds and crops were as follows: Harvest (rela- | | Harvest (rela- Plant and bed. eyemumbe): | Plant and bed. bey eet): Grain. | Straw. | Grain.| Straw. Wheat: | | Barley: Tl a ele 100 100 | il pene a Oe oat Rs PE ee ae 100 100 Ce 2p ee BO Tae ees Sea 132 129 | (ese Ex oat Seeing! SARIN, alee Mae we | 109 105 i, ESE ee ee ae 72a paar 1642 | law, See leee ee th 216 123 Rye: | Oats Laelia ee a Pe 100 100 AP ere cers se eee Cee ee ees ae 100 100 Orietas ASE L «072 Wes ee 3 p> | 28 | 136 124 pS a” SERPS: |e ee BS SS REARS ES | 133 116 Ce Sea ee poe ee ae oe | iil 219 Seed Sees ae oS | 182 | 126 Beds Nos. 1 and 2 showed about the same rate of growth. No. 3 showed a retardation. The barley and the rye were harvested from this bed four days later than from the other two. The quantity of harvest increased with the quantity of water, and the harvest of grain, except in the case of the wheat, was more increased by water- ing than was the harvest of straw; the quality of the grain showed only slight differences. Hellriegel experimented (1867-1883) on the influence of water upon the crops. He filled a number of vessels with quartz sand and maintained the earth at a different state of dryness. The experi- ments were repeated for several years on wheat, rye, and oats, the general results being that when the ground contained from 60 to 80 per cent of its full capacity of water the harvest was larger than when the ground was drier and about in the following proportions: i Wheat crop. Rye crop. | Oat crop. Mois- fob S = Tub-| ture : | oS: | Straw. Grain.|Straw.)Grain. Straw. Grain. bese | : 2a | Per ct. 1 | 80-60 22 11.0 16 10° | 16 12 2 | 60-40 21 10.0 15 10 | 14 11 3 | 40-20 15 8.0 12 8 | 12 8 4 | 20-10 ff 2.8 12 4 | 4 2 » | \ Hellriegel also varied the experiment by giving the tubs daily, each evening, as much water as they had lost during the day, thus : 118 maintaining a very constant state of moisture in each. with the following results: } \| Gone Harvest. Cone Harvest. 2. | LO) | ———S | | stant |- | Tub. ny | | || Tub. = | eneet Straw. Grain. | cance Straw.| Grain. | P. et. | P. ct. | 1 SO | 0 8.8 } 5 20 | 6.9 17 2| 60 | 12.8 9.9 Ga) a0 3.0 3.3 BF | 40 dee O52 Nas | 5 Orde |-2eseeee +} | 83] 8s 1 eee | | | \| } | The general result, therefore, was that the largest harvest is given by soil containing 40 per cent of its maximum capacity for water. The general appearance of the plants showed that those having too little water had a less intensive life and were suffering from lack of nourishment rather than from the want of pure water itself. Fittbogen (1873) conducted a series of experiments on twenty tubs in groups of four. The relative weights of his harvests of oats were as follows: i] | ; | Harvest. | , Harvest. Mois- |__ Mois- Tub. ture i | __ || Pub. ture | - ’ | Straw. Grain. | : Straw.) Grain. Pct: (PACs | it 80-60 oti 6.0 4 30-20 Syl | 4.0 2 60-40 | 6.9 5.8 5 20-10 OO ONG 40-30 | 7.7 6.1 || | These figures show that for moistures varying between 30 and 80 per cent there was very little difference in the harvest, while for drier soils the harvest was decidedly diminished; but it is notable that for the driest soil (No. 5) the grain ripened earliest of all. Haberlandt, in 1875, reports the results of experiments on three tubs sown with summer wheat. The quantity of water allowed to tub No. 1 was just sufficient to keep the wheat alive; the other quanti- ties, with the harvest, are given in the following table: P . : | | Num- | Equiv- Harvest. I Tub Quantity|ber wa-| alent | ‘| water. | ter- rain- : ‘i | ings. fall. SERIE ISR 3 | = . cc. mm, 1 6,200 | 381 | 24.4 | 21.8 6.6 | | { 2 | 14,400 | 36 | 56.6 | 20.4 | 16.4 | 3 24, 800 31 97.5 41.6 | 31.6 | Whence it would seem that the limit of useful water had not yet been reached. 119 Birner (1881) experimented on the amount of water needed by potatoes. Jour series of experiments were made, each including five tubs having different amounts of water, as shown in the following table, which gives the average of the four series: Harvest weight of ubers. Bee | Aver- | (plant. “fiber. P.ct. |\Grans. Grannis.) 1 |80-60 | 809 | 42 | 2 | 60-40 628 46 | 3 | 40-30 413 42 | 4 [ered 313 | 34 | 5 | 20-10 214 23 | | | | These figures show a steady increase in the amount of harvest with increasing moisture. The student will notice that in these experiments where the plants are kept in tubs under protection from natural rains the watering and growth go on under continued sunshine. The experiments therefore correspond with the case of irrigation in a dry, sunny climate, and it is not to be understood that the same amount of water deposited naturally by clouds, with attendant long-continued obstruction of sunlight and heat by the clouds, would have produced the same large crops. R. Heinrich (1876) experimented at Mecklenburg on the influence of water on grasses and clover. Ten sets of tubs filled with sterile sand were sown with grasses and clover and watered daily, with results as shown in the following table: . ._ | Harvest || - | Harvest Weight PGtv- | weight | Weight | EGuiv- | Vveight Tub.| of daily | anil |offresh- }|Tub. of daily anil, of fresh- water, See | cut water. raineallel cut ‘| grass. | ‘| grass. a : a Eee Grams. mm. Grams. Grams. | mm. Grams. ~ 1 100 | 1 35 || 6 600 | 6 138 2 200 2 44 || 7 | 700 7 148 3 300 3 sy || 8 | 800 8 161 4 400 | 4 8 || 9 | 900 9 156 5 500 | 5 110 || 10 1,000 10 170 | 1] This shows that the harvest increased steadily up to 8 millimeters of rainfall daily, but for 9 or 10 millimeters per day the increase in harvest was so slight that we may consider 9 millimeters, with an average harvest of 162 grams, as the best that could be obtained under the temperature and sunshine prevailing that year at Mecklenburg. Doubtless a different quantity of water would be required in order to obtain the maximum harvest in other climates. 120 IX. Wollny (1882-83) made seven series of experiments, in each of which five or six tubs received daily different quantities of water, except only that in the driest tubs extra water was given for the first few days in order to insure the sprouting of the seeds, and except, further, that in the experiments of 1882 the water was given every second or third day instead of daily, whereby was brought about the rather large variations in the moisture of the earth. The tubs were shielded from natural rain, were of the same size, and had the same weight of earth and aliment. Nothing is said as to whether special manure or fertilizer was used, but only that all were treated perfectly alike except as to water; the effect of manuring was shown only in the case of Nos. 6 and 7 in that No. 6 was treated lke the previous ones, while No. 7 received a supply of mixed, Peruvian guano, superphosphate, and sulphate of lime, gypsum, or plaster equivalent to 526 kilograms per hectare. Exact measurements were made upon six plants in each tub in order to judge of the relative harvests. An abstract of Wollny’s measures is given in the following tables: EXPERIMENT OF 1882. Grain harvest dried in air. Mois- Mixed Tub. ture. | Sum- pares grain. mer | Beans.| . rye rape seed. anara| - ~ — 1 | 100-80 4.3 9.2 2.4 11.0 2 80-60 Date i Lien: 4.4 13.9 3 | 60-40 | 5.1 | 11.6 | 4.9 1207 4 | 40-20 3.9 3.3 z.0 | 9.4 5 20-10 0.4 0.5 0.25 1.8 EXPERIMENT OF 1883. | Grain harvest dried. | Mois- Summer rape seed. Tub. ture. Loe r- | bean.a ot | aod Warmed. 1 100 eee | 0.2 | 0.3 2 80 | 21.9 3.3 3.9 3 60 | 14.0 4.2 4.3 4 40 10.6 4.6 6.9 5 re Ui 3355) 2.59 2.7 6 10 1.3 0.8 1.4 “A variety of English or Windsor beans (Faba vulgaris) raised in Europe for feeding horses. He concludes that, in general, the quantity of harvest is influenced to an extraordinary degree by the quantity of available water and much more than by any other factor of vegetation. In general the 121 harvest increases with increasing water supply up to a definite limit, beyond which the harvest diminishes steadily for any further increase in the water supply, until when the earth is completely saturated with water the harvest in some cases becomes almost mil. The most advantageous percentage of moisture in the soil varies for the differ- ent plants, depending on their own method of using the water, on the evaporation from their leaves, and on the number of plants to the unit of area of the field, namely, their closeness to each other. In reference to the needs of practical agriculture it would be improper to consider in such experiments as these only the water that has been used, since the number of plants to the unit area is of equal if not greater importance. It would therefore be improper to reason from these experiments up to the needs of another field or tub having a greater or less plant density. Again, as also shown by Wollny, more water is used in proportion as more nutriment is avail- uble in the ground, because the development of the organs of tran- spiration or the leaves is thereby increased. Therefore, in general, the quantity of water required to attain the maximum crop will increase with the richness of the soil and the closeness of the plants as well as the dryness and velocity of the wind. For different crops, moreover, the absolute quantity of water will depend upon the dura- tion of the whole process of vegetation, from germination to harvest. (See Wollny, 1881, IV, p. 109.) The character of the plant affects the quantity of necessary water, not only by the duration of the process, but by the relative quantity of auxiliary organs that the plant develops in order to produce the ripened seed, which we call the harvest. The ratio of the grain to the straw and chaff when the, maximum crop of grain is produced in each of Wollny’s seven cases is shown in the following table: Maximum harvest dried in air. Straw | |Grain.| and | Ratio. | chaff. | | TEA 11, Sr RAGE BATS) Saeco c abe e eo pO Ree Dae SEO SASS TS SAEs See eee eee | 5.7 12.0 48 SUM Fock re a NS Oe ee Ee SY cecdeee Soecnces | 11.6 15.4 | 75 TWO, (Sherer eye Tay oD) SEs hs eo ee ok ee lB eee | Avo) eee (ROM 65 TAY, TSWOyGEIS) [OVS Se a re ee mee | 21.9] 31.6 69 Wee Colzaiboan wathoutimanunrom ees. 9) teases nae a 2 ee eee ee | 4.6 15.4 | 30 Wiles @olza bean withscuano seen: sesh Sen oss aie. cc ces coceea eee |eeGOi Leas) 40 These percentages show the success with which the plant labors to perpetuate its species with the least possible waste of molecular energy on extraneous matters. 122 Hellriegel’s experiments gave 80 to 60 and sometimes 40 per cent, Fittbogen’s gave 40 to 30 per cent, Wollny’s gave 80 to 60 per cent of moisture for the maximum harvest. These differences undoubt- edly arose, at least in part, from differences in richness of the soil, the closeness of the plants, and differences in the sunshine and wind. These results are therefore in general only relative, and justify us in saying that the best crops are obtainable when the earth contains from 40 to 80 per cent of its maximum capacity for water and that the ‘percentage is higher in proportion as the soil is richer; as the plants are closer; as the leaves of the plants are broader; as the sunshine, the dryness of the air, and the velocity of the wind are greater; and as the barometric pressure is less, since all these increase the useful evaporation from the leaves and the wasteful evaporation from the soil. The growth of the auxiliary organs was shown by Fittbogen, who gives the weight of the organic matter as determined by burning the well-washed roots, and is also shown by Haberlandt by the weights of the roots and stubble. Their measures are given in the following tables: FITTBOGEN’S EXPERIMENTS. Organic Moisture} matter inthe | lost by soil. burn- ing. Per cent. mg. 80-60 470 60-40 | 429 40-30 | 440 30-20 359 20-10 109 | © HABERLANDT’S EXPERIMENTS. Weight of roots Water eal stubble. ce. Gram. 24, 800 5.35 14, 400 3.2 6, 200 2.9 123 . Again, the variation in the stock independent of the grain is shown by the measurements of the dimensions of the heads and stocks as given in the following tables: OATS (FITTBOGEN’S EXPERIMENTS). aa J Mois- Number Length | Dias: ture. of SSDS) of heads. Kenda. Per cent. > | mm. | mm. 80-60 | 8 | ° 555 3.9 60-40 3P| 4 ae 4.1 40-30 | 4 | 450 3.6 30-20 | 2 | 250 3.3 20-10 4 136 1.4 SUMMER WHEAT (HABERLANDT’S EXPERIMENTS). | A Height of stalks | oe (| | Number of stalks. bearing heads. | Water "Senet | . 4 Not | Bearing jearing Shortest.) Longest. heads. | ‘heads. | | em, em, 24, 800 | 18 12 | 70 95 14,400 | 12 | 13 | 30 65 6, 200 5 | 16 | 20 35 Similar experiments by Sorauer (1873) give results analogous to the preceding. He measured the greatest length and width of the leaves, at several stages of their growth, of barley plants in tubs of different moistures, with the average results for all stages of growth, showing that the leaves were longer and broader the more water was furnished, while the available nutrition remained the same. BARLEY (SORAUER’S EXPERIMENTS). | Mois- | Length | Width ture. | of leaf. of leaf. | Per cent. | mm. | mm. 60 | 182.2 9.4 40 166.3 9.1 20 138.7 6.8 10 98.7 | 5.6 | These and similar observations show that the assimilating organism of the plant (viz, its leaves), as also its organism for absorbing nutri- tion (viz, its roots), both alike increase with the increase in avail- able moisture near the roots in the earth, at least within the limits existing in these experiments, and to the same extent is the develop- ment of the plant favorable to the increase of its productivity. 124 Under such circumstances it is not surprising that the development of the crop of grain keeps pace with the increase of the available water, at least up to the point where the quantity of water is suffi- cient to give a maximum crop. The supply of water has an influence not merely on the quantity of the crop, but also on the rapidity of the development of the plant. Wollny (1881) shows that in general the grain ripens sooner as the quantity of water diminishes. This is well seen in the following series of experiments (Table 62) on the time of ripening of grain in fields that are sown more or less thickly. The thickly sown fields correspond, of course, to a less quantity of water available for each plant. WINTER RYE (WOLLNY, 1875-76). ‘Number Number] of of plants| square | Date of to the | centi- | ripening square | meters (1876). meter. to each | plant. 625 | 16 | July 18 400 25 July 21 229 44 July 28 100 100 July 30 | 25 | 400 Aug. 8 PEAS (WOLLNY, 1877). | Number | | Number | of - of plants) square Date of to the centi- ripening | square meters (1877). meter. to each | plant. | | ——— 22 £ 357 28 Aug. 15 157 64 | Aug. 17 | 89 118 Aug. 19 85 7 Aug. 26 40 254 Aug. 28 29 | 346 Sept. 5 POTATOES. Similar experiments were made by Wollny on the Ramersdorfer variety of potatoes. A plat containing 1 plant to 4,435 square centi- meters ripened by the end of September (1875), but a plat containing 1 plant to 812 square centimeters ripened the Ist of August, and other plats containing 1 plant to 2,500, 1,600, 1,109 square centimeters, respectively, ripened at dates proportional to the area occupied by each plant. As edch plat received the same amount of sunshine and of water, the dates of ripening must have been hastened in pro- portion as the number of plants in each plat were increased. ere EE ————— ee a ee 125 MAIZE. Similar experiments on maize showed a similar acceleration of the date of ripening, as given in the following table, which also shows in the last column what proportion of the maize was unripe in the sparsely planted plats when that which was closely planted was already fully ripe. MAIZE (WOLLNY, 1875). Number Number) : ; cE plants GN Ongor Percent to the | ee oO ) square mre ripening.| U27ipe meter. plant. 25 400 Ate Buy 16 625 2 0.0 9 | 1,109 Bilis 4.26.7 6 1,600 ye 34.8 4 2,500 5 56.2 FLAX. A striking illustration of the effect of scant water supply is given in the case of four plats of flax, which were sown at the rate of 50, 100, 150, and 200 grams of seed per 4 square meters of ground. During the drought of 1875 the plants sown most closely all died early in July, whereas those sown most sparsely withstood the drought very well; of the plants sown with intermediate densities the number that died was proportional to the density.. In general, if all other conditions are the same, plants ripen sooner and have a shorter dura- tion of vegetation in proportion as the soil is drier, or in proportion as there are more plants to the unit area. Evidently the plants whose roots extend the farthest in search of water will outlast the species or varieties whose roots are of smaller dimensions. RAINFALL AND SUGAR BEETS. Briem (1887) has investigated the effect of rainfall on the harvest of sugar beets. His observations were made at the experiment station “ Grobers.” . | Ker= |... | Crib |=soa7— | Cobs. | nels. Cobs.| nels, |FTC€D- |cured. cally } | dry. Ft. In. | P. ct. 1| Gourd variety of | 4.0x 6.0 | 3,188 | 14,273 | 2,726 |12, 132 255 239) 217 | 14 southern white | | Dent improved by | 20 years of careful | selection on his plantation. 2 | Early Mastodon_____- 3.0X12.0 | 4,134 | 11,764 | 2,954 | 9, 764 213 191 | 174 20 Cie ne (S\oy eee Bae es 3.0x36.0 | 1,821 | 9,559 | 1,174 | 7,647 | 171 151 | 187 22 4 | White Gourd __._..-- 4.012.0 | 1,393 | 7,316 | 1,212 | 6,218 131 122 11 15 5 | Large White __._____. 5.5x48.0 | 1,826 | 7,305 | 1,367 | 6,136 130| 121] 110 18 6 | King Philip -__---_...| 3.5x 3.0 | 1,776 | 6,683 | 1,154 | 5,717 119 112 102 19 7 | Eclipse variety early | 6.030.0 | 1,497 | 7,311 | 617 | 5,349 130} 105 | 95 | 31 | yellow Dent. | é | | | | With regard to the weather and other items during this season of 1889 at these seven stations I have found only the following notes referring to the prize crop No. 1: Cultivation—The seed was planted March 2, 5 or 6 kernels to each foot of a row; the plants began to sprout on the 16th; there was a good stand the 25th, and the stalks were thinned out to 1 every 5 or 6 inches on April 8; no hilling was done, but the whole acre was kept perfectly level. The crop was harvested November 25. Weather—In March the weather was warm and land moist. Good rains on March 3, 10, and 15; rain on 24th; 1 inch of rain on May 26; 6 inches of rain May 30; rain on June 4 and 5; rain on June 9. The season in general was rainy and wet as compared with other years; rains following frequently, and no irrigation was neces- sary. The record of largest corn crop up to this date had been that of Doctor Parker, Columbia, S. C., in 1857, who raised 200 bushels to the acre. The exact measures of all these 45 competing crops have been made the basis of a comparison showing that on the average of the 17 east- ern crops the percentage of nitrogenous matter was 10.78, but for 14 southern crops it was 10.33, and for 14 western crops 10.26, showing an imperceptible difference slightly in favor of the eastern climate and soil and seeds. In respect to the general advantage of fertilizers, and notwith- standing the apparent advantages gained by some of the heavy inanuring in these competing crops, attention is called to the fact that competitor No. 7 raised a very fine crop of 130 bushels green or 95 dry bushels to the acre without any fertilizer whatever, and that the crops reported by Nos. 4, 5, and 6 were even less than his in their 166 ereen weight, although larger in their dry weight, after what would ordinarily be called very heavy manuring. These facts are quite im accord with the general results of work at experimental farms, which, according to the South Carolina department of agriculture, have shown that increasing the amounts of the fertilizers beyond a certain point gives no corresponding increase in the amount of grain, and but few of the applications pay for their cost. There is abundant experimental proof that for any given soil there is a limit to the amount of profitable manuring. The process of improving the soil, like the process of fattening cattle, is comparatively gradual and requires time. The margin of profit in the application of manures 1s narrower than is generally supposed. It is equally important to attend to the selection of the seed, the thorough cultivation, and the natural fertilization that results from the cultivation of the Legu- nunose and the rotation of crops. PART II.—EXPERIENCE IN OPEN AIR OR NATURAL CLIMATE. Chapter X. STUDIES IN PHENOLOGY. Under the general heading we shall consider, first, the wild plants and their natural habits; second, the plants cultivated at experi- ment stations under instructive experimental conditions, and, third, the statistics of each and the experience of farmers in general from a practical point of view. The study of the forest or natural habits of plants leads us into the phenology of plant life. Phenology is a term first apphed by Ch. Morren to that branch of science which studies the periodic phenomena in the vegetable and animal world in so far as they depend upon the climate of any locality. Among the prominent students of this subject, one of the most minute observers was Karl Fritsch, of Austria, who in his In- structions (1859) gives some account of the literature of similar works up to that date. He distinguishes the following epochs in the lives of plants, and especially recommends the observation of peren- nial or forest trees that have remained undisturbed for at least sev- eral years. His epochs are: (1) The first flower. (2) The first ripe fruit. The next important are, for the annuals: (3) The date of sowing. (4) The date of first visible sprouting. In order to assure greater precision he adds: (5) The first formation of spikes or ears. As Fritsch considers that the development of the plant so far as its vegetative process is concerned depends principally upon tempera- ture and moisture, but that its reproductive process depends prin- cipally upon the influence of direct sunlight, therefore he adds a sixth epoch for trees and shrubs—viz : (6) The first unfolding of the leaf or the leaf bud or frondescence. This is the epoch when by the swelling of the buds a bright zone is recognized which opens out and the green leaf issues forth. Cor- (167) 168 responding with the formation of the leaf is its ripening and fall from the tree, which Fritsch adds to his list of epochs, viz: (7) The fall of the leaf or the time when the tree has shed fully one-half of its leaves; as the wind and heavy rains accelerate this process the date is liable to considerable uncertainty independent of the vitality of the plant. Therefore, in this, as in all other epochs, Fritsch, in endeavoring to lay the foundations of the study, rejected those cases in which any unusual phenomenon, such as wind or drought or insects, had a decided influence on the observed dates. Many plants blossom a second time in the autumn, although they may not ripen their fruits; therefore in special cases Fritsch adds an eighth epoch, viz: (8) The second date of flowering. Of course it is understood that if the second flowering is brought about artificially, as by irrigation, pruning, or mowing, that fact must be mentioned. When the flowers blossom in clusters, such that the individuals are lost sight of in the general effect, then, in addition to the first flower, we note the following item: (9) The general flowering or the time when the flowers are most uniformly distributed over the plant. For 118 varieties Fritsch gives in detail the phenomena that char- acterize the date of the ripening of the fruit. He also gives an equally elaborate system of observations on birds, mammals, fishes, reptiles, and insects, and especially the mollusks or garden snails and slugs. THE RELATION OF TEMPERATURE AND SUNSHINE TO THE DEVELOPMENT OF PLANTS—THERMOMETRIC AND ACTINO- METRIC CONSTANTS. teaumur was the first to make an exact comparison of the different: quantities of heat required to bring a plant up to the given stage of maturity, and since then many authors have written on this subject. I will here give a brief summary of views that have been held by prominent authorities as to the proper method of ascertaining and stating the relation between temperature and the development of plants. Reaumur (1735) adopted simply the sum of the mean daily tem- peratures of the air as recorded by a thermometer in the shade and counting from any given phenological epoch to any other epoch. He employed the average of the daily maximum and minimum as a sufficiently close approximation to the average daily temperatures, and evidently in the absence of hourly observations any of the recog- nized combinations of observations may be used for this purpose. Reaumur found from his observations that the sum of these daily temperatures was approximately constant for the period of develop- ment of any plant from year to year; hence this constant sum is ‘alled a thermal constant in phenology. For the three growing ; 169 months—April, May, and June, 1734—the sum of the daily tempera- tures for ninety-one days was equivalent to 1,160° C., but for 1735 it was 1,015° C., whence he concluded that the ripening of the vege- tation would be retarded in 1735 as compared with the preceding year. This idea had been familiar to Reaumur for some time previously, and in 1735, as cited by Gasparin, Met. Agric., Vol. II, 1st ed., Paris, 1844, he says: It would be interesting to continue such comparisons between the temperature and the epoch of ripening and to push the study even further, comparing the sum of the degrees of heat for one year with the similar sums of temperatures for many other years; it would be interesting to make comparisons of the sums that are effective during any given year in warm countries with the effective sums in cold and temperate climates, or to compare among themselves the sums for the same months in different countries. Again, Reaumur says: The same grain is harvested in very different climates. It would be interesting to make a comparison of the sum of the temperatures for the months during which the cereals accomplish the greater part of their growth and arrive at a perfect maturity both in warm coun- tries ike Spain and Africa, in temperate countries like France, and in cold countries like those of the extreme north. This passage, says Gasparin, is the germ of all the works which have been executed since that time in order to determine the total quantity of heat necessary to the ripening of the different plants that have been cultivated by man. Adanson (1750) disregarded ‘all temperatures below 0° C., and took only the sums of the positive temperatures. He expressed the law as follows: The development of the bud is determined by the sum of the daily mean temperatures since the beginning of the year. Humboldt early insisted upon the necessity ab taking the sunlight itself as such into consideration in studying the laws of plant life. Boussingault (1837), in his Rural Economy, introduces the idea of time by adopting the principle that the duration of any vegetating period multiplied by the mean temperature of the air during that period gives a constant product. He takes the sum of the tempera- tures from the time when vegetation begins and finds fhe length of the period of vegetation from germination up to any phase, to vary from year to year, inversely as the total sums of the daily temper- atures. Thus, for winter wheat to ripen, he found that there was necessary a sum total of from 1,900° to 2,000° C. of mean daily air tempera- tures in the shade, which constant sum is equivalent to saying that the average temperature of the growing period is found by dividing this number by the number of days. This method of computation takes 170 no account of any temperature at which the growth of wheat ceases. A lower limit for such temperature has been adopted by several investigators, such as the 0° C., already mentioned as adopted by Adanson. An upper limit has not yet been ascertained. Edwards and Colin put it at 22° C.; but in Venezuela Codazzi found wheat to mature under a constant*temperature of 23° or 24° C. throughout the whole period of vegetation, and, as we shall see hereafter, the upper limit undoubtedly depends upon the humidity of the air, the moisture of the soil, and the total radiation from the sun quite as much as upon temperature. Similarly Marié-Davy calls attention to the fact that maize grows poorly at Paris, where it is cloudy and warm, but well in Alsace, where it is dry and clear, the temperature of the air averaging about the same in both, the difference being in the quantity of sunshine and rain. Gasparin (1844) adopted the mean temperature of the day as de- rived from observations made at any convenient hours and took the sum of such temperatures from and after the date at which the plants, especially the cereals, begin to actively develop, or to vegetate, or when the sap flows readily throughout the day. For this “ effective temperature ” he adopts 5° C. Subsequently Gasparin adopted a thermometer placed in full sun- shine on the sod as giving a temperature more appropriate to plant studies, but still retaining the lower limit of 5° C. for the mean daily temperature of the initial date. Thus he obtained for wheat a sum total of 2,450° C. as the sum of the effective daily temperatures from sowing to maturity. Gasparin also observed the temperature of a blackened metallic disk in the sunshine and the temperature of the sunny side of a ver- tical wall, and again the temperature of a thermometer at the surface of a sandy, horizontal soil, all in full sunshine. He recognized that the loss of heat by evaporation must keep the temperature of the soil slightly lower than that of the surface of the wall; but, in default of better methods, he kept a record of the temperature of the wall for many years. From his average results I give the following abstract: Observations by Gasparin at 2 p.m. daily. | January. August. Locality. | Year. ms ; = = | Air. | Wall. | Air. | Wall. Oranges: s2s 286 2-2 ae Pee eee ee 1836-1850 | 6.7 15.4 30. 2 44.1 Parist.ce2 2220. po sic ol ee ee Se eee ee 1838-1850 | 4.0 6.3 23.6 30.2 Peissenberc: (Mbanich)) oases eee a eee 1786 | —1.3 11.0 14.6 22.0 The warmth in the sunshine is to the warmth of the air in the shade as though one had been transported in latitude from 3 to 6 degrees farther south. oe ———— ee ———————— et Another study into the total radiation received by the plants in sunshine was made by Gasparin by placing a thermometer in the cen- ter of a globe 1 decimeter in diameter, made of thin copper and cov- ered with a layer of lampblack. Having found by comparison that bulbs of different sizes gave different temperatures, he recommends this size to all meteorologists; but I do not know of observations wade by others until Violle (1879) urged the same construction and size for his conjugate bulbs. This bulb in the full sunshine and at a standard distance above the ground seemed, to Gasparin, to give what he calls the temperature of a dry opaque body. The differ- ence between this and the temperature of the air gave a surplus show- ing the effect of solar radiation on the leaves; again, the difference between this dry, black bulb and the temperature of the surface of the moist earth gave him some idea of the nature and amount of the influence of the Shae on the surface of the soil, which he illustrates by the following table, derived from seventeen years of observations: Temperature at 2 p.m. Black | | Black Month. Soil. | bulbin Month. | Soil. | bulb in the air. the air. STU AT Vee ee See ae eae 6.7 SSS GA eyo f= 00) ri ae i a a ee 43.1 44.1 Re pruarcy mime mans thas 122% 22.0" || September 2-22.) as 31.4 38.9 Ure 0) ER Ee RS ee eee 19.1 28.5 | OCtO DET aa ee a eee 20.2 28.7 JN Oy eile a a Re i ee eae 25.5 29. 4 | INOWeM bores = sas ees ee ee 12.1 | 19.4 SUE Ses Bs Aa ante Sa ha Se 27.6 3424. ||*" December tee. —-- so. see 5.9 | 15.4 June --.---.2-.--------.--.---- 40.9 39.4 | Mevorisoser. nie oe 24.4 29.6 ONIN S Ste ae ee ee ee ee 45.3 43.4 | | On this table Gasparin remarks: We see how much the difference of temperatures of the stems and the roots ought to modify the flow of the sap, and there is here an interesting subject for physiological study which should redound to the profit of agricu‘ture. The solar heat contributes also in a remark- able manner to cause the differences in the vegtation of the moun- tains and the plains. On mountain tops it is the heat of the surface soil and the roots in the sunshine and the effect of sunshine on the leaves that makes possible the existence of a great variety of pheeno- gams. The direct action of the solar heat is the explanation of the possibility of raising cereals and other southern crops in high north- ern latitudes. Gasparin (1852, p. 100) gave the following table, compiled for west- ern Europe, showing the mean temperatures of the day during which the respective plants leaf out, flower, or ripen. This early Sine. to apply meteorological data to the study of plants takes no account, as the author himself says, of other meteorological conditions than tem- perature such as introduce considerable variations into the phznolog- ical phenomena, but he gives it in hopes of helping thus to fix the rela- 172 tions of natural vegetation to cultivated plants. If in addition to recording temperature, rainfall, sunshine, and other meteorological elements, we could keep a parallel record of the stages of development of cultivated and uncultivated plants we could use the latter as an index to the effect of the weather during any season and predict from that the behavior of the cultivated plants. Temperatures at the respective phenological epochs for plants in European climates (by Gasparin). (1) LEAFING. aK On Wild honeysuckle’ (Lonicera peryclimenum) = = = ee eee 2.9 MhHOLN Ys SOOSEDELIY CEUOCS) MUG) CHUSD ;) ae ee ee Eid) TFA Ci Ae oe St ee ee eee ae Ee ee ed ee 5.0 ORCA TS Vox CUT AMD tH (LOE StU TiC) ee ee a ‘hosiery 6.9 Rroad-leated nwallows (SQ sCapnce a) = a ee een) Elorse-chesinut (Ca7SCulus hip pOCaStani)) == se ee (eas Apple tree (J/alus communis) ; cherry tree (Cerasus communis) ~~~ 8. 0 ie tree iGhiCusS*CAViCi) 5 Se ses ae ee ee ee ee ee 8.0 Grapevine,|Sho0ots:=22= 22543 es a eee ee ee ee eee 9.5 Mulberry tree covered with leaf-buds; walnut tree_______________________ 9.8 Sprouting Of lucerne: crassee= 2 ae eee 2 eee eee 10. Aden tree: £2 SS 4. 8 2 ee ee ee ee ee 12.0 Oak mulberry: tree developing deavess == a eee iPS 7 Acaciar CRODINIG DSCUCOUCOCIO)) 2s ee ee eee Soe (2) FLOWERING. Hazelnutetrees(ConylUuseavellandies Cy CSS = ae ees ee eee ay) Furze or gorse (Ulex europe@us) ; box (Burcus sempervirens) ; white pop- LArNCRODULUS: QlOG LSS La ae re ee eee ee ee 4.0 Rroad-leated wallow; honeysuckles= 22 oaks ee ee ee 5. O JY SY2W) BEAM 2 tak eee tere ent Cs el eee a 5. 4 Aimond: tree's apricot reeL22== a= See. ee ee ee ee 6. 0 Pear trees 22 bt) 8 ee as Be ee 9 es 2 Bo 18 a a ee 2 1 Sim ,apple tree S26) ees Ske a ee eo 2 ee ee eee a @herry ‘tree: -eolza: 2208 9e he Pe 8. 0 Milac: strawberry lant = see Se ee) ee ee ees eee 9.5 Broom (Genista, SCODGTIC) = 2 5 ofa Ea ae a eae ee eee 10. 0 IB@anGl 22s 2 = Le A are ee el PA eee 2 eee ee eee ee 2D beta) Prorse-chestmut22 222 2 fa ats 2 tS Be a eee 12.0 Hawthorn orimaya (Mespilusionycantng) 222 ee 12.5 Sainfoin or French grass (Hedysarum onobrychis, Leguminosee) ~~~ __=—- a PAE fi Keacias (RObONIG) = 2522s 2 eek Bee ee ee ee 14.0 RV@n 22 22. 4 ses > eke er ee ee ee -e ee 14, 2 Buckthorn (CRRAGMNNUS DANUTWS)) 2 ee ee ee eee 15. 0 Oates. ale uh eRe ee ee 16. 0 Wheat: barley. ian.) 2). Gee. Sol eee ae ee Ce 16.3 Chestnut tree: Mirst lower... 25.2 Sn ee ee eee 16.6 Bull flower'> = 2 2 282 Shanes Be oo pein! See a Eee Eee eed ee en eee 1. 5 Grapevine: Bull Mower sco 4 2 52 0s 2b dors sess ON Eee ee ere ee 18. 2 Hlowerppassed.. 22-82 2 = eee oe oF Wr ae ee ee 19. 0 Indian corn; hemp; olive tree____________- we ase 8 A A 19. 0 173 (3) RIPENING. During increasing heat: °¢, Ser inbeo ty cheselimnstree perenes = its © Sk pe ws ok ee ee ee ee 1250 (GRAM Teer Se ak eS ee ee ee ee ee 14. 2 Binsta Cherries a DLO AG MUCH IN See ee ee Le ae oe ee ee 16. 0 IESG OWN SRO feSaln Old =" ==. = Sp ae ee 2 eee 17. 0 Currants] raspberries + Sstrawherries: eherrieso"/ Ja ee 17.8 Morella cherry tree; apricot; plum tree; barley ; oats________________ 18. 0 InAyeNe 5 te eS SL hey eee 8 ee Es yar eee ie phe ye See 19. 0 Reachwerec wnarvest Ol CORN 4222 te te Ao a A 20. 0 HiEsigiesroTeene cage spiMms= 2 2 ee 200 First grapes, called madeleine; melons in free earth_______________-__ 2285 FSCS TPT [0 ee Same cee RS ee RD ede ee ee Bee 22.6 During decreasing heat (for fruits which have received a sufficient quan- tity of increasing heat) : THORS C=C HES tan Uits eee ee eee Se ee Fe ee a ee ee ee ae 18. 2 TCU COMET) O LATO CS a ee ee ee es ie ee ee Se Wee) Mois amide CheStiltS:. =e, en eS ee ae 16. 2 LE XG Sm SKe RTO EH SS i a a I ca eh 1525/0 Sel filets Tae eset ee ree er een, Md EY IA RASA oe ER oS PERN EB a 13. 0 COTS VS eee ey de ee NR ed Se Sr sees SEE pS Tete rg rd Vel eheles eh 10.0 Note.—It can be easily understood that the fruits which require the greatest prolongation of heat ripen last and are gathered at periods of the lowest temperatures. Lachmann, in his Entwickelung der Vegetation, counts the sum total of all the temperatttres at his station (Braunschweig, Germany ) from February 21 onward. Linsser, for north temperate countries, counts from the date when the temperature 0° C. is attained, but for warmer countries he counts from the date when the lowest temperature of the year is attained; which date would, according to his calculations, be the 8th of Febru- ary at Braunschweig instead of the 21st of February; but, according to the normal values resulting from the thirty years of observation by Lachmann, this change would only make his sum totals about 10° C. larger. Tomaschek, as quoted by Fritsch (1866, L. XIII, p. 297), takes the mean of all positive temperatures as observed at 6 a. m., 2 p. m., and 10 p. m., omitting the individual negative observations instead of the negative daily averages. He counts the sums from January 1; this method gives figures that agree very closely, at least in Hurope, with those given by Fritsch’s method. Kabsch, as quoted by Fritsch, attempted an improvement on the method of Boussingault. His formula is especially appropriate to the annuals, but not to the perennial plants. His method of comput- ing the thermal constant is expressed by Fritsch in the following formula: math( Fs on WY; 174 where the notation is as follows: C is the total heat from the date of sowing up to the date of sprouting; x is the thermal constant from one phase to the next, such as from sprouting to flowering; ¢ is the num- ber of days from sprouting to flowering; ¢ is the mean daily tempera- ture from sprouting to flowering; ¢ ¢ is the total sum of mean daily temperatures from sprouting to flowering; as this temperature is principally active during the daytime, therefore one-twelfth of ¢ ¢ represents the efficient heat during an hour; / is the duration in hours of an average growing day, viz, from sunrise to sunset; there- fore one-twelfth of the product ¢ h ¢ represents the total heat that has been utilized by the plant. The method of reasoning by which Kabsch arrives at the above formula, which I have quoted from Fritsch, is not known to me. Sachs, by direct experiment, finds that for each plant there is a temperature most favorable to its growth and two other mits, mini- mum and maximum, beyond which it will not grow. Deblanchis finds that the temperature on which vegetation depends is not the ordinary temperature of the air as given by a sheltered thermometer; he prefers to approximate to the temperature of the leaf of the plant by the use of his “ vegetation-thermoscope,” which is an ordinary minimum thermometer covered with green muslin and kept moist, as in the ordinary wet-bulb thermometer. He _ places his thermometer at one and a half meters above the soil and in full exposure to sun and sky. Evidently the sum total of his tempera- tures will be between the sums of the ordinary wet-bulb and the ordinary dry-bulb thermometers, but must differ greatly from the temperature of the roots on which the growth of the plant primarily depends. Hoffmann prefers to take for the daily temperature the excess above freezing of the maximum thermometer exposed to full sunshine and free air. Hoffmann’s temperatures approach more nearly the tem- perature of the roots within a few inches of the surface of the ground. Besides taking the sums of the average dailystemperatures of the shaded air thermometer, omitting all negative values or all those below freezing point, Hoffmann also took the sum of the bright bulb in vacuo and of the black bulb in vacuo, both in full sunshine; these latter temperatures are generally higher than those of the roots and much higher than those of the leaves. Hoffmann prefers to use the readings of the bright bulb in vacuo. Hervé Mangon (1879) modifies Gasparin’s method shghtly in that he takes account of the shade temperatures of the air from the date of sowing up to the date of harvest, rejecting all cases where the mean daily temperature in the shade is less than 6° C.; he had been led to think that the vegetation of cereals and other important crops ceases below this temperature. Thus he determines the sum total ob 175 needed for ripening the crops of the varieties of wheat ordinarily cultivated in Normandy, as shown in the following table: Sums of daily temperatures. | Date of sow- | Date of har- | From inean ing. vesting. sowing | arito| Total. to ae harvest. SHG Of Ge Nov. 17,1869 | Aug. 12,1870 356 | 2,000 2, 356 Nov. 5,1870 | Aug. 20,1871 359 | 2,158 2,517 Nov. 27,1871 | Aug. 4, 1872 395 1,914 2,309 Nov. 5,1872 | Aug. 3,1873 632 1,806 2,438 Nov. 27,1874 | Aug. 10, 1875 6 339 1,880 2,219 Noy. 4,1875 | Aug. 3,1876 490 1,828 2,318 Nov. 18,1876 | Aug. 2, 1877 701 | 1, 769 2,470 Dec. 6,1877 | Aug. 7, 1878 367 | 2,085 2, 402 Dec. 21,1878 | Sept. 1, 1879 171 | 2,085 2,256 Average, INOVvaliee-.| MuesSeec.- = 455 | 1, 924 2,379 By similar calculations Hervé Mangon obtains for other crops as cultivated in Normandy the following results: Mean date. Sums of = daily temper- = : mune aes arvest-| from Sowing. ing. sowing to har- vest. ve DCL (Giri ies wet ee ee ees a ee eer ae Mar. 7 | Aug. 5 1, 826 IDO ese ge Sots oe eres ee ae See ee eg ee ee eee Nov. 8 | Aug. 20 2,197 [Barloyvprs peer ree oes Ao ed See ee Coke ei kee eee Apr. 13 | Aug. 18 1,810 TENSIVE) ee 3467 3666 1 ESA fee ore to ie rd SER pe opel gy | Junel2) 1274 | June 15 1578 | June 15 3976 4075 STG Sees Sea he eins Bele cae ne no een Junel5 |) 1269; Junel9| 1567 | June 19 4376 4588 bv eos ye pe NY a Date ee ag RUM OP Ri a June 7 1264 | June 13 54s Eee 4298 4603 LENG eS hg AA ele SO nee nee» RN es June 10 Diop ee a - eee June 9 4506 e/a eee Tey Sore eee ee ae ae aes ee, June 19 | 2b6 "| Se ee nee Se cee | Seen 4296 ||| s2o22-= = Marié-Davy concludes that by keeping a daily summation of actinometric degrees it becomes possible, even at the epoch of flower- ing of wheat, to estimate in a very approximate manner what will be the final value of the resulting harvest. At this moment, even if we have already measured the sum of the products which should be applicable to the formation of grain, we can not be absolutely cert. in that the harvest will correspond to our expectations. A certain time is necessary for the nutrient particles to traverse the various parts of the stem up to the seed, and a certain quantity of water is necessary for this transportation. An excessive dryness or heat will interfere with this movement and will give a poorly developed grain, notwith- standing the abundance of nutrition reserved for it within the plant. But although water and nutrition are as important as heat and light, still we find that predictions based on actinometric degrees alone are very reliable. According to Georges Coutagne, the law that connects the rate of development of a plant with its temperature must be such that it has a maximum value for a special temperature and diminishes as we depart from this down to a zero rate at the freezing point and also to zero at some higher temperature at present unknown; all this is on the assumption that the sunlight, moisture, and winds are such as to enable the plant to do its very best at the given temperature. If this law were known we could then determine whether a plant would live and flourish in any given climate. This law of growth has been expressed by Georges Coutagne, as quoted by Marié-Davy (1883, p. 227), by the following notation and formula. Let— v» be the rate of development of the plant, assuming that other conditions are so adjusted that it attains the maximum growth possible for the given temperature; x be the temperature of the plant; VES, a be a coefficient that defines the rate of development so that the reciprocal of « defines the longevity of the plant; n be a coefficient that defines the sensitiveness of the plant to tem- perature, so that as increases a given change in wv has a less effect on the rate of growth and therefore the plant can flourish in a wider range of temperature; therefore its geographical distribution may be wider, hence Coutagne calls 7 a coefficient of ubiquity ; c be the temperature at which the most rapid development is possi- ble under the most favorable conditions of growth or the temperature optimum; plants with a large value of ¢ must live nearer the equator than those having small values of c; therefore ¢ is called the index of tropicality. - According to Coutagne these quantities are bound together by the formula: This formula represents the momentary rate of development, so that the total duration of the growth is to be found by integrating this expression, which result is written as follows: Van Tieghem, like Coutagne and others, finds that for each special phase of vegetation, germination, heading, flowering, or ripening, and for each age of a perennial plant there exists a special relation between the temperature, the light, the moisture, and the chemical composition of the soil and water that is most favorable to growth. We have, therefore, to decide whether the same formula of develop- ment can represent the growth in each of these phases as well as throughout the whole career of the plant. As we have before said, the plant can only rearrange the inorganic products that it receives and develop its own structure by utilizing the molecular energy contained in the sunshine or some equivalent hght. Its growth does not depend upon any force contained within the plant nor on the temperature, as such, but on the quality of the radiation; therefore any formula that considers temperature only must be a very imperfect presentation of the growth, especially in those stages subsequent to the full develop- ment of the leaf and flower. Lippincott (1863, p. 506) gives a few items relative to the phenol- ogy of wheat in America and the origin of the varieties known as Lambert’s Mediterranean China (or Black Tea), Hunter’s, Fenton, Piper’s, which were all due to judicious selection and careful culture. The average wheat crop of England is stated to be 36 bushels per acre and that of the United States 15 or less, which large difference is, he thinks, the result of judicious cultivation and care in the choice 180 of seed rather than the influence of climate, since large crops have been and can be raised in this country. The injurious influence of hot, moist, and rainy weather has, he thinks, a general tendency to deteriorate the quality of American wheat, as the plant needs a hot and dry climate. Moisture defines the southern limit of wheat cultivation while the northern limit has not yet been found. In 1853 the growing season in England was too cold to ripen, the average being 57° F. for July and 59° F. for August, so that only one-half or one-third of the usual crop of wheat was harvested. In Bogota, Colombia, where the temperature of the high plains is quite low, wheat that is sown in February is harvested in the last week of July, or in 147 days, at a mean temperature of 58° or 59° F. At Quinchuqui wheat is sown in February and reaped in July at a mean temperature of 57° or 58° F. Hence Lippincott concludes that in general wheat requires a mean temperature of 60° during the last month of its maturity, or a mean temperature of 56° during the whole period of growth. In England in 1860 wheat sown March 28 ripened August 20. Of these 145 days there were 133 that had temperatures above 42° F. In 1861 130 days were required of temperatures above 42° F. When the temperature of the soil during the last phase of growth (viz., from earing to maturity) falls below 58° to 60° F. no progress is made in the growth, and unless 60° is exceeded the crop never fairly ripens. These figures appear to accord closely with the requirements of the wheat plant in the United States, where it is found that those regions having a mean temperature for May be- tween 58° and 60° F. can not mature the wheat in May, but those having a June temperature above 61° can ripen the wheat in that month.. Those having a temperature of 61° in July can mature spring wheat which is sown the 10th of April or the 10th of May. Those having a mean temperature of 61° in May can mature the winter wheat in that month. Lippincott gives the following items: At Arnstadt, Germany, wheat requires from flowering to maturity 53 days at a mean tem- perature of 63° F., or a total of 3,339° F.: At Richmond, Va., Japan wheat headed. April 30, 1860, and was reaped June 14, or 46 days, with a sum total of mean daily tempera- tures of 3,086° F.: At Haddonfield, N. J., Mediterranean wheat sown early, headed May 18, 1864, and matured June 30, or 44 days, with a sum total of 3,024° F. of mean daily shade temperatures: In Monroe County, N. Y., wheat headed May 10, 1859, and matured July 8, or 56 days, with a sum total of 3,562° F. The preceding meager data are all that Lippincott was able to find 181 with regard to wheat in America after an extensive research, but within the past few years much more attention has been given to this subject. The differences between the quantities of heat required in England and America and the differences in the varieties of the wheat were apparent to Lippincott. Thus, he finds that in England the lengths of the periods and the sums of the temperatures were as follows: In 1860 a period of 59 days and a sum of 3,562° F.; in 1861 a period of 50 days and a sum of 3,225° F.; in 1862 a period of 56 days and a sum of 3,406° F. The reduction of the mean temperature during two months of 1853 by merely 2° F. cut off one-third of the crop and brought a famine that was already foreseen in July, 1853. On the other hand, it increased the exportation of wheat and flour from the United States from $14,000,000 in 1852 and $19,000,000 in 1853 to $49,000,000 in 1854. A careful study of the sum totals of rainfall, temperature, and sun- shine should enable one, in general, to foresee similar failures and corresponding successes in the crops of any region. QUETELET. The suggestive, but sketchy, studies of earlier writers on thermal constants were supplemented by more elaborate investigations and calculations of statistics by Quetelet (1849) in his Climate of Bel- gium, from his own summary (p. 62), etc., I take the following notes: The details hitherto given show sufficiently that the relative condi- tions of vegetation change at all times of the year in two countries situated at a distance from each other. Acceleration and retardation are quantities essentially variable, and it is erroneous to say that one locality has its budding period ten or twenty days sooner, for example, than another. This difference may be correct for one sea- son of the year and entirely wrong for another; and, moreover, we can only pretend to state a fact which apples to the majority of plants. Nevertheless the differences in the periods of budding are not so variable but that we can assign to them values very useful to consult in practice. On the other hand, science needs to establish some well- determined facts in order to arrive later at the knowledge of the laws upon which these variations depend. I believe that in the actual state of things I shall be able to settle upon the following epochs, in-order not to multiply too much the terms of comparison. Moreover, the numerical tables justify, to a certain extent, the dis- tinctions which I lay down. Let us first observe that the awakening of the plants is brought about by the cessation of the cold, and it suffices to consult the tables of temperatures for the different countries to determine the average epoch at which many plants will put out their leaves or their flowers. These first indications, which it is well to collect, still do not deter- mine, however, the general movement of vegetation which may 182 manifest itself more or less slowly. They are given by the budding of the Galantus nivalis, of the Crocus vernus, by the appearance of the catkins of the Cor ylus avellana, of the leaves of the Ribes ¢ GV Ossu- lavia, of the Sambucus nigra, of the honeysuckle, and of some spireas. The falling of the leaves is also determined by the temperature, and in our climate generally takes place after the first frosts. This period and that previously mentioned come ordinarily at the two limits of winter, and they separate to make place for the different stages of vegetation in proportion as the cold of winter has a less duration. The winter sleep lasts in our climate from three to four months; in southern countries it 1s very much shorter. We can even imagine a line on the surface of the globe where it ceases altogether for the generality of plants.” The great movement of vegetation commences in Belgium in the middle of March and terminates at the end of April. I will call this the period of leafing (feuillaison), because during this interval the different plants are covered with their verdure and some of them show their first flowers. The second period is that of flowering (floraison), which in our cli- mate would include the months of May and June and the first half of July. The third period would then come, which is that of ripening (fructification ). These three great periods should undoubtedly be in their turn sub- divided, but the present state of the observations does not allow of such detail. It 1s understood, moreover, that the names I have given to them only serve to designate the principal phases of vege- tation which take place. Thus, in making the general table fomit- ted—C. A.| I have classed the different plants according to the following seasons: Awakening of the plants—This period is determined by the plants comprised in the | omitted | table. Leajfing—This period comprises the plants which, in Brussels, put out their leaves from the 15th of March to the 30th of April, and which bud during the same two months. Flowering.—I have made use of the plants which have flowered or brought forth their fruit from the Ist of May to the 15th of July. a As I have already observed elsewhere, the awakening is an epoch that is not the same for all plants. I mean to speak here only of the epoch when the sap begins to circulate in the majority of the plants which grow in our climate. “All plants do not begin to vegetate at the same period,” says M. Ch. Martins, in the Botanical Expedition along the Northern Coasts of Norway. ‘Thus in some the sap begins to mount when the thermometer is only a few degrees above zero (centigrade) ; others need 10 or 12 degrees of heat, while those in warm climates require a temperature of from 15° to 20° C. Ina word, every plant has its own thermometri¢ scale, whose zero corresponds with the minimum tempera- ture at which vegetation is possible for it. Consequently, when we wish to deter- inine the sum total of the temperature that has determined the date of flowering (fieuraison) of each of these plants it is logical to only consider for each plant the sum of the degrees of temperature above zero (centigrade), since these tem- peratures are the only ones that have been efficient in inducing or sustaining their growth.” In tropical countries the great fluctuations in the vegetable king- com are not regulated by the same meteorological elements as are effective with us: there the rainy season produces very nearly the same effects as the cold season does in our climates. 183 Ripening.—This period comprises the stage of vegetation, which, for Brussels, extends from the 15th of July to the falling of the leaves, the last limit of the period with which we are occupied here. This classification has allowed me to put into [the omitted] table the observations gathered from other sources, as well as from the system of comparative observations which the Royal Academy of Belgium has succeeded in establishing at Brussels. The average influence of location on the annual progress of vegetation. | Acceleration or retardation of Position. hhases of vegetation relative to russels. ; Locelity: Longi mal Lati fealty aes: F Ti 2 = A c a tude from tude | ide, (ening.| ing. jering.| ing. | Of, Mm. 8. ° / | Meters.) Days. pee) ee: Days. | Days Naples es bees PIN Gbl es ete ee 47 40 E 40ND 7 |R228 2. =p OO we ansaeee le ease a |e eee NGO, 2 ee eee eee ee dae 3.4 657 E 44 7 143)| aaa +14} 412} +440 )2.2.... VET Conte! as Mee la he oh fh beer 40 4H 45 26 1} +20; +4) +18) +30 —19 SYPHON AS ea Ses ee, Been 31 59 E 44 48 49} +2) +2 +16) +51 —10 GounSt all a eee ees PE se 33 15 E 44:55 [2.2.22 +14) +7] +18) +49 |_2....- (GON OV aie eee ee ea ee a 15 15E. | 46 12 AOS) | 2= ofS eles 1 Fares 5 $l fetes a Dp | Lavreciinai lias sale IANS amie iy tie 46 Si) 53a} fT iy ae ie beeen AN Carisnih ere assess eee eae 2417 E 48 59 380} —11 | — 3} +15 |-.....- +11 ID Wa Che i had Se ee eae Oe eae we 10 48 E 47 19 2400; —3/] -—1 | +6) +15 +18 IE) oS ee ae a eh aS ae ee ae 0 0 48 58 BY hal eae aA Peeks Sao Pi eee | Seta MOntMOLENC Ya! 1-2 es ee eee 0 30 W 49 0 dO eer ee —' 8 S12 EAA ee Winlopnes)= S18 asso es pee ts 15 14 W gL 3 eee +27 Ov ssl) 19) eee eolperrowhing lands ese ee n= eran sees eens OURS | Seneae = sto tL) [er | Swath se ne land es » ek sees oe ree Ee LP ey sk te +26) —1 rai Alii A dase — 4 Merdonp tine ue ote be et) ch 945 W.| 51 30 SOI aR NM eles iem | Lem iee ters Makerstounls!! ==. ss sta sere ny 19 25 Wi. | 55°85 CaF ses SYHTAD) eres ART Net cok Pee Miley Cetaen nee med ENR NF 2A TIS 12 46 E. SOOT Saeeee = Pea 0 OF obs ae eee NOUV AUN ee ee ass ee Oe 9 26 E. OORba a eae ss = Wades 3 1 fal De Le SPUSSOIS mae sete aN oe see 8 6E. 50 51 60 0 0 0 0 0 (CSTE RS 3 ce a ee Sk eee 5 34E GPSS ee —3|/ —4] +1 0 +12 STU SOS ee say ee bn de ee aE 3 33 E lel Sileaoe aoe eee tO Mee eee eee eet. Stree see ee eo 220E Bla eee, ve oe 4 8 8 9 +8 TO GH EMG eases ee xt sb ys 6) Sul Pee fa) ge Oa el | oe —6 {| —15} —5/J]-......| — 2 Witrechiteesselce. ure kites eee ll 8E DSiOg | sees oe 15 18 6 15 3 Wahi ollanderseos! eat otk ema SPS een. | ee eee (ee eee —24) —18} +4) —1 +3 Oppo wHollan deers ssp at siete ete EN IIN .FOe AER Ree ee er KOM — 109 159 Se ee eee Cronineenwere sateen noe ele: 16 56 E. 53 13 2 20 23 18 29 2 Mirani Chee woe A er ee 7 SE. 48 9 5260 | 20h || | — LO) |) by eee 2 ene LETHE NG) BS eee eee eee 48 20 E 50 5 a tyf hl eee = Dial (p= |e coe +7 AION ON ese WENA Se oe he 26 51 E 48 31 SSI Soe See ei erase 3th ee atl ee erin epee ot ok a Peg a 44 14H 52 31 SG = te eo ake se | eeisees | wee Bireptine Ass StS oie aie ots Gone 48 54. | .58 25 |...___-- 2991) = O00 | tesla lee = 16 he Seaatae GER AGS SL Ps ee ee eae ee a 22 16 E Hotads |Seeeete| —44 |} —23 | —22 |.---..-|_---.-- Gottenborg ates tee att Feat 38 31 E. DINER) || eee SR cy fel| See HO ee | PE Emp pemberer- 22-5 sae eee kL BRN ERO SA) ACES Tree | Deane | aaa ee =F fl pe neta lea eS 2h oe IIASIN CO peS espn eee ee ec eee te te oe BOT Sa. soe aa |e een elt eee eee Steere | a Car lsta ditmes-s atk. Sasi en ee 44 4E 59 23 4.9) |e ais Me at mn Al A ae eee es ASTHOSEY 2 SoS a eee ea ee aoe | ee eee BO 146 ue oe are alba seen Dee et te | 4c ey | epee IDepyol ei nye| Sf 2" ee pea ag OS Cae ee 6830) ae eee Ee iy al |S Reel ae severe Lewes 2 United States of America, central ING? VEO es SO eel ae ree |e AS. 1|tie een eae 0.0) sane sites | dees 184 This table of average intervals shows how variable is the accelera- tion of one place over another during the different seasons of the year. This acceleration even often changes into retardation, conse- quently the isanthesic lines are far from remaining parallel. We therefore conclude that latitudes and longitudes are not the only and principal causes which regulate the phenomena that are enga- ging our attention, because these unchangeable causes could not pro- duce different effects; it is the same with regard to altitudes, we must only consider them as intermediary agents, and we should do wrong to take them as the basis of calculations for determining the epochs of natural phenomena.“ Let us see whether temperatures will give more satisfactory results. In order to facilitate the, com- parison I have gathered in the table (which unfortunately has not been completed for all the localities)” the average temperatures for years, seasons, and months. I must limit myself to consulting these elements, as I have not the necessary data to compute the base of daily temperatures and particularly to take the action of the sun into consideration. This first work will perhaps make us feel the incompleteness of the system of meteorological observations adopted at present (1849) in Europe. I have also been obliged to exclude the influence of the temperature of the earth, although it is absolutely necessary to consider it, in order to treat the phenomena of vegetation in a complete manner.? The mean temperature in winter at Brussels is 2° C. The most favored localities in comparison with it are Naples, Alais, and Pol- perro (near Lands End, England). I have not been tol to deter- a@Jt will be understood that I wish here to speak only of tie action of geo- graphical circumstances considered outside of the influence of temperature. This action has been but little studied up to the present time, but it is well worthy of our consideration. The following is what one of the most distinguished living botanists of the present time has written to me on this subject: “The distribution and extension of each species of plant over the earth shows us that the plants in general and each species as a unit are subject to organic changes dependent upon longitude and latitude. Each has a limited range; between these boundaries it has its paradise, where it thrives best. The organi¢e changes which take place in individual plants, if one compares those that are native in different places, are such that we might presume that even their periodic phenomena must be affected. For example, all plants are stunted in height and in the number of their leaves toward their northern limit (or rather polar limit). They change their general appearance in going from east to west on the same parailel; they alter as to the extent of inflorescence and the size of flowers in going north or south on the same meridian. Now, as it is only by means of these organs that the plant vegetates in the presence of the world outside of it, it is necessary in our observations to begin with the relation of those organs, or rather the consideration of the developed organs ought to enter into our notation of their vital action. It further follows from this that we ought to study plants whose natural boundaries are known to us; these are the true barometers for vegetable life” [i. e., as the barometer is the measure of the activity of the atmospheric forces, so the natural geographic boundaries are the measures of the vital activity of plant life]. (Letter of M. de Martin’s Observation of periodic phenomena, “ Mem. Acad. Royal,’’ Brussels, Vol. XVI, jay) 2115)) »b Further, it has sometimes been necessary to give the temperature of a neigh- boring locality instead of that of the place itself; thus for the temperature of Polperro I have taken that of Penzance, and the temperature of Makerstoun has been replaced by that of Edinburgh, ete. ¢T have omitted these figures in my copy of Quetelet’s table—C. A @T should have liked to supplement this work with maps showing the princi- pal epochs in vegetation, but the collected observations are not yet sufficiently Maat 185 mine the epoch of the awakening of the plants in the first two places, but in the last mentioned the acceleration is forty-one days. This acceleration is also very great at the other stations of England, as well as at Valogne, which has also probably a sea temperature. It has also been impossible for me to fix the time of awakening for places where the winter is the most rigorous, such as Lapland, Sweden, and the United States. We have seen, however, that there is twenty days retardation in places where the mean temperature is very little below zero. Jever seems to be an exception to this rule; but. Fhe results obtained in this place were only deduced from three observations. The epoch of leafing corresponds, as we have said, with the end of March and the month of April, and that of the flowering with the months of May and June. The first includes the commencement of spring, the other the end of it. Thus the temperature of Brussels in spring is 10° C. The greatest variations besides are at Naples and at Alais. It is also in these places that the leafing takes place first. Venice, Parma, and Guastala are very little in advance, but the month of March and the beginning of April are scarcely any warmer than at Brussels. The difference of temperature is only felt in a marked manner in the following months. The flowering also takes place about eighteen days sooner. Polperro, in regard to leafing, is about ten days in advance. ‘The temperature in March is much higher than that of Brussels, while in April it is about the same. The advantage is lost in the following months, when, as regards flowering, Brussels is in advance of Pol- perro, as well as of the localities in England. Brussels is about eighteen to twenty days ahead of the towns of Holland and Germany in the epoch of leafing, and is behind in the complete to allow of undertaking such a task. The first chart would have shown by a series of lines drawn over Europe the awakening of plants for each ten days, that is to say, a first line would indicate the localities where the awakening first takes place immediately after the coldest day of the year, which with us is about the 20th of January; a second line would pass through places where the awakening is on an average ten days later, and so on. Another system of similar lines traced upon a second chart would have indicated in the same way the beginning of budding, always proceeding by intervals of ten days. We should also have made similar charts for flowering and ripening and the fall of the leaves. By comparing these charts we should be able to see at a glance the principal changes which take place in these various systems of lines. In order to complete this study we should imagine other systems of lines relating to temperatures. Thus one system would show the localities in Hurope where frosts first cease, always advancing at intervals of ten days; then another sys- tem for places which, at successive intervals of ten days, and beginning from the awakening of the plants, have reached a sum total of temperatures amounting to 188° C., corresponding to the epoch of leafing; further, a third system of lines which should pass through places that, counting from the time of awaken- ing, have successively attained the total number of degrees of temperature necessary for the flowering of plants; and so on for further systems. The charts relating to vegetation and those relative to temperatures would, by comparing them, give much curious information. Unfortunately the observa- tions we possess of daily temperatures are still as rare as those of the flower- ing. I have therefore been compelled to renounce that portion of my work. 186 flowering season, particularly as regards Prague, where the tempera- ture in Xpril, May, and June isa little higher than that of Brussels. The retardation for stations in Sweden, the United States, and Lapland is sufficiently explained by an examination of the tempera- ture tables, and also in regard to the epoch of ripening (fructifi- cation). I have already had occasion to call attention elsewhere to the fact that the falling of the leaves (effeuillaison) depends less upon the tem- perature of the year than upon the effects of the first cold. Thus the leaves fall sooner in the north than in the south, unless they fall sooner here on account of a season of great dryness or excessive heat. It would be superfluous to consider the influence of the other me- teorological agents when we still possess so little information as to the mode of action of the principal cause, which, in our climate, dominates in some degree all the phenomena of vegetation. The temperature month by month at Geneva and Lausanne vary little from that observed at Brussels. The winter months there are a little colder and the vegetation is a little behind. Toward the time of ripening this ret tardation changes into an advance. ‘The tempera- ture, however, in spring and winter is no higher than that of Brussels. Is not this advantage to be attributed to the fact that Geneva and Lausanne, having a higher elevation, enjoy purer air and a more efficient solar radiation, ‘elements which are not indicated by the ther- mometer? By following the mode of calculation generally adopted one would say that the difference of latitude between Brussels and the two Swiss cities is compensated by their different altitudes. Ge- neva and Lausanne are 4° 30’ farther south than Brussels, while their elevation averages about 420 meters greater, which shows that a de- gree of latitude farther north is about equal to an increase in height of 120 meters. At Munich and Groningen the same plants flower almost simultaneously, yet their latitudes and elevations are very different. Munich is 5° 4’ farther south, but is 524 meters higher. Here again a degree of south latitude nearly compensates 100 meters of elevation. It is to be regretted that we do not know the annual temperature of Groningen. Berlin and Stettin seem to approach that locality very nearly in the natural epochs of their plants. In- deed there is very little difference in their latitudes, their elevations, and probably, also, in their temperatures. Carlsruhe and Brussels have about the same annual temperature. The winter and early spring are a little colder in the first than in the second of these cities, consequently the vegetation is a little later; on the other hand the months of April and May are warmer, there- fore, we see the vegetation changes its retardation into an advance. Carlsruhe is about 2 degeees. south of Brussels. For this reason alone vegetation should be about eight days in advance as at Paris; but on the other hand its altitude is about 300 meters greater than that of Brussels, and its vegetation should for this reason 1 be about twelve days later. Combining the effects of these two causes, Carlsruhe would still have a retardation of more than four days, which is con- firmed by experience for the first portion of the year; but in the second part we see ‘this retardation change to an advance of fifteen days. Should we not here again remark, as was done before, that, 187 other things being equal, vegetation is much more active on high plateaus, where the radiation is greater, as well as in localities where the annual variations are very marked? This activity is further reen- forced if the locality is near the polar regions, where the hight acts almost uninterruptedly when once the awakening of the plants has taken place. In this respect Russia and Lapland present us with notable examples of this reénforcement. Kupffer, in his “ Note relating to the temperature of the soil and of the air at the limits of the region of cultivation of cereals,” gives the following temperatures for the three principal boundary points of this region: Mean temperature. Longi- | Lati- | Alti- |— | : tude. | tude. | tude. oun | ee Spring. Sua: reece ut | anes e / oN Beet | OL, | (OF HO NN Or OOF AS GS Kee ee 101 15 | 52 17 | 1,300 | —0.25 | 14.1 0.2 | +12.5 + 0.8 INGEGCC ING Ka eeees ne te coe Le ee Sie See OO) | 3.2 | 21.7% | 1.0 | +12.9 —2.9 PATE ITT SO UME eee eS. fe ee || oe 2S ella Leases | +0.7 | —10.0 | —0.2 | +11.5 +1.5 | | “A comparison of the curves for Nertchinsk, Irkutsk, and Arch- angel demonstrates in a striking manner,” says Kupffer, “ under what climatic conditions the cultivation of cereals can be carried on notwithstanding the lowness of the average annual temperature. All the curves agree together in spring and autumn, whence it results that it is especially the temperature of spring and autumn which influences the cultivation of cereals; it is in these seasons, in fact, that occur the two most important periods of the year for agricul- ture—the time of sowing and the time of reaping. In the cultiva- tion of rye autumn plays a still more important part, because rye is sowed also in autumn.” Kupffer calls attention in another part of his note to the fact that some kinds of farming are carried on where the soil below the surface is frozen. ‘“ Experiments in farm- ing,” he says, “ have been made at Irkutsk, on a very small scale it is true, but which in many respects have been a success. This is due to the fact that the soil becomes soft on the surface and is thus capable of developing the germs received by it; its mean temperature is above zero four months in the year, which is sufficient to ripen the cereals in a country where continuity of the sunshine makes up for the weakness of solar action. Snow often falls upon the sheaves, but still they harvest them.” These examples confirm what we have said in regard to annual changes of temperature. In no locality in the world are these variations greater than here; at Yakutsk the dif- ference of temperature between the warmest and the coldest month of the year is 50.9° C.; at Irkutsk, it is 24°.1; at Nertchinsk, 39.°1; at Archangel, 28.2° C. It might be said, it is true, that the average temperature of the year should not be considered here, not even that of the free air, so long as the plants are covered by snow to shield them, for in this case the temperature of the air does not at all represent that of the plants. In this respect the conditions of vegetation would be the same at each 188 locality about the time of the winter awakening, and we should par- ticularly consider the temperature that follows after the thermometer has passed the freezing point, as well as the quantity of light radiated by the sun. It must therefore be admitted that cold, as long as it does not destroy the life of the plant, may be more or less severe or more or less prolonged, and thus lower the average yearly temperature, without causing any marked difference in the epochs of vegetation. This reflection explains, independent of all hypothesis, that for any equable mean annual temperature the acceleration in vegetation should be in favor of localities where the annual variation is the greatest, par- ticularly in northern countries, where the frost prevails during many wonths of the year and where duing many of the following months the sunlight never ceases to fill the sky. Admitting the hypothesis that the action is proportional to the sum of the squares of the tem- - peratures, the results are still more positive; for, other things being equal, the greater the annual variation the greater will be the sum of the square of the positive ordinates in the curves of temperatures. I will now present some conclusions that one can deduce from all that precedes. I must first of all warn my readers that this work must be considered only as an attempt to solve a problem as difficult as it is interesting, the principal elements for the solution of which are still wanting. 1. A great number of factors combine to produce variations in the periodic phenomena of vegetation, the most important of which in our climate is temperature. 2. It may be estimated that the progress of vegetation is in pro- portion to the sum of the temperatures, or, better, to the sum of the squares of temperatures, calculated above the freezing point, starting with the epoch of the awakening of vegetation after the winter sleep. 3. The cold of winter, if it does not injure the vitality of the plant, does not cause any perceptible retardation in its future development, particularly if the ground has been covered with snow. The effects that can be produced by the cold of winter must, how- ever, be considered, and especially the condition of the plant when it entered upon its winter sleep, a condition which should correspond to a certain sum of acquired temperatures (or heat stored up). As to the ripening of the harvest and because plants develop under the influence of the sun, we must consult a thermometer exposed to its direct action, and not a thermometer exposed to its direct action, and not a thermometer placed in the shade, as is commonly done. 4. The temperatures at night are not comparable with those of the day as to their effects on vegetation. The quantity of light received by the plants must also be taken into consideration. 5. An increase of 1° in latitude produces about the same retarda- tion in vegetation as an increase in elevation of 100 meters; that is to say, in our climate, a retardation of about four days. This result should be looked upon as only a kind of average of quantities that vary during the year, the differences of latitude and elevation having scarcely any real influence further than as they produce differences of temperature. 6. The variations of temperature, other things being equal, are 189 favorable to vegetation, and the same may be said of high plateaus pee radiation is more powerful. . The isanthesic lines, or lines of simultaneous flowering, do not oa any parallelism at different periods of the year; thus, the line which shows where the lilac blooms on a giv en day of the month passes ten days afterwards through another series of places where the same phenomena is then occurring. Now, the zone comprised between these two lines has not the same breadth throughout its whole extent, as would be the case with a zone between two parallels of latitude. It is not even constant, since, for example, a month later the isanthesic lines will have quite different forms, and localities that were backward as compared with others may then be in advance. 8. The falling of the leaves is a phenomenon which in our climate depends as much upon the current temperature as upon those which have preceded. It 1s generally controlled by the first cold of autumn. FRITSCH. Karl Fritsch (1881) gives the results of about ten years’ observa- tions of plants growing in the Botanical Garden at Vienna (1852— 1861). His list of plants embraced all those recorded in the previous lists of Quetelet, Sendtner (1851), and his own, in all 1,600 species and varieties, but of which he has only used 889. The epochs ob- served by him, as uniformly as possible throughout the ten years, were the following: (1) ‘The first visibility of the upper surface of the leaf. (2) The complete development of the first flower. (3) The complete ripening of the first fruit. (4) The date at which a tree or bush has lost all of its foliage. Having endeavored in vain to establish a connection between the moisture of the air and the growth of the plant, and finding it imprac- ticable to take account of the moisture in the earth, Fritsch resolved to reject observations made during special droughts or floods or other abnormal conditions and to consider only the sum of the average daily temperatures. These mean daily temperatures he deduced from the observations at 6 a. m. and 2 and 10 p. m., made at the Central Meteorological Institution in Vienna, where the thermometer was about 50 feet above the ground. The summation of the mean daily temperatures for comparison with phenological phenomena counts from the 1st of January to the date of the observed epoch, and omits all days whose mean temperatures are 0° Réaumur or lower than that. A comparison of the observations made on successive years on the same plant shows that the time of blossoming is uncertain by only one or two days in 96 per cent of all the plants, and the so-called “ tenipera- ture ” or “ thermal constant ” is uncertain by 3 per cent of its amount or less, in 97 per cent of all the plants. Similarly, for dates of ripen- 190 ing of fruits the dates of ripening as predicted by the temperature constants have an uncertainty of one or two days only in 94 per cent of the cases. In the choice of the date from which to begin taking the sum of the mean daily temperatures, it would seem that for annual plants the date of sowing the seed would be proper, but that for perennial plants the whole winter since the end of the preceding growing season would be proper; but instead of the latter, Fritsch has adopted that epoch at which the mean temperature of the day has its minimum value in the course of its annual variation, and this, com- bined with the ease of computation, leads him to adopt the Ist of January for all perennials. For the biennials and the annuals he would have preferred to count from the time of sowing the seed, but as the latter date was frequently not recorded and as most of the temperatures are below freezing in the early part of the year, he finds no large error introduced by adopting the Ist of January for these also, and this is very nearly equivalent to Quetelet’s method of count- ing from the time of the permanent awakening of the activity of the plant in the spring. In the following list I have given all of Fritsch’s results, and with reference to the practical application of these figures to the prediction of similar phenomena elsewhere quote his statement that he had con- vinced himself in many ways that the trees and shrubs observed by him in the Botanical Gardens at Vienna blossomed at the same time as those in the open country, but for all herbs this is true to a less extent, and only in a few cases are the departures important. Although many plants do not ripen in the short season at Vienna, yet he was able to determine their thermal constants for the date of blossoming. In general the plants and their seed had by long cultivation in Vienna become acclimated to that locality, so that by applying Linsser’s theorems to Fritsch’s results they become applicable to the phenomena that would be manifested by these plants in other parts of the world. As concerns the temperature of the soil, Fritsch states that the perennial grasses were partly shaded by trees until 1852, after which they were cultivated in a sunny spot. The annual grasses were uni- formly in a sunny region, slightly inclined toward the north. The orders or families, with the genera and species and sometimes varieties included within them, are arranged in the table as given by Fritsch, who states that it is in accordance with the natural sys- tem of Endlicher, which is generally adopted in Austria as prefer- able to a chronological or alphabetical. But for the convenience of American readers I have added to each of Fritsch’s orders the num- ber by which it is designated on pages 5 and 736 of Gray’s Manual of ee 191 the Botany of the Northern United States, sixth edition, 1890, as re- vised by Watson and Coulter. These numbers will be found in the brackets following the names of the orders in the following table, e585 | Gs 129%]. Thermal constants for the blossoming and ripening of SS9 plants (or the sums of the mean daily temperature above zero degrees Réaumur counting from Jan- uary 1st), as determined by Karl Fritsch from observations in the Botanical Garden, in Vienna, during the years 1852-1861, inclusive. [See Denkschriften, Akad. Vienna, 1863, Vol. XXI.] » [See end of table for footnotes. ] Flowering. Ripening. Designation of plant: Order, genus, and species. | gles Con. ee | Con- I. Graminex [G. 129]. | Sanit | ORE (MeZeammays ue (SOW) Apr29) canteen see eicc s-teecinecemeseci< | July 20 I 082" |e esas ante sete (2ealopecurusiprabensisila a: x-seaeece feces eect acielscinnie- May 5 42) ll se sejare ol bee reretete ste (3) Phleum pratense L. var. nodosom.......--.....-.---.---- June 19 981 | July 28 1, 595 Gombhalanis arundinacea leseecc-a5--see= sees se oeeeeee eee June 10 824 | July 2 1, 143 (&)) Jee G Enel) Secon saaeeses eens a BAS aa aenoSeRoLSceEses June 8 812 | June 28 1,111 (Glertoleustmollis Esc .c.o cas secceciccAstjciee.oe se s.erscleles aes July 2 TO Bess escess| Reese ose ()panthoxanthum odoratum Ibs s222 250. eee s-c se = ene 2 May 15 478 | June 10 | 888 (Sjpeanicum miliaceumi I. (Apr26)) 24-2-..2..- 22-4 - se 2-26 July 7 907 | July 22 1, 184 (ONEStiparcapillata Wiewos seas 2) Sesto ss sec scesceee doses nie == Apr. 21 Bit eeeeee et eo Paer oc (oy ESaullapmratensis Ma and Ri 2e es. cae eee ee ee = May 20 bc): Sil Canes eee Weooee tae (91) Ornithogalum pyrenaicum L. var. narbonense, mon- | | BELOSULIN Ge NA ee este cee eee ate Saisie cicero May 31 732 | July 22 1, 466 (92) Ornithogalum umbellatum L..........--.--------------- | May 12 {Vel erseneremese Reece (93) Mryogalum nutans Wink... 2.2.5.8. 6-- 2. -55--5-=2-- 22-22 Apr. 15 249 June 3 731 (94) Puschkinia scilloides Willd.............2---22----22----- Apr. 1| GAN | Mees et ge ene eae QOb yp Ade DAM Sees ose petarei= wie mrepe m= = a) wi a= am winiaim os = mim wim | July 9 (al yee es Ss ec (96) Allium fistulosum L. var. altaicum -.-.---.-------------- | May 23 603 | July 1 1,169 (27) anon areola Sopp eoco = seen es oes oooee acess ence. | Sune 5 | (i:'3)l Bee Be aeaeccec (98) Allium paniculatum Aut. (?)..........-.-2--¢2--2+2-2202+ | July 23 yy Peeper ee Be: Perpatilinmneparrinetiee.-o- Pintisisilestris al, = sets. Jaap ee ee = eee ee eae May 17 | DUG oc a-e ae te (75) Binusistrobus l, var.'compressa 2.2. 22.2 se.) sees eee | (175) (LIONS Mocs. oss teeeoeee (76) EPinusn imate Ramon yen ce mceeieieceeleciiensael ale | May 24 | 603 | Staite cc cuel seen eons 195 Thermal constants for the blossoming and ripening of 889 plants, ete.—Continued. : Flowering. Ripening. Designation of plant: order, genus, and species. one Gant Date. stant. Date. stant. XV. Taxinex (G.—; see G. 107]. ORE OPEC (Gz) eb axtisy DAC CHUA) lum scene aa nciaee = face cee a oe em=ie =i Mar. 28 149 | Aug. 18 1, 873 (178) Salisburia adiantifolia Sm. ¢...............-+.---------- May 11 (Gals) eee aaa eae eee XVI. Betulacex [G.—; see G. 103]. | (179) Betula alba L. var. dalecarlica ..........-.-----------+--- (179) (179) fees Sree See cece GSO eA mms corditoliaMenores a. 2) s22 jane fos. sche a -oame == Apres || 199 | Sept. 30 2, 524 (181) Alnus glutinosa L. var. pinnatifida .............-.-.---- Mar. 11 97 | Sept. 23 2,404 (32) Almus'subcordata C,H" Meyer -....--.-...--- 22-2. 2.0 Heb: di 55 | Sept. 27 2, 436 XVII. Cupulifere [G. 103). 1S3n Osinyalvull rami sd Cee eee etna see ae mee anlar aire May 3 Sto il eee ae Jsercee tees @34)) Curpinus betulusul ~.o....-32.22------- osc sceake eee PADI. 20 279 | Aug. 20 | 1, 836 (185) Carpinus orientalis Lam ...............-.- Bedjacis ssicees es May 3 S70) etek eel ees sae (@S6)eCorylusjamericana Rich!* 25222 cen. 2. ses se- ences =e ole Mar, 21 138i Ps. ate 8 22| Mech scecet (187) Corylus avellana L. var. globosa ....-.--..--.-----.----. Mar. 1 TQM esd declare ca] Beek actersse (CSS) mCorylustcolummamWeilld: 2 sce ccs e-her ea -snee ===] Paaed Ole (PA Bierce pemapnoese (S39) QAR MOBY by ise Sea ee sedoste= Soaps onemocpoodEonesuems (189) (LS9) ke lisetal so ssl Boekecees ICO O WERCUS COLTS tana anes acce aces ane sarmeree== = eines May 12 475 | Sept. 21 2,335 (191) Quercus,pedunculata Ehrh -.2-2...-2...-2.-. 22-2. Sece- May 6 420 | Sept. 14 2, 236 (G2) Tne ies ay ahs Of Steoasescps] es eeHers oases Sree Ssccec asec May 3 380 | Aug. 2 1,617 (193) Fagus silvatica L. var. pendula .................-.-..--- May 7 425 || secee s as | Sectors XVIII. Ulmacex [G.—; see G. 99]. (194) Ulmus campestris L. montana tortuosa .........-.------ Mar. 30 163 | May 18 540 LOD) Ulm Ste user VV LL Cee rare tata ce/ ts arateein cc ee siclejeiamieietsieiar 0: Mar, 31 162 | May 20 574 XIX. Celtidex [G. —; see G. 99]. » | (OG ECeltisMUStCAlIS Ts macs. ooo cee ne sce ee sese tie Apr. 24 PBI Se anos. | eee sere Gon CeltistoccidentalisiIa ssc sa-26 set... ee eee cee eke ee ae Apr. 29 350 | Aug. 15 1, 806 XX. Morex [G. —; see G. 99]. (198) Morusialba I; morettiana 2. 52 << 5.5. ae ce a ccc cciclee May 15 509 June 18 970 (@99) Morus alba) i; iructu migro. 52-26 2.- scence ace es cccre-= May 16 545 | June 21 1,015 (200) Morns/seabra; Wailldiqss 22 4-2eSeeee ees see eaccenese- an May 17 549 | July 8 1, 280 (201) Maclurajaurantiaca Nuttal-Ossss.. --.. 2 s----- eee ee June 7 818 | en Een nee aoe (202) Broussonetia papyrifera Vent. ¢ cucullata ............. May 11 491 |.....----.|---------- (203) Ficus carica L ...--.-- Bao See oor EE Eee EE (203) (203) | ge PP ee ae XXI. Cannabinex [G.—; see G. 99]. | (204), Humulusiupullusilin giu--2-2- 22 52t2=2-- eee eeee cee cose Aug. 3| 15653 | ae ote sb ac ae XXII. Platanex [@. 110]. (205) Platanus occidentalis L...........---. Sp neck oH mrs oe ie May 10 EG ll a epee ae Sse ee Be (206) Platanus orientalis L., 8, acerifolia, 68, grandifolia....) May 6 420) Seance ne ciotel| Ssiebre see ele XXIII. Salicinex [G. 104]. (Con); Salixsbalbylonmi ea ilys Oca. < coerce ce stewie ertectewciclenie Apr. 16 262).| -Stathe seedless oe coin (208), Salixedaphnoides Vill gio. <2 ae on seieejicjetse winieislose cletsters = = Mar. 3 AT ce es Cece cin a eae (20°) RS ali-xe punpume alae vsoctcw eine soem s cree cies ooee ust soe ce] Apr. 14 229 Nay 19 525 (210) Salix HEWES Ie 6p shsoo ao sedons os sescnbr obese eases cassie Apr. 15 Dn Le ed Oe a ee (i) Populus talibaiie Gran elics: tee tecce cess cee ese | Apr. 4 IR Banceedaee SoSeepeeee (212) Populus balsamifera L. % 6 suaveolens...........--.-.-| Apr. 12 DADA Weeiale inte =| 2)=1= == === == (213) Populus canescens Smith. # belgica........--.--.------ | Mar. 28 145 | Bes ocd jee tae (Qi; Populusidilatmta Ait. Og 222i) so. la. s 0 eeeaceneeeee | Apr. 9 220 | May 31 703 (lb) ME opultistenss Cav Abit Ores Soccernet eaccietiee osinsscte ss ale wleibie Mar. 27 131; May 1 371 (216) mPopulusimicraviy, Cerne sere eh oo oon. 5. sckeS- see Apr. 12 236 | May 30 | 683 (207) sPopulusttremiumlaan Gi Ors secesaciceiacisterccjeie sss aciemeccicee| Mar. 26 | 137 | May 8! 418 4 196 Thermal constants for the blossoming and ripening of 889 plants, ete.—Continued. Flowering. Ripening. Designation of plant: order, genus, and species. Date. Con Date. ae XXIV. Chenopodex [G. 87]. cRéaum. ORéaum. (218), Spinaciaoleraceat ss c-en eee ees smahiets site Coe May 12 484) June 21| —1,018 (CR)), Tks yablleihots AUS ee SereaoBadncesoensonconauabcosougseces June 11 216 | July 18 1,412 XXV. Polygonex [G. 89]. (220) eRheumilemodi Wall eessesee eee eee an eee ee eee June 4 T70il| . seo ceeces eee (221) Rheum hybridum Ait. (later R. rhaponticum L.) -..-.--. May 16 494 | June 21 1, 021 (222) Rheum palmatum L. (also later R. rhaponticum L:)..-| May 17 501 | June 18 983 (223) Rheum rhaponticum To ~ 5-2 ne: eee nie meet eae | May 11 468 | June 15 921 (CRLDY isporeyetony bash ERA biol Ui gap se aonassae socodcn er ocadesssenoe | May 13 480 | June 17 956 (225) Polysonum amp hibiumel assesses cece seen eee eee | June 28 L065: |2 252-20) | eae (226) poly sonumibistontaplit= a. sasencee sree nee eee ee | May 21 583 | June 14 946 (227) Polygonum fagopyrum L. (sown Apr. 24).......----- _.. June 10 552 | July 18 1, 096 (228) PRM exta Cetosa elas. Cece apts = sete eat aes =e ee tener June 1 | 709 | July 17 1; 399 (229) Rumex acetosella L. multifidus ...........-.-.-....-.-- | May 27 661. Gee Ae ee (230) Rumex crispus L ....--- BEE SID Ry a cre ee June 4 752 July 2 1,145 (231) Rumex nemolapathum Hhrhii!-_: -.- 0. ese ese | June 18 972 July 14 1,412 (232) Rumex patientia-l. conierta <-...2--- Sos. --- 2: es May 27 659 June 28 1,121 (235) UME Xs SCUTAGUS Jaren einem seer aa rice eee eee May 26 627 | June 20 997 XXVI. Daphnoideze [G. —; see G. 94]. | (234)eDaphitesalpina dues ea seeee ee erere ns eee ereein caer | May & 432 | June 21 1,011 (235))-Daphme launeola dite ss joe = cee msi sts nie elelelimei iat Mar. 28 LOSS 2a eee (236) sDaphn esmezereum Aah. ae acme Ses e Se pee einreteeeel= Jan. 25 36 | June 8 804 XXVII. Elxagnex [G. 95]. | | (237), Bippophee rhamnoides iy). 22: i228 cen = me oe | May 10 380: |<. seey cece enone eee (238) Eleagnus hortensis M. B. augustifolius ...........-.... | June 7 814 | Sept. 12 2, 267 XXVIII. Aristolochiex [@. 91]. | | (239), Aristolochia clematitis Iii): assss. 2.22 eee eee May 11 471 | Sept. 2 2,130 (240) PATIistolochiarsip Woe: = see erate ete alate terete snes tel May 21 BY (y Rano Sadag||Boacasnss6 XXIX. Plantaginex [G. 83]. (241i) ePlantae Ofc yMOps las seeeesee este mate a teers ot relate May 18 634 | July 9 1, 298 (242) lsmtbago Tamceol ate plies carte) setesioaaarer a oa oeale a late reer May 8 425 | June 28 1,157 (243) ab lamitae ome Gi sia ayete a teeta ere ae eee ete lele lalate taferal eta May 25 620 | July 16 1,373 (244) Plantago saxatilis M. Bieb....-. -...-..-.....---------- Apr. 28 359 June 29 1,148 XXX. Plumbaginex [G. 60]. | (CHE) Aaamncrak apie boc Alel se ooh see cou seo seonpoadensque= | May 19 566 | June 21 1, 086 (CAG). Statice Caspian yValll Gtr cote, =p = meters eee lla eet areata atcha ety ay 249 | eth 04g | Brel ererare cate ee eaee en (OED) StEN aK robe) eee Sa eroeaeas secousddoe sos seSc0nen esc June 14 927 | July 28 1,564 (248) )Staticedatitolias Sma: ee. -p sae ee ee cemeteries | July 22 1, 476 |e cone sen | eee eee (249) Statice limontum Lb... Possess teen 6. ee ear | July 11 1,382 oe ceoee eee XXXI. Valerianex [G. 53). (250) (Centranthusruloern DD) (Clear ao eee oe eee | June 1 746 | July 30 1, 626 IO MEN atharh opie ot: UM Uo aa esandees eee heoscodosnc>s5cseass | June 7 801 | July 1 1,179 (252) Valerian ai OMrU Operetta acteeacts eee eta = ee eee eee May 22 586 | June 26 eg XXXII. Dipsacex [G. 229]. 953) Dipsacus full onumiles eee see ees eee ae July 11 1,318 | Aug. 10 1,741 (254) Dipsacus sylvestris Huds..........:-.--+--------+------- | July 15 1,384 | Aug. 11 1,\792 (255) Cephalaria tatarica Schrad. gigantea ......--------2----- | July 2 1264 ee esc laclenoem seeire (256) skenauitiarciliataCoult 22 eeee ee ee ore eae June 4 182 eS Ahe ae Baie (257) Seabiosa caucasica M. Bieb. heterophylla. .....-..------ | July 16 1,376 | Aug. 4 1, 689 (258) Scabiosa columbaria Coult.......-...-...-...-----=----- | June 30 1,130 July 22 1, 482 (259) iScabiosa Ochroleuca ie 2. 2see scene eee ee ee | June 29 1,127 | July. 30 1, 597 (260)) Scabiosarsuccisa iy) ces ecee ee eee eee Be ss SO Ee | Aug. 4 1,677 | Sept. 6 2,188 ae 1G Thermal constants for the blossoming and ripening of 889 plants, ete.—Continued. Flowering. Ripening. Designation of plant: order, genus, and species. eae Con ae c on XXXIiI. Composite [G. 55]. | Serge: OD, (26l)pBupatoniumrareratoid esl. eo on. - 2. ee aan cesses cece July 23 | 1,481 | Sept. 2 2,191 (262) Bupsitorniumicanmabinuml Is: - 025.2. se scce seine sce ose = July 5) 1,231 | Aug. 9 1, 745 (263) Eupatorium purpureum (Aut.?) ................-------- ATED 1,774 | Sept. 19 2, 301 (264), Bupatorium syriacum Jacq -. 22.5.5. -2 + -~- nsec ewes sees Sept. 24 | DOO Ween se seco s|lonatas oars (Zo) wPussilaco petasitesily. 5< << ss cece ecie see | (20) 1) MCZ0)— \eapacecten||ptecesotsc (Qui) pAstermoviabeleiigNees 9... esol e 4. cesses een een [tet 7 ars lily (271) eae es [Pace eee (x(a) PAS EMS PULOSUS) WAU Gee oo societies ie Bebo we ccs sac ec ceeee | Sept. 12 OAS cscs acrtccll| Scisereel tote (223) PA stempyrenceuseDest <2. scnyecs sce eee see scence ee eane | Sept. 9 PE ly emcee ee lsat ee Bees (Ze PE TIS CTOM OCHO Mice: jctcecec5)f = op acae ais Gan wc cess tess ess 2% | June 14 | 902 | July 11 1,309 @Gi)pbmeeromicanadensis U2. o52 5.2 ee. ssce ests ccs sige =s July 9 1,264 | July 22 1, 459 (7G) PSOuMGReoOmlitissima, Wives 24 -)- 5-2-2 sostcacssc0cer May 22 B79),) Auger 7 1, 692 (ib sampbucuswracemosa wine sceeaee ee ace ee eee ree eee aes May 1 350 | June 22 1, 004 XXXVIII. Oleacex [G. 65]. (COB) keane rena yA 1) | s sh sdeso 6 oS donee de soececee June 3 746 | Sept. 9 2, 254 (4ii7) Braxinusiexcelsion Is. 2a. - seem ees eee nae eee Apr. 14 248 | July 23 1, 443 (418) Fraxinus excelsior L. PUPP) Se oenise de sosesa-eescSascs5a6 qo pdOsee 277 | May 22 590 (419) Fraxinus excelsior L. pendula.......... Bee asec | Apr. 20 | 296 | July 11 1, 281 (420) Aare im s!OTNUS Miss em ceieie = ae ee eee eee eens | May 18 | BBs Boceariaeso| ssa c0coScin (421) PEraxinusitamaniscitoliaiVabilio--c ase = -ceeeeceenese cee Apr. 8 222.) nyse celle eee (422) eSyrinea)) osikea) Jacqea scan. -cecss eee eee eee ene May 21 DOM | S25 2 See cena (423) Syringa persica... o< -ol oes sens -ceece cee ence cies | May 12 t UReltl ERAS AIA HS Beers oe (CEN Sha ab kee) \abdkeg hots Dae See cAme sondarsdacomsccs ced sehesizcene | May 6 424 | Aug. 26 2,014 XXXIX. Apocynacex [G. 66]. | (425) Vinca herbacea M. et K .....0....2-020eeeeeeceeeeeseeee | Apr., 26. 697 |) ao eee (426) vanes) minors: vanieratas ss. a2 5s.see tesa eee eee Apr. 16 | O65 hel eee Veda oe aes XL. Asclepiadex [G. 67). (427) Periplocajence cay) eam Ne aecte ew ce ere siecle else aie | June 6 71989. ages | ee eee (428) Vincetoxicum fuscatum Endl.......-.. Renee wesc cee ee | May 24 | 620 | Aug. 12 | 1,816 (429) vancetoxicumini rum? Mon Ghee. asees-- 42sec ee eee | June 2 | 719 | Aug. 20 | 1,935 (430) Vancetoxicum! officinale: Monch:::222-.5 5-2... --.----- May 16 529 | Aug. 24 1, $47 (siyeNsclepiasisymaCar br esse cen eee ane sere ey areeee ete ere | June 24 ARES | ooscomaecloodencs Sos XLI. Gentianex [G. 69]. | | (437) sMenyanthesitritoliataiics ns. sco ssenee er eee ete eee Apr. 29 B08 Ve daaie ace |e eee XLII. Labiate [G. 82]. (433) PcavandullayspicanD C2 ees seers a eee ee eee eee Aug. 4 1,696 | Sept. 24 2,430 (434) lay an cule WwerakD C2 sonata eeeetere nes secre se ee eeeeee June 26 |- 1,093 | Aug. 3 | 1, 650 (435) eMentha crisps Wie sen =e seees See ees ee ease aoe | July 14 fl '368)|5 5 eee |scaaeQnee (436) Mentha piperitaaiys. sos saese sea sree on eee eee eee | July 22 | 1,496) 22h sea ee ae (G37) eMenthapulecium hii. see ees eee er ers ee eee et July 21 W479) (SaaS eeSl eee See (438) e\lenthe rotundifolia see sesseceeso sear areren seas eeee July 23 1488. ecine re onl nese ree (439) ay. copusrenropaeus Titec ee-ck ses cieiesiee cei teeeeeeeees July 5 1,247 | Aug. 19 | 1, 931 (440) pSalviarargenteas the sek soe seach eee nne sen ee noes | June 10 879 | July 18 | 1,357 (al) Salvisnaustria calles eee sneer ee esee eee eae nae ee May 22 606 | June 15°) 929 (442) USalviavelitinosa Livises. tt ese ssa ae Soe areceaom neers July 27 1,559 | Aug. 29 | 2, 052 (443) sSallvianOnrein gis Mya. 3522 eee eee se aaaee eee meee eee June 1 722 | July 6 1, 241 (444) sSalviapitscheriMorr yee ee cones ee eee Oe neers Oct. 13 2,616) -sccce aaes | Seen ereeee (445) MSalviaipratensissie sea. sees cece ee saan noes eee eee May 16 |} 526 | June 9 823 (446) "Salviaisclarea Jacgie 2252 eee ne es ene ieee ae een eeee June 18 | 958 | July 27 1,562. (447) Salvia:silvestris be. 2 22-6 esccc ss soe see ie oacs Sones ee ae May 23 608 | June 21 1,015 (445 \eMonard al fisbulosam inser see weeee eater steerer July 10 1,294 | Aug. 23 1, 960 (449) (Origanum vulgare Deets oie eee ct eco te es seme cere sense June 22) _ 11,0285) Aug. (9 1, 736 | (450) thy musiserpylinmul: yullearisees. esse seeeeeee see May 22 | 589 June 16 1,018 (45) eihymus vulparishs 22s. se cescenc ce necee coset eee June 1} W2L, | meres oe collec Apr 224 | May ; 698 (464) Dracocephalum austriacum L..............--......----- May 613 | June 1, 053 (465) “Melittisimelissophyllum, L:-..--:..--2-.2---.--0------- May DTD: | 5 crore seis [ics ee ee (466) Physostegia speciosa Sweet --_ -2-......2..-002e+0---2--- | July 1,321 | Aug. 1, 746 (Lona tindonvyel alge ek = eisai e ica e eee ee cece May 400 | June 763 (265) sGeonmmusicandinenukss.- 224 sa2ce a+ 5--n--2ceccc~e sees | June 839 | July 1, 443 (469) Stachys alpina L. var. intermedia .........-.....---.--- June : 1, 052 | July 1, 582 (470) Stachys germanica L. var. oblongifolia............--.-- June 838 | July : 1,529 (ye) PB elOmuCa OMG MIS. seo 5- 2 ascee = = sce eee sieiee cease ate June ¢ 1,149 | Aug. 1, 805 MIMBO e ri GIS SGOLMLOIG CSNY) =, a no-p lon smcice tables cca cceeccees June 770 | July 1, 285 (io eNanrubimmsyuleare: Dna. Ja: ey. 2e soe. satel ciocss see este June 787 | July 1,417 (GepyieBallota migra, Woes 2. enc 22s Ep ae/e.c eee os aoe ie sae | July 1,185 | Aug. 1, 766 (7b) Pp Pblomisttuberosaiiu.-- -..-...-.--2.- neepe dns son seaer ae June 722 | July 1,311 (A7voyehewcrium chamecearys (hii. sa.s.becc- s <2 se nesses cee ss June 2% 1,036 | Aug. 1, 796 (Auf) me RCUCTHIMMAMONtAMUIMM = 922-255 s6ce Jo ndseeeiec-2Scens bee June 1,045 | Aug. 1, 742 (278) MRCuUcIiIm' SCOTGIIMM ys =: 65- astect sis. se nosis cis so ciaearere ie July it 47/83 | aS oasouie sapseeee ame Gio wATupa) SeneveNnsis ty. 4522-2. eno- snc eones-aassceeess-5 May AQRUNG aN eae tal Rae see ESO EAV UPA elas ulema cess tae ae on ices eco e kc cee teen nes May AGO! eure ealeeeeeeeeer XLII. Globulariex [G.—,; see G. 1]. | (Sie Glopulsni anvil arisie seo. sae oe. seioes omen ese seers May 397 | July 7 1,253 XLIV. Asperifolix [G. —; see G. 72]. | | (482) Cerinth emmin onlin a2. 2.-p 2s oss a ee nen ecg dee wes Apr. § 357 | May 70% (483) Echium vulgare iW ea BOE AE a et ATS Pl tee Saye June 78652 teem leeene eee (484) Pulmonaria officinalis L.........-. BR San 7 seen | Apr. 207k ee ees ee (285) Pulmonariasimoliis: Wollt =. .-0800 J. =o ee pate ene | Apr. PAU fin Wise a al Ee (486) Lithospermum purpureocceruleum L...........-.------ | May 564 | July 1, 382 a7) Pane husarOniGinalisiy = .: 22 seth, .\5.n0aa-2 520532 aese 35 May 599 | June 1, 056 (ass) eM OsoOtis palustris ROth. 2 55. soscccosascccenesncars ss | May COANE a8 Oe shee ee et (459) Svan phy tummofieinale ics: sese. se eeasecescoeeessaacc ss May : 619 | June 1, 098 XLV. Convolvulacex [G. 73]. | (SO) MCalystesiasepitimn: Ris sae .cestecs coe secs sccece cet sae se June 863 | July 1, 462 (491) Convolvulus tricolor L. (sown June 18)......-......-.-. Aug. 106345 25 Naess (492) Pharbitis hispida Choix. (sown June 18) ............- _.| June 295 omen aey more ane coc XLVI. Polemoniacex [G. 70]. | é (498) Phlox cordata Elliot grandiflora......................-- Sully DW ASGR Recs secme maa (404) (Phlox.speciosaPursht 2 iop 8061.2... 55. 0c.ce sess. ceed Aug. PASO yer cate aloe ree (295) sb olemoninm: coeruleuml Iijes cs 4-5-ecs 3 -c + -s cc beens ee May : 636 | June 1,103 XLVII. Solanacex [G. 74]. C290) eORGITASiram OMiUMmcln. Wesel ess. 2s-5<<22-s-cecncese June 626 | Aug. 1, 382 Come VOSe yams mig en Ty 4. ep VA se eens cence deces May 533 | July 1,638 (498) Physalis alkekengi L ....... Ste ee ae tt rr eee May 719 | Aug 1,755 (SS) WSolanumarciall cam ar selina sleet ccc ec c<<2aszaseeeeee July 1, 437 | Oct. 2,474 (500) Solanum nigrum L. (sown Apr. 26)............--------- July 867 | Aug. 1, 744 (501) Atropa belladonna L...... PER lt BTS oth aD | May 661 | July 1,458 Thermal constants for the blossoming and ripening of 889 plants, ete. 202 —Continued. Ripening. Flowering. Designation of plant: order, genus, and species. icon ie C | - on- Date. | stant. Date. |° stant. | XLVI. Scrophularing [G. 75]. ORéaum. | OReaum (502) ‘Verbascum gnaphaloides M. Bieb .........:2.:.....2.2- July 26 155 33))\ 2 aera reste |e aera (503) Verbascum lychnitis L. fil. rub. lanatum flocosum..... June 8 825 |. 2 sh. soe eccemanme (504) Verbascum nigrum L. lasianthum..........-.-.....---- | May 25 | 628 | July 25 1, 504 (505) Vierbascumyphlomoides Wi teeeee. nse. eee eases eee eee June 19 1,001 | Aug. 12 1,832 (506) BVierbascum phceniceum djs eesscesesieeee es sae eereee May 16 510) July 13 1,385 (507) Verbascum speciosum L. genuinum...-.....--...------ June 20 TOF er teee 2S oe eee (608) SVierbascumi tha psusilsasecsssee see tess ase essere aoe eee June 26 1,086 | Aug. 13 1, 842 (509), Scrophularia modosa b..-.2-22-.2.2222- ao bee eee May 28 652 | July 12 1,304 (S10) inariays cenistifolianMall Se. 22s esses ees oes aseeeoeseoe ene July 1 1,188 | Aug. 6 IE yl) (Gl) Blimamia valle ard SPV ae eee er eee ee ee eee 1 July & 1,220 |! Aug. 1, 756 (QD) Auniwsbadivboypnen wet ys UasccssoocasssocSossocodeesacoosaes | June 6 S16: |e sew 2a eee (513) Pentstemon barbatus Benth. robustum.............---- July 4 1,227 | Sept. 8 2,162 (Olt) erentstemonidigitalisiNuttmesssesacec see. seer eceen eee June 11 865 | Sept. 5 2,158 (515) Pentstemon pubescens Poland ............---- lan Sescede | May 30 690 | Aug. 3 1, 688 (O16) bi sitalis lutealiscee ccc see cere cine heeeoeeeeee June 9 845 | Aug. 1 1, 653 (ly Disitalisipurpurea Wi esse ee ee ee eee reese ereee= June 6 772 | July 20 1, 482 (518) Paulownia imperialis'Siebold=-:-:---.--...-.----:-----: | (518) ((18))) | Soeeesaee| see eeeeee (519) Dodartia orientalis L ..-...-.+.-.-: EE Uer cise este Ser ee eee June 6) TSIM AER bee al (520) pGratiolaroticinalis Tera. asses. sec ceee a2 ees eeeeee eee | June 4 | 758 | Aug. 8 1,730 (521) Veronica austriaca L. var. pinnatifida....:.......-..-- 5 May 17 504 | July 12 1,312 (622), Vieronicaslatifolia nh. var. maj Or 5-2. +5. 50sec ese ae June 4 761 | Aug. ; 2 1, 678 (523) Veronica officinalis L..........-- REE meee cele etemioeee este May 16 523 | June 26 1,098 (624), Veronicaispicataii. vari cristata. .1s---..2-- 25-0 -e-e eee July 5 W226) ec oeseenes seer eee x XLIX. Acanthacex [G. 80]. (p25) RATcCanthus spimosusilireeerrecermecehsaeameeeceeec crease June 19 985 | Aug. 19 1, 943 L. Bignoniacex [G. 78]. (626) RCatalpaisyrinecetoliaiSims!sca. se. see eee eeeee eee e rene July 3 TlO3 8 Octy ac: 2, 666 271) MECC COMA gran Git Oras WieCur aa-= eee ee ceaseless ee eae July 28 15602))| wins. arcc2 alee ester cere (528) Tecoma radicans Juss var. flammea .................--. Aug. 8 Te 746: | 22 oe Sent heceeeee LI. Primulacex [G. 61]. ~ (529) Primula auricula L.........-..- be ee aoe eee ena eee | Mar. 15 IIR eaqascnacs| |Henccaosde (@30)eCyclamenieuropsemmypl) sce. sere enact esac ceeeeeeeee July 18 14S (ile ase cece| teen cena (3))PDodecathecontmeadia Missa -eae-eeseerees = seaeeeereaaeee May 13 453 Tine 29 1, 093 (s2)\ebysimachia mummul anit Weeee se seem eee ese cements June 21 DM, O2D ere so2s Selene seeee (O33) Maysimachiajpun ctatallmere-ceeeececmees eee cence cere June 16 926) sebecciociea | aseeeieeens LIT. Ebenacexe G. [63). (534) DIOSPYTOSMOUUS suas ose eee eee eee seer eee June 16 Ut Seepeoes Sapa sccses LI. Ericacex [G. 58]. (935) PErical carne sly ae aaess cece ssecteecce tec caer eee rerenes Mar. 10 $0) steeds oe Meee eae LIV. Umbellifere [G. 48]. (536) Eryngium amethystinum W. and K.................... July 14 1,380 | Aug. 29 2,073 (GB) IDeaypekenhbhoolatshel noe \Wh00l os ee pose ce ocS boc eemnasecoosan July 15 1,388 | Aug. 28 2, 059 (638) eiinymoiumeplaniumbliee: sees eee ae See eee eee eee eee July 3 1,189 | Aug. 5 1, 645 (539) ;@icutanvairosa dit. o.o9 | sae ewe ie ccemenee oeeer eee: meer June 25 O25) liztenitaaea | Pee eeeee (540) RApiumMeraveglens ise. seems seen fee o ae a een ee June 11 885 | Aug. 16 1, 867 (o4h) Petroselimumysativum, Hottest ese eee ee June 26 989 | Aug. 11 Ltd (642): CarumCamuirh soc6 5 2 eee See en eee Apr. 25 338 ; June 12 884 (G43) Simm ssisamum gee a yee ee eee July 20 1436p wees Geter | Pen eee (544) Bupleurum ranunculoides L. y. elatium.............--- June 4 751 | July 21 1, 486 2038 Thermal constants for the blossoming and ripening of 889 plants, etc. —Continued. Flowering. Ripening. Designation of plant: order, genus, and plant. a f af i Laas Date. on | Date. {CDR stant. stant. LIV. Umbellifere [G. 48|—Continued. loueéanm| Ora. (545) Ginanthe phellandrium Lam......-..........-..-.----. June 20 Me Pesosadene|lsoeeaacsc> (546) ech USANeym api lem sen .- He aaa eee cee aoe se sce July 2 | 1,173 | Aug. 19 1, 936 (547) Hiceniculumuyuleare Garth .252.25 <2. once. comes = se June 27 1,114 | Aug. 20 1,920 (548) Seseli campestre Besser......5...-...-.-2---2---e0e0002- | June 15 QUO ee eee ean tee (azo) iibanotisnvulgarisuD C's a. cascsens oc icleeees)asis ae ane June 27 1,118 | Aug. 21 1, 965 (550) beyisticum! officinale Koch). 2--.-.-<-.=:.---c eee ee eee Sept. 17) (2;292)i5 2 ease hee eee (624) Aconitum lyecoctonum L. var. puberulum.....-.-..-..- | June 18 952 | Aug. 5 1, 684 (625) Aconitummnapellus We. :22 ee ae oe er eee NG 5 | 1,069 | July 30 1, 641 (626) SBotrophisitcteoides je ere a. - eee ee masse oe eae eee | July 1 | IEA oS apes 35||0 395235 (627) Peeonia albiflora Pallas. var. rosea ......-.-----.-------- | May 28 | 672 | Aug. 3 | 1, 678 (628) Peeonia moutan L. var. papaveracea ....-...-..-.-.---- May 16 514 | Aug: 7 | 1,759 (629) Peeonia officinalis Retz. var. puberula ....-.......-.- ..| May 18 | 548 | Aug. 8 | , 766 (G30) #Reoniastenuifoligiitee..-.s+ces= seseee oe oes ee eee May 7 | 442 | July 6 | 1, 247 LXIII. Berberidex [@. 5]. | | (G31) Meeonticewesicaria, Pall jee eee eer ee eee tee iets | Apr. 39 256 | SL oRcoeee | Baan eee oe (632) SE pime dit yal pin eee -e eee = ee eee ee eee | Apr. 26 | 341 | weg ictate Sal SEE eS (683) Berberis aquifolium Pursh. v. repens.............-....- | Apr. 22 310 July 25 | 1, 496 (634) Berberis provincialis Audib, Schrad. Lodd......--....-- | May 11 | 472 | Aug. 6%} 1,736 - * 905 Thermal constants for the blossoming and ripening of 889 plants, ete.—Continued. ——— 7 - s Flowering. Ripening. Designation of plant: order, genus, and species. ae Gon: ee Gon. LXIV. Papaveracexr [G. 8]. | eueeanine | °Réaum. (635) Chelidonium majus L..............022.00e.c2e-ceeeeeee- [May 5| 403 | June 5 785 : (GSb)ePapavenmonientalema =<... ccscita nieces octesicc bis cee ceeteeees May 25 645 | June 28 | 1,149 (637) Papaver rhceas L (from self-sown seed).......-.....-..- May 19 565 | June 16 | 946 (638) Papaver somniferum L (from self-sown seed) .......... | June 17 994 | July 10 | 1,219 NGao) PG AUelUMg LUCETINE SCOP mr too: ctiaim sain one se ae oe oe re See isis June 1 704 | July 21 1, 461 KGdO\ Huma rato tein wiSWl a y30. 22. Sos cc ee ~ a c-e ees ease | Apr. 24 316 | June 8 | 823 LXY. Cruciferx [G. 10]. ‘ (Gal)pRarbarca vuleanis ReBre. ccs. ects.) eee. esos. | Apr. 28 342 | June 30 1,144 [SSE BEAD ENG 2] oy FHC a8 GY Yo Ee er ee ae | Apr. 8 196 | June 3 | 747 : (G23) eBenveroalin camar WSC oo «ce micm scime alas deere Seimale a ei | June 13 895 | July 21 | 1, 453 E (G42) MAL yssumisarra tile Lis 22. era ciaiajcte's Gas eo en sce nce ce el Apr. 19 | 283 | June 8 802 ‘4 KGa ePATMOTA CIA TUSCAN ames = secs 2 ease ok acne Ssciog ce | May 15 512 | June 27 1, 103 . (646) Cochlearia officinalis L ...... Ba Sa tae se ecto ee | Apr. 5 | 214 | May 31 703 4 (647) Iberis sempervirens L..-.-....-. Poe acta ee Ra was | Apr. 23 | 317 | June 25 1,074 (648) Hesperis matronalis L ......---....---.----.------...---| May 20 | -544 | July 6) 1, 261 (629) MSIsvIn DrLMUVaAUStMaCumM WD ACQio. 2. ees- oes 2. o4ce ee soe May 6 | 396 | June 22 | 1,012 , (650) Hrisymum ecrepidifoliam Reichb .......2.......-2::----. | May 4 377 | July 4 | 1, 231 Roaimteonistuinetorin De: <2, .5-0..c803e<2 00. tn foe cetsce< ode | May 6 416 | June 14 | 893 (652) Brassica melanosinapis Koch (sown May 2)............ | May 31 QHD p | aes atercicicie.c|| ase eee (653) Raphanus sativus L. (sown Apr. 28)-.......2....2------ | June 12 + 703 | Aug. 5 1,376 = LXVI. Resedacex [G. 12]. : fesspbeseda lutea Wi t.*..2!2).: es ease ©. Fass eh es Ae May 20 7 ey [ape (655) Reseda; luteolay. <2: soc. sap oees See te cease ase af eses| May 9 437 | July 17 957 LXVII. Nymphxacex [G. 6]. NGaGi ee Niyan p loca al eritass = 222 tc sce oa Mente. See ee ae | May 25 (Sy be ees — ee nator aae a (QBSY)) AN Aveo a} oes EN DAE iS) 701 gee ee ere oe oR re Re Peer May 26 646 | July 28 | 2, 046 : LXVIII. Cistucex [G. 13]. | | (658) Helianthemum celandicum Wahlenb................... May 20 | 576 | June 22 | 1,002 (659) sriehanthemum vyoleare:Gartiee ose ccc ce enece ee May 23 §95, 1226.G0)2851 1,025 LXIX. Violariex [G. 14]. ss (G60) p\aolasiren aria DG ester een ee eet | Apr. 14 DAL) |e 32h cae seer (Gp) eVOlazbIr taste aMDIS Was S: acto e no boos moe eons See | Apr. WTAS NS cas csye.cian)| eae eciese ee (Ob2)myAolaymontana su! .e08- 3. Sst l onc ce jake caciniesic ee | Apr. 9 1 Pal tan Sra anes eae lens evinlgsorsiakeee Lok tt r,t "Mar. 30 157 | June 2 747 O52 Veo lanratensisy Mer Cte Kee a sca = se Semis eee al | Apr. 26 | 325, | June 15 | 919 Gobo) miVlolay Gricolor Tntee tes eee Slee Sd. oe Peak se sees Apr. 9 234 | June 12 907 LXX. Caryophyllex [G. 15}. | | (OCG) mOCrasii UML VeNSe irs - ase ane ances wc eke see ec cc May 7 | 419 | June 9 824 (667) Dianthus carthusianorum L. medius.................-- | June 4 | 769 | July 14 1,346 (668) Dianthus deltoides L ...........2-2-0-eeceeeeeeeeeeceeee | May 28 657 | June 25) —‘1, 064 (669) Dianthus plumarius eV VAT OMS! as tes ote cee May 22 592 | June 26 | 1,070 (G70) 9Gypsophila altissimanly 225 cae... 2. 2. es ek ie | May 28 689 | June 30 | 1,139 (671) Gypsophila fastigata L. elatior......- - .goleeecesonsede . June 13 890 | July 20 | 1, 454 (G72), Saponaxia: officinalis i: plena...52-. -.22 222.2225 ene July 16 1,399 2 ee eee mena 4! . (cio) otlenevintlata Smiithiees: eo sel lee. oe eee ‘June 4 759 | June 29 | 1,141 4 KGqa) sven ennutans dal bifloracs: aces 02 oc -0 <2. 22 de oo «a2 May 17 526 | June 12 873 r (GiayeSilenempseudotites:Bess =. <2. 22- M8snnc. -- 222 Sees we May 31 716 | July 7 1, 276 8 (CSAS ORS VEWES AEC Tayo ett E27 WG Ga le a A | June 1 | 733 | June 25 1,036 Bo (Ol) uy Chmis coronemigslam Sosa. o.. - June 12 S75) Le saaeteienie ol Racseece TEXOXLV. Zanthoxylex [G.—; see G. 24]. | (dai) btelea; tritoli ata: «oe. ais ninin = oeel- som ae seeeeee June 9 | 845 | Aug. 21 | 1,979 (so) PAnlanth iste land ul oss esi 22a. cle cae alecisiaieclclleie a\-[2.2= --=\- June 17 956 | Sept. 12 2, 255 LXXXV. Diosmex [G.—].. | (783), Dictamnusraxinella Perse... s205--202--+-<+5---- cee: May, 26 640 | July 19) 1, 448 LXXXVI. Rutacex [G. 24]. | (TBD) Tinie are eR Ot Cabs ees a skenor anepooodepsescmSeecas June 4 | 765 | Aug. 21 | 1, 954 is LXXXVII. Zygophyllex |G. —]. (isbn Zysophyllumsfabapo ls. sce cccc sac scales casein meee mer July 4 Ls 22D | 8 oeieratc= ie ae eee LXXXVIII. Geraniacex [G. 23]. (736) Geranium pratense L.....-..-- siapeje ate alesyaisie aieiaisieisteeietatesr June 8 845 | July 10 1, 289 (737) Geranium DYREN AI CHINE tec a eee eee eee seem May 25 622) |s. sioset melee -ces=ners (738) Geranium sanguineum L.............--------- os foeectee May 19 559 | July 4 1, 210 LXXXIX. Linezx [G. 22]. (7S))) ilioh vena Ay RIGAEKe bOI VE RS ee Sho concunbeodnosacsesaeeacde May 5 427 | June 28 1, 134 (740) Linum glandulosum Monch. var. flavum ........-.-.-- June 8 831 | July 28 1,619 (741) Linum usitatissimum L. (sown Apr. 29) ...-...--------- June 22 688 | July 2: 1,179 XC. Oxalidex [G. —; see G. 23]. (722) nO xalis;acetosellagimeesst ener ene sae Pyrus mivalisil 5552-222 9> 2. -2aae: seen eee a otee seer May 2 B95 4, Site a epee (7615) By ruse aliis i svarsaCelpae sae seas eee see eee eee eee May 20 533 Oy BeReer ssc) Seosocease (762) Pyrus prunifolia Willd. xanthocarpa minor ............ Apr. 26 343 \-July 27 1,538 (763)), Pyrus'sorbus Gart. var. pyTiOnNiss2 =. se. e cies sees May 13 AQT ho See See Eten eee (Gaz) ABA AnbSqrolaommboe NR edo Beas cb aedenoncoaoc cosh osodaaced||= se do 489 | Aug. 7 1, 758 (@e5)e Mespillttsis ermviamt caldye oseeeeee ee Apr. 29 291 | June 7 824 (S76) MOrobusversicolonGim ele ssc eece see sees see nena e eee May 9 444 Weel el Pacicemncese (Sia), Coronillasemeniswulsae see eee eee ne eee neeeanee May 10 454 | July 12 1, 364 (878) x@oxromilllasminim es eesess seeeeee eases eeeeee acer senees May 5 443 | July 7 1, 269 (879) RCoronillasmontanagiep ese eere eee eee eee SS ree eee ces May 27 664 | Aug. 1 1, 656 : é : a a July 26 1, 552 (880) Coronilila, vamiailure: < Soe feces sae eee eee ee (880) | June 12 869 Nae. a5 1,839 (881) "Onobry.chis:satia wis. .2---sece es scese eo eee eee aseeee May 22 634 | June 29 1,138 (882) Phaseolus vulgaris Savi. (sown May 2) .....--...--.--.- July ~ 2 778.| Aug. 8 1,387 (883) (Cladrastisitinctoria Wat ieee ase) eee eee ace. June 4 76D: esha ci oecte lle Sertacers (884) Styphnolobium japonicum Schott ...-............--...- Aug. 4 V5 672 Meee aw cindc celles some cis Za Thermal constants for the blossoming and ripening of 889 plants, etc.—Continued. Flowering. Ripening. at : F é = | ee Designation of plant: order, genus, and species. A . ‘ . Con- Con Date. Date stant. | cola as tert: | | = A similar computation had been made by Erman, but for the benefit of those who may in the future have to go through similar labors I would suggest that it is not more laborious and is certainly more perspicuous to compute the actual daily temperature for every fourth day of the year, beginning with January 0, and in the adjoining column make up the continuous summations. The differ- ence between the sums for any two dates is then the total mean daily tempera- ture to which the plant has been subjected.—C. A. 213 plants that were observed at Brussels and at Poulkova, which is 12 miles south of St. Petersburg: Date eer Sane Pare Brussels. | SnarEauar sf | Group | = = of P 1 | Squares T | Baa | plants. p.. 7 oul- | Temper-} of tem- emper-| of tem- | Brussels. jova. ature. | pera- | ature. pera- | ture. | | ture. | Days. IDES |\\ SCL SK. Os ae Cem ieee pe Sa jae | ee | 0 a 2-5) 98:9 | 1490 || \ 847 1,751 || 300 | 2,394 | Pee) © 1929 161.4 || 550 3,730 || 458 4,411 | hee 138.0 | 169.5 17 6,497 BYE) 6, 100 ae | 160.4 | 184.2 || 1,102 | 11,506 | 807 9,77 Gree 181.6 | 190.5 || 1,471 | 17,764 || 912 | 11,527 Tin a 222.0 | 223.0 || 2,219 | 31,615 } 1,460 | 20,700 | | if In taking these sums, which all relate to positive temperatures on the centigrade thermometer only, Linsser begins with April 8 at Poulkova, because on that date the gradually rising daily tempera- tures pass through the freezing point. It would have made no difference if he had begun with January 1, or December 1, or with the date of lowest mean temperature, which would be about the middle of January. On the other hand, for Brussels his sums begin with January 15, which is the date at which the lowest mean daily temperature occurs, which temperature is about +2.5° C., so that if he had begun with January 1 there would have been a constant sheht addition to all the numbers in that column. The dates of blossoming are given in days counting consecutively from the Ist of January, and may be converted into the days of the month or vice versa by the following table: Day of the | _| Day of the year. . | year. Date. aa Date. | = ae a : ead Leap. | — Leap Javelin jl 2 eae = = eee 1 PATIO US pil aes mee) 4c eee ee 213 | 214 eI GURIsygle ee ee ose oe | 32 32 September fe ee ee ee B45 Marchi 22 eg EB Te Ae 60 | 6 F October lke2 22 225 eee 274 275 eine goes ew eS Ot |) = “92: "November 1 ©--- 72. "2 = 2k 305 | 306 ILD ap 4, 2p ee Ale re 121 122 | Mecember le = ee eee 335 336 AUIS pe noes 2 oye ae ee ge ae 152) 158 | Jandaryeles eee ee ee eae ee | 866 367 raliysleten were ihe AER 182| 183 | | | | If we take the difference between the sums of the temperatures for the first and seventh groups of plants in the preceding tabie we obtain for Brussels 1,972° C., and for Poulkova 1,280° C., or a difference of about 700° C., which corresponds to about forty days at Poulkova, so that we must immediately conclude that the same stages of develop- 214 ment are attained by means of very different sum totals of tempera- tures at Poulkova and Brussels. But possibly we should have taken the initial point of vegetation at some other temperature than 0° C. In order to test this point Linsser performs the computations of the sums of temperatures above 1°, 2°, 3°, 4°, 5°, and 6° C., respectively. His result for-6° C. is as follows: Group. Brussels. | Poulkova. | Group. Brussels. | Poulkova. —= : = ; “Ef. XO! | Hf XG lites pierre 1 PAW) Goes pales 412 368 ie ee ee 20 72 | Gis NA Te 995 435 Sa pee 2 97 lis ie | Pee eee 1,154 788 4 : 212 224 None of these successive hypotheses as to the initial temperature for vegetation gives a uniform constant any more than does the original hypothesis of 0° C. A similar study of the sums of the squares demonstrates a similar result, so that in general at different places the same phase of develop- ment of vegetation requires different mean daily temperatures, dif- ferent sums of temperatures, and different sums of the squares of temperatures, and there is no zero point that can be adopted that will inake these sums equal. Linsser then shows that, notwithstanding this result, there still is a thermal law concealed in the above figures. For evidently the sums for Brussels and Poulkova go on steadily increasing through the whole period of vegetation, and at any stage the numbers are very nearly in the same proportion, and that proportion is very nearly the same as the proportion between the sum total for the year at the two places. These annual sums total are for Brussels 3,687, and for St. Petersburg 2,253. If now the numbers in the fourth and sixth col- umns of the table on page 213 be divided by these annual sums, respectively, we obtain the following: Ratio of the individual sums to the total annual sums of temperature above 0° C. if See | Brussels. | Poulkova. eounes Brussels. | Poulkova. enue es O07) ioe = O08 sane. 0.30 | 0.36 Die AL ae 09 | sly [Gece eee 2 .40 40 Bi aati eee sily | 20 teal Panto 60 | . 65 Ae thay Ne 21 26 | | The agreement of these numbers is quite close enough to justify the conclusion that’ in two different localities the sums of positive daily temperatures for the same phase of vegetation is proportional to the 215 annual sum total of all positive temperatures for the respective locali- ties. The discrepancies between the above figures also show that a systematic influence is at work to shghtly increase the ratio for the northern stations, since the ratios for Poulkova are appreciably larger than those for Brussels. This influence, as Linsser suggests, is prob- ably to be found in the fact that a larger proportion of heat is con- sumed at the northern stations in melting the snow without changing the temperature, which heat is therefore lost to the growth of plants. The law thus discovered by Linsser is tested by him for each of the 15 phenological stations studied in his first memoir, and not only does the ratio appear the same for each phase, but the slight increase as the latitudes increase is also confirmed, or, in other words, the ratio increases slightly as the annual sum total of positive temperatures diminishes, the increase being nothing for the first group of plants that blossom early in the spring and about 0.1 for the seventh group of plants that blossom in midsummer per diminution of 2,000° C. in the annual sums, Linsser also states this law in the following form, in which it has a more popular expression : Every individual plant possesses the ability to regulate its vital activity as demanded by the total heat available in its “dwelling place and according to the habit inherited from its ancestors, so that indi- viduals of the same species living in different places arrive at the same phase of development by utilizing the same proportions of i total heat to which they are accustomed. The vegetable world, far as we consider its vital phenomena, is indifferent to ieee below the freezing point. The preceding principle has been deduced primarily from the study of one phase, viz, the blossoming; but a study of the figures of the other phases gives a similar result, so that the method by which heat exercises its influence on plants is the same for all stages of develop- ment. The phase recorded as “ the falling of the leaves,” which indicates the approach of the winter sleep of perennial plants, is the only one that to a high degree depends upon the actual temperature at that date. Apparently the statement, frequently assumed as a senen al law, that the dates of leafing and of the falling of the leaf at the same place have the same temperatures is only approximately true for a single plant and a special locality, as, for instance, France and cen- tral E furope, and does not hold good for the same plant for northern or southern Europe. Linsser’s law has a most important application to the natural dis- semination of seeds and the acclimatization of plants. When we, ata given place, from year to year, see the same cycle of vegetation recur without changing the behavior of the plant with reference to the annual sum total of heat, we must conclude that the ability to develop itself in proportion to the total heat is transmitted from each 216 mother plant down to the seed produced by it. Therefore in every kernel of seed there is concealed the whole relation between the development of the plant and the total heat of the locality where it was produced. ‘Two seeds of the same species, one of which comes from a mother plant that has lived under the influence of an annual total heat of M, but the other of which comes from another mother plant that has lived under a total annual heat of N, possess powers of development, or a sensitiveness to equal temperature influences, that are inversely proportional to the sums M and N; or, in other words, the rate of development is equal to the sum of the effective tempera- tures divided by the normal values of the total annual sums for the mother plant. Applying this law to seeds that are artificially transported from their homes to other places having different climates as to tempera- iure we are enabled to predict approximately what their behavior will be. Thus Von Baer observed that cress seeds that had been — raised in St. Petersburg (lat. 60°) and transported to Matotschkin- Schar (lat. 73°) developed in July at only one-third the ‘ate that they did in St. Petersburg in the month of May. Now the annual sum of positive temperatures for St. Petersburg is 2,253° C., and the average temperature of the month of May in St. Petersburg is 11.2°, while that of the month of July at Matotschkin-Schar is 44°. Therefore the rates of development per day of the same seed at these two places will be in the ratio of 11.2 to 4.4, or 2.6 to 1. Again, for cress seeds raised at Matotgchkin-Schar, where the annual total heat is 330° C., the rate of development will in general be 2253, or 6.8 times more rapid than the development of seeds brought from St. Petersburg. Vice versa, seeds carried from Matotschkin-Schar to St. Petersburg the rate of development will be 6.8 times more rapid than for those that are native to the latter climate. Linsser was thus able to enunciate the first step in the rational ex- planation of a phenomenon with which agriculturists had long been familiar—viz, that the seeds raised in northern zones retain the power of rapid development, so that when sown in southern regions they grow more rapidly and ripen earlier and give a richer harvest than those that are sown in their native warm locality. Similarly, seeds of mountain plants, when carried by rivers into the warmer plains of the lowlands, develop plants whose blossoms antedate the spring blossoms of the plants native to the lowlands.” We may thus accept the general statement that plants or seeds transported to colder countries reach a given stage of vegetation later than the aA beautiful illustration of this law is found in the abnormal early flowering of seeds brought from the cold uplands and lodging on High Island, on the Potomac, about 5 miles above Washington, D. C. as 217 native plants, but when transported to warmer regions they blossom and ripenearler. Thus in 1859 Schuebeler sowed 6-rowed barley that had been raised in Alten (lat. 70° N.), where it required only nine weeks to rigen, in Christiania (lat. 60° N.), where it ripened in eight weeks. In the same year some of the same barley was carried from Breslau, where it required nine and a half weeks, to Christiania, where it ripened in twelve to fourteen weeks. Linsser arranged these experiences as shown in the following table, in which he assumes that both at Alten and at Christiania the barley is sown when the mean daily temperature is about 8° C. hee Janine Date of | Date of : Sums of Barley raised at— sowing. |ripening. Interval. Penapere Weeks. Con Alten and sown at Alten -_-....--....--- pee eae eae c June 14 | Aug. 16 9 | 700 Altenandisown at Christiania! --_.-..:-2.22.<-..--2_------- | May 5| June 29 ei ieee BAU Christianaand sownat Christianae--- = -so52)22 282 ee do ....| Aug. 1-9 13 | 1,400 The annual sum totals of heat are 1,300 in Alten and 2,600 in Chris- tiania. Therefore we see that the heat required by seed acclimatized at Alten (700) is to that required by seed acclimatized at Christiania (1,400) in the same ratio as the annual sum totals. It can also be shown that barley acclimatized at Christiania and transported directly to Alten can not ripen in the latter place, since the 1,400° C. required by it at Christiania are not received at Alten. It is only by gradual progressive acclimatization at numerous inter- mediate places that the plant has been enabled to adapt itself to suc- cessively smaller sum totals of heat. In continuation of this process the barley that is now accustomed to ripen at Alten can be used to pioneer the further northward progress of its species. The attempt to transport barley from Denmark to Iceland has thus far failed, but doubtless barley from Alten would succeed. Barley cultivated in the Caucasus at an elevation of 7,000 feet and transported to St. Peters- burg should, according to Linsser’s computation, experience an accel- eration, so far as climate is concerned, as though it were coming to a warmer climate, but this acceleration may be more than counter- balanced by the differences in the nature of the two species of plants, as it is well known that the Turkish oats (Avena orientalis) require more time to ripen than the ordinary oats of northern Europe; the variations In times required by different kinds of oats, barley, and wheat, and even winter rye, are oftentimes larger than the variations due to differences of climate. But such variations, as observed in plants that are only partially acclimatized, will disappear after a few generations if the plant has the power of adapting its internal organ- 218 ization to a new climate. The geographical limits of any species, in latitude, so far as these limits depend upon temperature alone, are those points at which a certain sum of positive temperatures can be attained between the first and the last killing frost. The northern and southern boundary lines of such a limiting area are the curves corresponding to two very different sums total of positive tempera- tures, the northern limit having a smaller sum and the southern limit a larger, beyond either of which the plant is unable to modify its internal organization so as to properly utilize the respective prevail- ing small or large quantity of heat. Linsser notes that different plants, especially those that blossom early in the year, show a strong tendency in certain years to blossom a second time, and he finds that when the excess of the total heat in a favorable year exceeds the normal annual total by a quantity equal to that ordinarily required for the first blossom (and this can easily happen on account of the small sum required for the early spring blossom) then the plant produces a second blossom.“ Tn regard to the effect of daylight as such, Linsser says the opinion has been expressed that possibly the duration of the daylight, which, during the growing period, increases as we go northward, must compensate for the diminishing sum total of heat; but his figures show nothing of this influence, since the discrepancies or departures between his observed and computed figures have altogether the char- acter of accidental errors. In fact, his law of the constant quotient or percentage of heat implies that the plant does not need any com- pensation as the heat is diminished, but directly adapts its cycle of operations to the diminished sum and transmits this power to all further generations. In addition to this, however, since the impor- tance of light to the plant is proven, it is necessary to remember that with the increasing duration of the day as we go northward there is a steady diminution in the intensity of the daylight because «Ought we not to infer from this that after a perennial plant has received sufficient heat to blossom and eventually to ripen its fruit it then at once begins to repeat this cycle of processes, and is ordinarily only delayed by the cold of winter? If this is true, it must be considered that with the warm weather of spring the plant takes up these vital processes at the point where they were jeft in the autumn. Therefore, in such cases, our sums total of temperature, moisture, ete., Should all begin to be counted with the ripening of the fruit, or the fall of the leaf, and not merely with the cpening of vegetation in the spring.—C. A. esr aelpanncaagmap Pe ieet) Ra 219 the sun’s altitude diminishes. This Linsser shows in the following table.“ | Maximum dura- | Altitude of sun at) Relative Gunntity of heat 1 re- | tion of Se: | noon. ceived by the ground in 1 [gases ‘a =| day under an atmosphere Date. | Menion Ne St. Pe- | Se pape. whose tr AUIpATENCY, is 0. ie Gat. 45.40/*8burg | gat, 45.4¢ tersbuire N_). (lat. 60° Ne (lat. 60° Tht Lat. | Lat. | Lat. N.). N.). | 40° N. | 50° N.| 60° N. | 70° N. Hours. | Hours. | De grees. | Degrees. | January 16 .-....----------- 9.0 | Geshe) 2325 9.0| 150 vO es wats 0 February 15._..-...---.---- 10.3 | 9.2] 381.5 16.9} 210 155 65 14 I Prct (ee 1.9; ws] 42:8] - 282] 400) 205] 190 95 aprile ye tenet Sait B.5| 14.5} 543) 38.7) 520) 450 | 360 255 Winn 7 dL = oe ee 14.8 | ibrar 63.6 | 49.1) 615 570 | 505 | 425 ume tl yee. es. 15.6 | 18.8 67.8 | 53.4 | 650 625 | 570 | 505 rity Gee es! See 15.3 18.1 66.0 51.5} 630 585 | 525 450 PANT OUIStIO) sae s a 14.1 | 15.6 | 58.4 | 43.9 5a0 | 480 395 295 Sentomberilst=asse ns s- 12.6 | 13.0 | 447 33.2] 430] 385 230 125 Octoborloeuse ses ue | 10.9 10.2 | 35.8 Pla 280 | 185 | 90 | 25 November 15__.___.._-. Lee 9.5 7.6 26.2 | VEC 85 20 0 Wecemiberi6 2-.222-2- =. --..- 8.7 | 6.0 21.3 | 6.7 135 | a) 2 0 In reference to the first part of this table Linsser remarks that the intensity of the light of the sun varies as the sine of the angular altitude of the sun, so that from the maximum altitude on any day we get an approximate idea of the influence of sunshine; and we see also that the farther north we go the longer duration of the sunshine is partly counterbalanced by the diminishing intensity of its influence.? Linsser remarks that the theory of compensation between duration of the day and intensity of sunshine may also be tested by considering the effect of ascending a mountain, where there is no increase of dura- tion but a great increase in the intensity, of sunshine. If the rapid development of the plants on the mountains is due to the increase in the intensity of the light, then how can the diminution of intensity in northern regions bring about the rapid development that is demon- strated in the experiments of Von Baer and Schuebeler and Ruprecht which are quoted and analyzed in the following paragraphs? @To which I have added three columns of “aaiee fae of the total heat received in twenty-four hours on each date, as interpolated from Angot’s tables, for a coefficient of transparency equal to 0.70.—C. 4 b The exact figures that give the relative sum total of the direct sunshine and the diffuse daylight for various latitudes and solar altitudes for clear and cloudless days have been published by Marie Davy, Angot, Wiener, and others. The figures that I have given in the last part of the above tables from Angot show still more clearly to what extent the effect vf sunshine diminishes as we approach the pole, but how surprisingly powerful are the consecutive twenty- four hours of sunshine on June 15 within the Arctic Circle.—C, / 220 In his second memoir Linsser (i869) begins by showing that many well-recognized facts have been found which harmonize with the conclusions at which he had previously arrived. Thus, in the first and second halves of the eighteenth century the northern limit of the cultivation of grain had not passed beyond latitude 60° 30’ N., and many unsuccessful attempts had been made to ripen the grains im more northern regions; but in 1829 Erman found a small successful beginning going on at Yakutsk, and since then it has spread in all directions and has extended to barley, oats, rye, and wheat. Similarly in Lapland the cultivation of grain succeeded only for a long time in the southern regions, but now it extends to the north and even among the mountains In Lapland this cultivation succeeded only when the seed was brought from near by, not from a distance, and Von Baer says that it was commonly said that the grain had aceli- matized itself, or, as he expresses it, “ It seems to me that gradually a quick-ripening variety or ‘ sport’ has developed that is not injured by the early frosts of summer nights.” F. C. Schiibeler (1862) in his memoir on the cultivated plants of Norway states that in 1852 the seed of yellow maize brought to Nor- way from Hohenheim, near Stuttgart, was sown on the 26th of May and reaped one hundred and twenty days later, but after continued annual cultivations, in which every harvest came a little earher than its predecessor, Schiibeler, in 1857, sowed the seed on May 25 and har- vested it in ninety days, while the seed of the same variety brought fresh from Breslau and sowed on the same date ripened only after one hundred and twenty-two days. Even Kalm had remarked that maize when transported from a southern to a northern latitude gradually overcomes the difficulty of ripening and eventually gives a nearly constant variety of grain. Morren, in the Belgique Horticole (1859-60), says the principai problem to be resolved in Norway in the amelioration of its agricul- ture is the introduction of new varieties and the development of -precocity. This precocity increases year by year, as if the plant could not all of a sudden obey the new climatic influences under which it had been brought. Plants cultivated many years in succession under a northern climate when transported to a southern climate preserve something of their former rate of development and are more preco- cious than plants of the same species that have remained in their first situation. Just as wheat carried from Germany northward into the Baltic Provinces of Russia fails to ripen its grain, so grain carried from the valleys up to the highlands in Switzerland fails to ripen. Bastian quotes an old English author who says that in the accli- matization of plants the graduation of the process is the principal necessity, and that a sudden acclimatization in a new home is impos- sible, so that a plant gradually learns to live in a climate in which 991 its mother plant was sickly and its grandmother would have died at once. It was in recognition of this view that in the eighteenth cen- tury the botanical garden at Teneriffe was established (the so-called acclimatization garden at Durasno and the Colegan Garden at Oro- tava, at an altitude of 1,040 feet) in order to furnish a temporary resting place for tropical plants that they might accustom them- selves to a cocler climate preparatory to their cultivation in southern Europe. According to Déllen, the same principle is applied in the acclimatization garden at Algiers to tropical African plants before their transportation into southern France. As the guiding thought of his second memoir, Linsser now remarks that we must divide the vegetable phenomena of the world into two divisions, viz, those in which temperature controls the annually re- curring cycle of phases, as is the case in the Temperate Zone, and those in which moisture controls, as in the Tropical Zone. Thus, on the grassy plains of South America, where the year is divided into a dry and a wet season, the entire course of vegetation depends upon the latter; the hottest and driest season exerts upon the vegetable life an influence like that of the northern winter, bringing, namely, rest and even death. Such a contrast is even found at Madeira, where, accord- ing to Heer, the weeds of northern Europe begin to vegetate in the fall after the dry summer months of trade winds and when the first rains fall, whereas in the hottest summer time all these weeds slumber or die, as with us in winter. In the steppes of Orenburg, Russia, when the sun melts the snow in April, it starts the first sprouts and the blossoms, and by the beginning of May the vegetation of the steppes has attained its highest brilliancy, being distinguished by the great number of many-colored tulips, as has been so often described by travelers; but this beauty passes by with remarkable rapidity, and when in June the dry, hot summer of the steppes begins, all the ver- dure is dry and dead, and in place of the blossoms there are seen only the dry, empty hulls; so that the whole life of the plants on the steppes is condensed into the short space of eight weeks. We thus see that for large portions of the earth the heat as such ceases to be the principal regulator of plant life, and moisture becomes the controlling influence. It is evident that the life of plants depends upon both temperature and moisture. In situations where there is always sufficient moisture the influence that decides whether or not a plant shall develop is the heat ; but in regions where there is always sufficient heat that deciding influence is moisture. Therefore Linsser proposes in his second me- moir to first state the influence of heat on vegetable phenomena more precisely than he had previously done, and then to develop the influ- ence of moisture. 222 Linsser’s second study is based upon a much larger mass of pheno- logical observations than that previously used by him, and, in fact, more than has ever been used by any other investigator of this sub- ject. The accompanying table gives for each of his stations the initial and final dates when the normal mean daily temperature is 0° C., or the date when the mimimum of the year occurs if that mini- mum is above 0° C.; these are the limiting dates between which the sununation of temperature is made according to Linsser’s method. The sums total of positive temperatures for the whole year are given in the third column in centigrade degrees. | Annual , Station. Initial | Final | DoSitive | set's tempera-| zones. = | tures. oc: Ressam': £0500: S5,! oJ) YOR oe a kee oral ein ane, | Jan. 15| Dec. 31] 5,226| A Let ina: ys ae he ede hae re See oS ge Lata Smee 5) a ee Jane dielaadomee 4, 797 B \Sir tga ee ae ae Se, Sa he nee ee | Jan. 1 |....do.| 4,669) A 1D (oh ab Re Rat ee Roe Aho eM OTL 3 oes ge | Janey |----do. nd 4,251 A Gide berg ee Ree See oo ge ee anes a DERE Ue as Sie ae | Jan. 14) see doess 8, 933 A FAT ee Ue hn 2 Ye we a a ee cae Hie | Jan. 13 |----40--- 3,929] A IN ATU ee 2 See eee. on emer. Oise Dees ae emer. eee en ae |....do j28| ee doz 3, 865 | A Giionty Nee vO Oe ae igh ene renee ae Chay eR | Jan. 12 lc dot], 285815 Ieean RSCHiin Ci Rss coke ee eee Pee ye oes ee ee ee ee | Mar. 2]| Dec. 8 Bie) || 183 RVLeTi Tapia: ewe WR RES een Peed ee sian et i oe | Feb. 8| Dec. 18| 3,%57| B Osterid She tao War oe RG Bree ie A ce eee Jan. 14| Dee. 31] 3,787] A IBRUSSe 1S Say eee eet teen Lie et a yay 3 a else oe eee | Jan. 16 |_...do--- 8,687 | A lepeeVeqb Vey as aehe A Sy Sree eee DAO DUT ERRORS tog eat RMMilR Yee a Re Feb. 16 | Dec. 16 3,582 B FS) EIU El Gz) 00 piled ers Me receipe @ a tg (ap A NEY Se Me oe Jan. 20 | Dec. 31 3,520} A IB TUNIS WAC kt ee sere Ss fects cee | Ten eee eal oer eee et Feb. 8 |..-do_..| 3,483 }) A Nareptas ase ok 2 he eae oe ons hs a le oe re | Mar. 27 | Nov. 12 Ber {ele 183 Sitaviclope tee Jak Parse ee kN PRO s eee oe lene ee Paty eae | Jan. 20 | Dec. 31 Baa AN Mian Chine srs Bell gh sk eed Le, ene Oe a ee ' Feb. 14| Dec. 16! 3,125| A Tin pin genes eh eh eee NS ae ee eee ee ON Feb..9| Dec. 1] 3,12] A DS bebtim sets ee eS ee Mee ee ak Se nr ee et ee oe ae a eee Feb. 18 | Dec. 18 | 3, 115 A Wet semet iweb in sete Se S456 Jy ean AEE See Ue Gea ena Mar. 16 | Nov. 21 3, 085 B GREW YA 0} 0b if) A Se RS rs ene Pe does ee nk SC | Feb. 28! Dec. 16 | 3,018 | A Gorlitzeet? Verto Sa i) Sed Be eee les Ne oF eee | Feb. 19 | Dec. 6| 2,975| A Breslait =) 20 se oa eee CoM ee ee eel he ne ee eee | Mar. 2 |----do --- 2, 953 B OTe one a: Nain s fae OES Epes Se re eee es 1 ta eS |; Apr. 1 | Nov. 138 | 2, 807 A WE OSCO Wied oaks cee at ee sat Sel yee oe eg ee ee Apr. 4/ Nov. 4 | 2,631 A 15 1s ee er cel ne ne REMERON MCT Pt, Mar.26|Nov.22) 2,574) A @iris Giermiay sees oe re We eet ce ee ee do...|Nov.11| 2,389] A 1 oe err Ve ne UR a aie cer DA ait ee oe Apr. 8 | Nov.13| 2,303] A StvPetersbure. so eb eee. eos te ee eee ee ee Apr. 8} Noy. 9 2, 20¢ A CO 7 cl Koe epee eseaaey er eee ae pega TEEN cher pai Mn ytd Pia ge NIE | Apr. 19 | Oct. a) 1,898 | A A plant has access to water by two methods—through its roots it absorbs the water in the soil, whereas its leaves come in contact with the vapor and the rain in the atmosphere; but Linsser con- siders that the relation of the plant to the water in the soil is the important feature that decides as to the development of the peren- nial plants of temperate regions, which are those considered in his second memoir. So he leaves the study of atmospheric vapor and plant hfe to the future, while confining himself at present to the relation between raizfall and the periodic phenomena of vegetation. It is not necessary to reproduce the tables of normal monthly rain- fall given by Linsser for each of his stations, and generally based upon many years of observations. Of course, these numbers express- ing the local rainfalls are, as is well known, less directly applicable to a neighboring locality than are the mean monthly temperatures, and they must be used with correspondingly less confidence. The constant fractional part of the annual sum total of heat, as previously established by Linsser, afforded him a valuable suggestion or a working hypothesis as to the relation between the life of the plant and other factors, such as sunshine, rainfall, nutrition, and in fact every factor that influences the hfe of the plant. If, namely, a plant utilizes one-tenth of its annual cycle of heat in order to bring it to the leafing stage, why may it not also require one-tenth of its annual cycle of rain or sunshine or some similar constant fractional part? Now, in the development of a plant there is necessary, first, the material, viz, rainfall, or irrigation water with the nutrition con- tained therein, and on the other hand one or more forces, such as sunshine and heat, by the help of which the plant can utilize that material in its process of assimilation. The different phases of the development of the plant, such as the appearance of the blossoms and the ripening of the fruit, are work accomplished; in this work the water supplies the principal material, while the heat, says Linsser, plays the role of the principal force; but the work of the plant—that is to say, its progressive development—will only be in proportion to the force, so long as the latter finds a sufficient quantity of material present to insure the complete utilization of the force. Evidently a force that is competent to convert a certain quantity of material to the use of the plant will only be half utilized if only half of this quantity of material is present. In other words, the development of the plant goes on in proportion to the quantity of heat only so long as the plant has at its disposal the maximum quantity of material that can be worked over by this heat. Therefore any further investigations as to the relation of the life of a plant to its external factors must necessarily consider the dis- tribution of material with reference to the distribution of heat. In our present case it is the distribution of the quantity of rain with reference to the heat, and if such relative distribution is not considered then its omission is only permissible under the assumption that dur- ing the whole period of vegetation the material necessary to the growth of the plant is always present in such quantity that at any 224 moment the force then acting can be completely utilized. This assumption as to rainfall is actually fulfilled over by far the largest part of the European area hitherto studied by Linsser. Of course, we can not speak of absolute quantities of heat or nour- ishing material. We have to do only with their relative distribution during the period of vegetation—that it to say, with the ratio of the quantity of material (7) to the quantity of heat (w). If we con- sider that the quantity of material that a definite quantity of heat is able to work up for the use of the plant is directly proportional to this quantity of heat, then the ratio 7/w will have for each plant and phase a certain definite value that may be called the most favorable ratio and for which value the material on hand is completely used up by the heat or active force that is present. If the material that is present is not sufficient for the heat, then f/w is smaller than this most favor- able value, and in this case the material is completely used up; but a portion of this heat remains unused and wasted. If, on the other hand, the heat is not sufficient to use up all the material, then f/2 is too large and the heat is completely used, but a portion of the material is wasted. The fractional portion of the annual sum total of heat that is needed to bring a plant up to any stage of vegetation is by Linsser called the “* physiological constant ” for that phase and plant, and is constant wherever the plant is acclimatized. The ratio {/w, as com- piled by him month by month for each of his stations, 1s a local cli- matic constant, which is large when the climate is favorable to the growth of the plant—that is to say, when there is abundance of rain—but is small when the climate is more or less unfavorable to the plant—that is to say, when the summer rains are deficient. The vegetation of the whole world is, according to Linsser’s views, to be divided into zones (A, B, C, D, E, F), according to the annual distribution of the monthly ratios f/w. Thus in the highest lati- tudes (Linsser’s zone A) and in the greater part of the European region covered by Linsser’s researches, there 1s during the entire year a deficiency of heat, but a sufficiency of moisture and of material to employ all the heat force that is available. In the Steppes of Rus- sia, however, there is a deficiency of moisture during the summer and autumn, and the fraction f/7# becomes quite small for the zone B. The other localities that have a wet and a dry. period annually may be divided into three classes, viz, C, where the drought comes during the months of July and December; D, where the drought comes dur- ing the months of January and June, or E, where there are two annual droughts, January to March and June to August. This latter arrangement is shown in Madeira in the vegetation of certain kinds of apples. Finally, we may have in zone F a perpetual abundance { ieee ee 4 { 225 of both heat and moisture, in which case all annual periodicity dis- appears and the plant goes through its cycle of vegetation independ- ent of the months of the year, as in the warm and rainy regions of Java. As before said, the absolute value of the ratio f/w need not be considered at present, and in fact it changes with the units of time, of temperature, or rainfall, ete. Linsser divides the depth of the monthly rainfall, expressed in Paris or French lines, by the average temperatures of the respective months expressed in degrees Centi- grade. In order to ascertain which of his European stations lies in the zone A and which in the zone B it is necessary to adopt some limit- ing value for the ratio f/w, and to this end Linsser examines these ratios in connection with the phenomena of plant life, adopting the principle that as two plants from different places, accustomed to different quantities of heat, behave differently when they both receive the same quantity of heat, so also two plants from places having dif- ferent distributions of rain will behave differently and arrive at the same phase at different times when they are brought into the same place or under the same local climatic influences as to moisture and temperature. In order to decide as to the limiting value Linsser studies the ratios for the hottest months of the year, which all relate to the ripening phases of vegetation, and finds that for the units of measure adopted by him the value of ratio //w, that represents approximately a dividing line between the stations that have an abundance of rain in summer relative to the summer heat and those that have little rain relative to the heat, is 1.2. I have indicated in the preceding table by the letters A and B the stations that have f/w>1.2 and f/w<1.2, and which Linsser puts into his zones of abundant and scanty sum- mer rains, respectively. I give in the following table some of the more striking and perma- nently important results of Linsser’s computations. His original work, based on about 30,000 observations, gives for each of his 31 sta- tions and for 118 species of plants and for each of the three phases— leafing, blossoming, and ripening—the ordinary phenological con- stant or sum total of mean daily temperatures above 0° C., and also his own physiological constant, which is the ratio of this sum total to the annual sum total for the station. In the following summary I give the physiological constant as it results from the average of all the individual stations in the zone A; but for the sake of quicker comparison between the results for zones A and B the summary gives not the physiological constant for B, but its departure or difference 2667—05 m——15 226 from that of zone A. For example, for Acer campestre the constant in zone A for leafing is 0.131, but for zone B it is less than that by 0.039, and would therefore be 0.092. Tabular summary of Linsser’s results. Departures of phys- Physiological con- iological constants stants for zone A. for zone B from Orders, suborders, and species. those of zone A. Leaf- Bloom-| Ripen-j Leaf- Bloom-) Ripen- ing. ing. ing. ing. ing. ing. Sapindacez (Acerinez): INGER CAM CSULO sae see ee ee ee ee a ee 0.131 | 0.170 | 0.803 {—0.039 |—0.072 | —0.098 iAicerplatanoidesst se. see 22 see ee ae | .100 . 105 .875 F— .020 |— .019 | — .318 AicerpseudoplatanuUs == sess 22 se= sere eee . 182 161 .808 J— .029 |— .067 | — .110 AceritatariCuiates-- voce ses ee ose ee . 182 220 ROY Beas ses — .053 | — .182 Sapindeee: Nesculus/hippocastanum): sess 4ase2see==e sane 107 . 187 .821 J— .030 |— .054 | — .064 Nes culusiitea sees terete eas se oe eee 114 . 196 OOOMIEs ayet eels Se | eee Aesculus pavia -...----------- says: a ek See Gat . 132 . 232 «89042 212 |e eee Cupulifere (Betulez): ; INOUE! fediiviibavoyst he ease ee a Ns . O88 047 . 930 g— .012 |— .019 ; — .199 Amygdalez: Aumnys Gals communis sss sesso aoe mae 099 . 093 . 768 J— .017 |— .010 | — .068 Amys Gals persica = cee en ae eee ree sees 101 O71 .684 f— .017 |— .009 | -- .051 Aristolochiacee: ATIstolochialsipho sews sss tee ee eee ee 125 ha Mie eee — .0385 |— .053 |__-____- Berberidacez: Berbers pais ees epee espe aie alee . 092 .188 . 748 J— .026 |— .086 | — .182 Cupulifere (Betulacez): Betulatalbavass pee tee wee owe Oe aa 112 116 . 743 f— .034 |— .050 | — .010 Be bulatebrts ene saree re tees yee Bae ie ype 121 048 Poy (ay) Perera irre aie ae Bignoniacese: iBionomacatalpae sso. ss. sees ae SLED opel Aree 185 AT2 .889 f— .059 |— .092 }__--___- Euphorbiacee: ° BIESUSISCDUPOM VATS ore es ae ee eee ane 079 087 695 f+ .071 |— .018 |___-___-- Papilionacez: CaraganaiarbOrescens 2222 2=4-es. 2 teres sea . O84 168 649 f+ .016 |— .050 | — .201 Cupulifere: Canpinusibe hulls eee yaaa ae ee .110 pb Us| ee ay — 020 |= 035,|a=naas Leguminosve (Papilionacez): Cercisisiliquastrumiysss. 9 ess nne sree eee ne eee . 149 . 192 . 836 f— .009 |— .0380 | — .026 Coluteaiarborescens es. =- 8a ss) ee 105 270 . 762 J— .045 |— .065 | — .267 Tiliaceeze: Corchorus japOniCusees=- 422 =e eee 061 1b) hee +\.029 |— .045 |__-_---- Cornaceze: Cornusialbayts see 1. eee ee | See eee | .086 211 .518 J— .016 |— .032 | — .058 Corus mascula eens) a. aa ee | 119 045 .691 J— .015 |— .010 | — .077 Corniisisancuin cayenne = ae ee | 092 e2Dl . 738 J-- .012 |— .042 | — .125 Cupulifere: Cornvlusfaiy.elliana) tae ee | .095 021 .710 f— .028 |— .006 | — .105 Pomaceee: | Cotoneaster vulgarista--pos-se-- === == eee |, = 078 . 192 .586 I— .038 |— .083 | — .231 Rosaceze: | Crates ons COCCINGa oseet ea eee a ees .110 . 225 COOL es | ee | Crateectisioxyacant hase sts eee eee 091 . 210 . 739 F— .026 |— .066 | — .149 Leguminose: Gry bistisi eb rer cr ea ee eee ee nulilys . 192 .705 ¥— .027 |— .050 | — .151 227 Tabular summary of Linsser’s results—Continued. Orders, suborders, and species. Physiological con- stants for zone A. Departures of phys- iological constants for zone B from those of zone A. Leaf- | Bloom-| Ripen-} Leaf- ‘Bloom- Ripen- ing. ing ing. ing. ing. ing. Thymeleaceze (Daphnoide): | Daphne aureplaensso: 282-0 ee ehok oe a ee S|) ON090)|) 0.040)), 0. 375298. iON 080)) ae aeone Daphnowezereum 5245.55 fek-- = bh see | . 061 . 039 . 433 }+0.009 |— .026 | —0.163 Celastracez: | EUODVAN S| CULOPMUS)a2.-22 eee shee ee 110 228 852 . 036 078 . 232 Huonymusiatifolus eee 2 eee Pees ee . 106 . 192 . 167 F— .006 |— .029 | — .147 IRGOmyMUSiVOrPUCOSUSE: --- = ceee. aoe tome Nesey . 094 - 253, SiC) (aS USES SKS | eee Soe Cupuliferee: | Hacusicastaneas..o2- oes 2s-. ets. see es ose | .148 . B02 S04 — Osu Eeee eee sed 2 nee Becusisylvatica..-.20..-_. 2b. debs oles | .152| .188] .737[— .050 |— .058 | — .217 Oleacez: HraxtnsiexColsiOnse sae =- soos e oe note ee eae - 161 . 136 845 049 . 050 . 365 Mpa Ss OTM Ust ees ee eS a a a . 156 . 184 806 J— .066 |— .050 |______-. Leguminosve (Papilionacez): | Gileditschia triacanthos ......-...--.-.--.-___- 176 rOLOp | Seaaee es — .086 |— .094 |________ Araliacez: | Hedoraphclixweeresee se Ss ote pie nee Fe ae . 120 iOnieaeaeee —= 020: |— .09% |.22. 22-2 Eleeagnacez: | Eippophssrhammnoides|_---_ 2-2. --- 22 _____.- 116 . 133 -6380'f— .053°/— .003 |_------- Ilicineze (Aquifoliacez): | Mextaqiitoliuanmre tte Stee 2) ee eS 095 Pol Ee eee ape olla) UN Juglandacez: | ee leanspmicrraeneeNas ses oat en eee oe eee! | .202 227 | 298 {— .102 |— .077 |... ---- MIAN NC Oa sete a= § eee Leeds Ae 161 196 . 794 J— .059 |— .060 | — .046 Oleaceze: ICUSHMUIMev Ol ates se. c chee IAL . 082 . 323 .841 J— .O17 |— .055 | — .121 Magnoliacez: Liriodendron tulipifera ___._2________- ene . 142 . 343 SOO) fer O28] erent eye ee Caprifoliacez: Honicersca prt oliaimie oss aoe ee ee eee | .050 . 259 .670 J— .030 |— .060 |_______- onicera;periclymenum, .-22225._- 2.2. __-._- 049 . 286 . 663 009 . 033 133 Lonicera symphorycarpos -.-....../..2..-.__.- 072 . 265 ((0 sy) eee alert Se RRC See WOniceratataricasesee ss se nae seen oe eS 048 Bib a¢ 587 f— .008 |— .040 | — .227 monicerapylosteumiass=--- eset ee RE . 085 . 190 .624 J— .018 |— .054 | — .254 Pomacez: iWespilusironmanicarsses sso. ee ee . 130 . 246 .921 J— .070 |— .068 | — .121 Magnoliacez: Maonoliatyulan= 3aee-— wee 2S lee oka | 1387 . 108 .880 I— .037 |— .008 |__------ Urticaceze: : Magu stall pape cere ee ee ee ee ek . 166 se49 eee 2 — .057 |— .088 |_------- VOT Usha OT som em eeu ter nee . 169 267 .566 f—- .059 |— .027 | — .158 Saxifragaceze: Philadelphusicoronarius —_ 2 3822222) . 062 . 265 746 J— .006 |— .048 | — .110 Phvadelphuslatifolins!---22-2 320 2 i -101 316 fay (ree peers estar ees ee ae Coniferee (Abietinez): imusiarixet coo 3 one a eee ee 093 A098 |S oeeeo et ——«O19h |= 028"| 22a. = = Platanacez: Platanusoccidentalist 2: <2. 89-02 ek | 168 276 . 930 I— .061 |— .119 }__-____- 228 Tabular summary of Linsser’s results—Continued. Orders, suborders, and species. Salicaceze: Populusialbae.s- 2232 2-e asco seanae eee eee Populus ibalsamiuterass= = --sesseee ae eee IPOpulus'CaNeSCenS Sanaa aoe eae eee Populusifastiqiata cs. see -ee =a 2=-= eee eee Populusmigracsts.-Jes4.5- oe soe ee ease Populusitremulaseses sean eee ae ese ee Amygdale: PPTs IM CMIACA eee nee eae IPT UTS aval! See ee seat 2 ere eee Sees IPTUNUSICCT ASUS = =-es ae ee eS eee Rutacez: Pteleastritolatars=- 2a05 se see Serene Smee Rosacew: IPVPUSiCOMMUTIS Sas. eee eee ae ee Py TUS Cy Gone =~ 2-2-1 see oe eee By Tus a poOnilcaeaeerse sa) =. aeeeee Sith! Ger Soa PayrusiMaluss sce soo See ee ee es eee eee IPyEus Specta Wiis ess. e-s2 ess ease eee =e eee Cupuliferze: Q@uercusspedunculata l= <2) sess eee eee ee eee @U6rCuUs TODUR Sar. eee e ot ee eee ee eee QUercusisessiuhOra cea sate n= eon Rhamnacee: Rhamnus ca bhartica. sss sa ae ee Remmi sett) ee ee er Anacardiacez: Rhus; cobinusee = Se ae s oeeee eeeee RbUS sty phinais fe. sasees eee ea ee eee Saxifragaces: Ribes' alpiniwt sis. 2a. Se. coe lee eee ones Ribes env osswlaria seaee coe oe eee eee eee eee Ribpes nisrumM. =f fo ee ee ee oe Leyloyesstae ul overeat Se oe See ee Leguminosze: Robinia pseudo-acaciacessss sss esses oe eee ee Robinia Wiscosa wae eee eee = eee eee Rosacee: osa Canina, 2S. eee ee eee eee eS oe Rosa Gentifolia= ss 2-5 s=-— soho 2 ae ee ee ene (Rosarrallicg.2= 282 5a) oee cea: © Sees ae Jeni) oyoRs|iYo ks =u ts pie poe ee Re Rubus odoratus Salicacez: Salix’ allbats. ot. oe ce sts eee ee eee eee Salixicaprieass-. obese es Se eee Salixitragilis= 4. 25 2cce ee cee een eee Physiological con- stants for zone A. for Departures of phys- iological constants zone B from those of zone A. Leaf- |Bloom-| Ripen-] Leaf- |Bloom-| Ripen- ing. ing. ing. ing. ing. ing. 0.124 | 0.072) 0.517 J—0.030 |—0.031 |.-.-_--- . 108 . 068 DOO Sees +2002) sees {cue 1074 (lose ce SE 2-2 | = 026 |e 127 0807) 22222 eadsa ses =. 050 1n2e2enes 107 . 093 .480 f+ .010 |— .024 | —0.250 . 139 . 050 .175 f— .081 |— .011 | — .035 . 104 . 066 .621 J— .016 |+ .002 | — .199 090 091 c40L SS ee + .001 | — .144 110 123 419 . 037 - 040 053 107 111 .659 J— .013 |— .009 | — .095 091 . 150 545 J— .036 |— .042 | — .185 . 093 2119); S 28 ees — .036 |— .040 |__._---. . 156 292 |- eons — 026 |— .052)|_.-5-2-- 107 23 . 728 J— .033 |\— .022 | — .227 . 103 . 186 827 f+ .027 |— .037 | — .063 053 . 074 ASTD) eee soba | eee ee | . 113 . 160 815 . 036 057 188 . O91 . 152 or eee — 0025 | Ree ee . 150 190 .849 J— .050 |— .055 | — .111 . 130 1885/5 see Fee OLON Sse ee eee . 186 225 .870 J— .076 |— .075 |_-__---- 114 . 280 5 SOOWR Fee 1/1008 I esseee= 128 . 246 SHEN Beane — .069 | — .367 176 .319 , .560 J— .093 |— .1386 | — .146 . 147 5416/2238 = 037 \— 9. 1 0F beeeeeee 072 oilalil BBY) | eee =. 0310 |e eee 051 . 099 .454 [— .030 |— .033 | — .073 . 069 124 sASR ipo es Soe 2 eee 075 112 .414 J— .032 |— .036 | — .117 - 158 . 269 .827 J— .048 |— .067 | — .092 147 ASS ee eee ee oes =) 048 . 069 OO Ties Seerae + .011 |— .068 |_.--_-_- palalal . 297 794 J— .044 |— .050 | — .054 . 104 Bi itsy| Peewee a — .074 |— .101 |.--__--- . 082 . 256 .460 J— .035 |— .072 | — .085 126 348 <480) |: eee "O42" 2=t2e2 5 . 122 115 .294 J— .062 |— .067 |-------- -1i1 057 . 236 J— .021 |— .027 | — .116 097 116 pOAQURs $22.2... 229 Tabular sunmary of Linsser’s results—Continued. Departures of phys- Physiological con- iological constants stants for zone A. for zone B from Orders, suborders, and species. those of zone A. Leaf- Bloom-| Ripen-} Leaf- | Bloom-| Ripen- ing. ing. ing. ing. ing. ing. Caprifoliacez: | Sambucusiobulus.. +... 2522252024) 222k ee O05) ) OFs6L\) (O1750) Fe -----—_ +0. 005 | —0.150 Sambucusmigray.-12-2--- === fed oe Wa Sey RIE . O67 . 280 . 674 F—0. 029 . 066 053 Sam DUCUsiMACOMOSAs seen eee e as eee ee eee ae 069 . 132 526 039 |— .018 | illic Rosacez: | Sorbus aucuparia (or Pyrus aucuparia)___-__- | .096 202 -646 F— .028 |— .047 | — .189 SOInSSan De aie esa et es es en oe ea a ee a O94 227 STOO UNE ces ee eee oe oe ees Spiraea hypericifolia________- Sees a See eae | .109/ .199] .600[— .059 |— .077 | — .290 Spinsearleovigatars o:-.0- voto --e.25 o-oo see] . 050 . 164 POSOi ees sate ree 8 ee Spireasalicitoliae eee meee ae cece hie ce OU eer 80K) 9 5820) see SUBIR |e sence Spina SOnvilOlancee se seca see eee sae -018 381 .850 #+ .052 |— .156 | — .270 Sapindacez: Stapnyleapinnatas.22. 222-8 se See 22 eee . O94 eRe Ae arid ft) O06: | — ie O41: Saas eae Stapnylestrifoliate, 2722 2-2-4 8s eo bese aii ly( . 180 ploc Wests cela Ssos omen ceee Saxifragacez: SVM Pa OVSiCRemana2a2- cen coe ees sansaase .086 | .183 .803 J— .018 |— .036 |---_---- SIME sine yi el Se SY 078 | .174 740 |— .005 |— .049 | — .025 Coniferee: NUTS ACCH bar asem Sassen eee eo ak 127 . O86 748 J+ .018 |— .029 | — .128 Tiliacez: PUT ATEUTO Preae =: oe-= eee et ek eS 110 OOO: (eros an aso d: - esas seees 9 ee Miliapoeranditoliawes sees syst te see Se eee . 124 . 366 BUCA \as re eee i— .046 | — .242 Rilianpatvat Olas em nor see fae ee oe 136 ALT .806 f— .032 |— .087 | — .108 Urticacese: Wilmustcampestrist = $2522. eas te ee ctee 127 072 . 244 048 028 | . 067 (Willman s\efhusap: = iasse) =. 2s ee ee me ce IS . 063 . 286 . 003 O15 | 096 Caprifoliacezw (Lonicers): WalbornturmMian bana ~-25 2 oa a A ee . O91 aya 706 051 057 . 152 Wall ojehaayohaa/Yoyoyil tbls) peop use Oo SUE ESS ed . 100 233 780 027 075 . 208 Vitaceee: ‘Wikinls} salah fey rit eee ee ee ee ee ee | alle . 366 . 821 O51 076 . 108 In the original, from which the foregoing abstract is copied, Linsser gives the so-called probable error or the limit of uncertainty as deduced from the agreement among themselves of the numerous individual determinations of the physiological constants in zone A, whereas the mean values alone are given in our summary. It appears that the uncertainties are larger for the ripening phase than for the leafing and blooming phases, if we consider only their absolute values, but decidedly smaller if we consider their relative values. In general the uncertainty of the constant for leafing is about one-twentieth of its own value, the uncertainty of the constant for blooming is about one-fortieth of its own value, and the uncer- tainty of the constant for ripening is about one-fiftieth of its own value. 230 The values of the constants, as deduced from stations that lie in the dry zone B, vary much more than those in zone A; but this is a necessary consequence of the law of growth, since in such dry regions the quantity of heat required to produce a given phase ceases to be a simple constant and becomes a complex function of the available heat and moisture and depends upon the individual ratio f/w at each station. It will of course be noticed that, with few exceptions, the figures in the columns of departures are negative, thereby indicating that the quantities of heat actually utilized by plants in the dry localities in zone B are less than the quantities utilized by the same plant when it has an abundance of moisture in zone A. Most of the 17 positive figures among these departures relate to the period of leafing, and many of them are but little larger than the limit of uncertainty deduced by Linsser for the respective plants. All of the plants investigated by Linsser belong, as is seen by the above list of names, to the exogens. They are also perennials, but lus intention was to extend this investigation to the herbaceous annu- als, and a large mass of work in this direction had been accomplished before his untimely death in 1871. The conclusions drawn by Linsser from the data, as summarized in his published tables, may be presented as follows: Although the general fact above mentioned, that plants growing in regions that have scant summer rains utilize less heat and less moisture to produce a given phase of development than similar plants having the same quantity of heat at their disposal with plenty of ‘ain during the summer, might be considered as only a further con- sequence easily deduced from the principle that underlies the theory of Linsser’s physiological constant, yet we may also consider the fact as one established empirically and seek for the most probable expla- nation. Any general relation between the vital phenomena of plants and their external influences can, according to the ideas established in Linsser’s first memoir, be looked upon either as due to temporary influences or asa consequence of the habits of the plant. If we adopt the former view, then the cause of the accelerated development of plants in zone B will consist in the fact that from the beginning of vegetation onwafd one or more accelerating forces have come into play, the intensity and duration of whose action is greater for sta- tions in, zone B than in zone A. Such accelerating forces may consist in a greater quantity of heat or of sunshine or possibly other influ- ences. But when we come to examine the temperature curves for stations in the two zones we see at once that heat alone can not be considered as the stimulating force. A similar comparison shows that rainfall during the growing season can not be the stimulus. Again, stations such as Parma and Pessan show that great differences in ° 231 sunshine alone fail to give a sufficient explanation. Finally, a natural and sufficient explanation is found in the study of the relation of the rainfall in summer to the given climatic conditions, as has already been done in the study of the heat; it is not the rainfall of the spring months that stimulates the plant, but it is the drought of the suc- ceeding summer, or, as it were, the knowledge of that approaching drought which stimulates the plant to hasten and complete its devel- opment in the springtime or earliest summer. The plants of the north are accelerated because of the rapidly approaching autumn; the plants of the highlands because of the shortness of the approach- ing summer; the plants of the steppes and of regions with rainless summers hasten in order to have their work finished when the time arrives at which their activity should come to an end. The plants at localities in our zone B complete their labors in the springtime be- cause of the drought of the coming summer; under almost the same external conditions the plants at Parma hasten their develop- ment while those at Venice live leisurely along; the plants at Vienna, Breslau, and Kief accelerate their growth, while the same plants at Heidelberg, G6rlitz, and Orel live leisurely. The problem, so often discussed, of the reforestation of the steppes is thus referred back to another more definite problem, viz., the acclimatization in the steppes of those plants whose normal cycle of vegetation in their native locality is such that when transplanted to the steppes these processes, especially the blossoming and leafing, can go on with sufficient rapidity to be completed before the begin- ning of the hot, dry summer. Quite similarly the problem of culti- vation of fruit in those regions can be thus exactly defined. Thus Helmersen states that experiments with fruit trees brought from Hamburg to Orenburg entirely failed. But here we have to do with a double violation of the theory, since the plants brought from Ham- burg came to a locality having a much smaller annual sum of heat and were not yet adjusted to the dryness of the Orenburg summers, wherefore they continued living at Orenburg according to the easy habit acquired at Hamburg. Lainsser suggests that success would be much more likely if plants were taken to Orenburg from Bokhara or Khiva, where the extraordinary rapidity of development, on account of the great dryness of the summer following after a rainy spring is well known. Further questions as to the temporary influence of rainfall during any part of a cycle of vegetation must be investigated by studying the hfe of plants at localities having very different climates. After studies on the development of vegetation in various climates throughout the world, in all of which the rainy season is the blossom- 232 ing time, while the dry season is the ripening time, Linsser gives the following general conclusions: There are two especial laws regulating the life of every individual plant, (1) the individual habit; and (2) the principle of economy. The application of these principles explains and gives us a better comprehension of the course of vegetation under the equator as well as near the pole. The principal factors in the life of plants that we have thus far considered are heat and moisture. If the former is that whose periodicity gives warning of the necessity of economy, then the whole life of the plant is intimately dependent on the course of this heat, as in the extreme north and the greater part of the Temperate Zone where the moisture is otherwise sufficient. If it is the moisture that is subject to large periodical changes and the question of sut- ficiency of heat becomes unimportant because of its uninterrupted abundance, then the cycle of vegetable hfe depends upon the peri- odicity of this moisture, as in Madeira. If, finally, the variations of the climate are such that there is sometimes insufficient heat and moisture, then the necessity of economy in the use of both of these materials is enforced, and in the course of the year the plant seeks to develop as far as possible in accordance with both these necessities, as in the Steppes of southern Russia and near Bokhara and in isolated shady locations such as mountain sides. The law of fractional parts of the total annual quantity of heat, as demonstrated in Linsser’s first memoir, is therefore now seen to be only a special case, for northern and temperate latitudes, of the gen- eral proposition just enunciated. The former was the first approxi- mation toward a rational theory of the periodical phenomena of vege- tation, just as this more general proposition is the second approxima- tion. We have thus far studied principally the differences in the life of plants due to differences of climate in different localities. It still remained for Linsser to study the peculiarities of the same plants in different years in the same locality, to which end his manuscript material already offered a sufficient basis. Of the questions proper to be considered in this second category, viz, the study of plant life as depending on temporary variations of local climates, Linsser enumerates the following as having already been taken up by him, viz: (1) The influence of cloudiness, insolation, and atmospheric pressure; (2) the especial influence of the various distributions of rain on the individual periods of vegetation; (3) the relation of the length of the day and the night, as also of light itself, on the plant; (4) the influence of the nonperiodic variations of temperature; (5) the influence of cold or warm winters on the sub- sequent summer’s growth; (6) the investigation of the sums of tem- 233 perature for the same phases of plant life from year to year, and the reason of their variations. On this last point he concludes by stating that it is well known these sums do vary from year to year for each phenological epoch. For the present he states only that these temperature sums are not only apparently, but in reality, not constant, and from his preliminary work for this second series of studies the most important causes that determine the sum total had already become known to him. Without anticipating too much the course of further investigations, he states that studies already finished demonstrate that’ there should be differences annually in the tempera- ture sums, as is evident from the following consideration: If seeds brought from Stuttgart to Christiania accelerate in successive gener- ations in successive years because of the smaller sum total of heat in their new home, then exactly the same would occur if the plants remain in Stuttgart and we at that place offer them the sum total of heat peculiar to Christiania. That is to say, seeds that have ripened at any one place in colder years produce plants that develop more rapidly than do seeds from the same place but which were ripened in warmer years. APPLICATION OF LINSSER’S RESULTS. This application to each plant and each locality of the principle of economy which Linsser had established from the geographical dis- tribution of plants offers to us by far the most important principle yet discovered and well established to guide us in the development of grains and plants appropriate to the vicissitudes of our chmate. For instance, in general it is desirable to sow and plant so as to avoid the early autumn frosts and the late spring frosts—that is to say, to secure varieties of plants whose course of vegetation will be complete in the very short time that is free from danger of frost. Therefore, if we wish to develop plants that will ripen in the earliest summer, before the droughts destroy them, as in the region from Nebraska to Texas, then we have to remember that the seed perfected in Kansas in a dry year is already, by its own experiences, prepared to become the best seed for sowing in anticipation for the next dry year. The seeds raised in dry years should therefore always be preserved for sowing, as likely to be far more appropriate than any seed that may be brought from a distance, unless brought from a region where equally dry, short seasons prevail, as in southern Russia and Bokhara. The rule of sowing one year the seed raised the preceding year 1s, in general, not the best rule. By always utilizing as seed that which is raised in the driest years one may hope speedily to develop plants whose vegetating period will be so short that the crop will rarely be injured by the dry, hot winds of July. A similar rule holds good for any modification we desire to make in the seed. If we wish to 234 raise plants peculiarly fitted for wet climates or for cold climates, we begin with the seed that was ripened in wet or cold seasons. I think that probably a further prosecution of Linsser’s studies would have led to the conclusion that the influence of sunlight and dif- fuse sky light is the next important factor in vegetation, and that the quantity and quality of the seeds produced—that is to say, of the crop as distinguished from the mere epoch of ripening—depends upon the ratio of the nutrition carried up in the sap to the total intensity of sunshine. The grain harvests of the world may be divided into zones a, b, c, analogous to the phenological zones*that Linsser has given, and in which the quantity of the harvests is large when the nutrition is sufficient to use up all the sunshine, but is small when either nutrition or sunshine is deficient. As the plant begins a new cycle so soon as the last is finished and usually is delayed by the speedy approach of winter cold or autumnal drought, therefore Linsser’s laws would lead us to the conviction that by artificially regulating the temperature, moisture, sunshine, or artificial light, and the nutrition in the soil, we ought to be able to develop an ideal method of cultivation that should greatly increase the number of crops per year and the yield per acre, and especially so within small, limited areas that are protected by cover from injurious frosts. The need of water for the varieties of plants and seeds usually cul- tivated has led to great engineering projects for irrigation, and the scarcity of natural rainfall has led to wholesale condemnation of many arid regions as being unfit for profitable agriculture, but the progress of knowledge now shows us that nature has a power at work eradually overcoming these disadvantages, and that man by taking advantage of her ways may profitably cultivate crops in extreme cli- mates and soils, not so much by irrigation as by developing seeds and plants that suit the natural circumstances, just as our own ancestors developed our European grains from the grasses of Asia or our wide- spread maize from the weeds of Mexico. It is the duty of our agri- cultural experiment stations to lead the way in this evolution of new varieties quite as much as in the mere introduction or acclimatization and study of old varieties. Now that we have learned the secrets of Nature’s method of evolution we must hasten to apply it to the needs of mankind. DOVE. In 1846 H. W. Dove wrote as follows: In the tropical regions the mean temperature of any year differs but little from that of any other, but the quantity of rainfall differs largely. The result is that the yield of crops varies exceedingly, not only on lowlands that. depend upon the periodical floods of the rivers, but also on the islands, where there are no large rivers. Therefore in these climates the agriculturist cares less about the temperature than about the rainfall. 235 In Europe, however, the connection between the temperature of the air and vegetation is so intimate that some investigators maintain that on the ¢ occurrence of a given temperature the plant enters at once upon a corresponding definite stage of development, while others maintain that in order to enter into this stage a definite sum total of heat must be received. Therefore the former determined the stages of development by the ordinates of the annual curve of temperature, while the latter determine them by the area of the space that is bounded by such ordinates. It is evident that if under a given lati- tude the temperature of the atmosphere is the principal factor, while under another latitude the moisture of the atmosphere ts the princi- pal factor, then neither of these should be entirely overlooked, but the part played by each must be examined. To this end the study of the geographical distribution of plants gives very little information. Again, the study of the influence of per riodic variations of the atmos- phere on plants is useless in the attempt to distinguish between the effects of temperature and moisture, because as a general rule the atmospheric conditions all attain their maxima and minima at about the same time. The study of the nonperiodic variations gives prom- ise of greater success. But in studying the relation of temperature to vegetation the data given by thermometers hung in the shade, as to the temperature of the air, can have little to do with the life of the plant as compared with the temperature given by a thermometer exposed to the full sunshine by day and the radiation from the sky by might. Dove then discusses the observations of maximum sunshine and minimum radiation thermometers made in the botanic garden at Chiswick, near London, from 1816 to 1840, and shows among other things that when the mean temperature of the air is low the freely exposed radiation thermometer is especially low, and when the aver- age temperature is high the freely exposed solar thermometer is es- pecially high. He then investigates the observations of earth tem- perature made by Quetelet, of Brussels, from 1834 to 1843, and shows that the upper layers of soil, whether dry or wet, have temperature variations parallel to those of the temperature of the air. He then studies the phenological observations of Ejisenlohr at Carlsruhe from 1779 to 1830. These show that a plant enters into a defipite stage of development when the air attains a definite degree of tem- perature rather than when the plant has received a definite sum total of heat, this conclusion being, of course, based upon the internal agreement of the computed figures for these fifty-one years of observations. Analogous results were obtained by him by studying similar ob- servations made in the State of New York and at Wurttemberg, Germany. With regard to the influence of rainfall, Dove finds that it is not so plain as that of temperature, and that it is not so much the quan- tity of rainfall that is important as the frequency; too great fre- 236 quency is injurious, inasmuch as the cloudiness cuts off the influence of sunshine. The fact that years of low temperature are always years of poor erops is a fact that must be generally considered as a local phenomenon because of the simultaneous conpensation as to temperature that is continually going on in contiguous localities. HOFFMAN. Prof. Dr. H. Hoffmann published, first at Giessen and afterwards in the Memoirs of the Senckenberg Association at Frankfort (Vol. VIII, 1872), the details of a work which he began in Giessen in 1866 on the relation between the development of plants and the tempera- ture recorded by a maximum thermometer in full sunshine. Some account of that work and its subsequent continuation at Giessen is given in successive papers published in the Journal of the Austrian Meteorological Association (Zeitschrift O. G. M.) during the years 1868 to 1891. The detailed references to these will be found in the list of papers appended to this present report. Hoffmann’s first conclusion, as stated in 1868, was that he had found a precise, intel- ligible, and comparable expression for the quantity of heat that is needed for the attainment of any definite phase of vegetation. He would take the sum of the daily maxima of a thermometer fully ex- posed to the sunshine. His first work at Giessen was done with a naked glass bulb, self-registering, mercurial, maximum thermometer, graduated to Réaumur’s scale, attached to a wooden frame and set out in full sunshine 4.5 French feet above the soil or green sod in an open portion of the botanic garden at Frankfort. The exposure was indeed not perfectly free, but was such that the sun shone upon the thermometer from sunrise to 2 p.m. in January and until 4.30 p. m. in June. Hoffmann’s summations begin with midwinter, or January 1, and he gives the sums of the positive daily maxima (1. e., above 0° Réaum.) up to the dates of leafing and flowering for 10 plants. Apparently preliminary values are given in the Journal of the Austrian Meteorological Society for 1868 and 1869, but final values in the memoir published at Frankfort, 1872. In the Meteorologische Zeitschrift for 1875 Hoffmann says that after four years’ work at Giessen (1866-1869) his thermometer was broken. A new one was constructed by Dr. J. Ziegler, of Frankfort, in accordance with their mutual understanding; this had a mercurial bulb, but was very many times larger than the former, and therefore very much more sluggish. Observations with such instruments, graduated to accord with the Réaumur scale, were begun in 1875 by Hoffmann at the botanic gardens at Giessen, and by Ziegler at the gardens at Frankfort. In order to compare these two series together and to unite them with the earlier Giessen series the ratios of the sums as given by the earlier and the later thermometers for the same 237 plant were taken, and it was found that the ratios are very nearly the same for all plants; therefore the ratio given by the best series, viz, for Lonicera alpigena was taken as a standard and applied to the series for the other plants, so as to reduce all observations with the later thermometers back to agreement with what would have been given by the first thermometer had it not been broken. The ratios of the sums observed at Giessen with the new thermometer as com- pared with the sums observed at Frankfort, also with a similar new thermometer, agreed closely for all the plants, and as the two new thermometers agree closely with each other when placed side by side, it was assumed that the ratios thus obtained represent the reduc- tion from the climate of Frankfort to that of Giessen. Adopting the same standard plant and the ratio of its sums for any place to its sums at Giessen as the standard ratio, all the sums for plants at that place can be reduced to what would have been given by the same plants at Giessen and to what would have been given by the first Giessen thermometer. Although these reductions are very arbitrary, yet the agreement of the sums thus computed for Giessen with those actually observed was quite close. But, as we shall see, subsequent years of observations have shown that such agreements do not always recur. In the Zeitschrift for 1881 Hoffmann shows that it is not the low temperatures but the subsequent too rapid thawing that injures most plants; thus the hill stations suffered less at the close of a period whose lowest temperature was —31° Réaum. than did the plants in the lowlands; the shady side of the tree suffered less than the sunny side. It is indifferent whether the sudden rise in temperature is caused by great solar rays or by a sudden warm wind; the sudden rise from —12° Réaum. to +13° Réaum. is as bad for plants as the sud- den rise from —20° Réaum. to -+-5° Réaum.; the amount of injury is proportional to the extent and to the suddenness of the rise. In the same volume of the Zeitschrift (p. 330) Hoffmann gives the results of observations at Giessen for 1880. He finds that the blossoming in springtime is so subject to disturbances by frost that the midsummer and autumnal phases of vegetation are more proper to show the accuracy of his methods. He finds that these later phases, as observed at Giessen (1866-1869), when reduced to the new stand- ard thermometer at Giessen agree within 1 per cent with the actual observations of 1880 at that place. For plants that bloom in the spring he finds that if these are protected from injury by frost by placing them under glass covers there is then a better but still unsat- isfactory agreement between the observations at Giessen and Frank- fort. On computing the mean temperature of the air in the shade for the dates of blooming at Giessen he finds no apparent connection, so that from the date of blooming we can not infer the mean tempera- ture of that day nor can we reason from the temperature to the date. 238 The sum total of daily maximum sun temperatures at Giessen is much more nearly constant. In the Zeitschrift for 1882 Hoffmann gives the sums of the daily positive readings of his naked bright-bulb mercurial thermometer in the full sunshine; he also gives the sums of the temperature in the shade, and computes the average discrepancy or probable error of these numbers as deduced from their internal agreement year by year. He finds the probable uncertainty of the sums of maxima to be plus or minus | per cent and of the sums of shade temperatures to be plus or minus 10 per cent. ‘These latter sums relate to low-lying stations, such as Vienna and Dorpat, and these discrepancies diminish very much when we consider high mountain stations, where the shade temperatures of course give much smaller sum totals. He recognizes that the advantage of using the shade temperatures lies in the greater comparability of the observations made at different stations and with different instruments, but that the sunshine method is also greatly improved if the thermometers are perfectly similar and properly compared together, as in the instruments made by Doctor Ziegler at Frankfort. (See the report of the Senckenburg Association, 1879- 1880, p. 337.) Hoffman’s observations with a variety of instruments convinced him that this difficulty as to instruments and exposures is not insurmountable. He collects comparative readings at several places and shows that the difference between the average tempera- tures in the sun and in the shade is larger at higher altitudes; thus at Giessen the average difference in summer at midday is 5° Réaum., and the whole range of the differences between sunshine and shade is from 3° to 15° Réaum. The corresponding average in the Hochge- birge, 7,000 feet, is never less than 8° Réaum. At the Bernina hospice, 8,113 feet, it is 25° Réaum. The average temperature of these mountain stations is 16.4° Réaum., corresponding to an elevation of about 6,000 feet. Similarly, J. D. Hooker observing a black-bulb thermometer in the sunshine in the Himalayas, found a difference of —15° Réaum. at 7,400 feet elevation, as contrasted with 4.4° at sea level. R.S. Ball, also using a black bulb, finds a difference of 18° or 20° Réaum. in the Hochgebirge and of only 3° at Chiswick. These differences show the effect of the great dryness and mechan- ical purity of the air in the Hochgebirge. Hoffmann considers the smoke and clouds above us as affecting the difference between the sun and shade thermometers, but says nothing of the earth’s surface which completes the “ inclosure ” of the thermometer. The date from which Hoffmann begins his summation for Giessen is January 1; but as it would seem more proper to begin with some definite phase of vegetation, therefore he investigates the accuracy with which we can determine the initial phase and the effect of errors therein upon the ultimate sums. By painting the buds of certain 239 trees and examining them very frequently Hoffmann seeks to deter- mine how accurately the date of the beginning of vegetation or the flow of sap can be determined by the swelling of the buds and the visible cracking of the delicate pencil lines of paint. He finds that the date can be determined to within one day when spring comes on rapidly, but within eight days when it comes very slowly. The cor- responding uncertainty or variability of the sums of the maximum sunshine thermometer from the swelling of the buds up to the date of the first blossom, for instance, for Castanea vulgaris, is 4 per cent while the uncertainty of similar sums, counting from January 1, is only 1 per cent. These and similar data are only deducible from observations made upon the same tree or bush from year to year; the variations are materially increased when different plants in dif- ferent localities are observed; moreover, they are based upon observa- tions for only four years, which period is not long enough to give a reliable value of the relative uncertainties. As in previous cases 1n making up these abstracts, I give Hoffmann’s actual figures in the following summary, which I have compiled by collating the few observations published by him in the Zeitschrift during the years 1870-1890. I have selected only the few plants for which he has published the sums for several years or for two localities, so that comparisons may be made and a judgment arrived at as to the pro- priety of his method. It will be observed that Hoffmann has, when possible, observed the same tree or bush from year to year, so that the problem of the influence of heat is much more definite than when different plants or a general mass of plants is observed; but, on the other hand, single plants are more lable to irregularities produced by special disturbances which would exert no appreciable influence on the average of a large number of similar plants. Temperature sums at Giessen (Hoffmann’s method) from the first swelling of the buds to the first blossom. [Z. O. G. M., Vol. XVII, 1882, p. 127. All in Réaumur degrees. ] Plant. 1866. | 1867. | 1868. | 1869. Castanea catigmmessee oan ses Me eee ae Len, Leh ee AA EAD eae cee ees 2,044 | 2,142) 2,085 2,317 Gatalparsyvain caroline secs es aan teen c ens nae RE aS Re Ss 2,149 | 1,984 2,547 Lonicera alpigena: | ins ti SMeCiMNe nis sims meee er ieee 2M ae Se Tee 891 1,058 1,014 SCCOnG SPCCIIN ON yaaa aaa ae se os 2 Re ees e5t vecceesi[sses—ese 919} 1,058 1, 032 Persica vulgaris: IESi SpeCimMenii se see es eee eowee aes sed So cee sous ee ese 659 678 774 788 Secondsspecim Cn aesse aa ae seen eee eee Seah cone eee 893 670 O84 eee sees Syringa vulgaris: St SPECUIMON Hs sae 5. > hie eee e eee Seren ooo oS Vanes same sone 1S S88h|Peeeeeo- 1,315 1,248 SECONd SPECIMEN shat 5 Se Seer Ne aE ae es Leese Sse! TOO res aces 1,181 1,166 Vitis vinifera: y HPStispecimenee asda a 5 eR mye ee oes ee ee kee ees beple ss Sarg a 1,040 1,531 SeOcondrspecimicnrysses 4 os rere ee ee ob ee cee sec teesccec |b saseas8 856 1, 222 240 Temperature sums from January 1 to the date of first blossom (by Hoffmann’s method) at Giessen and at Frankfort. [Z. O. G. M., Vol. X, 1875, p. 251, and Vol. XVI, p. 331. All in Réaumur degrees. ] Giessen. Plant 1866-1869,| 1875, nae forts 1845, eels ner _| Ther- Ther- 1 URE ae mre Stek pee: mometermometer| — B,. 1. | 2 Moniceratalpi genase. s22- as eaea ae eee eee eee i Bakeyy O16 boas [oot fees Ee Sambucus migra. = Scns e Sect omen a ee eee 1,678 GES 9 a iy ee ee a eee IBeErvoristVUleatis seees eee eee ete ae eee 1,377 TOON | 2225 Sue S28) '- ee Se 1,110 IPrunusiaVvillM ne. oa seess eee! eee eee eee 1,077 S20" 0 222 352. ee oe eee 800 Svan oa tyUl Cad S een eee eee ee 1,393 VS OOVs\ 22. oes ee | ee Aesculusihippocastantum\: 222-2. escss=s=-se nee 1,317 L069 | 22:2 5 = Sane See eee 1,065 Va bIS: VANITOLS 82450 a So ose tae hee 2d SEE She EES 2,600 1,995 2,697 2603)\ tae et IPTrUNnUS'SPIN OSA pease esa ese eee ee eee eee eee aes 81942 Shee ee ae ee 822 Temperature sums (by Hoffmann’s method) at Giessen from January 1 to first blossom, for plants that blossom in midsummer and autwmn. [Z. ©. G. M., Vol. XVI, p. 331, and Vol: XVI p. 1305) M. 25 Vol. I, ps 40%, and Vol sii, p. 546.] Ther- | Thermom- Thermometer By. mom- eter By. Plant (always same stock). eter A, | 1866- | 1880. | 1881. | 1880. | 1881. | 1882. | 1883. | 1884. | 1885. | 1886. Aesculus macrostachya ___| 3,853 | 3,504 | 3,479 | 3,191 | 3,254 | 3,929 | 3,846 | 3,639 | 3,546 | 3,556 Aster amellusi seco) 5 225 ole 8,980: | 45.091 | 4,003) | 3,753 | 3,768 | 4,522) 4,569) 4,363) |- 2222S )e 2 Secae Lilium candidum -____.-_-- 2,710 | 2,872 | 2,855 | 2,603 | 2,639 | 3,112 | 3,228 | 3,010 |.-...._].------ Linosyris vulgaris --------- 4,083 | 4,091 | 4,260 | 3,753 | 4,040 | 4,555 | 4,670 | 4,502 |_.---.-|------- Plumbago europaea ------- DESL Sed, 40D u kas 2ol sas Ook Oli eee ye eee ae) eee 5,386 | 5,494 Pulicaria dysenterica----_- BSyS81F 23; GIS xs 2Goul tal OO alo O40 lee eee | emer ae |e ee | eee The contrast between the ordinary spring of 1881 and the very early spring of 1882 with its preceding warm winter, affords a test of the question as to how much the thermal constant is lable to change with the variations in the seasons. Hoffmann finds that although the first blossoms in the spring of 1882 occurred fifteen days earlier than usual, yet the sums of the maximum temperatures since January 1 were not much changed. The figures as given by him (Z. O. G. M., Vol. XVII, p. 460) are reproduced as follows: Thermal sums. Date Recee to Plant. i 1881. 1882. 1881. 1882. Canpinus betulus2<* 22: 22 2 Se eee 1,159.7 | 1,184.6 | Apr. 19} Apr: 2 NAnixXcOUlr OPACH.-2225 aa-k eens eee ee ee eee 789.9 759.9 | Mar. 30 | Mar. 15 moniceraalpivena- 222. -6- fae se- ae eee a oe eens 1,471.7 | 1,490.4 | May 6) Apr. 19 IPrunUS SpINOSa. 2 <5. So Lee eoels = eee a eee eee ae | 1,159.7 | 1,091.6 | Apr. 19 | Mar. 31 Ribes svOssullariat se se. 2s ke eee See eae eee eae ee 1,086.5 | 1,091.6 | Apr. 16) Mar. 31 @ratacrusioxyacantha..- 22225)! ae eee oes 1,681.6 | 1,782.5 | May 15 | Apr. 30 Sarothammussvll paris: «2- <= see: oe ee ee eee 1,790.8 | 1,751.9 | May 20°} May 1 Berberisvallearis’: 225 3! esa Poe eeens eee eee eae 1,681.6 | 1,751.9 | May 15 | May 1 wks 241 Many of the plants observed by Hoffmann show such discordant sums from year to year as to prove that his method has no meaning for them, but for others the agreement is such that he recommends them to be observed in connection with the cbservations of the sun- shine thermometer, as follows: For the following plants observe the temperature sums from the first swelling of the buds to the first flower blossom: Castanea vesca, Bupleurum falcatum, Corydalis fubacea, Dianthus carthusiano- rum, Lonicera alpigena, Salix daphanoides, Syringa vulgaris, Amygq- dalus nana, Alnus incana, Alnus viridis, Atropa belladonna, Betula alba, Crataegus oxyacantha, Larix europaea (up to the date when the pollen first falls from the anthers), Ligustrum vulgare, Lonicera éatarica, Prenanthes purpurea, Prunus padus, Prunus spinosa, Rham- nus frangula, Ribes aureum, Rosa arvensis, Rosa alpina, Salix caprea, male (for the catkin, or the flowers of the willow, the beginning of pollination, as ascertained by a light stroke on the flower, is to be considered as the date of the first blossom). Hoffmann also applies his summation of sunshine maxima tempera- tures to the interval from January 1 to the ripening of the fruits and shows an excellent agreement between the numbers for 1880 and those for 1881 at Giessen. In the Zeitschrift for 1884 Hoffmann gives his results for 1889, 1883, and 1884 as collected in the preceding table and says that the vexed question of the thermal constant for vegetation is still far from being settled; either temperature and vegetation are independ- ent of each other, which no one can easily believe, or they stand to each other in a relation for which the correct expression is still unknown. Pfeffer in his Pflanzen Physiologie (Vol. II, p. 114) has stated that the approximate uniformity of the sums of temperature, from year to year, can only mean that, in general, for each year the heat received from the sun amounts to about the same sum total for the same date annually; but this is not in strict accordance with facts, for if it were true a small change in the date should make a small change in the sums, which is not always the case. Thus, if for Linosyris vulgaris the dates of blossoming are August 15, 18, or 20, the sums from January 1 for different years will be as follows: Year. Aug. 15. | Aug. 18. | Aug. 20. The S38 25 pens stl A a ean 4, 555 4, 637 4,698 NS83 ef Se et SSS iS SCE ESE Eee et a 2 4,597 4,670 4, 728 Leelee SS SESE Bee cps ee ie ee ae Aa Tee ne ee Se eS 4, 363 4, 452 4,500 From these figures we see that the sums vary from year to year quite independently of the change of date. The thermometer B,, similar to B,, having been sent to Upsala for observations at that place, it gave from January 1 to the first blossom 2667—05 Mm——16 242 sums that agree so well with those found at Giessen that Hoffmann thinks no better can be expected. In the Zeitschrift for 1885 Hoffmann continues to give the com- parative observations at Giessen and Upsala, and remarks that the question is not as to whether his method is correct and the others are wrong, but as to which of all methods is even a little better than the others. Of these others only one can, he thinks, be compared with his own, viz, that of Karl Fritsch, who takes the sum of all positive mean daily shade temperatures. Hoffmann apphes Fritsch’s method to the observations at Giessen and Upsala and finds the argument not in its favor. He also tries another form of thermometer, viz,. the so-called black bulb in vacuo, but finds it too sensitive, which he thinks is because its bulb is too small. In the Zeitschrift for 1886 (p. 546) Hoffmann gives a summary of observations at Giessen and Upsala during 1886. In general the sums are smaller at Upsala and so also for high Alpine stations. He is thus led to the laws established by Karl Linsser, as published in St. Petersburg in 1867 and 1869, which laws he expresses as follows: “ Every wild plant has in the course of time so adapted itself to the surrounding local climate that it utilizes this climate to the best advantage.. For any given phase of vegetation it uses a certain pro- portional part of the available annual sum total of heat. Thus, if the annual sum at Venice is 4,000 and if the corresponding sum at St. Petersburg is 2,000 and if the plant utilizes one-fourth in order to bring it to the flowering stage, then it will require 1,000 at Venice and 500 at St. Petersburg.” From Linsser’s law he concludes; (1) plants that have been raised in the north and are transplanted to the south reach their phenological epochs earler than plants already living there, while southerly plants carried to the north are retarded as compared with those already acclimatized; (2) plants raised on colder highlands when transplanted to the warmer low- lands have their epochs accelerated as compared with those already domesticated; plants raised in the lowlands and transplanted to the colder highlands develop more slowly than the acclimatized plants. In the Zeitschrift for 1886 (p. 113) Hoffmann determines the rela- tive retardation of vegetation as determined by the dates of the first blossom of several plants at different altitudes. The result is for the Pyrus communis (pear tree) and allied varieties a retardation of 3.7 days per 100 meters, and corresponding to this a retardation of 2.8 days per 1° of latitude. The analogous data for Pyrus malus (apples) are 2 days per 100 meters and 4.4 days per 1° of latitude. Charts are given showing by means of isophenological lines the eradual progress northward of the development of vegetation as spring advances. 243 In Petermann’s Geog. Mitth. for 1881 Hoffmann gives a general phenological chart for central Europe showing the acceleration or retardation of the phases of vegetation with respect to Giessen. In the Zeitschrift, 1882, Vol. XVII, page 457, Hoffmann gives the results of his study of observations collected by Karl Fritsch, showing the dates of blossoming and ripening of fruits in Europe, as reduced to the latitude and altitude of Giessen; and, second, the thermal con- stant by Hoffmann’s method from observations at Giessen for the years 1881 and 1882, as collated in the preceding table. He also shows that the advance of vegetation in the early and very warm spring of 1882 did not materially diminish the sums total of maxi- mum temperatures, the figures for which I have reproduced in the preceding table (p. 240). MARIB-DAVY. The extensive researches conducted at the observatory of Mont- souris (Paris) are scattered through many annual volumes, from which I have culled sufficient to show the views held by Marié-Davy and his coworkers, who distinguish very clearly between thermometry and actinometry, and attempt to determine separately the constant amounts of air temperature and of sunshine which constitute the total molecular energy needed to develop the plant. In his Annuaire for 1877 Marié-Davy quotes from Tisserand (1875) and Schuebeler (1862) the results of a series of observations on the culture of grain in. Europe. Special praise is given to the records from Norway and to the high state of education among the Norwegian farmers. The durations of the periods from sowing to ripening are as follows: | Mean Sowing to ripening. Locality. | fade. Reese Spring | Spring |,. Ours | ture. wheat. rye. ley. ) eee aie CKO Days. Days. Days. Reigns) eee alae a Se eee Sanne eee ee | 59.47 6.3 133 139 17 TEYOYO Oy, Ga he a ee eee Rae ee a oe SR 67.17 | 3.6 121 118 102 Sins eee ee a ee | 68.46 2.9 115 116 98 Slcibat tena saeeae ee ene hao! Mie 2 ose | 69.28 2.3 114 113 93 LNW SARE Se SS eo ee 36745) |Reeeen ease 142 Vos Saal oe ee Paris) (Homilleuse) 22 2sss252---42--os=-5---e 2s 2= ) P4850 eu Ses. cede 189) |p eee es soe | | For other plants—oats, peas, beans, vetches, ete.—the duration of the vegetating period diminishes in a similar manner as the latitude increases or as the temperature diminishes; therefore we can not assume at once that warmth hastens the ripening, for in this case cold appears to hasten it. I say “ appears,” because with the cold comes in another influence, viz, the amount of sunshine. Thus as we go 244 northward we have a greater amount of possible sunshine during the growing period, although the actual sunshine is very materially diminished by the quantity of cloud and fog. Tisserand calls atten- tion to the maximum possible duration of sunshine as given in the following table for the season of spring wheat from sowing to ripening: | Maxi- atitude |e Correspond- north. Soe ing locality. tion. QF Hours. 48 30 | 1,996 | Alsace. 59 «(O 1,795 Christiania. 59 30 2,187 Halsno. 40 2, 376 Bodo. 68 00 2,472 Strand. 69 30 2,486 Skibotten. These numbers of possible hours of sunshine should be diminished to actual hours of sunshine on account of cloudiness. Moreover, actual actinometric observations would have shown that owing to the atmospheric absorption the efficiency of the sunshine is less at low altitudes and, therefore, at high latitudes. But in the absence of fundumental climatic data Tisserand 1s probably correct in conclud- ing that the temperature of the air has apparently little to do, in and of itself, with the duration of the time from sowing to ripening, but that this depends principally on the sunshine, so that at northern latitudes the wheat ripens best in localities that have the least cloudi- ness or the sunniest exposure. On the other hand, the temperature of the air does appear to materially affect the chemical constitution of the grain, since the northern crops are richer in hydrocarbons, and the proportion and quality of the starchy principle increases and the nitrogenous compounds diminish as the locality approaches the equator. The acclimatization of plants is accompanied by notable changes in their nature; frequently the leaves increase in size relatively to the rest of the plant, and their colors are more pronounced, as if the plant sought to supplement the low temperature by a more complete absorption of the solar rays. A similar change as to the leaves and colors takes place in the flora of high mountains as compared with that of the plains below. The aromatic principles of plants are also developed in a remarkable manner in high latitudes. Thus the beans have a more decided flavor in Norway in proportion as we go north- ward, and at Alten (lat. 70° N.) the most aromatic cumin (Cuminum cyminum) of all Europe is cultivated. The incident sunshine seems to be the productive climatic element in effecting the growth of plants; it furnishes the total vis viva, or 245 the mechanical or molecular energy, that is at the disposition of the plant, but it is also the last consideration to be studied and under- stood. The temperature is the next important climatic element and that which has been most studied; the heat involved in temperature is the mechanical, molecular energy that is utilized by the vital powers of the plant. Each plant utilizes a fraction of the molecular energy that is at its disposition, according as its sunshine, temperature, and sap are favorable to the formation of the chemical substances that it can elaborate within its cells. The remaining elements important to the production of crops are: (a) The water that enters the root, which may be natural rain or artificial irrigation. (6) The chemicals dissolved in the water. (c) The soil that furnishes these chemicals. (d) The atmosphere that furnishes nitrogen, oxygen, and carbonic- acid gas. (e) The evaporation of moisture from the plant and soil, mostly through the influence of the wind and heat. Of these, only the rain water, the gases in the atmosphere, and the evaporation are, properly speaking, meteorological or climatic ele- ments not under the control of man; whereas the irrigation of the soil and its chemical constitutents are largely under his control. The quantity of water actually consumed by the plant or evapo- rated from its leaves and that which is daily evaporated from the soil or which drains away to other localities, and thus becomes useless to the plant, have been the subject of many experiments, some of whose results may be summarized as follows: Thus, for example, Lawes and Gilbert, at Rothamsted, England, from experiments in vases entirely under their control, derived the following numbers, showing the weight of water evaporated relative to the weight of grain produced per unit area of ground: ss Wolght eight jof evapo- . Manure. of grain.| rated Ratio. water. Grams. | Grams. INOS) 2S ee Sa ote iS Se ee a aes eee ee epee 9.6 7, 353 766 MM eran Gl ZOnS mea es Ne eee eine eee ek A Se Se er 6,488 882 Mineraliandiammoniacal fertilizers: ----- 2-222 2-1-2 2 -2e le ee 4.2 3, 627 864 In these experiments, therefore, the ground during the wheat sea- son consumed water equivalent to a rainfall of from 184 to 212 milli- meters in order to produce a harvest of 30 hectoliters, or 80 kilograms in weight per hectare. @1Ts it not in fact the vital power of the plant?—C. A. 246 Thus, again, Risler, at Caléves, in France, measured the harvest and the rainfall in an open field, having an impermeable subsoil. He measured the quantity of rainfall and the outflow through the drains, and allowed for the moisture in the soil at the beginning’ and end of his experiments. The result attained was that a field of winter wheat consumed 256 millimeters in depth of water from April to July. He does not give the quantity of grain that was harvested. Marié-Davy, at Montsouris, cultivated winter wheat in twelve sam- ples of earth of very different qualities, in 1874. The soil was enriched with compost, with results as in the first part of the follow- ing table. In 1875 the soil was enriched with Joulie’s complete fertilizer for cereals at the rate of 1,000 kilograms per hectare, with results as in the second part of the table. Evaporation and crops at Montsouris. Experiment of 1874. Experiment of 1875. aa ae Evapo- | Crop, | Ratio. | EYP | crop. | Ratio. Kilos. |Grams. Kilos. |Grams. dS a ee ee ee Se Seah ne eben 380 394 | 964 362 394 919 Die See Se Ub a Ro ea SEES Me cree Ol Wong oat one 360 187 | 1,924 856 372 957 a ee a oe ee ee re 348 300 | 1,160 345 474 728 7 le ee BE a ee ee ep nae Meal I ee 347 380 913 364 479 760 Lip fA Reka ae BOS pela Pa es eee a ae ees BAC Eee es 340 303 | 1,122 356 425 837 Greate eee mio Eee SUES See eee ae 365 256 | 1,426 363 262 1, 386 a eee GA Bee ie ene ne a oie a | 344 328 | 1,049 366 435 841 Oper FALL ee ret ee Be ee ee ek oc B29 324 | 1,015 344 424 811 Operas eee Aire bor et ees Race eee ee 389 312 | 1,086 346 387 894 (1 Oe bike Hai So Ses eh Ee eee 359 308 | 1,165 366 379 965 10 tes ee ee eR eee a See S 346 313 | 1,105 | 346 469 738 LP RREAI aes Se owen eee! oe ER Sean soe aes | 372 236 | 1,576 | 363 | 379 958 AN CVE PCRs kaos sees aoe ce cea eee 352 303 | 1,140 | 356 407 877 We remark that in these two years the quantity of water evaporated has remained the same, but the harvest changed notably, being in both cases much superior to those of Rothamsted and Caleéves. A box of earth, similar to those containing the wheat, lost by evapora- tion from January 26 to June 9, 1875, 114 millimeters, while a box planted with wheat lost 356 millimeters, and the Piche evaporimeter lost 302 millimeters. Similarly, in 1876, from the 22d of February to the 5th of July, the soil covered with winter wheat lost 426 milli- meters, but the naked soil 163 millimeters and the Piche 465 milli- meters. However, in this connection it must be noted that while the boxes containing naked soil received only the natural rainfall, those containing the growing plants received weekly the water that they a 247 had lost by evaporation the preceding week. These latter, therefore, show us the maximum effect that water can have on vegetation in the climate of Paris. The proportion of water that is consumed is exaggerated, but the crop increases at the same time, but less rapidly _ than the consumption of water. We may, therefore, say that to a certain extent, water can with the aid of the sunshine supplement the fertilizers, although we can not say that a deficiency of fertilizer is a good thing. In general, all the observations recorded in France, Switzerland, and England show that the total annual evaporation from cultivated soils is 70 to 80 per cent of the total annual rainfall. A large part of the rain falls in the autumn and winter when vegetation has ceased. The rains of these seasons partly filter into the earth and feed the subterranean springs, but they must first return to the soil its own water supply. Now the more the soil is impoverished by cutting the crops the more it will take up of the autumn rains and the less will be received by the subterranean water beds. It is then easy to understand that in cultivated lands the mean flow in the water courses diminishes in proportion to the progress of the cultivation. It seems certain that in France, and especially in the central portions, the grains do not find in the soil all the water that they could profitably use to the advantage of the crop and that irrigation would be advantageous in these and many other crops wherever there is a good soil and an abundance of sunshine. Notwithstanding this necessity for water, the rainy years are frequently bad for cereals. Rainy summers are deficient in light and dry summers have too much. It is the relative chassis “ot heat, sunshine, and moisture from day to day throughout the whole season that is important. From a meteorological point of view we should say that from the sowing to the formation of the embryo grain sunlight is indis- pensable, but from the formation to the maturity it is far less important. In his Annuaire for 1878 (p. 468) Marié-Davy gives a summary of the meteorological data, month by month, for several years, as a sample of what may be done by way of explaining the general rela- tions between meteorology, as hitherto pursued, and the crops of the agriculturist. He says: Meteorology, as seen from the agricultural point of view, has for its ultimate “object to enable the farmer to anticipate the future of his current crop. This.explains why we think it necessary to study the influence that each of the meteorological elements has on the progress of the development of the plants in the successive phases 248 of their growth. The tables of statistics of the climate and the crops, or the corresponding graphic diagrams, allow us to take exact account of the features of the past years and to approximately com- pare these characteristics with the agricultural features of the cur- rent year. Let us compare among themselves the five crops for the years from 1873 to 1877. Of these five years, 1873 gave a poor crop. _ On the contrary, 1874 gave a very good crop, both as to quantity and quality. The crop of 1875 attained an average as to quantity, but the quality of the grain was below the average. Notwithstanding the great irregularities of 1876 it gave us a good average as to quan- tity and excellent grain as to quality. In 1877, notwithstanding a great development of straw or stalks, the crop of grain was below the average as to quantity and quality; therefore, as regards their crops of grain, these years can be classed in the following decreasing order: 1874, 1876, 1875, 1877, 1873. We will compare these harvests with the following meteorological tables for these years, as based on observations at Montsouris: MONTHLY RAINFALL. Month. 1872-73. | 1873-74. | 1874-75. | 1875-76. | 1876-77. mm. mm, mn. } mm, mm. O@ctober.s fo sse2cee se este ae oe eee eee eee ee 66.9 | 65.2 51.0 76.9 29.2 INOVEMIDET Sees soe eae one ae ees eee eee es 128.1 | 36.5 44,2 75.4 51.0 DECOM CT. oe oes ee ae ee oh ee ee 84.6 | 6.0 81.8 22. 4 34.8 PANU cee eceeee oss eee ee ee eee No jos 31.3. 23.1 63.2 | 9.1 42.2 Mapua yee teste abened ate me ime ee AEs 59.1 17.5 10.9 57.8 42.9 MaiiGhvses oe ate uonceetie ace fae cee eee 40.4, 11.4 8.6 62.7 70.5 INGA EUE pigs REN Ore A IRS WA ees bt aE 44.5 | 16.1 10.1 24.3 55.9 INCA gees Sm Oe Ree ses Oe ena Ae Sete bey ab EC eS 45.2 36.6 24.6 14.3 69.5 ATT ae Se ee aR ee. ori at, 137.9 47.8 82.0 70.6 66.7 SRV he len ee ee eee ee Met orn een M ES, Eee | 38.8 54.5 82.1] 24.6 57.7 PATIOS hte ee eee tn Ane Lene eo ohana ah ete 42.7 | 23.1 vom 72.3 36.7 Septemberscse assesses cee te. Ph hee 53.6 65.1 32.8 65.3 50.1 MONTHLY EVAPORATIONS, AS MEASURED BY THE PICHE EVAPORIMETER. mm. mm. mm. mm. mm. Octo bers: iss 55-2 ae ee = eee ee ee ees 58.2 52.1 47.1 26.8 39.3 INOVeMIbeh sSac6e see oa ae ee ee Oe 55. 4 52.9 34.1 | 40.8 33.1 December 2 2:08:32 as Dae A eee es 48.3 2.4 32.0 11.3 58.9 J ATMUBINY (os sae ae eee ee Se ee eee te eee | ee 36.8 34.0 8.0 53.3 Me bMUaARY sees SL ek Wafers se a ae PEAS Chee eee ay eee 50.5 25.0 31.5 40.5 Marchi ts .stevenac, = rope ue 30s be alban eee ieee nee 85.5 | 80.6 84.3 63.3 46.5 PATI eee ns Seen oe ee ee pe ene See 5 ee A 110.5 99.0 135.0 | 107.2 90.5 Mayes fase oe as PO Se ee eee eee 121.7 TLONOF) a 5S0 | 147.5 90.8 SPURT O Pareto ee i fo Ae cee aN et 97.4 142.8 92.3 115.8 120.7 alygeemerrn es a ee nk es eek ne see ae ee iat ee 121.7 149.8 81.5 | 144.2 99. 2 PANUSUS Gere ete coo cece gee na a oe 129.7 130.6 84.7 123.7 93.8 September sas4--secao = 2 ee eee 72.4 78.3 65.6 44.2 63.0 249 DEGREES OF HEAT OR MONTHLY SUMS OF THE MBAN DAILY TEMPERATURES. Month. 1872-73. | 1873-74. | 1874-75. | 1875-76. | 1876-77. G4 XBL °C: Kor, XG} (OGG) eo ee ee ee ee ee eee 326 350 360 291 406 INION ENON NP 3 eae le eee een nee 258 216 180 186 213 ID YSOEN TAN] BLS) ese 2 ee 2 en ees ee 202 99 22 71 220 AID IMIDEDAS £, SEs SRA a Bei eS ES oe ee ae RA 152 146 167 3 198 IHG DLs Tiygete mete ane Sree terees Yay AL TEE aa | Oey ee 62 120 48 122 196 TE RCH aN DR a Seo oe 254 223 174 205 183 Pap Tsileger eres kets fre ee Se NE ak Jo BE ee OA ene 267 312 312 301 303 Vici eee ee ee A Pe 2 ee scone 75 366 487 355 357 TUG Bok Boe SE ee Ee Ae ae te ee eee Ee eee 510 528 528 500 594 ATHIKY econ Rees Se a ee a ae Ee eee 628 667 552 634 570 LNG O KESTER EE aR a el 601 561 608 606 583 Septem bertessers ese 2 te. ee es 435 507 534. | 453 390 DEGREES OF LIGHT OR MONTHLY SUMS OF THE MBAN DAILY ACTINOMETRIC DEGREES. ° Actin. | °Actin. | ° Actin. |-° Actin. | ° Actin. OC LOD OT eee nse ee ee ee oe: 552 |. 598 738 604 583 Novemiber=.225.- 2. 2255 $a Se ee: eee eee 276 403 414 372 195 WECeMperas me: Ain Dna ese 2 Ue co bees 332 282 285 267 233 PUTA Tyg erated Ae Heke lt deme oe Ee 440 397 363 406 363 PEG lax Bs yee eee ens h ee By e k 353 490 426 453 353 Vine nem eee ene meee ae les eee AS So a 791 871 766 800 763 JNyOp USCS Ss A gh Pe eS Une Soe ee ES SRC 909 lb? 1,248 1,191 1,050 IHGA Sd Aik ae, 6 Se ae ee A Oe eee AP a 1,401 1, 442 1, 453 1,482 1, 134 AERONEY' tied Ss = sues eS ee PIR eee ena Le aoe RD 1,398 1,566 1,359 1, 458 1, 622 ANGIE eae pet Sly Se Sidi EE 8 SS os on a 1, 702 1,590 1, 428 1,569 1,489 PUIUIS Peewee tenner eet PR a ty ae te 2 ih 1,376 1,311 1,172 1,248 1, 254 ODES Cre ame he NE el ks Oe 930 945 1,041 900 898 Our summaries are divided into three periods. The first, October to February, corresponds to the sowing and the winter season; the second, March to July, corresponds to the vegetatiofi of the cereals; the third, May to September, corresponds to vegetation of the vine. In these summaries the years are rearranged in the order of the decreasing value of the grain harvest. Summary from October to February. 1873-74. | 1875-76. | 1874-75. | 1876-77. | 1872-73. Rainey a 22a See Pe ie Coa e oh tree: bck BBs ich a 148 242 251 200 376 TBO CLD RGIS sae ee es en en ee 2 eee 215 118 172 22D) Sete eee IDYSYSARGYSS} OME.) OEY TH Hee alee a ee Sn 931 673 (HOF 1, 233 1,000 Derreediotilioht= sae k es aw te Sek! Lae 2,187 2,102 2,226 1,727 1, 953 In the first period, or the winter, the climatological facts have very little apparent bearing on the crops. The sowing period may have been more or less difficult, but very pronounced anomalies in the climate must occur in order to compromise the harvest in an irremedi- able manner. The year 1872-73 is the only one that presents a fact of 250 this latter kind. The excessive rains of autumn drowned the wheat and produced disastrous inundations. Up to that time we perceived the influence of the hght, which strengthens the young shoots and gives them a real progress, but which may be promptly effaced by the subsequent bad weather. Summary from March to July. 1873-74. | 1875-76. | 1874-75. | 1876-77. | 1872-73. PR ait al Pee sere ee ap ee ae enn Oe ee eee oe oad 166 197 207 320 307 IVA DOLAtiON ee. an sees es eae 2 Bo eee 582 558 508 448 5387 Derrees of heats = 2 s.28 soso ce eee Se 2,096 1,995 2,053 2,007 2,029 Heprocsioflight)s-- ses. sok he ea oe eee eee 6,621 6, 450 6,249 6,008 6,201 In the second period the light is the element which appears to be of the least importance.- Its variations do not correspond to the value of harvest attributed to each year. It is not the same with the rainfall, which increases regularly in proportion as the harvest becomes less favorable. The two last years, 1877 and 1873, differ little from each other in general characteristics. Experience shows that we may water grain planted in pots or in free earth every day and only increase the quantity and quality of their product instead of diminishing them. It is not, therefore, that rain water in itself is injurious—far. from it; but rainfall brings with it cloudy weather, which diminishes the light. We see in fact that the sum of the actinometric degrees decreases regularly in proportion to the increase in the value of the crop year, except in the case of the last year, 1873, which only descended to this rank in consequence of the meteorological accidents of the autumn. In reality 1873 would have been a more favorable year for the crops than 1877 if the autumn had not been so exceptionally unfavorable. The crop of 1877 only recovered its value, because of the abundance of the wheat stalks. Thus we see that it is in vain that the season be favorable as regards weather if the heads of the grain are scarce. Résumés from May to September. 1873-74. | 1875-76. | 1874-75. | 1876-77. | 1872-73. Rainfall. 250 5-24 a2. estes ee ee eae ee ee eae 227 247 295 281 318 HWVapOLatlONie-=.2 sesh =ssee- ase eae = eee ee eee 612 575 439 468 543 Merreesiotihea tice. eee saaat sees ee oe eee 2,629 2,548 2,709 2,494 2,544 Degrees of light= <2 -- 2-4 sses25 to2 22 aes 6, 854 6, 602 6,448 6, 347 6, 807 This third period relates to the wine crop. During this period, as in the others, heat seems to play only a very secondary part for the same country. There would not be the same difference in the nature of the product from one country to another. On the contrary, the quantity of light decreases regularly from the first or best crop to the year before the last or poorest crop. The last year, on the other hand, which was so bad at the beginning, recovered in a most extraordinary manner at the end, and as regards the quality of the ee 251 wine this year should have had a great similarity with 1874. Never- thelss, the wine of 1878 was not of very good quality, which can perhaps be attributed to a too prolonged growth of the vine stems, caused by the humidity of the soil. If in general a good wheat year corresponds with a good wine year this rule is far from invariable. In regard to quality the vintage depends but too often on the late spring frosts. The extremely important part played by light in agriculture makes us regret that the actinometer should still be so little known. It perfectly replaces the thermometer for agricultural purposes, but the thermometer can not take its place. In his Annuaire for 1882 Marié-Davy gives the following study of the development of cereals, wine, and other crops: Cereals.—The cereals offer a great number of varieties, and this number increases annually, but often the differences that we see be- {tween them are due to certain influences of the soil and climate which disappear by change of locality. However, there are some varieties whose qualities have been fixed by long-continued cultiva- tion in the ordinary way or by long-continued selection, and which present decided advantages for the specific climates. The varieties brought from the south are more sensitive to cold than those from the north, and can not be propagated without special precautions in higher latitudes or at greater altitudes than belong to the localities where these varieties were gradually developed. The varieties brought from the north are generally more precocious and suffer more from dryness. The expressions “ early ” or “ late” have reference to their behavior in the new locality. The grain brought from the south comes to maturity at a later date than that raised in the north. Influence of heat and light on development of wheat—We shall divide the development of wheat into four phases, whose dividing epochs are the processes of (1) sowing and germination, (2) heading out, (8) flowering, and (4) ripening. According to Gasparin the ger- mination of wheat begins when together with the necessary moisture it also enjoys a temperature in excess of 5° C., and it sprouts when it has received a sum total of effective mean daily temperatures (above 5° C.) equal to 84° C. Its sprouts shoot above the soil a few days later. Some wheat sown by Marié-Davy April 23, 1880, was up on the 4th of May, the sum of the mean temperatures being 96°, so that the germinating sprout had taken about two days to grow from the seed to the surface. In the following table columns 2, 3, 4, and 5 show the duration in days of the period required for the germination of wheat supposed to be sown at Montsouris in the different years on four different dates—a, b, c, d—as stated at the heads of the columns. These durations are calculated to the nearest whole days, on the 252 assumption that the sum of the mean daily temperatures in the shade must be 84° C. [Date of sowing: a, October 1; b, October 15; c, November 1; d, November 15. Aver- age date of germination: a, October 7; b, October 22; c, November 14; d, December 18. Average date of heading: a, February 8; 0b, March 4; c, March 3; d, Feb- ruary 26.] Duration eect ane aie Duration of heading stage. Year. a. b. @ d. a. b. (o d. Days. | Days. | Days. | Days. | Days. | Days. | Days. | Days. 83 Be err ae ae any eae ee 5 6 12 13 111 159 142 142 TS Ce a eas Sea a ogee ere Eh 7 6 9 23 151 166 163 143 Iii as ae eee UE as Co ee ae 6 7 9 40 151 165 148 118 SiGe soe ree Cee Oe ee ee eee 5 7 13 12 59 87 93 113 IS GF Pie, eae eR me a ee ee al, 9 10 8 ay 128 180 149 137 STG Bea Se Leet: See ne aa BE 6 6 26 45 151 179 151 128 S(O Meee ies Sete eek ee 5 ee i 9 11 94 155 156 152 57 ICH) ple se Be et OE ae ge SORA Fe eed oe 6 9 16 23 86 133 125 87 Average duration._-...__.... 6.4 7.5 13.0 33.4 124 147 140 116 Counting from the date when the mean daily temperature is 5° C. and the wheat begins to sprout to the date when the wheat begins to head, Gasparin adopts 430° C. as the sum of the mean daily shade temperatures. Marié-Davy finds from the date of actual sowing of the seed to the date of heading out a sum of 555° C. after rejecting all daily mean temperatures that are below 6° C. according to the rule of Hervé Mangon. He also finds 639° C. for the sum total of tempera- tures between the dates of germination and heading out after reject- ing all days below 6° C. On this last hypothesis are calculated the duration of the heading stage and the mean dates of heading for the respective years as given in the columns 6 to 9 of this table. These computed dates of heading out show that the sowing of wheat on October 15 or November 1 or 15 brings it to a head at the end of February or beginning of March, but when the sowing occurs on October 1 it is brought to a head so much earlier in February as to expose it to great chance of injury by the frost; for although the grasses and the green wheat plant resist the action of frost, yet the embryo seed in the ear or head does not do so, and if once destroyed by frost will not be replaced unless the soil is very fertile. The third epoch, or the flowering of the wheat, takes place in France, according to Gasparin, when the mean temperature has risen to 16° C. or when the sum total of daily shade temperatures has amounted to 813° C., counting from the beginning of vegetation in the spring or from the date when the mean daily temperatures is 5° C. in the shade. This figure relates, of course, to an average of many years, and the individual years may vary very considerably. Marié-Davy, as before, adopts the views of Hervé Mangon as to 253 rejecting all mean daily temperatures below 6° C., and thus finds 1,496° as the mean value of the sum of temperatures from the date of sowing to that of flowering. The similar sum from the date of head- ing to flowering is 860°, or 1,496° less 639°. The fourth epoch, or the ripening of the wheat, occurs when the sum total of the mean daily shade temperatures since the date of flowering, rejecting all below 6° C., amounts to 815° C., and in the climate of Paris this occurs about forty-five or forty-six days after the date of flowering. The range of uncertainty in this last interval is only four or five days, owing largely to the uniformity of the climate at this season. It is the best defined of all the periods and so well ascertained that, knowing any actual date of flowering we can safely predict the date of ripening. In proportion as we approach the latter date the process of ripening seems to concentrate itself more and more within the wheat; water and sunlight become less and less important; rain becomes a source of uneasiness as to the harvest, and the intensity of ‘sunshine has only an indirect influence on the quality and quantity of the grain. The influence of sunlight during the first phase or germination is negligible and probably nothing; it is a maximum at the beginning of the fourth phase, but diminishes rapidly as the fourth phase progresses and in proportion as the wheat becomes more yellow. We shall therefore consider the amount of sunshine, or more properly the total radiation from sun and sky, during the first thirty days after flowering and neglect its amount during the remainder of the period up to maturity. The following table shows the amount of radiation, as expressed by Marié-Davy in actinometric degrees or percentages and com- puted from actual observations of his actinometer at Montsouris for the various stages of growth, viz, the second or heading stage from germination to heading, the third or flowering stage from heading to flowering, and fourth for the first thirty days of the fourth or ripening stage immediately following the flowering: Total radiation received Total radiation received | Total radiation received during 30 days of ripen- Year of sow- during heading stage. during flowering stage. ing stage ing. ‘ a. b. Cc. d. i, {| i. | C. | d, Gi) bs C. | d. I Gis See ee 842 | 1,332 | 1,755 | 1,848 | 3,205 | 2,979 | 2,870 | 2,954 | 1,176 | 1,608 | 1,548 | 1,581 ik k a A See 908 | 1,191 | 1,663 | 1,938 | 3,031 | 2,983 | 2,620 | 2,482 | 1,403 | 1,220) 1,171 | 1,194 Gay. 32 = eens 904 | 1,009 | 1,161 | 1,247 | 3,214 | 3,169 | 3,169 | 2,821 | 1,419 | 1,504 | 1,526 | 1,558 ioe 6525 | 608ciemo461l A SLT ee sb ashee eae Es Remar) pe veal [a Al bf cae | a \weewete’: 1G 5 733 739 977 | 1,255 | 2,096 | 2,302 | 2,282 | 2,208 | 1,103 | 1,199 | 1,399 | 1,450 iD 2 seus 800 | 1,382 | 1,476 | 1,743 | 2,749 | 2,634 | 2,630 |.2,506 | 1,320 | 1,496 | 1,131 1,184 TS es Seen 840 | 1,251 | 1,582 | 1,600 | 3,095 2,580 | 2,658 | 2,607 | 1,076 | 1,092 | 1,321 | 1,362 ic) 1,000 | 1,578 | 1,924 | 1,991 | 3,519 | 3,106 | 2,849 | 2,865 | 1,391 | 1,433 | 1,493 | 1,486 Average of | | | | | | | 6 years-.-_- 857 | 1,117 | 1,497 | 1,653 | 2,977 | 2,808 | 2,728 | 2,629 | 1,268 | 1,363 | 1,360 | 1, 363 254 If we sum up the second, third, and fourth series of figures we finally obtain the sum total of the effective radiation received during the whole interval from germination to ripening, as given in the following table: Total radiation received from Rela- germination to ripening. tive Aver-| value Year. age for Oct. 22.| _ of a. b. C: d. “| actnal crop STS ee ae So = ee ee a 5,223 | 5,919 | 6,17 6,383 | 5,924) 25.2 TY Se ae ge et es aye mak See eee 5,342 | 5,344] 5,454] 5,614) 5,438 19.0 DBs oie te GATOR LY Wal Vales Se dees ee be 5,587 | 5,682 | 5,856 | 5,626] 5,676 | 26.5 S76 Ss esc he Se Se re ee oe ee | ee 22.5 1B Uget a wer ee eee Ree yo Bere eae ee ee eee 3,932 | 4,240 | 4,658 | 4,913 | 4,436 15.2 Sy fee en a AE See ae OU es ae 4,869 | 5,512 | 5,287 | 5,433 | 5,263) 11.1 TiS yAc NS Saba ER ese ste, neers oe em suet TNE Bese al 5, OL) 44923785. 561 15) 560n | ip s2obn = ase S80 eee tere Os Re oe ee ee ee 55910) 65474)" (63206; 653455) 6i1455)Saeeeeee PAN OTUE ClOLIGWV CATS hea scree see ne eee ---| 5,102 | 5,288] 5,550) 5,645] 5,396 (ee cee The relative value of the wheat crops, as observed at two stations, is given in the last column of the preceding table, and the comparison of the figures shows that a deficiency of sunshine has a decided effect in diminishing the relative value of the crop; but the converse is not true, for we may have an excess of sunshine and still get poor crops, owing to a deficiency of rain or irrigating water. In fact, the pre- ceding study only shows the nature of the influence of the solar radiation ; the exact quantitative effect on the amount of the crop must vary with the irrigation or rainfall, with the fertilizers applied to the soil, and with the peculiarities of the seed. As to the rainfall, it was in the preceding cases distributed as shown in the following table: Rainfall during stages. Total sunshine take ee rom Year of sowing. Germi- _ | Flower-| Ripen- |germina- : Heading : A : nating. i) sing? ing. tion to ripening. 1LS\ (3 oe Ree eee COUR Ae idlel okt Le easy Let ee 1.19 0.75 0.78 1.72 5, 924 1 hoy (5 ee ee RE Ree tee ns ye Arye oe See eeepc ed 2.97 1.36 0.99 1.44 5, 676 2b (2 ee eee, see eeeceneeie eneeetras ye ie) Cen Se ot et 1.84 1.90 1.65 1.94 5, 263 From these figures we conclude that the excess of rain in the wheat season of 1878-79, which would have been advantageous with a clear sky, as in Egypt," was at Paris accompanied by too little sunshine, and therefore the crop suffered. For a given quantity of sunshine a certain quantity of water is best for the crop; if the sunshine is diminished the plant can not use so much water, and that must be correspondingly diminished. a Or as in the case of irrigation in the arid portions of the United States—C. A. a a ee ee ee 255 The influence of the date of sowing and its relation to sunshine and frost is fully shown in the table for Montsouris, which gives the sum total of actinometric degrees from the time of germination to maturity for seeds sown on successive weeks in 1879, 1880, and 1881, and harvested in 1880, 1881, and 1882: Total sun- Total sun- shine from shine from Date of sowing. Feat Date of sowing. Fe ae (actinomet- (actinomet- ric degrees). ric degrees). ee Ee EN 1879. 1880 eto per lessee ema ceete 5,011. |) November 24-2 222_ =... 23-22 6,393 WCLO WONG ras aoe ees at pees hee eee 5al44: | December We 255 a ee 6,461 Wet hebrew ee. = teen eee ee SeOvsa | December = see 8 eae eee 6,529 (WCCODGI ee seen = as tas ane moses Pd,514)\Mecemiber Ibses 2. st es.. eae eens 6, 611 TANG SK CEN) OT eee Deol |MOOCOMDOIiee C5 saae ass oe teen. eee 6,504 INGVeMmper Oia. 24 0s25 252 5sp96||, December 20e:s-2.5- = sas - ee 6, 245 Niowemiberdb-. . 2.2. 2-2--25--5-5-22- 5,569 1881 INOVGIMUDOI 2222-22 <—---- s=nscn- === January Dost ee... oe! | 1880. - (2) JaTuuseiyg lee aa ee ee (f) HERS ty Osan e hee eos eee SO JANUALY LOSS Sess ss ke See TRS Orne? 1S ee ae ee eee e622 lh Seale ye eose ts Ae otek eee ee cee | 6, 245 Re pruanyiesise-sesaso-5-- 6525-28] S59 (| MMOD EUAT yi se ee ae reer 6,018 Rene ae ei 558i ||) February 9: -...--.-.-.--<..-22 2... | 6,047 (0) Nebruaty 16) 2 22-2 oe cee 6,043 Septem bemey Ch 2x2 5-2-4 25223 | NOT O} | |Mebruainy 25 soe sates peace 6, 037 WetobemGce esa ae ee a | 62052, ||pMarchiO ee Ses seers ee ese 6, 037 (CGH AGG See Sia aaa | Grll7, lt March Occ. 3. Se 5, 57 Ocho bere Ges Sok es eer a ie GF09F || Piiare hid Gee sees oe 2 ee 5, 286 Wcloperigid =-sess ao te The Ge Soll Mian cai 23 erie sae tae eer seem 5,271 Movember $2.2... c.----- G2 90d) | Marehg0) sso o.-ce ee ese 5,215 November (222-22 .. 2222 s2-2-- 632045 PAprili Gece yas ce els ee 5, 144 November ly. --. 2-2. =-.- se ossSnsce 6,343 a See note 2 in text. e See note 3 in text. f Frozen ground prevented sowing. a¥Frozen soil prevented sowing. oNo sowing during this interval. ¢ See note | in text. Aniong other conclusions that may be drawn from these figures are the following, most of which are also given by Marié-Davy: 1. The season 1880-81 was characterized by much sunshine and little rain, which hastened the ripening, but delayed the flow of sap, -and therefore of nourishment to the grain, so that the crop was rather poor. 2. For the crops of fall wheat the sunshine increased more and more us the seed was sown later from September, 1880, even to the end of December; then it began to diminish, and for the spring wheat, sown in March, 1881, it was too small. 3. By considering other. weather records it is evident that the freezing of the ground in January, 1881, not only prevented the sow- ing of the seed, as noted in our table, but prevented the germination of the seeds sown on December 22 and 29, 1880, which would other- wise have sprouted on February 4 and 19, 1881, respectively. 256 4. The wheat sown September 29 and October 6, 1880, which headed out December 30 and February 19, was injured as to the heads by the subsequent frost. 5. The seeds sown October 20, 27, and November 3, 1880, flowered between the 4th and 8th of June, 1881, but at this time there was experienced at Paris a spell of very cold weather, the minimum daily temperature being 3.1° C., and even white frosts were reported, so that wheat which was then in flower was badly injured. 6. In general, the dates November 10, 1880, to December 15, 1880, are those indicated as most favorable for sowing wheat in that year, and the crop of 1881 may be predicted as likely to be small, but of excellent quality. The grape and wine crop.—tn a short study on the relation between the vine and the weather, Marié-Davy (1882, p. 290) states that, in general, the annuals, such as the cereals, concentrate all their energy in the formation of the ear and the seed or grain. Their work is then finished and they die. The next year’s crop of these annuals is largely under the control of the husbandman, who can obtain seed from more favored regions if his own crop was inferior. On the other hand, the work of the vine, like all perennials, is not merely to ripen its fruit and seed, but to preserve its own individual self for usefulness in future years. Therefore it elaborates out of its own sap not merely leaves and fruit and seed, but a store of woody fiber. Corresponding to this more complex system of growth the relations of the perennials to the chmate are apparently more complex than the relations of the annuals, and, it may also be added, the range of geographical distribution, whether by nature or by cultivation, 1s more restricted. Our studies will be confined to the data furnished by the observa- tions at Epernay (1873-1881), to which Marié-Davy adds other data computed from the observations made at Montsouris, in which latter computation certain laws of growth of the vine as established by Gasparin were adopted. In the neighborhood of Paris the leaf buds of the vine burst open in May when the mean daily temperature has permanently passed above 11° or 12° C. Assuming that the mean of twenty days, as observed at Montsouris, will give this date (which was unfortunately not observed at Epernay), we obtain the figures in the first three col- umns of the following table. In some of these years the early leaf buds were undoubtedly killed by nocturnal frosts, but they were soon replaced by other buds, and the dates here given must be adopted in the absence of actual observations, especially when we remember that the quantity and quality of the final crop of grapes depend not only 257 _on the meteorological conditions, but, equally or more, on the condi- tion of the woody fiber of the stock and stems. Similarly the date of flowering is calculated by assuming, with Gasparin, that the sum total of the mean daily temperatures in the shade must be 466° C., count- ing from the date of leafing. This number is more especially appli- cable to the vineyards of Champagne and Burgundy, and is not necessarily strictly applicable to Epernay or to the vineyards of the south of France. The fifth and subsequent columns of the table give the mean climatic conditions for a period of sixteen days, in the middle of which is the calculated date of flowering. There appears to be no simple relation between this latter data and the resulting wine crop, nor has the crop any apparent relation with the total sky radiation during this period. In fact we may conclude that up to the time of flowering the energy of the vine has been devoted to building up its own structure as a preparation for the work that is to come. The development of the grape does not depend upon nitrog- enous particles stored away in the vine, but on the power to elaborate the sap which is to become the juice of the grape, and that power depends upon the leaf surface, the roots, and the stock during the first stages of the growth of the grape, but eventually upon changes that go on within the grape itself. These facts are brought out by the study of the conditions prevail- ing during the last stages, viz, from flowering to maturity : During 20 days. | During 16 days. CoS te oie | Average| otal pel ec of flow- Average | Average | Total : jtempera-| ..cinfall. : tempera- radia- | rain- ture. ture. | tion. fall. ones mm, | oes ° Actin. | mm, May 21, 1873_...---.------ | 12.1 Dro lt Manes eee ee eee 18.7 46.1 88.1 Maye 20s 187422222. 2252-22 H 13.2 PU ts | fea Rudavey 1B} See Se eee Sao 16.8 41.5 26.8 Mayeos 8 inte s-- = 228 - ee 16.0 DA tay ANE UUs (ey ees Seen eee see 19.0 55. 2 38.3 Mayas. 1 Si62.---5-.2--.25 14.2 SHOR UM e20) ease | eee cee 19.4 49.0 52.3 WiaveoloeI Site oc. 2 oe 115 Oath | huhasyibjee See Pee ee 20.9 51.6 18.3 Maryal6, 1S%Sc se... =. 14.1 Bleve | ume 6 2282 eo eos e | 16.4 40.3 bowl Maya ol SiQe 2) ase se 12.6 35.9 | June 22 ___.-_---- 2a eee { 16.6 43.0 ai Marya 6:1 S80ka see 3S 14.0 OLOnl itunes 6 =. ees eee ee Pee | 16.2 37.6 45.5 Marvoel leas a2. 2 22.52 14.6 29:07 Sumer8@.---- =. 22 sesse4 <2 14.9 48.7 15.2 Average May 18 __-| 13.6 27.5 Average June 16 _- Ue 45.9 40.6 According to Gasparin the grape reaches its maturity when it has received a sum total of mean daily shade temperatures of 1,926° C., counting from the date of flowering, but the grape ceases to be nourished or to ripen when the mean daily temperature falls below 12.5°. If, now, we ascertain the date of maturity by summing up ‘the daily temperatures, as required by Gasparin’s rule, we obtain the results given in the first column of the following table. If we 2667—05 m——17 258 take the mean values for the twenty days previous to the date of maturity we obtain the data in the second, third, and fourth columns, and we notice that although in the warmer seasons there may be a great variety in the value of the crop, yet in the cold seasons, 1877 and 1879, when the mean temperatures fell below the limit (12.5°) required for ripening, the crop was very poor or failed altogether. Tf now the total radiation from sun and sky is computed according to Marié-Davy’s method for the period between leafing and flowering and again from flowering to maturity we obtain the figures in the columns five, six,and seven. Here we see, as before, that the variation during the flowering period was of little importance, whereas that during the ripening period has a direct relation to the character of the wine crop, such that in general the larger the total radiation the better the crop, provided the temperature of the air has not fallen too low. Pure Dees 20 | Total pee uon by Goeneralicharactodat Pepe eA —— zs pies oe Calculated dates of | Mean | | Flow- | as ripening. daily pee | Total paoete Sain Juice. tem- | ,. AEM rain- ABs : | Sum. |— — Wine crop. | pera- | 4 fall | ripen- 7 . RD tion. ing. | Sugar.) Acid. ing. | ae ee E °C, |° Actin.| mm. |. actin. ° Actin.|° Actin. October %, 1873. -.-.---- | 16.1 30. 2 20.3 | 1,278 | 4,590 | 5,868 162 8.2 | Excellent. September 25, 1874- ---- 16.0 27.6 28.8 | 1,343 | 4,544 | 5,887 179 | 6.1 | Finest. September 21, 1875. ----| 17.4 40.6 | 5.9 | 1,306 | 4,322 | 5,728 181 | 5.4 | Good. October 7, 1876__-__---- 16.2 27.7 16.7 | 1,222 | 4,205) 5,427 174 | 6.8 Octoberi2; 1877__ 2 == 11.9 30.4 8.2] 1,280] 4,603 | 5,883 186 8.7 | Very poor. October 2, 1878..-...... 13.3 25.5 23.8 | 1,288] 4,165 | 5,403 181 6.7 | Good. October 15, 1879-__--._-- 1D) 26.1 6.3] 1,355 | 4,033 | 5,388 154 9.5 | Very poor. September 29, 1880____- 1552 27.8 25.0 | 1,305) 3,966 | 5,301 188 6.4 | September 26, 1881_____ abs st 24.2 81.2 | 1,575 | 4,262) 5,887 180 | 6.1 | Excellent. Average Octo- | Der 2 ees pes 14.7 28.9 24.0 | 1,322 | 4,302 | 5,636 176 TA In general, Marié-Davy concludes that the number of grapes to the bunch and the number of bunches to the vine do not seem to have any clear relation to meteorological conditions, except in the case of spring frosts, which can destroy a crop. Besides the conditions as to pruning the vine and dressing the soil, the number of grapes that have set (on which principally depends the quantity of the crop that will be pro- duced) is a result primarily of the meteorological conditions during the previous year and of the state of preparation of the woody stock. On the contrary the final size of the grapes and the quality of the juice depends on the meteorological conditions of the crop year and those that accompany the flowering and succeed it up to the time of maturity. A final sum total of radiation is not sufficient; it is necessary to take account of its distribution with reference to the 259 phenological periols and of other accompanying circumstances. Thus in 1877, with a low mean temperature and a high radiation during maturity, and in 1879, with a low temperature and a low radiation during the last phase, both alike gave a poor crop, but the sunshine of 1877 was able to make a large quantity of sugar as compared with the small quantity of sugar in 1879. Sugar beets.—Marié-Davy (1882) and Pagnoul (1879) give the data of a research into the relation of climate to the development of sugar beet as cultivated at Arras, the agricultural station of the Department of Pas de Calais. The following table gives the results of meteorological observations and chemical analyses of sample beets taken up every ten days during the season. The beets were sown April 5, 1879, averaging six plants to the square meter. They were of a poor variety, but of the kind ordinarily planted in that section; they were of a rosy color, and were planted a great distance apart in order that they might grow more rapidly. During the decade. At end of decade. | Total Average | | ee) Le radia- | weightof— | ca ee eat ota oo) | Decade ending (sum of |sunshine] (sum of | eer: Weight | Weight 1879. Total | mean | (daily daily ‘a aes of sugar | of sugar rain. daily |average |} actino- | rey y| per 100 per | shade | of clear | metric | Root. | Leaves.) smige beets. | hectare. ‘ttempera-| sky). | degrees ICE: tures). at Mont- | souris). | Beau- mm. SiGe Per cent.| ° Actin. | Kilos. | Kilos.| mé. | Kilos. cilos. fre baveyt i Lae es ee 33 156 41 393 1 8 | 2.9 3.08 2 ie bars yy) Dae ss Se 37 162 30 479 | 7 41 2.8 2.138 9 play le fae S22 18 159 31 444 Blis|) sysh10y| 238 5.18 %6 Ub yalill=eeee ss 56 | 138 16 399 105 | 222 | 3.5 | 5. 38 339 galysOly ss s222s< 59 165 26 320 220°)" 383 | 3.2 | 5.88 776 euliye ll tps Me eee ee 26 | 158 28 378 346 | 462 3.9 | 6.85 1, 422 August 10__.-__.- 8 | 179 31 416 486 452 | 4.0 | 6.5 1,848 August 20__..<_- 24 | 182 43 361 666 | 433 4.2] 7.69 3,073 ATIOUST S0e s==- 2 - 18 | Vi7 36 373 77 335 4.1 | (ete || 3, 534 September 9_____ 4 | 159 56 385 878 312 4.4 | 8. 20 4,320 September 19 ___- 27 165 34 326 | 1,040 200 4.3 | 7.46 | 4, 655 September 29 ____ 10 | 131 49 251} 1,048) 126) 4.1 7.46 | 4,691 October 9. =e (3) 129 25 334. 1,048 194 } 4.4 8.06 | 5,068 October 19 _.__.--. 18 95 12 | 161 1,056 98 4.1 7.46 | 4,727 October 29 ___...-. 23 87 26 | ~144 | 1,050 128 4.5 7.94. | 5, 002 } | | The influence of sunshine is to be found by studying the fourth col- umn of the sum total of daily average cloudiness at Arras, as result- ing from twelve daily observations of the amount of cloudiness. The clearness of the sky, as given in the fourth column in percentages, is : 260 the complement of the cloudiness and represents the relative duration of sunshine, but owing to the varying altitude of the sun can by itself alone give no idea of the intensity of the radiation received by the plant. To obtain this !sst item and as no actinometric observa- tions were made at Arras I give in the fifth column the results of observations at Montsouris, expressed in actinometric degrees. The beets are reported to have sprouted very late and very un- equally; this was due not to dryness, since the rain during March and April was in excess of its normal value, but was directly traceable to the low temperature, which was especially low in April. The study of the development of sugar, week by week, as given in the last two columns of the above table shows that after September 9 the sugar crop increased slowly, became stationary, and then fluctu- ated very much as the weight of the leaves fluctuated. The rainfall had at that time become light and the development of the beet seemed to depend mostly on the temperature, so that it may be concluded that the beet ceases to increase in its quantity of sugar after the mean daily temperature falls below 13.1° C., and that there is no probable advantage in leaving the beets in the soil after that date, which in this case is September 29, 1879. Marié-Davy points out that the actual increase per decade of the weight of the roots coimecides with the increase of the rainfall and the temperature, but the proportion of sugar increases with the degree of radiation or total sunshine; the sunshine precedes the formation of sugar, since its action is slow and indirect, being through the assimilation that takes place within the leaves. It is therefore not an excess of water, but a deficiency of hght and heat that causes rainy autumns and summers to give poor crops of sugar. Therefore, if during dry, clear, warm summers having large radiation, one could irrigate the fields properly one would realize the best conditions for a good crop. Therefore, every ray of sunshine that strikes the ground instead of the leaf is a loss to the formation of sugar and by helping to evaporate the moisture of the soil it also causes further great loss of sap to the plant. These conclusions agree with other experiments made by Pagnoul, who raised beets both in darkness and under a transparent bell glass, and again in the free air, and found the amount of sugar to increase with the strength of the sunshine. The following table gives a general survey of the beet crops in Pas de Calais and the corresponding climatic data at Montsouris, which is about 90 miles south of Arras. The numbers given in the columns Yor quantity and quality of the crops are the estimates obtained from many planters and are recorded on the following scale: 1, very small 261 = or very bad; 2, small or bad; 3, passable or mediocre; 4, fairly good; 5, good; 6, very good. . Dates when mean | temperature of | | General character of : 5 During the season. sugar crop in Pas air ther 4- 5 : | tee in SHadee® Dura- de Calais. tion gl su Pes Year. | eS ae best Sum of Sum of | | ises as) Salers mean mean | Total | | Den- | above below season. daily air daily rain- | nas Sue sity of [ Eo: IB} (Cf tempera-| radia- | fall. y- Y- | juice. | | ture. tion. | | | ; pies Se | ae AG SIND Hea | Beau- | Weeks. eG ° Actin.| mm. | meé. Meee. ex, 5 ee. 2 | Mar. 23 | Oct. 12 29 BAO) |S 5292-22: 393 | 4 5 5.3 Ct 3 | Mar. 16 | Oct. 19 31 3,389 8,968 264 5 3 4.6 TUS (Ges WS Rei ee i ee re | Mar. 380 | Oct. 5 27 3, 172 | 7,900 313 6 3 4.2 ASU Guerre Ee ee: | Mar. 23 | Oct. 19 30| 3,003) 8,589 299 1 3.9 ier ae Re le a do .._| Sept. 21 26 2,786 | 7,326 | 344 4 6 5.5 Its}(c} = oe i ae Aas GO) eas hOnee 24 2,791 | 6,552 347 | 5 3 4.7 They it) ast SEES Se ea Arp Iss 20) |aan2dor == 22 2,359 5,815 | 278 | 1 3 4.4 TSI) eA oe pe Mar. 2| Oct. 11 32 SeISo Meera 1OLle | C280) |e ese se) ee eet ee ISIE eee ie oo Apr. 6) Sept.28 25 2,520 G56 |), pe BLO! hem tae | eee La Se Average __... Mar. 26| Oct. 4 27; 2,915! 7,484| 306 | neAS Pen = The climatic data given in the above table as directly applicable to the seasons of growth of the beet root illustrate what should be given for any similar study of development of any crop. But it is com- monly the case that the dates of the various phenological epochs are not exactly given, and that we have to rely upon general tables of general climatic conditions month by month, such as are recom- mended by the International Meteorological Congress of Vienna and by that of Rome. Therefore, for the sake of comparison with other climates whose data are given on the so-called international forms, IT give in the following table a part of Pagnoul’s tables of average tem- perature Centigrade and rainfall in millimeters as observed at Arras: | Mean daily shade temperature. Total monthly rainfall. Year. SSS SSS — —| - | Apr. May.|June.| July./ Aug. |Sept.| Oct. | Apr. | May. June.| July. Aug. Sept. Oct. ae = jo —s = ae | Ey peeeee ts 8.6 | 11.0 | 16.7 | 19.17] 18.2 | 13.5 | 9.9 | 48.6 | 45.5 | 63.3 | 26.2| 40.3 33.5 | 56.1 eye 5 oe Ss Ae OS Mea TGrOnle 20s Me) OF Maroy) TION 20h 7 s2a9 12557 | 6K0 | 34.2 | 92.3 | 47.2 = 2 x | | - IG ee eee 9.6 | 14.7 | 16.7 | 17.4 | 19.1 | 16.6 | 9.0] 8.0 | 30.7 2.0 | 63.7 | 62.0) 74.5) 61.6 VSG ee see 9.3 | 14.8 | 16.7 | 19.6 | 19.3 | 18.9 | 12.1 | 41.3 | 15.3 | 32.0 | 23.8 | 87.3 87.0 24.5 ksi (fies es Oe | 8.8 | 11.3 NOM aS. |) dives || bead Sera 5.0 | 88.2 | 23.0 | 61.2 | 96.5 | 50.3 | 48.5 TOYS ra. Se 16.3 | 14.2 | 17.2 | 18.0 | 18.6 | 14.9 | 10.6 | 53.7 | 88.4 | 60.6 | 46.7 | 86.6 42.9) 87.3 G4!) oe = ee 7.6 | 10.6 | 15.9 | 15.5 | 17.6 | 15.1] 9.8 | 48.4 | 51.7 1138.6 (142.0 | 50.5 | 89:5 | 45.4 | | The preceding study gives a first idea as to the relation between climate and the development of the leaves, the roots, and the sugar, and offers a first step toward determining how suitable for the beet- sugar industry any climate may be, and especially does it suggest to 262 the planter how he may early in August begin to safely predict from week to week what his probable crop will be early in October. Thus, table on page 259 shows, by the samples taken August 20, that there were then in the beets 3,073 kilograms of suger per hectare, whereas on October 9 there was 5,068, or five-thirds of that present on August 20. ‘This factor, five-thirds =1.67, is, therefore, that by which the figures of August 20 are to be multiplied in order to obtain those of October 9. 'The following table gives similar factors for the succes- sive decades for the crop of 1879, and when a succession of years has been thus treated we shall know something of the accuracy with which the harvest crop can be predicted. The regularity with which these numbers run shows that after the Ist of September the error of pre- diction can only be a small per cent. Crop fac-| . Date of sampling (1879). | tor for Weight ‘this date. of Sus ar. PASI UIS Gil OOS Sajcra tea Se eee Sis SE ee eee) A oC ee ee ge 2.74 1,848 PSST ODEs ore ene Be ee Seen es ee eee be oe heen EEE ee eset Oh 2 ise 1.65 | 3,073 PATIOTIS b SO ae Ie wate eres Sd Ba es See ee Oe ee Oe 0 ee eee eee Step ea 1.43 3, 5384 DEDUCMUDOIIO eee eas tet Nor ie oo ce pigs Es State See nn ee tee en ne ee Ie sy 4,320 NED lember Moe See ee eet Some See eee mee a eee te Renee Sn eee ene 1.09 | 4, 655 September 2Ois'3 hah le Ri elas ye SPA ORs ig eee Pe a ot S's | 1.08 | 4,691 October'9/ 2-255 22-55 ee sh ee Se ee ee ee kee ee er ee eae 1.00 | 5, 068 Pagnoul calls attention to the fact that the roots contain a consid- erable portion of nitrates, although the soil in which they grow had not received during this or previous years a trace of these salts. This salt could only have come into existence by the nitrification of organic nitrogenous matter, and it is well to insist upon this fact, for we can thus remove from the minds of certain persons the idea that if the beet root contains nitrates they must have been put into the soil by the cultivator. This mistake has frequently caused un- happy contests between the farmer and the sugar manufacturer. If the beet root had at its disposal only a proper proportion of nitrates that had been formed in the soil before sowing, these salts would be rapidly absorbed; they would by their decomposition give rise to a large and prompt development of leaves, and, consequently, to an easier elaboration of sugar, and in proportion as vegetation advances we should find smaller quantities of nitrates in the beets. This fact was proven by Marié-Davy in 1878. If on the contrary the nitrogen is furnished by a process of nitrifi- cation that is prolonged during the whole season, then the absorp- tion of the nitrates goes on continuously and their total weight per hectare increases steadily to the end of October, as shown in these analyses for 1879. 263 Some further experiments by Pagnoul (1879, p. 486) on the beet as grown in darkness and in sunshine shows that the former were exceptionally rich in alkali, ash, and especially the nitrates. This is explained as above, viz: The nitrates will not decompose within the plant except under the influence of sunshine; if the plant is kept in darkness it stores up the nitrates within itself without having the power of utilizing its own nitrogen, so that the substances in the formation of which this nitrogen ought to be of assistance can not be formed. From this one must conclude that years that are bad for the beet- sugar crop are so not only because of unfavorable temperatures and humidities but above all because of a defect in the insolation. Lively complaints have been made of the quantity of nitrates in certain harvests; now these salts that accumulate in the molasses and in the inferior products and augment the difficulty of the work occur often in beets cultivated upon a soil that has never received a trace of nitrates as a fertilizer. It is therefore not to the abuse of nitrates as a fertilizer that we ought to attribute their presence, but rather to a too cloudy sky. We know that the neighborhood of large trees is injurious to the vegetation around them. Ordinarily we attribute this injurious influence to their roots. It would perhaps be more exact to attribute it to the shade that they cast, and the more so because it has been demonstrated by Cailletet that green light has no power to bring about the decomposition of carbonic acid. In the Annuaire for 1883 Marié-Davy studies the influence of the date of sowing. In order to ascertain the best dates for sowing and trace out the various vicissitudes to which the crop is subject, whether resulting from tlie climate as such or from the ravages of insects or fungi, it is necessary to make a rather detailed study of the state of development of the plant under the assumption that the seeds were sown on successive dates—for instance, on a given series of successive week days. An elaborate study of this kind is given for wheat by Marié-Davy (pp. 244-285 of his Annuaire for 1883), from which the following tables have been extracted. In general the varieties of wheat cultivated in the south of Europe are more sensitive to cold than those of the north, but the studies of Marié-Davy for the latitude Montsouris, when paralleled by similar studies for localities in the United States, can but be of the greatest value both to the farmers and the statisticians of this country. The study of such tables will enable one to very closely predict the time of harvest, the quantity and quality of the crop, and the range of uncertainty. To this end it is, of course, understood that corresponding elaborate tables of 264 : ae & : 2 ; meteorological conditions must be accessible, samples of which I have prepared for twenty United States stations.“ If we suppose some wheat to have been sown on the 22d of Septem- ber, 1871, near Paris, and if we adopt the rule established by Gas- parin that the vitality of the seed is actively aroused as soon as its temperature in a moist earth exceeds 5° C., and that it germinates visibly when it has received a sum total of mean daily temperatures that is equal to 85° C., and that the sprout rises above the surface of the earth in a few days after the seventh, then we obtain six days as given in the following table for the interval from sowing to germina- tion. A similar computation for every other date of sowing, as given in the following table, shows at a glance the effect of the temperature of the soil on this phase of plant life. Duration, in days, from sowing to germination of winter wheat at Montsouris, France, for the years 1872-1881. | ' Germination. | | | Av- | | | | erage | |e ae | ; dura- Date of sowing. | 1871. | 1872. | 1873. | 1874. | 1875, | 1876. | 1877. | 1878. | 1879. | 1880. | 1881. | tion | Aver- | | for age the | date. years | | 1872- | | 1881. | = ee Senta E Nes September 22__- 6 7 it 5 5 7 Samad gy G 6 7 | Sept. 29 September 29 __- HOA 10 ee Oval saener 6 6 8 | 7 (Nes Mea 10 7 | Oct. 6 October 622.022]. 18) 8.) Wl AN AOE et eBets pS HA PSN Ne aT ae Aleaneon Ocrammts October 13 ___... 81) 78.9) v6.) 8 rl On ol OO le ee Su@e med October 20 ------ 12 8 13 TKO) Ap UY alt 7 ) 22 15 11 | Oct. 31 October 27 -_--.- 70 8 13 g) il 16 8 29; 14 18 13} 20]! Nov. 16 November 3....| 72] 15] 15] 14] 8| 12] 8| 2| 16] 14| 7] 20| Nov.23 November 10.... 77 | 15) 17) 32 8 8) 14) 48)) 98\| 695) 105) 33)) Decras November17_..| 70| 9] 12} 49] 41] 18] 12] 44] 93] 21] 10] ‘86| Dee. 28 November 24 .._| 638 10 | 25 53 42 11 25 39 | 89) 17 26| “37 | Dee: 31 December 1----- | 56 16| 43) 48 35} 8 46 69] 82} 12 42} 42) Jan. 12 December 8. -.-- | 49 16) 36 42 28 | 22 67 62 75 | 11 67 41 | Jan. 18 December 15.---| 42] 12] 25 35 Bail 12 60 55 | 68 13 60 35 | Jan. 19 December 22..._| 35 11 | 30 28 56 14 55 48 61 | 43 57 38 | Jan. 29 December 20....| 28 LOMie= 26 21 53 9 49 42 53 | 44 50 | 34] Feb. 1 | | | | In studying the preceding table we recall that the duration of germination varies shghtly with the condition of the soil and the depth of the grain below the surface; these two considerations will be perfectly allowed for if we observe directly the temperature of soil by a buried thermometer. Such observations are earnestly recom- mended to all agricultural experiment stations, as they are, evidently, more directly applicable to the growth of plants than any crude @'These tables are omitted in the present edition. 265 approximations derived from the observation of the temperature of the air only. If when the grain has sprouted the soil continues very dry, the nourishment having all been drawn from the seed, the young plant may droop and die. If, again, the frost penetrates to the seed while it is germinating, many of the seeds will perish, and the field will appear as if sparsely sown, but this latter mishap is generally repaired by nature if the soil is good and the springtime favorable, for the sowing is generally in excess and the extra heading will supply the loss of the seeds that have perished, but in poor soil the harvest will be notably diminished, and often it will be profitable to plow the soil for a new sowing. In any case the chances for a successful crop vary very much with the date of the sowing, as we shall see by the study of the following table, which shows that in each year the season for sowing that is favorable to the crop of that year is very much restricted by the early arrival of the winter cold. Thus in 1871 the sowing was stopped on the 20th of October by the cold weather; in 1872 it continued through- out the autumn until the 29th of December; in 1880 it occurred on the 3d of November. Sometimes heavy rains prevent the sowing, but in 1881 neither cold nor rain prevented field work until the middle of December. [In order to save space I have omitted the elaborate tables of frosts, low temperatures, and rains given by Marié-Davy for each of these years and weeks.—C. A. | The grain now arrives at the epoch of heading, at which the orig- inal stalk becomes several branches, each of which bears an immature head on which the rudimentary seed can already be counted under the microscope; the number of such seeds will not increase in the further development of the plant, but many of them may not come to maturity; therefore a careful count of these rudimentary seeds over a small area of the field would give a first estimate of the maximum possible crop. According to Gasparin the length of time that elapses from the moment when the mean daily temperature of the air in the shade is 5° C. up to the date of heading of the wheat is such that the sum total of the mean daily shade temperatures is 430° C., but as the initial date is difficult to determine we shall in our calculations adopt the rule of Hervé Mangon, according to whom the sum of the mean daily temperature in the shade, rejecting all that are below 6° C. (at which the wheat does not vegetate), is 640° C. if we count from the date of sowing, or 555° C.if we count from the date of germina- tion. The following table is computed by counting from the former date; a parallel computation from the latter date shows that on the a 266 average of ten years there is no appreciable difference between the results. Duration, in days, from sowing to heading of winter wheat, at Montsouris, France. | | | | ever | Average for | | | | 1872-1881. Date of sowing. | 1872. | 1873. | 1874. | 1875. | 1876. | 1877. | 1878. | 1879. | 1880. | 1881. | 1882. |. ——___ | Dura- | | | | ‘tion. Date. | bara Te September 22---| 152 67 8v | 58 91 57 | 61 | 167 160 85 | 154]! 99] Dec. 30 September 29..-| 158 72) 116 113} 147) 64 | iliKa))|) alvat 161 92) 159 | 120 | Jan. 27 October 6 ___---- 161} 80} 161 15D alee bs: | 84} 135} 180 | 161 | 136 157 | 141 | Feb. 24 October 132. -—-2 | 168 | 90 164 | 172 164 88 | 140] 173 | 164] 147 | 155 147 | Mar. 9 October 20......] 168} 133] 163| 175} 163| 107/ 138) 178| 164] 148] 150| 154 | Mar. 23 October 27... 163) 140} 162) 174) 160 106 | 145) 185 | 164) 147) 152] 155 | Mar. 31 November 3 ....| 162| 141| 158] 172] 156| 107| 156| 192) 162] 141| 146| 154| Apr. 6 November 10...| 155 | 140| 158] 171) 159/ 108| 156] 175| 158] 128| 146| 151| Apr. 10 November 17_..| 148 | 134] 153) 165| 156| 128) 150) 168] 153] 141] 144| 149 | Apr. 15 November 24 ...| 141] 134) 148 | 159 | 160) 125) 147 | 162 | 147] 135) 141 | 145 | Apr. 18 December 1.....) 134| 136 | 142] 154] 143] 123] 148] 156) 140] 181 | 136] 140 | Apr. 20 December 8.__.- 127 | 182] 185| 148] 186] 120} 198| 149| 188] 127] 129| 135 | Apr. 22 December 15....| 120) 126] 128] 141) 129) 115) 131) 142| 126] 124| 122) 128 | Apr. 22 December 22....| 113 | 129] 121 | 184] 124] 111] 126] 135) 119| 126] 118| 124-| Apr. 25 December 29___- 18 TRAP AEE key 120) a 1a 131 | 112] 123) 111] 118 | Apr. 26 This table shows that on the average of ten years the seed that was sown, e. g., on the 27th of October and required one hundred and fifty-five days to head, is that which took the longest time; for sow- ings before that date, as well as after it, the durations steadily diminish; in other words, this sowing is that whose development was the most retarded by the winter cold. If we compare this table with those given by Marié-Davy, showing the frosts, we find a com- plete inversion in the chances of injury from frost; wheat as a green plant has as little to fear from frost as has the dry grain. But during and after the formation of the embryo seed, as well as during germination, on the contrary, frost is very injurious, and if the embryo is seized by frost it perishes. If this accident occurs it is possible that the progress of heading may permit a new formation of embryo to replace those which have perished. Such accidents must have occurred to the seed sown in the hope of reaping an early harvest in 1874, 1875, 1876, 1877, 1878, and 1881, but did not occur in 1882. This accident is not incompatible with an excellent harvest, as we see in the case of 1874, but it causes a decided retardation of ihe harvest, as in 1877. The mean of the ten years shows that the heading occurs at an epoch in the spring when the mean temperature of the air is between 6° and 13° C., and when the rainfall is generally abundant, so that at this epoch damage does not generally occur to the grain; only in case of the sowing of September 29, 1878, did the en ea Se 267 heading occur during the very cold season likely to be injurious to vegetation. We pass now to the period from the heading of the wheat to the flowering. According to the determination of Herve Mangon, the sum total of the mean daily air temperatures in the shade necessary to flowering is 1,500° C., counting from the date of sowing, or 860° if counted from the date of heading. If we consider the date thus fixed for the flowering we shall find that it corresponds to a mean daily temperature at that epoch of 16.5° C. on the average of many years; but if we consider the individual years we shall find the actual mean temperatures of that date to vary from 8° to 22° C., and also that for temperatures below 13° the flowering becomes uncertain, prolonged, and detrimental to the crop; but as to the upper limit, 92° C., there is no evidence that even higher temperatures will be injurious. The following table gives the calculated number of days that elapse from the sowing to the flowering, together with the aver- age duration and the corresponding average date. The correspond- ing tables of mean temperatures and lowest temperatures at the date and the quantity of rainfall are omitted for want of space. Duration in days from the sowing to the flowering of winter wheat at Mont- souris, France. | | | | | | Average for | | | | | | 1872-1881. Date of sowing. | 1872.| 1873.) 1874.| 1875.| 1876.| 1877.) 1878.| 1879.| 1880. | 1881. | 1882. | | | | (Ber| Date September 22-..| 244] 228 | 239) 237 | 2388] 208 | 231) 261} 242 | 2385] 239) 236 | May 16 September 29_--| 243 | 226 | 237 | 238) 242 | 209 229 259 239 | 235 | 239 | 236 | May 23 October 6 _.._.-- | 242] 220 287 | 238 | 243] 214 | 227| 258| 238} 233 | 235 | 235) May 20 October 13 _..--- 241 | 225 | 234 | 284] 240] 217 | 222] 251 | 236] 231 | 232] 233 | June 3 October 20 _.-..- 238 | 225 | 231 | 231] 237] 219| 216| 249| 234| 229/ 225] 231 | June 8 October 27 ....-- 232 | 222| 226| 226) 232] 215/ 210| 249| 232] 224 | 222] 227 | June lz November 3..... 228] 219 | 220] 220| 227] 212| 217 | 245| 227} 219/| 215] 223/ June 14 November 10...| 221| 217 | 218| 218 | 223) 206| 215| 238] 223/| 214| 214] 219| June 17 November 17... 214] 211 212 | 212) 219] 203/ 209) 281) 217) 211) 212| 214 | June 19 November 24 ...| 207 | 207 | 208| 208| 213] 198) 206 | 224| 211 | 205 | 208) 209 | June 2l December 1_-__-- 200} 203; 202) 202) 206] 191 202 | 218 | 204) 199| 202) 203) June 22 December 8_-_-- 193 | 200} 195| 195) 199] 188| 197) 211 | 197| 195) 196| 197} June 23 December 15....| 186 / 194) 188] 188 | 192 | 184 | 190) 204] 190) 191 | 189 / 191 | June 24 December 22....| 179 | 189} 181| 181 | 186] 177] 183] 197 | 183] 186| 183] 184 | June 24 December 29....| 172| 185 | 178| 178| 180] 171| 176| 191| 176 | 181 | 176 | 179 | June 26 The ripening of wheat is perfected when the plant has received a sum total of mean daily air temperatures in the shade of 815° C. since the date of flowering. This result happens on the average of Paris forty-four days after flawering, and the individual irregularities searcely ever exceed four or five days. Therefore the date of flower- 268 ing can be made the basis of a very cfose estimate of the date of ripening. The date of flowering occurs at the time of the greatest vital activity of the plant, which at that time is actively drawing its nourishment from the soil and is transpiring, assimilating, and increasing in weight. But very soon this work is relaxed and is confined more and more to the interior of the plant, conveying into the seed the elaborated materials formed within the leaves and stems. It is especially in this latter part of the life of the plant that the mternal consumption can exceed the gain from without, and the plant tends to diminish its dry weight. This period has a great influence on the final result, not only because the plant can gain as a whole, but especially because of the distribu- tion which is made within it of the material which it has brought together. The straw has only a secondary value. It is the seed which constitutes nearly the whole value of the harvest. Therefore all that passes from the straw to the grain is a benefit, though this passage should be accompanied by a notable consumption of the nutritious materials of the stalk. It is neither the state of prepara- tion of the stalk, nor the heat, nor the radiation, nor the moisture which of itself alone produces the best quality of grain. There must be a reunion of all these various elements in a proper proportion, which latter will vary with the weather and with the locality even with the same weather. The blighting of wheat is an accident that one dreads most at this period. The bhght, properly so called, is due to a tem- perature and a radiation that is too intense for the movement of the sap in the plant; the seed has not time to receive the sum total of the nourishing particles that have been prepared for it; therefore it becomes small, lean, and shriveled up. os, aan ne TE-26 Tole LG meZOLy |) 681 O8 F "9 FSi 8°6 6° 0°99 €°@s L | POL GLP | Oeste | an |e Sa ORGS Oe -_ y aee 96-Ge QOLBYAL O'EL meZOL| FEL | 96°E 4°89 FG 0°6L 68 Lg 9°T8 6 O'eL 6 OP Fe SAO ret a et Cele) Pen oe see nee Te-LT Gorey ¢°0 USeZzOLy| LCT | F6°S 6°69 GET Th 8°§ L'6F 0°18 h | SIL LIS Crema ALS Oe | Ee aren ce ear Pamere so 9T-@L Wore 661 SO'S £66 46'S 6 TL ULL 6 OL Th OLF 608 6 | areal 1 Cho es eee ae Se er ie, , a ae eines TILL Gorey 00 uezoly | 66 ¥6 6 £°¢@9 6 OL 6S PO |) Ite § "64 & él 0°Sg CS) cee (an a a ee ee eee Re ese gor es 9-6 GQoreyl 6S uezoty | 6°1L c0'& 6°99 BL 8'T POs asker. 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In 1880 the Central Meteorological Bureau of France, under the minister of public instruction, organized a system of phenological observations; the resulting data have been studied by Angot in a series of memoirs. In his first paper (1882) Angot grouped the dates of the wheat harvest as observed during 1880 and 1881 at several hundred stations in France in groups of four or five stations and plotted these upon maps showing the elevations of the stations. By a careful comparison of neighboring stations he shows that the date of the harvest is everywhere quite uniformly retarded with increase of elevation, and at the rate of four days in time for every hundred meters of ascent. Apparently this retardation is the general result of a complex sys- tem of influences in which rainfall, drainage, soil, sunshine, tempera- ture, and other local peculiarities combine. It is evident that the spe- cial influence of any local climate on the crop can not be successfully studied until the observations have been corrected for the general influence of elevation. He therefore reduces all the dates of harvest to sea level by applying the preceding correction. A similar calculation showed him that the phenomena of flowering are also retarded at precisely the same rate of four days per 100 meters of elevation and these dates also are thus reducible to sea level. Angot’s charts, showing the dates of flowering and harvesting thus reduced to sea level, show great regularity and the isanthesic lines show the perfect regularity with which the reduced epoch of flow- ering begins in southern France on the 11th of May and advances northward until it reaches the northern boundary of France on the 25th of June; in a similar way the harvesting of winter wheat begins in southern France on the 10th of June (reduced epoch) and in northern France on the 9th of August. The variations of these isanthesic lines from year to year may be compared with the ordi- nary charts of temperature reduced to sea level or with other mete- orological data in a very simple manner. Angot has modified and apparently improved the methods of determining the influence of temperature on the date of flowering and harvesting. He says that since 1837 Boussingault’s idea that the ripening demands a certain sum total of heat, which is constant for each species of plant, has been generally adopted. At first this sum total was calculated by adding together all mean daily tem- peratures from the germination of the seed or the beginning of vegetation after rejecting such means as were below freezing point. Then, as C. H. Martins, De Gasparin, and A. de Candolle had shown 279 that the temperatures useful to the plant vary with the species and are decidedly above freezing, therefore students have taken other limits. Thus Gasparin and Hervé Mangon adopt 6° C. for the initial temperature in the growth of wheat. In order to ascertain the preper method of counting temperatures Angot has accomplished the labor of prosecuting three parallel computations by three different methods, as follows: (A) First method.—By observations of daily maximum and mini- mum temperatures. In this method Angot has examined separately the observed maxima and minima of the thermometer in the shade. After rejecting all observations below 6° C., he subtracts 6° C. from all the others and takes the separate sums of the remaining maxima and minima for each month and then the average of these two sums, which consequently represents a sum total of heat received during the month in excess of 6° C. (B) Second method.—By the daily means. In this method the mean of each day is first computed by taking the average of the maximum and minimum; 6° ©. is then subtracted from each of these daily means and all negative remainders are rejected. The sum of the positive remainders represents the sum total of heat received in excess of 6° C. (C) Third method—By maximum temperatures alone. In this method, which is a modification of that proposed by Hoffmann, a max- imum thermometer is exposed to the direct rays of the sun and the sum total of the maximum temperatures is used by Hoffmann. But Angot prefers to use the maximum thermometer in the shade, as in the first method, and, as before, takes the sum total of all the posi- tive remainders after subtracting 6° C. In all these methods the principal difficulty is to fix the epoch from which the summation should begin. Sometimes the date of sowing has been adopted as this epoch, but from the date of sowing up to the date of sprouting the seed and the young plant are sub- jected only to the temperature of the soil, and not to that of the air, which often differ considerably. It would perhaps be better to start with the date at which the plant appears above the earth, but the date of sprouting is not generally given by observers. He there- fore provisionally adopts the 1st of December as the point of depar- ture and calculates the sum total of temperatures for the nine stations in France for which the dates of flowering and harvesting of winter wheat have been best determined for the years 1880 and 1881. The agreement among themselves of the numbers calculated by these three methods for nine stations and two different years is such that no decision can be arrived at as to which method*is the best, and such decision is reserved for a future study of other harvests. 280 A similar elaborate study of the harvest of rye gave the following results : (1) Retardation for altitude is approximately four days per 100 meters, with some indication that the correct figure is rather less than this. (2) The date of harvest reduced to sea level begins with the 5th of June in southern France and ends with the 25th of July on the northern border. (3) The sum total of temperatures computed by the three methods A, B, C, above mentioned, shows that whatever method be finally adopted as the best, these sums are less for rye than for winter wheat. A similar study for spring barley shows the following results: (1) A retardation of four days per 100 meters of altitude suf- ficiently harmonizes the observations. (2) A retardation of thirty or forty days in the date of sowing has no appreciable effect on the date of harvest, which varies from the 20th of June in southern France to the 14th of August on the northern boundary. (3) The sum total of temperatures from sowing to harvest is too variable to be determined. A similar study of the flowering of the narcissus (Narcissus pseudonarcissus) shows that the retardation of the date of flowering is at the rate of four to five days per 100 meters, and four days can be adopted without notable error. A study of the currant (2?2bes rubrum) shows that the retarda- tion is between three and four days per 100 meters. The sum total of heat from December 1 up to the date of flowering, as deduced by the second and third methods, but under three different assumptions— i. e., that the initial temperature is 4°, 6°, 8°, respectively, seems to show that 4 is the proper figure for this plant. A study of the flowering of the hlac shows that a retardation of four days per 100-meters best satisfies the observations of both leafing and flowering. The latter begins in southern France on the 22d of March and ends in northern and eastern’ France on the 6th of May. The calculation of the heat required for leafing shows that the most accordant results are obtained when we take the sum of maximum daily temperatures above 4° C. and count from the date of the last heavy frost, which sum is about 360° C. For the flowering, on the contrary, we have to take the sums of the mean daily temperatures, counting from 4° C. and from the same date of frost, which sum is then 350° C., while the sum of the maximum daily temperatures would have given 695° C. A study of the leafing and flowering of the horse-chestnut (4’s- culus hippocastanum) shows that the retardation of four days per 100 meters also satisfies these observations. The dates of leafing, as 281 reduced to sea level, begin with March 12 in southern France and extend to April 21 in northern France. The dates of flowering begin with April 6 in southern France and extend to May 16 in northern France. The sums of temperatures are counted from the last severe frost, and the most accordant results are obtained when the sums of daily maxima are taken, counting from 2° C. The sum total is 715° to date of leafing, and from leafing to flowering 1,070°. The leafing of the birch is found by Angot to have the same rate of retardation—very little less than four days per 100 meters—and the reduced epochs of leafing begin the 9th of March at the southeast corner of France and extend to the 16th of April at the northern border. The sums of temperatures up to the time of leafing are best computed by taking the sums of daily maxima above 2° C., but are very uncertain. The leafing of the common oak (Quercus pedunculata) has a retardation of four days per ascent of 100 meters, and the reduced epochs begin with the 6th of April in southern France and end with the 6th of May in northern France. We can provisionally admit that the leafing of the oak occurs when the sum of the maximum daily temperatures has attained 940° C., counting above 2° C. and from the date of the last heavy frost. The flowering of the elder (Sambucus nigra) has an approximate retardation of four days per 100 meters. The reduced dates begin on the 6th of April in southern France and end on the 10th of June in northern France. The flowering of the elder occurs when the sum of the mean daily temperatures since the date of the last frost has attained 840° C. if we count from 2°, or 630° if we count from 4° C. The flowering of the common linden (77/ia europea) or the Tilia silvestris is retarded three days. per 100 meters’ ascent for the moun- taimnous countries, but four days is adopted for the whole of France, and the reduced dates of flowering begin with the Ist of May in southeastern France and extend to the 20th of June in northern France. The flowering of the linden occurs when the sum of the mean daily temperatures, counting from the last heavy frost and above 2° C., has attained 1,090° C. It would seem to result from all this that the leafing of the trees and shrubs occurs when the sum total of the maximum daily tem- peratures, counting above a certain limiting value and from the date of the last heavy frost, has attained a certain value characteristic of each plant. But for a certain number of plants the flowering seems rather to depend on the sum of the mean daily temperatures. 282 In his second memoir Angot (1886) studied the additional data for the years 1882 and 1883. A new determination of the influence of altitude on the epoch of leafing again gave an average retardation of four days for each 100 meters of altitude for the lilac, the chest- nut, the birch, and the oak. The average mean daily temperature of the air at the date of leafing varies between 5° and 12° C. for the lilac, with an average of 9.1°; from 4° to 14° C., with an average of 10.1°, for the chestnut; from 7° to 15° C., with an average of 10.7°, for the birch; from 5° to 16°, with an average of 11.3°, for the oak. These ranges are so large that it 1s impossible to indicate any simple relation between the leafing of these plants and the mean daily tem- perature at this epoch. The mean of the daily maxima were also computed for the epoch of leafing, and were 14.6° for the lilac, 15.7° for the chestnut, 16.1° for the birch, and 16.4° for the oak. But again the variations were too large to attach any phenological impor- tance to these numbers. As to the sum total of temperatures Angot adopts, not a constant date, as December 1 or January 1, but dates that are variable for each station and each year and approximately represent the close of the last period of freezing weather. They vary in this case between the 18th of January and the 13th of February. After laborious caleu- lations by different methods and starting from different initial tem- peratures he concludes that the leafing of the four plants under con- sideration occurs when the sum of the mean daily temperatures, counted from 0° C., or the sums of the maximum daily temperatures, counting from 0° C. and beginning at the date of the commencement of vegetable growth as above defined, attains the values given in the following table: | Sums of | Sums of Plant. | daily daily | means. /maxima, | SO 5 Of | Bat ECR Sk Seer it Pere tn SO Mee ee al CRC Rohe Se ne 0 ee LS 333. 550 Indian: chestnwts. cS Ss. ots ge ee re ei IE er ee | 522 845 Birch oie Se ee etree aati eae an Jeep ne, ene fee: 838 Oalen a abt ee ae cee ee ee eee ee eee eee 677 1, 082 In order to decide which of these two modes of calculation, daily mean or daily maxima, are most proper it will be necessary to oper- ate upon a much longer series of observations. The flowering of the narcissus, the lilac, the chestnut, the elder, and the linden was studied in a manner similar to that of the leafing. The retardation for altitude is, as before, four days to the 100 meters. The man daily temperature at the date of flowering is: For the nar- cissus, 6° to 14° C., average 9.4°; for the lilac, from 8° to 15° C., 283 average 12.2°; for the chestnut, 8° to 16° C., average 12.0°; for the elder, 9° to 20° C., average 13.9°; for the linden, 12° to 21° C., aver- age 16.4°. The mean daily maximum temperatures at the date of flowering for these same plants is as follows: Daily maxima. Daily mean. Plant. = SG ae —= = => Range. | Mean. | Range. | Mean. ©} (6) NCEA oO! OG} TSR OEE) es a eee ae ie | 9__20 14,9 | 6_.14 | 9.4 TAT cet aa eh ee Ne 13.21 16.6| 8..15 | mee (Nesters. meee oe eee eee ee eee eee eee 13_-25 a6 8_.16 12.0 IDCs lies 22s Sen ene soe eee ee See ees See eee | 14..26 19.7 9_.20 13.9 Thieves) 2S Se Ee eee ee Se See eon eee oe 17_.29 22.5 122221, 16.4 Evidently the maximum temperatures have no clearer connection with the date of flowering than have the mean daily temperatures. The sums of temperatures from the beginning of vegetation to the date of flowering have also been computed by different methods and from different initial temperatures. The following are the results when the initial temperature is 0° C.: Sums of | Sums of Plant, postive | Dorit means. | maxima. aa ak = OOF OXOp INRIC ISU S eee tee ae ee ees Shr yh aa ea ee cee a erie ca Sue ence saee emcee ee Sant 359 591 Dri st Cane eee ea, Fy miele Set 2 ns eee ee Hae Oe Wo oe 613 983 Glos ire twee epee come tee wate! Deco. A ees, oe Co ts ON ede Loose teeeeeicsw eos 771 1,217 DONG? «5 sonna donee k Spee Ee Be ee eee ee eae EEE le 990 1,542 TAG So Be ee See eee CES ee Bee ee eee eee See one ot | 1277 1,938 Here, again, as in previous cases, the relative value of the different methods of taking account of the temperature“is determined numer- ically by taking the sums of the departures from the average for the individual stations and years. In the present case the mean depart- ures as thus determined are exactly the same for both methods, so that four years of observations, 1880-1883, have not sufficed to decide as to which mode of calculation it is proper to adopt as the best. A similar calculation as to the amount of heat received by the lilac and the chestnut between the epochs of leafing and flowering leads to the same indecision as to the methods of calculation. The actual sums between the leafing and the flowering are as follows: Sums of | Sums of positive | positive Plant. daily | daily means. | maxima. Koh a1 121 Cem ie Or ae eee tee Naeee Jou eek a Beak lee seen cc acearelsesees 280 | 433 (GUNES HNGDR oS eSoSe false Bees ace Le Sie ees eee ae ee oe eS ee eee oe eee ete 250 372 284 The flowering and ripening of winter wheat during 1882 and 1883 has been studied on the basis of data from about 500 stations, com- bined with the previous data for 1880 and 1881. The mean daily temperature at the time of flowering is for rye 13.3°; but the individual numbers range from 9° to 18°; similarly for winter wheat the mean is 16.2° and the range from 10° to 21°. The commencement of vegetation for winter wheat is uniformly adopted as December 1. The sums of the mean daily temperatures have been calculated from several points of departure and seem to prove that the lower limit of useful temperatures is very nearly 5° C., so that we can take 6° C. as the point of departure, as has been done by many authors. The sums of the mean daily temperatures, less 6° C., rejecting the negative remainders and counting from the Ist of December, are as follows: Periods for winter grain. Rye. | Wheat. 20. | °C. Hrom December tonilowerin e222. 52+. seeree eee ee eee a eee eee 420 596 HromeDecemiberlstovharvests-25:.25 0-2 eae ae ee ee ee ee ee eee 955 | 1,099 rom) flowering towharvestecncs-.- see oe asec ee Sere ee ee eee eee ae aa eee 535 | 503 The harvest date for spring barley is shown to depend in 1882 and 1883 quite as little on the date of sowing as it did in 1881. The retardation due to altitude is as before, four days per 100 meters. Adopting the 20th of March as an average date of sowing, the sums of the mean daily temperatures have been considered up to the date of harvest, with different assumptions as to the fundamental temperature. As before, the best result is given when the sums are taken of the excess of the mean daily temperatures above 6° C., and the resulting figure, 984, is seen to be between the two figures for rye and winter wheat. In his third memoir Angot (1888) studies the phenomena of 1884 and 1885 in combination with the preceding. The same allowance is made for rates of retardation. The relation between the times of leafing, the mean daily temperature at that date, and the maximum 285 temperature at that date, is computed by the same process as before, with the following results for the years 1884 and 1885: . Daily mean tem- Daily maximum Pitat. | ae se ane ponent. 5 | Mean. | Range. Mean. Range. | oC: | Kae Oy oF o¢. Inilac-ve2= 2 >. ee ees Pe est ee Arnie ee seenccencs| EL I ais (eae es 14.7 | 4.7..20.8 (Ep ADO aes (SS ee ee 9.6) 6.3..13.7 15.3 | 10.9.-22.3 VBS) Bae ae a 10.1) 5.8_.14.3 | 15.9 | 9.7--22.7 CE ek 5 See Ce eee Oe eae aS 10.3 | 6.0_.15.18% 15.7 | 11.9_-21.0 The mean values here given agree well with those of the previous years, but the individual numbers have such a wide range that we can not conclude any simple relation between the leafing and the mean temperatures. The relation between the leafing and the sums of temperatures is found, as before, by assuming the end of the last period of frost as the commencement of vegetation; for these years this corresponds with the last few days of January. The useful temperatures are considered to be those above 0° C., and Angot has computed both the sums of the mean daily temperatures and also the sums of the maxima alone with the following results: Sums of daily | Sums of daily means. maxima. Plant. | 1884. | 1885. | 1884. | 1885. Cet INGE OOF | 2G IRs 255 2 oye Oe ef ee ee ee eee ee eee Oe ee Se 428 414 686 666 WHOS Tn eta at oe = Se eee aaa ee ee oe tas seen Sees seems es 568 575 | 924 | 925 TES: Chee ne See ee Se ree ne eee ences | 609 587 | 988 | 944 OM Rs sees se eet eee ee I EE a ae ie eee ce | 709 717 | 1,149 | 1,146 The reliability of these sums is, as before, determined by examin- ing the departures, although not according to the strict rules of the law of probabilities of errors, but sufficiently so to show that the uncertainties of each of these figures is larger than the differences for successive years. The average of the two years, 1884 and 1885, are considerably higher than those for the previous four years. The flowering of the lilac, chestnut, elder, and linden is again inves- tigated by using the observations at some 1,200 stations or less. The reduction for altitude is as before. The mean daily temperatures 286 and the maximum daily temperatures for the dates of flowering give the results in the following table: Daily mean tem- | Daily maximum Plant. ie Ie eh 3 : belive ane Mean. Range. Mean. Range. (6h (Et ouG: ou: aCe eee eee cree Soe ee ee eee ee oe 10.1 | 4.7_-15.4 15.6 9: 1222210 Chestnuteo te 55 eae ee eS ee eee INE | Gpieeabeal | 17.9 | 13.5_.26.3 Wilden ites se ni eet Rae A een ee wee em ee ee | 15.3 | 10.7--19.6 | 22.2 | 15.0_-29.5 Dindon 25.2022 Bie A catches © eee Lae 16.8 | 12.9..20.8| 23.0 | 16.9..29.9 Again the accord with the results of previous years is satisfactory, but the individual variations are so large as to show that there is no clear connection between the epochs of flowering and the mean tem- peratures. Next the sums of temperatures received by these plants since the last severe cold is computed, assuming 0° C. as the initial temperature, with the following results: | Sums of daily | Sums of daily > mean tem- maximum Plant. peratures. | temperatures. 1884. | 1885. | 1884. | 1885. °¢. | °c. | cc. | ce. TLC Bete ee ee re ee ete eo ee ee eee ee eee 689 672 | 1,097 | 1,070 Chestnuts. 0156 oaaie. Se ee een be cas aes | See se eae ee eee 846 841 | 1,345) 1,304 Rider eee Se Re Fee er Te en eed ee eer ee ine 1,038 | 1,108 | 1,619 1,685 PIN GON ee sa Soe a = ee ek eee eae nie eee en en ee 1,366 | 1,354) 2,091 | 2,022 These sums agree well among themselves for the two years, but are notably higher than the sums for the four previous years, the excess being so much larger than the uncertainty, as deduced from the agree- ment of the numbers among themselves, that we can scarcely con- sider that such sums as these represent the true influence of climate on these plants. The dates of flowering and harvest of rye and winter wheat at 700 or 800 stations give the following results: The mean temperatures at the date of flowering are, for rye, in 1884, 14° C., and 1885, 12.2° C.; for winter wheat, in 1884, 15.1° C., in 1885, 16.4° C. These figures agree well with the previous four years, but the individual discrepancies show that there is no simple relation between the flowering of these plants and the mean temperature. Again, the sums of temperatures are computed from the Ist of December; 5° C. is subtracted from all the mean daily temperatures and the sums of the positive remainders are given. Since in previous years 6° C. has been adopted, whereas the evidence points toward a lower figure, therefore Angot now gives the results of a recomputa- 287 tion of the five years, adopting 5° C. as the lower limit of useful temperatures, with the following results: Sums of mean daily temperatures, less 5° OC. and rejecting negative remainders, from December 1 up to the dates of flowering and of harvesting. Rye. Winter wheat. Year. Flower- | Harvest- | Flower- | Harvest- ing. ing. ing. ing. PRS eee vie ore ee 537 1,113 | 730 1,235 SS eee ee oan caw os oe bas oo ess ecSoccsceu oe 602 1,180 793 1,311 TEED Lo ok Bare acl 496 1,0%5 720 1,271 1GSD 2 22ee es eee See ee ee ee ae ae 460 1,076 638 1,248 TRE! oh eas 527 1,089 727 1, 268 [ite bonne Se ee, Ste ae a eee ee ae ee ee 469 1,047 686 1,245 AVEO ieee eee oe ee ee eae See eee Se eee | 515 1,096 | 716 1, 263 The differences between the numbers for flowering and harvesting show, as in previous years, that although winter wheat requires more heat (716° C.) to bring it up to the flowering point than does rye (515° C.), yet after having attained that point the wheat requires less heat (547° C.) than does the rye (581° C.) in order to ripen the grain to the harvest. This fact, which has shown itself in each of the six years, can be considered as well established. The harvest of spring barley.—The dates of harvest are, as before, reduced to sea level by allowing for retardation at the rate of four days per 100 meters. The sums of mean daily temperatures, less 5° C., counting from the 21st of March, which is the mean date of sowing, and up to the date of harvest, are given for each year in the following table: Spring Spring ela a Pcntad arves . arves Year. sums of Year. sums of tempera- tempera- tures. tures. Of oT; IRS) Se OE ei ie 0 a Or NOt | LSS ee a eee ee ey eee 1,083 NSS hentai Nas eo eee ete esa SDP T ST ())) | BSA Se See ek es Re 1,049 LSS 2 ree aerate at ere oe 2S et oe te OSH Pl SBb een wes se seen WS. St eee 1,042 The general mean for these six years is (within the range of its probable error) the same as the corresponding figures for winter rye. In a fourth memoir, Angot (1890) gives similar computations for the harvests of 1886 and 1887 in France, the number of stations being now appreciably larger than in the preceding years. A new computation of the retardation due to altitude gives him 3.7 days per 100 meters for the llac, 4.0 for the chestnut, 3.7 for the elder, 288 and 3.5 for the oak. For all these he adopts 4 days, as in previous vears. Leafing—The mean temperatures at the dates of leafing for 1886 and 1887 are given, as follows: ' Data for 1886 and 1887. Mean of Mean of Mean of |daily max- Mean of |daily max- Plant. daily tem-| imum Plant. daily tem-| imum perature. | tempera- perature. | tempera- ture. ture. ° CG: ° C: . ° GC: ° (OL Telacee eae en Sele ey 9.4 14: Sh|| Birch ees. e ete | 9.9 15.3 Chestnuts 6-2 10.6 16:23|| {Opto eees eee eee Ly, 17.6 The sums of temperatures received by these plants from the last freezing period up to the time of leafing, and counting from 0° C. as the initial temperature, are as follows: Sums of daily Sums of daily means. maxima. Plant. ee ee 1886. 1887. 1886. 1887. On OF (OR Of, CHIEF TAGES ese i ee ey ea ee Cee ee See ee ee . 3856 402 622 772 Westboro See oe 469 531 788 983 TBST RO) 0g es EE SE ge Te PS ESD Es ee SEE 465 531 796 981 Oakes 2xieee See Seles ee eas Be tee, 2s 8 Clo ey nee 622 682 1,016 1,208 The flowering of the lilac, chestnut, elder, and linden.—A new determination of the rate of retardation of flowering for these plants gives 4.7, 4.2, 4.4, and 3.8 days per 100 meters, respectively, for which, as before, 4 days is adopted. The mean temperatures at the times of flowering for the years 1886 and 1887 are as follows: Plant Day | Dey MOL |) Oe WH AC2 Fae doses echo sees akesd Gesss Sele ae See sme neni tee Re ee cee oo eee eee 12.2 17.8 Chestnuts. ho. ee sass Sa Fe Be ee ee ee eee ere ee ne 12.8 18.7 DG Vc) hes Rael an oe epg er nea ee Meo ek Pee a a LR eh Se 15.2 21.0 ini enters: Salute sc ee ee 8 ae cere ee (alee estes Se ce Nhe oie eee 22.5 16.4 The sums of temperatures above 6° C., counting from the last freez- ing period and up to the date of flowering, for the years 1886 and 1887 are as follows: Sums of daily | Sums of daily Pikae means. TEES 1886. | 1887. | 1886. | 1887. (Gf one: a Of Op Diilae ce eee es Se a ee ee ee ee eee 621 661 | 1,020 1, 184 Chestnut, oo fechat ese tk & lo heh atin DUE ys ein ere we ecules eae 704 773 | 1,147 1,351 Mlderitie ds soo. t kes ty ea Rea UE Ue. heab ees See ee ie ee eee 975 | 1,001 | 1,548 1,682 ein ets ete oe a ee ee ce ee ee See ee 1,269 | 1,245] 1,949] 2,014 289 The probable errors of these sums, considered individually, are quite large, and their agreement from year to year is not sufficient to justify the belief that we have attained to a satisfactory expression for the connection between the temperature and the date of flowering. Flowering of rye and winter wheat—Harvest of rye, winter wheat, and spring barley.—A new investigation, based on an increased number of stations for the years 1886 and 1887, gives for the rate of retarda- tion of these epochs the following figures: Flowering of rye, 4.2 days per 100 meters; flowering of winter wheat, 4; harvest of rye, 4.5; harvest of winter wheat, 4.3; harvest of spring barley, 4.2. We can, therefore, as before, take 4 days as an approximate value for all these phenomena. The mean temperature at the time of flowering is determined, both for daily means and for daily maxima, as follows: Daily mean. ‘Daily maxima. Flowering of plant. 1886. | 1887. | 1886. | 1887. oh Ge OO on Gk NG: EUV OMe ee oe Ee econ hoes ewe J 4o 5 Hee cea sasaiuac ges ceaes ese e522 15.4 12.3 22.1 18.3 \AVO@ Rb oe ee ea NAR el So RR ee a 16.2 17.3 22.0 24.3 Again, the average numbers agree well from year to year, but the individuals from which they are derived have a wide range. The sums of the mean daily temperatures, less 5° C., counting from December 1 for the winter rye and wheat, but from March 21, for the spring barley, are as follows: Sums of temperature. | ae Aver- Plant and stage. | 1886. | 1887. age. lec | oa | ce EOMOTSEE SOREN O Mos at peas Rutt ha ket be ed Be MANADO A Le Sa ae ake 313 415 364 Hiowenrine of winter wheats 25-25 64) 9s =e Se ere see eee 735 630 2 FERRE OSLO Lets yi Clee eee tae en ee oa See Ae ae eye et ee te ee ES | 1,080] 1,017 1,048 EA EVeS TO LaWall COnnwilea ti cee mee se neers Sense eee ee ee ee | 1,286 | 1,185 1, 236 Harty oso OMSprin ps DaliC yess =. een nce tee ees ee UE eee | 1,214 | 1,120) 1,167 From the flowering to the harvest, on the average of these two years, rye has received 1,048—364—684° C., and winter wheat 1,236— 682—554° C., but on the average of eight years, 1880-1887, the sums of temepratures, less 5° C., have been, for rye, from December 1 to the flowering, 477° C., and from flowering to harvest, 607° C.; for winter wheat the numbers are, respectively, 708° to 549° C. From the beginning of vegetation up to harvest the numbers are: For rye, 1,084° C.; winter wheat, 1,256° C.; spring barley, 1,103° C. These results can be considered as having definitely established the fact that 2667—05 m——19 290 in France rye requires less heat to bring it to the harvest and winter wheat more; but, on the other hand, from the flowering to the harvest rye requires more and winter wheat less. The following table gives a résumé of Angot’s general average dates and temperatures for sea level for the whole of France for the years 1880-1887: > | Mean daily tempera- ture when— Plant. | Leafing Flowering occurs. oceurs. DEE rCGh, NAG BaF locas te = Sete ee ee Ne Stee ee Oe Oe eo 9.1 11.2 Indian chestnut): < se 552 2 ee a a SLE PO ee ee a eee 10.1 14.6 Binehy: cles) es sean A geen re ce See ore a ee we OO 2 a ne 1O}4"| oe ae Oakes so 28. 8 fase ao a Be eee ae eae Aah oe te Alene ke, oe ee a ae 013 Ue Wah epee eS Wider 1.56) 28s see rte desc Seton dvek See veseder et eee a the ee | ene eee yes Ws dem yaa 2 Bee Stee a Re tore a ie a ee a Ee ae ee | 18.9 IRViGee 2S Raa Pte = bee a thnk ES eae ae oe, ee eet | ee 13.4 Wranter wheab:|s2=s6- “118° | 116 118 107 110 | 166 162 | 132 130 | 38 | _ 88 46| 45 315 | 292 341 | 395 50 50 320 299 398 321 479 | 455 468 448 147 144 152 148 152 149 7 401 47 48 91 98 322 207 214 200 166 160 165 160 165 * 159 315 293 188 177 528 533 335 401 311 289 389 335 108 107 | Amorpha fruticosa L | Asclepias cornuti Decaisne Genera. Common names. Acer rubrum L-.....- Acer dasycarpum Ebrh._---_-----_------- Acer saccharinum L Achillea millefolium T-_---------.------ ING SEN TAU ove NU UG | os te Ee Actea alba Bigelow Aesculus hippocastanum L Aesculus glabra Willd ‘Aesculusilava Aits22 25. -52- -_-22+-2 Aclantus plang ulosasss spe se nas ee Amelanchier canadensis Amygdalus nana La Anemone Memorosalies--- --2--4-22- === Aquilegia canadensis L Arctostaphylos uva-ursa (Spreng) Asimina triloba Dunal Azalea nudiflora L ; Bignonia (Tecoma) radicans (Juss) ---- Castanea vesca L Canyalallban Germany Switzerland Germany Switzerland (Rhine). (Zurich). (Rhine). (Zurich). Decade. | Above} Below | Above] Below Decade. Above | Below | Above | Below aver- | aver- | aver- | aver- aver- | aver- | aver- | aver- age. | age. age. age. age. | age. | age. age. 1600-1609. __...-.. pase Saeeae 8 1 9 || 1760-1769 ..____.- 4 | 6 5 5 HGIO=1619E ee. jeet etn ees ee 4 OOO eee = 5 | 5 7 3 H620=16292 22025 -= | Saad Pee nee 2 8 || 1780-1789 _______- 5 5 8 2 LG80S1GS9 22s oe Semi oe ecaeh ace 3 4 6 || 1790-1799 ....__.- 2 8 8 2 1640-1649. __...... 1 9 2 8 |} 1800-1809 .......- 5 5 5 5 1650-1659. -_.__-_- | 2 8 3 7 || 1810-1819 _______- 4 6 2 8 1660-1669____.___- | 2 8 5 5 || 1820-1829). .-- .-.- 4 6 6 4 167O-1679_ | 3 7 5 5 || 1830-1839 -....-.- 5 4 5 5 1680-1689. ________| 4 6 7 3 || 1840-1849 _______- 3 uf 6 4 1690=1699-" .= -- = | 3 7 1 Oa el 850 =1 850 eee 4 6 4 6 147 (0, 00S ee | 5 5 6 4 || 1860-1869 _____..- 4 | 6 6 4 PAOD 22.2. | 5 5 4 6 || 1870-1879 ._._...- 4 6 2 8 UiQ0=1729"" Nee 8. | 6 4 9 6 || 1880-1887 --..---- 2 6 p 6 1730-1789. __.__--- | 3 i 5 5 Gxt 1740-1749. --___._- 6 4 | 3 7 average.| 3.9 6.0 4.5 5.4 5017598 5 5 5 5 298 Good and poor wine crops, by years, since 1820. [From Fritz (1889), pp. 298, 295, 296.] 4 . 2 4 ral 2 H , ! 2 | Soi|8o) ee Be Bi | oaleran eee gS gal oriailies Z| p a fs) eS] Sea eae Sede | 8 ae ler epee lSea isha | Be | Ra) 3a] $8 |ee] & Ba | be los | es Year. Be | se /M@n| de | Sa] 3 Year. Be | de lan | aa #8 | 28) ua| 88 | eo) 8 88 | 08] .8| #8 SAPS EAMETS bch ee | Ce (Ea | Pa | Of 8 25/85 | gh a 8 28|35 | «Hh B esr ipcicse are ae Sal B Ses ects se E |esjes| 22/8 | 2 | E |fs\es| 22 Ay fy Hy) q © AY Fy By 1a 162028... | 2208 ile re eee, em ene yaens uch eee! 1.938 2 2: |e ae ict ea 0.69 i ea Pataieneel SD eh Tit eee nee 3.82 " Td BPS e032 t ide 10s FG ||) pean eee Nien Ree || 1856 ....-- Brigi\ sai] = aor iegegaee? 5.70 (fil tes os) Sete ce Pre ghee eee 9.95 | 22 i ae 5 TSH eS SSI) drt eT) Sas oll era eO Be || 1858 __..-- 10.75 | 26] 64 | 12.88 SP yeee ee B20) eennOy go ee fae |eeeeeey eee |) 1859... 2.2. 9.07 | 1% | 27 | 12.88 1826222. 15565; (2 7 82:1 400) Sse sal ee a eet, 1860 teas 5.94] 10] 12 | 13.17 aly ite 4.55 | 22 ile eed ee a MC 1g61peee 4.62 6 6| 8.78 ifs TGH45y|/. 12O4[ se R5 Qi ake see ee oe aa Loe 1862222 = BOF aly | sess 9. 66 1820052 BAGH) welGe | tao |e eee Rl eee eee 18652 =" Pde gly oes 9.08 IGF Ta eee 0.80 5 Vga, Pel eee oe 1864 2223! 540") bile 11.00 ASS Ieee se 8x67 ue Pe Sas oral eee {ee eee | ESO B sss sens ae 7a ee 6.10 TCG eee FS COS | el gece al ae 1866 rsa te tReet ts 13) (2% 13.21 [SSR PEL IQ. 35; 10 sOAlp Rbisaleseeee Aloe we eee ASGy eee Ea es GHEE 15.23 1S SAE Sees al 15843319 cOO ye ed nyleme sen wieeu en lseules We] S68 8 = |e eae 7 | aaa 24.59 19352 2 TONGHalS VSSulty ABBr le nek Melee an als Gast 186922552. ge Sal Mb ylaeee 28.99 [BSG ete e el Sr ee 18 Pahl pe Soe ee eee ck 1870 anes bo ae 1S ee 13.76 Posie ees A EI || FOO Iles eel 4 |e ae | eto | gl cya eee aes eelly Thal ee 16. 46 1938 aes CMe SIO SB NL Wil SVs eee [ees ic sate ees [e509 eae EOBMe 217 Ummah» Sule ae | eet 15732 2s ees 7 seal ee Ips see AUDA Ul DION PS alah eee ene A eee Tye as es beat || es | ce netteee = E36 ti kcal dae cal ae 187552. bole orale een eee ABAD So srek PA SHO5: le eal’ | dnl ee as, ee | eae TRYG! sete ah ks 1 ae ee IQA ea 2 | 2.83 Oily ali ceases tease, Reeete 180s eR ce 10a eee 1844.7. | 3.98 eh Ci pean Resets 4 een MulIR@ (cy feces Ae. eM eee Were 1GAn NA ak 5.36 este ies a a ac ea ABOU ee ale es a aeeea anne ST See MNS ERG H Wire a faites | area eel eal es bs ‘1GG0 peeeees | eaten Oi|2: Mie alow TS 210 008\| eet 4b eee 23 eee ele lees IS8h eee BP ata 2 an eee 1848. _.....| PAQG al e221 eee ee eee |e | ae He1RB2 askew 2 Mee led: Ra 1 S49 feet GROOW IE ol Silk al Oise 2 alee eee eee [pI S85) aee sean (eae Sy eee a ee cee THOR el (6-68 ie lie! pails eee slo eae ee 1GS4) orcs encom i Ee eee (Bs 1851 Ps has lp es) He eee 1895.2 S| eee AQ alee. Meal eee TSO, aed ave als Slay eee elie SP | ey TREE ake e ca beer Pid i i S53 oe ae bOI LO, | dese ecee| ets Wedces alsin espe 1 Pe eee J | Principality of Hesse. | Ohio (gallons per acre). ee, I8sie ese 28.0 | 41.8 44.3) 21.4 28.4 | 39.8 46.5 | 19.1 31.7 | 14.9 23.6 | 236.7 8.8 | 91.7 3.7 | 24.4 LOFON ON; 32.4 | 106.9 51.8 | 24.6 27.8 | 63.8 19.8) 59.1 31.2 | 80.0 9.3) 90.3 3.9 | 126.0 36.7 | 83.0 13.5 | 121.0 33.3) 28.0 299 Wheat crop in Ohio, by years, since 1850. [From Fritz (1889), p. 303. The figures for 1850-1877 refer to the average of two coun- ties, viz, Belmont in the southeast and Erie on the north border of the State. The fig- ures for 1878-1883 are averages for the whole State.] Bushels || Bushels || Bushels per acre. || per acre. per acre. ~ |i AE ak fee cee DIE. TAO, Soe ae oe Ss Ego ula yf eee eee US 17.8 tsi oe 2 eee TON Pi 3 Oe ro) || acy ieee ee 13.3 Acne ere te - Wee ldees|| teed oes Ps rah lf eae 14.5 TORS Gk ae hb HSS ieee ee Ne TX GES) | e1Svieee estore 11.6 TES BR ee aaa Oui IGGGseeseee eee ne LOST MIST Sines Sena tent 16.9 HGnnee Meese scr 0.2 te . AVR | 1S ty ell ee cee TE A | Sy We ee ee 17.7 (U2 ites a ee dae 4119682 wel Tete TEEN |e eeOer ee tek cere ead 17.1 1857 ___..- ei eee TORT] lel S69 Se ee ees eae ISISS ies a ewe er oanae | 13.8 fgpouien aie Weare te OL eli Merow Ubi te) Ae Ue ceay TE hae ey A Ae SR 15.6 se Coe ee IAPs lee lee ta en NCD lise ae der pee vas § 16.6 iC) ee LSSBA | RIBT oben see ee 8.5 || (17 ape eee Ne SUEY I TRIOS ue So ee toe 14.4 || GRASSES. Relative to the acclimatization of the grasses Sporer (1867) says: As in the Alps and Himalayas up to altitudes of 15,000 to 16,000 feet, so also in the farthest north, beyond the limit of trees, the grasses flourish. The varieties that compose the grassy carpet of Taimyr are still somewhat numerous. They embrace 10 families and 21 species; about one-half belong to *the sour-grass family, the binse or rushes, ried (reed), woold or cotton grass. But fully one-half are the sweet grasses, such as in central Europe are esteemed the best fodder, and not less so in Taimyr Land, where they extend to the shores of the icy Arctic Ocean beyond latitude 75° 30’ north, including among them the “ wiesen ” or meadow grass, the rispen or ray grass (Poa pratensis), and the “ rasen schmiele” or turfy hair erass, Aira deschampsia cespitosa. It is not surprising, therefore, that the best milch cattle, the so-called “ cholmogor breed,” the suc- cessors of the cattle transported thither from the Netherlands by the care of Peter the Great, should flourish in the desert polar regions at Mesenja. The sour grasses, as genuine early spring plants, form their flowers in the previous summer season, and at the beginning of the northern summer (July 10 to 20) are in the fullest bloom and have already turned brown when the sweet grasses begin to show their flower buds. In general the ground thaws only to the depth of a few inches and the roots do not penetrate into the frozen soil. The tundra of north- ern Russia and Siberia rests on such a frozen soil; the steppe or prairie or llano rests on unfrozen, deeper, and dryer soil. The modest circle of plants that surrounds our Arctic Circle is not so complexly constituted under different longitudes as are those of the warmer phenological girdles of the globe; everywhere we have the same species of plants and the same families; everywhere the graminex, the cruciferee, the caryophyllee, and the saxifra- gaceee, are the dominating families, and among the genera the Draba Sawifraga, Ranunculus, Carex, and the meadow grasses; all these 300 high northern varieties are enduring; only a few of them fail annu- ally to set their fruit and ripen their seed. An annual plant disap- pears when for a single season it fails to ripen its seed. A comparison of the flora of Spitzbergen and the high portions of the Alps and Pyrenees shows that the former are the lost children of European flowers that have since the Glacial epoch survived at great altitudes in the mountains as well as in the damp, cold morasses of central Europe. A comparison of the flora of Taimyr and the mountains of southern Siberia shows that the northern flora has wandered thither and be- come acclimatized from the southern, and that this process is still golng on. CEREALS. The elaborate report of Brewer on cereals, in the Tenth Census of the United States, contains the fullest information as to the rela- tion of climate and soil to our cereals. From pages 10 to 27 of this volume I quote the following general remarks: We may say that, as a rule, in all former times, and until modern means of transportation came into use, the grain most largely con- sumed for bread in any country or region was the one most easily and most surely grown at home, or at least at no great distance away ; the bread, of necessity, had to be made of such grain as could be grown or procured with the facilities then enjoyed. Rye, buckwheat, oats, barley, and millet had among our ancestors an Importance as bread plants that they have now lost and will probably never regain. This fact, apparently so obvious and yet so hard to realize in prac- tice, lies at the bottom of that agricultural revolution already alluded to, which is now going on everywhere among nations and peoples of our civilization, and most notably in western Europe. Seven species (calling buckwheat a cereal) are cultivated in Amer- ica in sufficient abundance to be returned in the census tables, and three or four more are occasionally cultivated in a few localities. Taken altogether, these include all the more important cereals of the world. Of the seven species we have to deal with, six are natives of the Eastern Hemisphere and one of the western. No cultivated grain has originated on an island, if we except canary grass, and none in southern Africa or Australia, regions otherwise very rich, botanically, in species. Humboldt called it a striking phenomenon “ to find on one side of our planet nations to whom flour and meal from small- eared grasses, and the use of milk, were completely unknown; while the nations of almost all parts of the other hemisphere cultivated the cereals and reared milk-yielding animals. The culture of the differ- ent kinds of grasses may be said to afford a characteristic distinction between the two parts of the world.” The genera to which the principal cereals belong are: Oryza, or rice; Triticum, which includes all the varieties of wheat and spelt; Avena, oats of various kinds; Hordeum, the various kinds of barley; Secale, rye, and Zea, Indian corn. Among the true cereals—that is, belonging to the grass family—there are various species of millet, belonging to several different genera (Panicum, Pennicillaria, Emil- cum, Setaria, Holcus, and Sorghum) ; durra, a species of Sorghum 301 (called also Indian millet and Guinea corn, and spelled in various ways, as “dura,” “ dhura,” “doura”); canary grass, Phalaris, and a few other species belonging to the grasses. In addition to these botanical cereals are the buckwheats, which, for convenience in this report, are classed among the true cereals. They belong to the genus Polygonum, two species of which are cultivated in this country, and perhaps others elsewhere. Several species belonging to the genus Chenopodium have been cultivated in various parts of the world, particularly in India and central Asia, but none are of impor- tance to European nations as grains. Of a considerable list that might be made, wheat, rice, and Indian corn are the first three in importance; oats, barley, and rye next; then durra, the millets, and buckwheats next; all the remainder being of insignificant importance to the world at large. However defined and classified, and however used, all the cereals are agricultural grains, all are starchy, all are breadstutts, and all are annual plants. Being annuals, they are adapted to almost universal cultivation where the summer climate admits, for “an annual plant may be said to belong to no country in particular, because it completes its exist- ence during the summer months, and in every part of the world there is a Summer.” This fact underles the agricultural importance of the cereals. Every gardener knows that annuals may be brought from almost any country and be made to flourish in cultivation in any other country in which they can complete their life in one summer, and that, even if the summer is too short, varieties may be produced by art which will mature quicker, and then their cultivation may be extended to cli- mates unlike that of their original home. T his may be continued up to certain limits set by nature for each species, which limits can be determined only by experiment. Not so with perennials. They must have not only a favorable summer climate, but also a favorable winter climate and a favorable average climate, and, moreover, be able to stand occasional wide deviations from the average climate. The exceptional heat of one year or cold of another, a too “wet season or a too dry one, may kill the tree or perennial which has lived and thrived for many years. Hence all perennials are restricted in their growth to very much narrower hmits than annuals. Moreover, annual plants are believed to be much more variable under different external conditions than perennials are. They vary more in nature, and it is among the cultivated annual species that we have the widest variation known to science. They can adapt themselves more readily to changes of soil, climate, and other variable conditions than peren- nials. Thus it is that the plains of Dakota and Manitoba, with their genial summers and fertile soil, even though the winters be of Arctic severity, and California, with its rainless summer, but genial winter, can alike send wheat to the mild-wintered and moist-summered British islands. Illustrating the first point regarding excellence of seed, both as to its actual condition and its pedigree, there are numerous illustrations recorded; but the famous experiments of Mr. Frederick Hallett, of Brighton, England, may be taken as a good illustration. The experi- ments were planned with so much intelligence, conducted with such 302 patience and care, were so profitable in their results—the essential results have been confirmed in so many other ways and by so many practical men—that they are worthy of being quoted in this con- nection. . He began with a single,head of wheat, chosen irrespective of size or vigor, but of a variety producing a good quality of grain. The head was 42 inches long and had 47 grains, which were carefully planted in rows, 1 grain in a place, 12 inches apart each way. At harvest the plants were carefully compared, and the one with the largest number of heads was chosen, and the grains from the best head of this best plant were planted the next year in the same way; and this was continued year after year, choosing each time for seed the best head from the most prolific plant. At ‘the first harvest the best plant bore 10 heads, at the second 22, at the third 39, at the fourth 02, the best head of which was 8? inches long and bore 123 grains. (Jour. Roy. Agr. Soc., Vol. X XII, p. 371, and plate.) This was the origin of the famous “ Pedigree wheat.” Later, and in a similar way, he made the varieties of “ Pedigree oats” and * Pedigree barley,” all very prolific, and each becoming famous. He gave the name “ Pedigree ” to these varieties because his process was precisely analogous to that of improving live stock by breeding to points and strengthening the heredity of the good points by pedigree. Still later he gave his riper conclusions (Trans. Brit. Assoc. Adv. Sci., 1869, p. 118) drawn from his long series of experiments, in sub- stance as follows: That every fully developed plant, whether of wheat, oats, or barley, has one ear superior in reproductive power to any of the others on the plant; that every such plant has one grain more productive than any other, and that this best grain grows on the best ear; that the superior vigor of this grain is transmissible to its progeny; that by selection this superiority is accumulated; that the improvement is at first very rapid, but that 1 in successive years it evradually grows less; that an improved type is the result, and that by careful selection the improvement can be kept up. Another paper on his pedigree system, read before the Farmers’ Club at Birming- ham in 1874, giving many interesting facts, is republished in sub- stance in the monthly reports of the United States Department of Agriculture for August and September, 1874, page 381. The practical fact underlying this relates to selection. “ Natural selection ” is undoubtedly the “principle by which species are pre- served, whether it accounts for their origin or not, and artificial selection of seed is the only method by which any variety of grain can be improved or even maintained. Without it the variety always either runs out or changes; how rapidly this takes place depends iipon various circumstances. It is unnecessary to multiply further proofs, because all experi- ment points the same way, and the law is universally recognized. I have merely cited a few out of many scientific experiments. The principle is never denied; it is simply too often neglected in practice. In this connection it is well to remember that it is easier to detericrate a crop by using bad seed, or even by simply neglecting the selection of the good, than it is to improve-an already good variet y; the down- hill road is the easiest traveled. The selection of seed to keep up the vigor and the fruitfulness of the varieties cultivated are more 3038 important than fertility of the soil as factors in permanent grain growing. The matter of soil exhaustion is so well known that it is the staple argument with the majority of popular writers and speakers on agriculture; but, so far as I have personally seen or have been able to learn from the observations or the experience of others, in every locality in this country where wheat growing has suddenly risen to large figures the quality and the yield have diminished more rapidly from carelessness in the selection of the seed and in the care of the crop than from mere soil exhaustion. While there is no absolute proof that any variety of cereal has ever originated ina “ sport,” nevertheless the indications are that some have so originated. The new variety of Bamia cotton originated in a single plant, entirely unlike its fellows, found in a cotton field in the Nile Valley in 1873, and the variety has already nearly revolutionized cotton culture in Egypt. (McCoan, Egypt as it Is, p. 187, and Kew Rept. for 1877, p. 26, fig. 7.) Cotton is propagated from the seed as the cereals are, but shee plant being a more conspicuous one, a sport would be more lable to be noticed. ~ A single cereal plant, unlike its fellows, in a great field of grain would be g ‘gathered unnoticed unless some very unusual accident “secured its preservation. It is well known, however, that many varieties of grain have origi- nated in some single plant differing from its fellows found growing in some exceptional place, but how that plant acquired its special characters, whether suddenly, as sports do, or not, we have no knowl- edge. We simply and only know that here and there some single plant has been found that represents to us a new variety ready made, and varieties have been perpetuated from such plants which have grown true to the seed and which have been valuable and enduring. The variety of oats known as “ potato oats ” is said to have originated in a single plant found growing in a potato patch (hence the - name ) in Cumberland, England, in 1778 (Allen, New America Farm Book, p. 163), or, as some say, in 1789 (Stephen’s Farmers’ Guide, I, 449). This variety, after nearly a hundred years’ existence, is still one of the best and brings, it is said, the highest price in the English markets. Its excellence has been proved throughout Europe and entir ely across the continent of America, for it is in common cultivation from Maine to Oregon and Washington. The Clawson wheat originated i in a single plant found growing by a stump in the State of New York. Darwin says that the Fenton wheat was found growing on a pile of detritus in a quarry in Eng- land. The Chidham wheat originated from an ear found growing in a hedge in the same country, and numerous other examples are recorded in the agricultural literature of this century. It is only fair to say, however, that many varieties of such origin have been rejected on trial as of no value, just as numerous varieties of seedling apples and potatoes are rejected. It is only the few that are actual improvements on what we had before. In ornamental and other garden plants the tendency to “sport” is much increased by cross- ing varieties, and this is probably also true of all classes of cultivated plants. Using seed which has been grown in some other locality, or, as farmers say, “a change of seed,” has been practiced by grain growers in all ages; and that this is very often attended with an increase of . 304 crop has been proved by the experience of centuries. Sometimes this change of seed means bringing in a variety previously cultivated there by bringing it from some other place more or less distant. To illustrate: Potatoes grow well as far south as Louisiana, the Bermudas, and other warm climates, if the seed is yearly brought from a cooler region. The same fact is true of peas, and there are large importations of seed peas from Canada to the United States every year. Most garden vegetables behave in a similar way, and on this fact the modern business of growing garden seeds is largely founded. In Connecticut, onion seed is imported from Tripoh. The first crop grown from this seed is of such excellent quality that the trouble and expense of the importation are justified; but if the cul- tivation is continued from seed produced by the American crop, in a few years the onions degenerate to the size of acorns. The constant sending of the seeds of squashes and other garden vines from the New England States and other places east of the Appalachians to the fertile prairie soils of the West is another familiar illustration, and similar facts have been observed all over the world. Melon seeds from Tibet are taken every year to Kashmir, and produce fine fruit weighing from 4 to 10 pounds; but vines growing from the seed of melons produced thus in Kashmir yield the next year fruit weighing but 2 or 3 pounds. Seed of the sea-island cotton have been carried to every cotton-producing country of the world, but the variety rapidly degenerates in every place yet tried distant from its original home, and if the excellency of the fiber is kept up elsewhere it is only done by the use of fresh seed. Now, it often happens that such a variety, specially prepared for a region by a long process of adaptation, may be better suited to it than any new one, and in such cases no increase of crop follows a change of seed. For example, heavy oats taken from the cool, moist climates of Canada or northern Europe, used as seed in the north- ern or middle United States, usually produce at first a crop weigh- ing more per bushel than that produced from home-grown seed. But in various places, notably so on Long Island, where special varieties have long been grown from seed “carefully selected as to weight until this weight reaches that which is produced from foreign seed, no increase of weight is obtained by any change of seed, This appears to be the case in several localities reported. Another example to the point is in the local varieties of corn sometimes culti- vated on farms in New England and the Middle States. Where a single variety has been cultivated for a man’s lifetime in the same neighborhood, or even on the same farm each year, the seed having been carefully selected and prepared until no further improvement is reached by such selection, here it often happens that such home-bred local variety yields better than any variety introduced from without. But it also happens that, having been so long purely bred, it is of especial value in mixed planting, as already described, - 305 COTTON. H. Hammond, in his report to E. W. Hilgard on the cotton produc- tion of the State of South Carolina (Tenth Census U. S., 1880, Vol. VI, p. 475), says: In a handful of ordinary cotton seed three varieties may often be recognized, presenting well-marked differences. The largest of these is covered with a green down; another smaller and much ‘more numerous seed is covered with a white or grayish down; the third variety is naked, smooth, and black. It may not be possible to say whether these three sorts of seeds correspond to three classes under which the numerous varieties of cotton are arranged. These are, first, the “ green seed, corresponding with the Gossypium hirsutum, or shrub cotton, attaining a height of from 10 to 12 feet, a native of Mexico, and varying as an annual, biennial, or perennial, according to the climate in which it is grown; second, the ‘“‘ white seed,” corre- sponding with the Gossypium herbaceum, or herbaceous cotton, an annual, attaining a height of 2 feet, native of the Coromandel coast and the Nilgherries; third, the “black seed,” corresponding with Gossypium arboreum, or tree cotton, a native of the Indian peninsula, but attaining a height of 100 feet on the Guinea coast, and producing a silky cotton. The black seed, however, is not distinguishable from the seed of the long-staple or sea-island cotton. HISTORY OF THE LONG-STAPLE COTTON. It would be a matter of much interest to determine the origin and history of the varieties of cotton now in cultivation. The difficul- ties of doing this are much increased by the very wide geographical range occupied by the plant. The earliest explorers, Columbus, Magellan, Drake, Captain Cook, and others, seem to have found it almost everywhere in the broad belt extending from the equator to 30° south and to 40° and 45° north latitude, where it now grows. Although it is not found among those oldest of vestments, the wrappings of Egyptian mummies, its use was known to manin Europe, Asia, Africa, America, and the outlying islands of the sea in the remote past, far beyond the historic age. Its very name itself bears evidence to this, occurring, as it does, in many and in the most ancient languages. Nevertheless nothing can show more clearly the importance of tracing and understanding the history of plants under cultivation than the variation and improvements in black seed cotton since its introduction on the Carolina coast. It is known that the first bale of long-staple cotton, exported from America in 1788, was grown on St. Simons Island, Georgia, by a Mr. Bissell, from seed that came from either the Bahamas or the Barbadoes Islands.* Singularly enough, the authorities leave this matter in doubt, the Hon. William Elhiott saying it came from Anguilla, one of the Pahamas,? and Signor Filippo Partatori (Florence, 1866), saying it came from Cat Island, one of the Barbadoes.¢ But as Anguilla is one of the Barbadoes“ and Cat Island one of the Bahamas? it would seem difficult to decide to which group of islands we are indebted for these seed. However, as Mr. Thomas Spalding, of Sapelo Island, says, in a letter to Governor a Sic. 2667—05 m——20 306 Seabrook, in 1844, that three parcels of long-stapled cotton seed were, to his knowledge, brought in 1785-86 from the Bahamas to a gentle- man in Georgia, it would seem certain that the seed reached our coast from those islands. There it was knownas Gossypium barbadense, as coming from the Barbadoes. In the Barbadoes it was called Persian cotton, the seed having been brought from that country. In this manner its descent from the G. arboreum of India 1s traced. Be.this as it may, Mrs. Kinsey Burden, Burden Island, Colleton County, S. C., obtained some of these seeds from Georgia and planted them. This crop failed to mature, and the first successful crop of long-staple cotton grown in South Carolina was planted in 1790 by William Elbott, on the northwest corner of Hilton Head, on the exact spot where Jean Ribault landed the first colonists and erected a column of stone, claiming the territory for France a century before the English settled on the coast. Mr. Elhott’s crop sold for 104d. per pound. Other planters made use of this seed, but it was not until Kinsey Burden, sr., of Colleton County, began his selections of seed, about the year 1805, that attention was strongly called to the long staple. Mr. Burden sold his crop of that year for 25 cents per pound more than did any of his neighbors. He continued to make selections of seed and to improve his staple, and in 1825 he sold a crop of 60 bales at $1.16 per pound. The year subsequent his crop sold for $1.25, and in 1828 he sold 2 bales of extra fine cotton at $2 per pound, a price not often exceeded since. The legislature was on the point of offering Mr. Burden $200,000 for his method of improving the staple of cotton, and Mr. William Seabrook, of Edisto, was prepared to pay him $50,000 for his secret, when it was discovered that the fine cotton was due wholly to improvements made in the seed by careful and skillful selection. Since then the greatest care has been bestowed upon the selection of the seed, and to such perfection was the staple brought by this means that the crops of some planters were sold not by sample, but by the brand on the bale, as are the finest wines. During the war of 1861-1865, the cultivation of the finest varie- ties being abandoned on the islands, the seed removed to the interior greatly deteriorated in quality. So scarce, on this account, was good seed directly after the war that J. T. Dill, a cotton merchant in Charleston, at one time had, in an ordinary letter envelope, the seed from which are derived all the better qualities of long staple now cul- tivated. Nor have the improvements made by careful selection of the seed ceased in later years. The staple has kept fully up to the best grades of former days, and the proportion of lint to seed cotton has been increased. Formerly 1 pound of lint cotton from 5 pounds of seed cotton of the fine varieties was considered satisfactory. Thanks to the efforts of Mr. E. M. Clark, a cotton has been recently found which yields 1 pound of lint to 34 of seed cotton, preserving at the same time the length, strength, and evenness of fiber charac- teristic of the best varieties. BEANS. The history of the derivation of the bean (Vicia sativa, Vicia faba, and Hrvum lens) is given by A. de Candolle (see Agr. Sci., Vol. I, p- 58), who shows that its cultivation began in Persia, and that the common white bean, which has been cultivated since prehistoric times 307 in Europe, has some similarity to a bean cultivated in India since the earliest times. The characteristic peculiarities of the cultivated bean and its uncultivated relatives have probably existed for at least five or six thousand years, and the original stock from which the cultivated bean was derived has long since become extinct. PEPPER. The derivation and varieties of peppers from all parts of the world (genus Capsicum) are described by E. L. Sturtevant (Agr. Sci., Vol. II, p. 1). The general effect of climate is to diminish the size of the fruit when the seeds are planted in higher latitudes—that is to say, with a diminution of temperature. Similarly,-the effect of cold nights is to check the growth, diminish the size, and promote early ripening. KENTUCKY BLUE GRASS. The germination of Kentucky blue-grass seed (Poa pratensis), as also that of red top and timothy, has been studied by Thomas F. Hunt at the agricultural experiment station, Champaign, Ill. Al- though the object of the experiment was primarily to determine the relative vitality or honesty of the seeds and samples from differ- ent sources, yet the results have some bearing upon the question as to the best temperature for germination and the possibility of accli- matization. Kentucky blue grass, raised in Kentucky, when sown in the Geneva sprouting apparatus, would not germinate in thirteen weeks at temperatures from 70° to 80° F., whereas 80 per cent of meadow fescue and 95 per cent of mammoth red clover sprouted during the first week in June, 1888. Again, in 1889 a specimen of blue grass from the same locality would not sprout in sixty days at an average temperature of 67° F., whereas during the first eight days 98 per cent of both timothy and red clover and 85 per cent of meadow fescue sprouted. Again, a sample from another dealer in Kentucky, tested for thirty days under similar conditions as the last, gave one sprout to a hundred seeds. Another sample was sent from Chicago to Manitoba and thence to Champaign for testing. Out of 500 seeds not one sprouted, but in the best of subsequent samples 7 per cent sprouted. Finally, samples were obtained from 19 different sources, mostly in Kentucky, and were all tested uniformly in the Geneva apparatus at Champaign, IIl., from July 23 to August 31, 1889. The range of temperature in the apparatus was from 63.5° to 73.5° F. Out of all 308 the samples the maximum and the minimum percentages of sprouting were as shown in the following table: Average Variety. Maximum.| Minimum. of 19 Per cent. | Per cent. | Per cent. Kentucky: blueierass:: 2-3-5 2262 e2 so ee ne eee ee ae 7 0 Z Red top sc. 2 vases Pech se soe eae, eee neace ee Jes eoseencecees 63 4 25 Mimothy 222 A: Se ese She as see Sh ee ce SS 96 42 76 These are not lhkely to be abnormal percentages, since, according to Professor Hunt’s calculation, with an ordinary seeding of 30 pounds to the acre, if only 2 per cent germinates there would be 40 plants to the square foot. But the question may still remain as to whether the soil or the temperature were unfavorable or whether the seed of the Kentucky blue grass was in some abnormal condition. (Agr. Sci., Vol. IV, p. 4.) : Chapter XII.? RELATIONS OF SPECIAL CROPS TO SPECIAL FEATURES OF CLIMATE AND OTHER INFLUENCES. The preceding chapter on phenology has given several illustrations of the influence of the date of planting upon the dates of the resulting phases and on the amounts of the harvest for special plants. The exper- iments at experiment stations now about to be quoted were under- taken with a view to the further direct elucidation of this relation. From such experiments we obtain definite data by which to decide as to the best date for planting and the probable resulting crop both in normal and abnormal seasons. We see to what extent the seed and plant have acquired habits suitable to the prevailing climate, and furthermore, what climatic influences the plants were not able to withstand when the seeds were planted too early or too late. It is, of course, of prime importance in each case to know where the seeds were grown or to what climate they were acclimatized before being planted at the experiment station. By measuring the weight and nutritious value of a sample of a crop at various stages of development we are able to form tables showing the relation of the mature ultimate harvest to the immature plant, and this relation is found to be sufficiently constant to justify one in predicting the harvest per acre from its condition on any given day several months before harvesting. Examples of this process have already been given and others now follow. BEETS AND POTATOES. DATE OF PLANTING. Briem finds the crops of beets and potatoes that have become accli- matized in Austria-Hungary vary with date of planting, as given in the table following. aA chapter on “ Forests and climate,’ which was originally intended to pre- cede this chapter, is omitted. (309) Average From sowing to harvest. | weight of one tuber. Date of sowing. esis BE meen Number Total of days. eae when aa Beet. sPotato. Armia, (free fell. ey boy (Ch _ mm. Grams. Grams. Marchal 3.32 esse ee ee eee 234 3,271 108 519 298 196 MarchslG 2:22 ates aoe eae ene eae 219 3, 209 108 | 506 231 | 222 PAST ee ees oe ee eee ee. ee, ee 203 3, 151 102 | 496 207 272 PDT Gi ease eer ne Sea re ee ae 188 3, 020 94 | 453 304 257 May ilteee 5200 cowie 4 Perio stores eaten 173 2,881 87 | 417 306 | 302 Mai yal Geely ee ee nee ee tine 158 2,726 80 373 266 | 228 Jjariepll? Wie ete + and.richer in nitrogen. In Colorado, where irrigation is practiced, a large grain is grown which is rich in nitrogen. On the northwest Pacific slope the grain is large, very starchy, and with less nitrogen than anywhere else. The above conditions, as at present existing, are probably in a state of transition. ; The following table shows the difference in the composition of the crops of standard varieties of wheat in Minnesota and Dakota: Albumi- F Albumi- Crop. noids. Crop. noids. Per cent. | Per cent. SS 2k Some ae eee, 13210 |GisSde ses 8 8 ee ee eee eee 14. 28 Ieeoh re reuters ILE eal 15.14 | ipegae sls | AUIS aa 15.99 313 ‘The following table shows the differences for the varieties raised in the respective States: Weight | 4 tbumi- Weight | aipumi- of 100 | noids. of 100 | “noids. kernels kernels. Grams. |Per cent. Grams. |Per cent. All North America_--------- 3. 644 2 5 y | ROM IOR sS2 > ae oe 3.476 12.838 Atlantic slope: 2.222225: 2-5" 3.489 1185? ||| "Dennessee=-* 222222. -225.=:- 3.150 12.50 Central’ Statess 2222. fo 22. 3. 684 12466), ||P Wenbucktye-e sane eae eee ee 3. 454 13.15 INOrtihiwest sos =24 > 22 59.22 3.205 14S O%a || Vaeininy £2 pee ene 3. 433 12.10 NiortnePacince. 2 ---2-—-5— 4.091 SEOs GeOk PIR ons aetna ees 3. 578 11.78 (CORTRXOE, BS a ee ee ee 3.325 LONS7-|| Alabam~ay- =~ 2-2 see 3. 424 11.29 Miehiosamtess ne) kee 3. 969 11. 67 The effect of climate and soil on wheat is strikingly shown in that a soft plump yellow wheat from Oregon and a small hard red variety from Minnesota, when used as seed in Colorado, in three years’ time had lost nearly all their differences, so as to look more like Colorado grain than like their own originals.¢ A study of 38 varieties grown during seven yedrs on one farm in Colorado shows a progressive change, as in the following table: Year. eat abe: bie : Year. Wes AYeota Noe : grains. * | bushel. grains. * | bushel. | Grams. |Per cent.| Pounds. Grams. |Per cent.| Pounds. 1st eee ae eee 4. 865 UBE4ON S25 tee 1c yee ar ease bee bees 4, 222 12.53 65, 2 iG ae ae ees 4, 283 DSiO£: fs - ee ABS e 4 2 Se. te se aee 3.810 11.34 | 62.2 NGSS ie a ees re. 3.941 JA G4 Woe eae | These determinations show plainly that the soil and other condi- tions in 1885 would not produce as good a crop from introduced seed as in 1881, and that the drop in character of the crops as a whole is due as much or more to soil than to season. The seven varieties grown for several years in Colorado which showed no signs of deteri- oration are on this account worth considering, since they are perhaps the varieties to select for the locality, because they may be more suited to the conditions there existing than any others. Attention is called to the fact that deterioration in quality, as evidenced by diminution of albuminoids, is shown by the loss of weight per bushel. In the present case a drop of 1.2 per cent in albuminoids was accom- panied by a loss in weight of 3 pounds per bushel. No other cereal seems to be influenced by its environment in the same way as wheat. Oats are more changed, by climate and soil, in the outward physical appearance and properties of the grain; barley is modified in its «There is nothing to show how much this may have been due to spread of pollen from one field to the other.—C. A. 314 chemical composition; maize is modified as to its size; rye varies very little with change of conditions, except as to the effect upon the straw; but, as we have seen, wheat changes both its external appear- ance and its chemical constituents. With regard to maize, the high ripening temperature of the South- ern States appears to diminish the size of the kernel and prevent a large formation of starch. But the variations in size peculiar to the varieties are much smaller than variations that are due to the climate and soil, thus Dent varieties of corn from Tennessee and Indiana have been Fanta weighing, respectively, 64.1 and 13.9 grams per 100 ker- pels, or a ratio of 5 to 1 in the weights of the kernels. Hence a comparison of the yield per acre by the weights of the crops would differ very much from a comparison by volumes in bushels. The per- centage of albuminoids varies very much less in the large and small kernels of maize. As to oats, the climatic surroundings cause a very large variation in their physical appearance. The extreme weights per bushel are 48.8 and 24.7 pounds; the extreme ratios in the weight of the kernel, with reference to the weight of the kernel plus the hull, are 79 and 55 per cent. The average composition all over the country as to the percentage of albuminoids is between 12 and 10 per cent, except in a few extreme cases of 9 and 19 per cents, which are as lable to occur in one locality as in another. Barley is not as variable in composition and appearance as wheat and oats; the extreme weights per bushel are 60.2 and 50.4 pounds, and the extreme weights of 100 kernels are 4.900 and 2.630 grams; the extreme percentages of albuminoids are 14.88 and 8.75. For malting purposes the large quantity of albuminoid is not desirable, while starch is desirable. WHEAT—GENERAL RELATIONS TO CLIMATE AND SOIL. In his tenth census report Professor Brewer says: While the cultivation of wheat in a commercial sense is determined by a complicated set of conditions, in an agricultural sense the matter is very much simpler. The yield and quality of the crop practically depends upon but five conditions—the climate, the soil, the variety cultivated, the method of cultivation, and the lability to destruction by insects. Even under poor cultivation and exemption from insect depredations, if the other three conditions are favorable good crops of wheat of good quality may be very often grown, and in a good climate and with a good v ariety of wheat an excellent quality may be grown even where the soil is comparatively poor. The yield may be small, but the grain itself will be good. As regards soils, we may say ina ‘general way that light clays and heavy loams are the best for wheat. On the one hand, very heavy 315 clays often produce good crops, both as to yield and as to quality, and on the other hand the lighter soils may yield a good quality. It is simply smaller in quantity. The best crops, however, come from moderately stiff soils, but any fertile soil will produce good wheat if all the other conditions are favorable. Geologically considered, the most of the wheat grown in the United States is over the region of drift, but much of the wheat soil has been so modified by other geological influences that the geological factor is not an important one, the essential character which gives it its value being as largely physical as chemical. Good wheat lands agree in this. that they are sufficiently rolling for natural drainage; are at the same time level enough to admit of the use of field ma- chinery, and are easily tilled, admitting the use of ght field imple- ments in their tillage and thus allowing of a very large production of grain in proportion to the amount of human labor employed. The facility of putting in the crop and harvesting it is really the controlling condition in many localities, so much so that the very important wheat regions, where some of the most speculative farm- ing of the United States is practiced, are in regions where the cli- matic conditions are such that the average yield one year with another may be as low as 10 bushels per acre. In such cases this low average is usually due to climatic reasons rather than to a lack of fertility in the soil, and in favorable years the yield may be very much larger. The ease of cultivation, the facilities for gathering the crop, and its good qualities in favorable years incite to the hope that all years will be favorable, and in good years the profits are large. In color, in the amount of clay contained, in physical and in chemical characters, there is much difference in the different soils of the coun- try. Some contain much vegetable matter, others but little. We may say that the soils of all the more important wheat regions (so far as we have chemical analyses) are rich in lime, as well as in those other elements of fertility, such as potash and phosphoric acid, which are necessary for a good crop and a good quality of grain. For commercial as well as for agricultural success climate is an all-controlling condition. Wheat is normally a winter annual. For a good crop the seed must germinate and the young plant grow dur- ing the cool and moist part of the year, which season determines the ultimate density of growth on the ground and, consequently, mostly determines the yield. Wheat ripens in the warmer and drier parts of the year, which season more largely determines the quality, plump- ness, and color of the grain. In climates with winters so cold that all vegetable growth is suspended we have two distinct classes of varieties, known, respectively, as spring and winter wheats. Through- out all the Northern States, from ocean to ocean, and to some extent in those Southern States which lie east of the Great Plains, these two classes of varieties are very distinct as regards their cultivation and to some extent also as regards their characters. In California and in similar climates, as in Egypt, this distinction does not exist in respect to their cultivation, although the varieties partake more of the character of winter wheats than of spring, both in their mode of growth and in the character of the flour made from them. But in all climates and whatever variety may be grown, the crop must be sown and have its early growth in a cool part of the year. 316 Wheat branches only at the ground, and produces no more heads than stalks. It only sends out these branches early in its growth or dur- ing cool weather and when the growth is comparatively slow. The branching of wheat (called “ tillering ” in the Old World, and “ stock- ing,” “ stooling,” and “ tillering” in different sections of this) must take place before the plant attains any considerable height or it does not occur at all. Hence, in climates like those of the Northern and Eastern States this takes place mostly in the spring, and a cool, pro- ionged, and rather wet spring is therefore best for the ultimate ‘yield *of the crop; the grain then stands heavier on the ground. On the contrary, a warm, “rather dry, rapidly growing, and early spring in those parts of the country diminishes the yield of wheat, because of this habit of growth; there are then fewer stalks, and the heads are fewer. Consequently, when from the nature of the season or the general climate of the region there is an undue tendency for the wheat to shoot up without “sufficient branching it is common to check the growth by pasturing off the grain in the early spring, as is a common prac tice in many of the Southern States. In a country of cold winters, for good crops it is better that the ground be continuously covered with snow. Bare ground, freezing and thawing, now exposed to cold and dry winds and now to warin sunshine, is exceedingly destructive to wheat. It “ winter-kills” in two ways—what may be frozen to death by cold, dry winds, or, as s more often the ease, particularly on soils rich in vegetable matter, “heaves out,” and by the alternate freezing and thawing of the sur- face soil the roots are lifted out of the soil and the young plant perishes. The means of guarding against this or of lessening the danger will be spoken of later. After the wheat comes in head more sun is needed and less rain. Too much rain, particularly if accompanied with heat, induces rust, mildew, and other diseases, and, on the other hand, too dry winds shrink the grain. The ideal climate for wheat is one with a long and rather wet winter, with little or no frost, prolonged into a cool and rather wet spring, which gradually fades into a warmer summer, the weather growing gradually drier as it grows warmer, with only comparatively light rains after the blossoming of the crop, just enough to bring the grain to maturity, with abundant sunshine and rather ‘dry air toward the harvest, but without dry and scorching winds until the grain is fully ripe, and then hot, dry, rainless we: ather until the harvest is oathered. This ideal is nearer realized in the better years in Cali- fornia than in any part of the United States, and it is there in such vears that we find the greatest yields known to the country. The quality of the grain is largely determined by the climate, a hot, dry, and sunny harvest time being best for wheat of the first grade. The berry is then brighter, and ‘millers say the quality is bet- ter if the climate has been hot and dry before the harvest. The wheat of sunny climates—those of California, Egypt, northern Africa, and similar countries—has always ranked high for quality, and the statement is often made that ‘the wheat of such climates is also richer in gluten—that is, makes stronger flour—than the wheat of cooler climates. Of this latter assertion I find no proof from the mod- ern and fuller chemical analyses. The chemical composition depends 317 more upon the variety cultivated than upon either soil or climate. The spring wheat of Dakota and Minnesota produces as strong flour as does grain from a sunnier climate. It is true that certain varieties of very hard wheats only grow in hot, dry climates. Such is said to be the case with the best macaroni wheats. It is claimed that the macaronl wheats of California are equal to the best of northern Africa or of southern Europe and that the macaroni made from it in San Francisco is equal to the best Italian. But while, as a whole, the quantity of gluten and the strength of the flour is determined more by the variety of wheat than by the climate or the soil, yet both of the latter have their influence on chemical composition. Although direct chemical evidence is lacking, derived from a large number of chem- ical analyses from samples chosen with this special object in view, it is claimed that abundance of phosphates in the soil increases the quantity of gluten in the crop. The millers of western New York say that the flour has grown stronger with the increase in the use of superphosphates in growing wheat in that region, and that the same has often been stated as a fact in English experience. The particularly bright character of American grain, however, depends upon the climate rather than upon the soil. The sunny climate of the whole United States south and west of New England is favorable for this, and from the time of the first settlement of the colonies the bright color of American grain, as compared with that of northern Europe, particularly that of Great Britain, has been remarked. The table of distribution according to annual temperature (Tenth Census, Cereals, Table XIX, p. 14) shows that the greatest produc- tion is where the mean annual temperature is between 50° and 55°, 173,895,149 bushels, or 37.8 per cent, being grown in this belt, and 136,401,822, or 29.7 per cent, where the mean annual temperature is between 45° and 50°. Adding these two, we see that 310,296,971 bushels, or 67.5 per cent, is grown where the mean annual tempera- ture is between 45° and 55°. Considered in respect to the mid- summer or July temperature (Table XX, p. 14), which has much to do with the ripening of the grain, our figures are of less interest in this crop, because over considerable regions of the country the crop is already ripe before July begins, notably in California; but we find that 223,852,371 bushels, or 48.7 per cent, grows where the mean temperature of July is between 70° and 75°, and 178,530,037 bushels, or 38.9 per cent, where the midsummer temperature is between 75° and 80°, or an aggregate of 87.6 per cent where the July temperature is between 70° and 80° and 97.3 per cent where it is between 65° and 85°. While the ideal climate for wheat is one of mild winters, and some of the most noted wheat regions of the world are where snow and frozen ground are unknown or very rare (as in Egypt, India, and California), nevertheless most of the wheat of the world grows in regions of cold winters. The table of distribution according to mean winter temperature (Tenth Census, Cereals, Table X XI, p. 15) shows that in this country 46.6 per cent grows where the mean January temperature is between 20° and 30°, 68.9 per cent where it is below 30°, and it is safe to say that 70 per cent of the wheat crop of the country is grown where the 318 average January temperature is below the freezing point. This same condition marks most of the great wheat regions of the world. The wheat countries (which are also the countries of oats, barley, and rye) are where the summer season only is the growing season, and the comforts of winter must be provided for by forethought and labor; and hence they are also the countries of labor, industry, and enterprise, and where the highest civilization has been developed, the result being correlated to these climatic conditions. The table of distribution according to rainfall (Table X XII, p. 16) shows that 132,152,234 bushels, or 28.8 per cent of the crop, grows with an annual rainfall of between 40 and 45 inches, 62.7 per cent where it is between 35 and 50 inches, and 92.4 per cent where the annual rainfall is above 25 inches, although some important wheat regions, notably those of California, are where the mean annual rainfall is less than 25 inches. We have an explanation of this in the seasons at which the rain falls. The table of distribution accord- ing to the rainfall of the growing season (Table X XIII, p. 16) shows that 220,656,637 bushels, or 48 per cent of the crop, grows where from 20 to 25 inches of rain falls during this season, and 366,381,658 bushels, or 79.7 per cent, where the rainfall during the growing season is from 15 to 25 inches, 6.4 per cent where it is below 15 inches, and only 1 per cent where it is less than 10 inches—a fact of much significance for great tracts of our country. CULTIVATION OF CEREALS—EXPERIMENTS AT BROOKINGS, S. DAK. WHEAT. The first annual report of this station, for the year ending June 30, 1888, gives following table of results of experiments on different varieties of wheat, at Brookings, S. Dak. (lat. 44.3° N.; long. 98.5° W.), in April and May, 1887, on plats of ground that had already borne one crop of wheat or flax or oats. Some were sown broadcast and had no subsequent cultivation; others were “ drilled by hand ” and subsequently hoed twice or thrice. The columns giving the calculated sums of degrees of temperature are based upon observations at the Signal Service station at Huron, some distance to the westward, because the special station at Brook- ings was not then established. The meteorological table for Huron follows the agricultural tables, so that the student may make such further studies as he desires. A fragment of the meteorological record at Brookings for 1888 is given in the station Bulletin No. 5, which I have compared with the record for Huron and find that no important error will result from using the Huron records. ; 319 . ee Sums of Variety. parr Barvont: tenpora! ing. tures (T—438°F.). Sown broadcast: 1887. 1887. DE. Saskatchewanrhtomssseres spe -s eben) Seca as Sekt ec Apr. 2 | Aug. 1 2,367 Hrenchelmporiala piso. 22 sss eecon ac eee enne sence eceeeeeee- .---do-..| July 29 2,279 Hand drilled: Blountn COLAC O we aes sett as eeee oko see Soe aes e eect Apr. 30 | Aug. 10 2,518 WiellmanisiSaskatchewans--- 22220 -20e. Ste els epee hen doe Aug: 9) 2,484 PUTO SCOLCHENITO) He Sas oS easy pea ete te tee et eh ton ee eesu eee = do ..-| Aug. 6 2,397 Russian Fife __--..------- Re ee ee ee ee ere ARES | May 3) Aug. 11 2,514 @hitay Reaee ee ee eee OS Pee Shy ee ok (eee oat ee orem 2,514 MelvetiChattoriblive Stem] 282. se sas2 2225 ses ee eres eketenee ate [Peeedoees|foilivacd 2,168 IBlountispebyOnidsiNOs Lbwessec er so eee css see ae eee eee ese sene Apr. 30 | Aug. 9 2,484 Bloumtisprby brid NO se se. eee ase ce so eat acne oes s se ee eee | May 3] Aug. 6 2,373 Champ laine 22) te soso ss oso see sc ene as ckcS eS Sere eee May 8| Aug. 8 2,311 GoldeniDrops 3 tins taos sed octet tee eee teste ewecesecesckele | May 3/| Aug. 4 2,326 Blount susie roo ies secs ae SSeS Sacre se ecco we eee ole oe do..-| Aug. 8 2,437 eerless|onip lack: Bean 6 Wee. a= en oat ee ee ea eee we eee ose do ..-| Aug. 20 2,728 Pringles Grandeoe 224000) 222 ae eee eee cede. op eeee rete a2 eens se do ...| Aug. 12 2,534 BARLEY. The following table gives the results of experiments on different varieties of barley at Brookings, S. Dak., as given in the first annual report of that station. For further details see the preceding section on wheat experiments. Variety. Date of sowing. Sown broadcast: NVAISCONSINManNS hurry! 2 22s ses ee nee | Saree eee eee ma perialvily brid sae ss5 eee eee ee ee eee eee Hand drilled: Man SITIIy He sae As te fase: Secroe SE ee ee HW Oe EVO WOU scone este eet Ree ec Se aa ot oe imiporialle pase sso ase | awe oe el Pe tat OURS EGO WiC eect ae eee i ee ne eta Woe ee IBaTleyeNOnS east sees ce te eee Bi ee Se eS Black Hullesssete sak eerste Dees Le eee BEATE L 1887. eee. ee Apr. 25 een ee bees (oes Sees see eedowes Date of harvest- ing. 1887. July 18 July 23 July 18 = donee July 23 July 22 July 20 July 25 ee dOee- July 20 July 28 Sums of positive tempera- tures (T—48° F.) OE 1,977 2,095 1,977 1,977 1,946 1,922 1, 880 2,010 2,010 1,880 2, 099 320 OATS. The following table gives the results of experiments on different varieties of oats at Brookings, S. Dak., as given in the first annual report of that station. on wheat experiments. For further details see the preceding section Sop | sume of ate of | positive Variety. nn Ged tenipers: (T—43° F.), Sown broadcast: 1887 1887. Ae IPTODStICn 7. Sese see ee see ee ee ee ee Apr. 23 | July 29 2,279 ‘WielCOMm@s:@ ne Be Sere Ne ean eee ee ee ee Apr. 25 |---.do- 2,279 White; Beletum . 2-2 20% 25 Seen oe se ee ae ee ee ee ee ee eee dots) Augie 2,367 Wide Atwake 2 2.2222 soos cceesis cat cctees oe tee ae ne oe Pee | do .-.| Aug. 3 2,319 Wihite*Bonanzass iiss) a 2S 22 oo a ee en ree ere a eee aa Apr. 26; Aug. 1 2, 365 Hareecti Ss WiHIbelSelZUberssases sess see eee eee eee ees Pere ee seen \----do.-.| July 22 2,069 Hand drilled: ; | White VACtOniaas siete occa ee ae ee ae ee ee ar May 5] Aug. 3 2,270 Blacks NOLWAY= 22s2so5 soon 0 See ane ee ee eee do...| Aug. 8 2,399 Black! Tantarian S22. 2.22.6 ete tae ee ae ee ee eee dot |2=-2dor 2,399 DakotaiChicftain = 2.25 2 cae es Ree Pee a) See ee ae eee ee | aeaee do..-| Aug. 1 2,218 No Names: Ws) eee cc cot cnet nena aan See eee eee ee Goees|=e== do -.- 2,218 Golden’ Russian: 225355. 2b ance REN ee a ee foes |----do ---| July 28 2,099 White: Surprise: 2. si: sag. ses. asthe ete oe Soe a akeee |...-.do...| Aug. 1 2,218 Holsteins /<)o-2 52S 2bsees fone sews ee en cen eee ee eee [S20 doses} do _- 2,218 The meteorological record for the “ Huron is now given for detailed comparisons. give the temperatures computed by the two methods of Boussingault and Angot, respectively. growing season” of 1887 at The last three columns Meteorological data for Huron, Dak., in 1887. ee | Rela- Date. ter Dem ie Wind. pera- mid- ture. | | ity. | 1887. oW', | °F |Per ct.| Miles | Apr. 1 | 7 28 55 | 127 2 48 33| 60) 151 3 26 15| 64! 437 4 Bi |= 6410250 5 40 | 22 52 | 222 6 47 29 54] 187 7 53 33 53 | 354 8 73 36 32] 514 9 64 47 | BY | 476 10/ 30] 30| 72] 365 ll 52 44; %6| 323 Clouds.) Rain. Sum of daily tem- Posi perature. tem. | All : posi- pera- = Frosts. ture | All (eae (T | All. jabove ae —43° | 43° 7H |e MS). || above 43°F.). In. Dates | OF: i ORT on paces 1 | 4 7 47 4 O03; Reasons 5 95 95 9 Bll eee eee 121 95 9 See eee eseeseallesscse d 149 95 9 Se se ee ee 189 95 9 Soetces 6 4| 236}; 142 13 Bee ii 10| 289} 195 23 AO4N 22a eo ce 30 362 268 53 B20 Wbeeeeees 21 426 332 7 Plies ses. So leseeeee 465 332 74 61 | Jewetecs 9 517 384 83 321 Meteorological data for Huron, Dak., in 1887—Continued, es | lve see Godage a a ae Date. | tem- point. hu- |Wind./Clouds. Rain. Frosts.| 47g pera- mid- (T ture. ity —43° F.). | - = 1887. | °F. | oF. |Perct.|Miles.| Perct.| In. | Date.| °F. Apr. 12 54 43 i 60 (Gale [eats u 13 49 47 93 | 300 LOE) riety 6 14 41 37 89 | 265 (ivy ea | ae eee (ea 15 38 30 75 | 369 100 1 Oot easnereacha Mieaeeeg 16 43 35 15 58 LOO eee ries ta 0 17 43 28) 59 52 (Or) es 8 eee 0 18 44 2 50 85 (A eee 18 1 19 45 26) 53] 109 Sse ..| 19 2 20 Ay 27| 54| 158 Nye ee area | eee 4 21 46 40 S| 413) 70 Gh eee 3 22 35 Slee G2ue SOI BOE Ohh: aes 23| 32} 23| 69| 278 Br eHOS NN Ves |e 24 34 25 68 | 222 Dall GAs vat tocar fo 25 41 23/ 51] 147 Oia Die Gao aes %| 45| 33| 64| 144 DIAN e208 |e 2 BGs Oo, BS) b5r| B20.) Ga} 02 |e 13 Bare Beh G asta 4 90H) « Sa, oe ccf 15 29; 70| 39| 36) 473 7S ed ell BRE 27 30 73 46| 41] 358 Oy Nc | ec 30 May 1| 357 45| 64| 301 Br lo heee [sears 14 2| 39/° 31) 73) 634} 80] .08 | garners acto 3 53 26 42] 285 3| Tr. a3 10 4 61 35 47 | 334 (ks BC, aes (nee 18 5 63 34 Be fost eG taal ee 20 Giles. doe) me aoely aaah ga ih. asilba se |) 8 ees 28 12 68 7 67 | 384 (ire lee hatte QB 13 65 55 76| 359 CEI Gr 4 recess 22 14 57 39 56| 314 Dit eae ead tenet 14 15 62 44 58) 207 BO cols eect 19 16 44 36 74) 377 Ce alin aC Ae se | 1 17 51 37 62) 116 7 Ca ea 8 18 63 45 56 | 367 Op item | ess 288 | 20 19 73 52 50 | 559 (Os | eee NE 30 20 5 57 55 | 470 7 ueeeeee lis ane. eee 21 59 54 83} 302 S77 48a ier16 22 5T ay 70| 211 Byall yer, COs eee 14 23 60 46 63} 324 TA Maectek 9) eo 17 24| 56 38 55 | 221 Q); [ceeeeell cael ae 13 25 62 40 52 " Bris toe lk eens 19 26 66 43 50 | 331 C1 eae eae 23 27 66 45 52] 186 py eee. Nelle 28 28 61 58 76 | 208 Soil) 204A tena! 18 @ Light 2667—05 m——21 Sum of daily tem- perature. All | a All. above Sees ture above 43°F), of | op, | oF, BY1| 438| 94) 620| 487 | 100 | 661 487 | 100 699 487 | 100 742| 487} 100 785 | 487 | 100 | 829| 531] 101 | 814 576 | 108 921 623) 107 7 | °669.| 110 | 1,002 669] 110 1,034 669) 110 | 1,068 669) 110 1,109| 669! 110 | 1,154|/ m4] 12 1,210| 770| 125 | 1,268 | 828| 140 | 1,338 | s898| 167 1,411| 971] 197 1,468 1,028 2u1 1,507 | 1,028 | 211 1,560 | 1,081 | 221 1,621 | 1,142} 230 | 1,684 | 1,205 | 259 1,756 | 1,277 | 288 1,831 | 1,352 | 320 | 1,901 | 1,422 347 1,973 | 1,494| 376 | 2,047 | 1,568 | 407 2,118 | 1,639 435 | 2,186 | 1,707 | 460 | 2,251 |1,772| 482 2,308 | 1,829) 496 | 2,370 | 1,891 515 2,414 11,935 | 516 2,465 | 1,986) 524 2,528 | 2,049) 544 | 2,601 | 2,122 574 2,676 | 2,197 | 606 2,735 | 2,256 | 622 | 2,792 | 2,313 | 636 | 2,852 | 2,373 | 653 | 2,908 | 2,429 666 2,970 | 2,491 | 685 | 3,086 | 2,557 | 708 3, 102 | 2,623 | 731 3,168 | 2,684 | 749 322 Meteorological data for Huron, Dak., in 1887—Continued. Sum of daily tem- Posi peratures. 1ve Gee ee L . tem- we Date. tem- : hu- |Wind.|Clouds.| Rain. | Frosts. s tive pera- | Point.| jnia- 7 All ae (tem- ture. ity “age * gop | Dera- ture F.). above 43°F). 1887. ) JaL, °F. |Per ct.) Miles.| Perct.| In. Date SE oy 7 7, Che May 29 63 39 46 | 421 ey || anes ose 20 | 3,226 | 2,747 | 769 30 53 43 70 | 469 (67h emer | Speers 10 | 3,279 | 2,800] 779 31 56 46 69 | 237 535 eee. (fomanmin 13 | 3,835 | 2,856 | 792 June 1 61 44) 59] 212 PE lee 1 cana, 18 | 3,396 | 2,917 | © 810 2 65 51| 64] 316 ICO Dhl te ee eet PAR 22 | 3,461 | 2,982] 832 3 59 49, %2| 360) yells B28} goers 16 | 3,520 | 3,041 | 848 4 56 40 60 | 190 (0) cee sae aa 13 | 3,576 | 3,097 | 861 5 70 54 60] 371 (| Seamer Eee See 27 | 3,646 | 3,167 | 888 6 83 59 47 | 441 ial eebdee ses |e ee ee 40 | 3,729 | 3,250 | 928 7 70 62 77 | 284 Cia 4h | ae 17 | 3,799 | 3,320} 945 8 67 54 65 | 119 S7ig| earemee e -.-----| 24 | 8,866 | 3,387] 969 9 70 58 68 | 141 GBhEeraaaea |i seeesa 17 | 3,936 | 3,457 | 986 10 69 66 BO BIL WRN TTB} ee 26 | 4,005 | 3,526 | 1,012 ll 14 65 "7 | 183 GOlle lial eemeee 31 | 4,079 | 3,600 | 1,043 12 72 61 72 | 160 Cyl) Were, ieee 29 | 4,151 | 3,672 | 1,072 13 74 66 78 | 196 al eee (3 | eee 31 | 4,225 | 3,746 | 1,108 14 80 67 66 | 340 Hs | one et eect 37 | 4,305 | 3,826 | 1,140 15 81 69 68 | 461 (On| aeetoes oe ea 38 | 4,386 | 3,907 | 1,178 16 17 56 52| 301 Diy ee! | Serco 34 | 4,463 | 3,984 | 1,212 17 15 49 45 | 280 Quit ceees (oe ae 32 | 4,588 | 4,059 | 1,244 18 73 59 63 | 211 PBN Oates 30 | 4,611 | 4,182 | 1,274 19 val 59 72 | 249 (atte Nike? Ye beens 3 28 | 4,682 | 4,203 | 1,302 20 65 50 62 | 336 iyi lin meals fee ueia 22 | 4,747 | 4,268 | 1,324 21 63 43 52| 374 3 ia eae eee el 20 | 4,810 | 4,331 | 1,344 22 60 39 51 | 348 OR eee ee 17 | 4,870 | 4,391 | 1,361 23 59 37 51] 116 F135 rece | eee 16 | 4,929 | 4,450 | 1,377 24 65 52 64 | 287 AQ Wie, eee ate 22 | 4,994 | 4,515 | 1,399 25 69 54 62 | 423 Flee ee | eae 26 | 5,063 | 4,584 | 1,425 26 73 62 70 | 608 5 eae | eer 30 | 5,186 | 4,657 | 1,455 QT a 64 67 | 438 BO NS Necemmssee 34 | 5,213 | 4,734 | 1,489 28 70 63 81] 108 1009 anO2 3 eee 27 | 5,283 | 4,804 | 1,516 29 73 60 67 | 290 SO) 503) gas ee 30 | 5,356 | 4,877 | 1,546 30 73 64 76) 277 S01 |i 2,1 | Seems 30 | 5,429 | 4,950 | 1,576 July 1 72 59 Cia 18 58h elBBrleeceeeee 29 | 5,501 | 5,022 | 1,605 + 2 63 58 84] 214 98.1 = 56u nese oe 20 | 5,564 | 5,085 | 1,625 3 64 59 84 | 266 AO) ses Ses all ese ae 21 | 5,628 | 5,149 | 1,646 4 70 57 65 | 129 7g leek eae 17 | 5,698 | 5,219 | 1,663 5 72 53 58 | 190 1 (eee See 29 | 5,770 | 5,291 | 1,692 6 73 5Y 61 92 Oi] See te eee 30 | 5,843 | 5,364 | 1,722 7 76 58 60 | 186 GO} eee |e ene ts 33 | 5,919 | 5,440 | 1,755 8 76 61 62 | 280 SO} |e OSH eee 33 | 5,995 | 5,516 | 1,788 9 71 51 56 | 119 Oi Reena: ee 28 | 6,066 | 5,587 | 1,816 10 82 56 43] 424 SB ecco hae ceo 39 | 6,148 | 5,669 | 1,855 11 68 61 80} 304 #0) Sc See 25 | 6,216 | 5,737 | 1,880 12 70 5D 64] 101 OF MT a er aes 27 | 6,286 | 5,807 | 1,907 13 81 67 64] 321 43 hier OB ere ea 38 | 6,367 | 5,888 | 1,945 14 86 61 48 | 502 | 17 AR eee || ete 43 | 6,453 | 5,974 | 1,988 15 80 65 62 | 324 | 43 |e Echaee |i Sees 37 | 6,533 | 6,054 | 2,025 323 Meteorological data for Huron, Dak., in 1887—Continued. Sum of daily tem- ors ewer amioc st tive Sri gaa ly tom: ee) Date. | tem- 5 hu- |Wind. Clouds.) Rain. | Frosts. tive pera- point.) wid- ture All ene ture. ity. i als goer) pera- F.). ‘| ture a above 43°F .), 1887. KY, °F. |Perct.| Miles.| Per ct.| In. | Date. | °F. Or af oiRT. oFRr July 16 69 58 69 276 UBS bees eae ee 26 | 6,602 | 6,128 | 2,051 17 70 56 65 167 GORE aes a3 Bees ae 17 \a6,772 | 6,193 | 2,068 18 72 52 56 174 35 | See es eae 19 | 6,844 | 6,265 | 2,087 19 67 61 81 163 SOR Seas ass eaeee oma 24 | 6,911 | 6,382 | 2,111 20 71 60 72 169 80) Peete oer see 28 | 6,982 | 6,403 | 2,139 21 67 53 66 166 Sie |e oa aoe ee 24 | 7,049 | 6,470 | 2,163 22 61 43 55 183 Pash ae ae els Billa a ee 18 | 7,110 | 6,581 | 2,181 23 67 57 63 294 BUA OO bere eee 24 1 7,177 | 6,598 | 2,205 24 72 58 64 196 Cul oneieaeep eres | eee 29 | 7,249 | 6,670 | 2,284 25 78 63 65 47 7 OSs ee ee 35 | 7,327 | 6,748 | 2,269 26 73 60 69 276 OT aeons eee 30 | 7,400 | 6,821 | 2,299 27 71 60 72 131 AQ) ec cesey ee ay 28 | 7,471 | 6,892 | 2,327 28 74 65 7 283 AQ Geaeeag tere rae 31 | 7,545 | 6,966 | 2,358 29 74 59 62 311 Pl ete a ee east 7,619 | 7,040 | 2,389 30 69 57 59 124 On| eee sellers 26 | 7,688 | 7,109 | 2,415 31 72 57 64 286 yO) ae, lie 29 | 7,760 | 7,181 | 2,444 Aug. 1 76 60 60 130 20 Ol} |ESeses > 33 | 7,836 | 7,257 | 2,477 2 7 59 70 349 100 Boel mee tees QT | 7,906 | 7,327 | 2,504 3 68 58 74 198 40 oF] La jig esos ge 25 | 7,976 | 7,395 | 2,529 4 62 55 79 228 67 AOE ears 2a 19 | 8,088 | 7,457 | 2,548 5 64 46 56 132 10 Hei |e ert a 21 | 8,102 | 7,521 | 2,569 6 68 54 63 358 Si erase ee 25 | 8,170 | 7,589 | 2,594 7 79 63 61 413 33 S19) |b s2 aa 36 | 8,249 | 7,668 | 2,630 8 71 58 67 273 G5) Haaser eka 4 28 | 8,320 | 7,739 | 2,658 9 66 58 |, 79 257 93 O14 | eeses 23 | 8,386 | 7,805 | 2,681 10 72 64 76 231 43 AB Y (eae ee 29 | 8,458 | 7,877 | 2,710 ll 68 51 60 121 BG Seep beer ae 25 | 8,526 | 7,945 | 2,735 12 63 56 78 206 100 RAS) cote 228 20 | 8,589 | 8,008 | 2,755 13 65 61 85 202 LOOF 49) eee 22 | 8,654 | 8,078 | 2,777 14 70 60 (al 107 SOM Sereda |e aoe cee 27 | 8,724 | 8,148 | 2,804 15 66 59 80 171 GY jute A NS del en Bede 23 | 8,790 | 8,209 | 2,827 16 66 56 72 116 90 LOT hee een 23 | 8,856 | 8,275 | 2,850 ly( 70 : 56 64 91 3 a Obs eee ace 27 | 8,926 | 8,345 | 2,877 18 Yi 53 66 | 109 a [ee | 24 | 8,993 | 8,412 | 2,901 19 69 58 70 185 Gel eee ee eee 26 | 9,062 | 8,481 | 2,927 20 65 58 80 188 50 GATE sia 22 | 9,127 | 8,546 | 2,949 21 68 57 70 197 EN Fae Me eh 25 | 9,195 | 8,614 | 2,974 22 57 44 65 296 07 eae aaa 14 | 9,252 | 8,671 | 2,988 23 51 41 71 146 Sia) CET Sele 8 | 9,303 | 8,722 | 2,996 24 53 40 65 78 GON arts 22 =ceee 10 | 9,356 | 8,775 | 3,006 | 25 52 44 76 99 83 SOZK es ee 9 | 9,408 | 8,827 | 3,015 26) 55 45 72 139 LOO} 32 3 Poe eee 12 | 9,463 | 8,882 | 3,027 27 63 52 71 3382 93 JOG Ee enwe "20 | 9,526 | 8,945 | 3,047 69 57 67 423 Op Peeee se |e ee 26 | 9,595 | 9,014 | 3,073 29 64 59 86 | ‘381 67 AO See eee 21 | 9,659 | 9,078 | 3,094 30 67 63 88 248 50 Bd (| eee 24 | 9,726 | 9,145 | 3,118 31 67 64 92 196 Hol MRO n Seee eee 24 | 9,793 | 9,212 | 3,142 _ “On and after July 17 the numbers in the column “Sums of all temperatures” must be dimin- ished by 100. 324 Meteorological data for Huron, Dak., in 1887—Continued. Sum of daily tem- Posi- perature. tive ete, | Ma | Dew | BP? Io 3 tom- ese ate. | tem- point. hu- |Wind.|Clouds.) Rain. | Frosts. care Au | tive fare, Es (T | All. jabove| Oem ; = 43° F. ture : above 43°F.). 1887. oF of. |Perct|Miles.| Per ct.| In. Date. | °F. hE OR Wy 26 Sept. 1 68 61 so) 119 Sie uae, [eee hoes, 25 | 9,861 | 9,280 | 3,167 2 70 63 79) 171 BGR ee _.....--| 27 | 9,931 | 9,850 | 3,194 3 67 60 78 | 238 53) [eee | eerie 24 | 9,998 | 9,417 | 3,218 4 67 59 7 | 298 80s earn ae ree _.| 24 110,065 | 9,484 |-3, 242 5 74 65 ite 330 1) ae 04 | eee 31 |10,139 | 9,558 | 3,27 6 68 55 6° | 289 Bip Gnkes teense = 25 |10,207 | 9,626 | 3,298 Ph 6 | ae) 68st 140 (Oa ee tires | Se 16 |10, 266 | 9,685 | 3,314 8| 73] s7| 6?| 440 FES ged (eae Ee 30 |10,339 | 9,758 | 3,344 9} "5811 39) 62 - se0 Oi Ssssze een 9 {10,391 | 9,810 | 3,353 10 50 46 86} 159 CEH aul fen ee 7 110,441 | 9,860 | 3,360 ol 62 56 82 | 313 HO aes See | one 19 |10,503 | 9,922 | 3,379 12 62 56 80 | 382 Gya| sates | ees 19 110,565 | 9,984 | 3.398 13 55 34 52) 411 i leat ee 12 |10,620 {10,089 | 3,410 14 55 38 59 | 151 $5: e eet Seen 12 {10,675 {10,094 | 3,422 15 53 36 59 | 172 3 lol tye | eee ee 10 [10,728 |10, 147 | 3, 432 16 63 45 58 | 586 Sa|ee ose |e eee 20 |10,791 |10,210 | 3, 452 17 64 52 66 | 359 GY (ir? | eee 21 |10,855 |10,274 | 3,473 18 66 51 59 | 285 Pi Rea ie Bee 23 |10, 921 |10,340 | 3, 496 19 70 59 69 | 545 63 ate n| es 17 {10,991 |10, 410 | 3,513 20 67 53 64.| 855 73: ete | eee ea | 24 111,058 10,477 | 3,537 21 58 41 67 | 135 AD || Wa ees | 10 |11,111 |10,530 | 3,547 22 46 36 T1 | © 225 71 dal Nei ap 9 | 3 11,157 10,576 3,550 28 45 28 55 | 230 43 | Tr. 23 2 {11,202 10,621 | 3,552 24| 58| 42] 57] 248 3 (| Sorrel aes | 15 [11,260 110,679 | 3,567 25) BA | 85 54 83 SR yearn oe ia | » 11 [11,314 /10,733 | 3,578 26 60 45 63 | 311 AQ) | D2 m | eee | * 17 111,374 [10,793 | 3,595 27 49 41 1 365 Giff haere hee aE 6 {11,423 |10,842 | 3,601 28 49 33 58 61 | Ss ere, | 6 {11,472 {10,891 | 3,607 29 58 38 62 7 (Sy eee se 234 (ee eae 5 | > 10 111,525 10,944 | 3,617 30| 53/ 39| 66| 158 34 eee ee 10 11,578 10,997 3, 627 | MAIZE. The record of the plantings and general condition of the corn for the season of 1888 is taken from the station Bulletin No. 9 by Prof. Luther Foster, director and agriculturist, and is as follows: The corn experiment embraced a set of 39 plats, each containing 60 rows 24 hills in length. Thirty-three of these plats were planted with different varieties of corn, 18 of Dent and 15 of Flint, the rest being used for experiments in deep and shallow cultivation. On the first 33 plats the planting began on the 7th and 8th days of May. Two rows of each plat were planted every day for thirty con- secutive working days. It may, perhaps, be unnecessary to state that these daily plantings were made with the object of determining the corn growing season, when germination begins, and the extreme length of planting time, 325 Preparation of soil—The land used is a sandy loam, with a sub- soil of clay, and slopes slightly to the northwest. It was plowed the previous August to a depth of 6 inches, and thoroughly harrowed in the spring ‘just before planting. It had produced two crops of small grain, and had never been manured. Planting —The rows were made with a marker 3 feet 6 inches each way. Part of the corn was dropped by hand and covered with the hoe, the rest being put in with hand planters. Of the Dent corn, the hills contained 3 and 4 grains; of the Flint, 4 and 5. The stand.—The early part of the season was not favorable for corn growing, being cold and wet. The coming up was quite irregu- lar, from six to ten days frequently elapsing between the appearance of the first and last hills in a row. This was especially true of the first fifteen days’ planting. The stand in general was poor, resulting in part from unfavorable weather and bad seed, but principally from the work of ground squirrels. This latter evil was the most persistent and damaging one with which the corn experiment had to contend. The per cent taken depended upon location of the variety, whether more or less remote from the unbroken prairie. Notwithstanding all efforts to destroy the squirrels, the damage done was very great. For several succes- sive days previous to planting poisoned corn was placed in every squirrel hole that could be found. This was done not only on the experiment ground, but also on the whole 80 acres and on the edges of the land immediately surrounding it. This work, reenforced with the trap and shotgun, was continued throughout the whole plant- ing season. Cultivation.—All the plats were given four different cultivations, a six-shovel corn plow and a double spring-tooth cultivator being used for the purpose. In addition to this they were twice hoed. Cultivation began on the 11th day of June and ended on the 17th day of July. General remarks.—tIlt was observed in all the plats that the earlier plantings grew larger and stronger than the after ones and that the silks and tassels made their appearance more regularly. The ears of nearly all varieties of the Flint corn were infested with a species of worm. These did but little damage beyond mar- ring the appearance of the ears. The Dents were not disturbed by the worms. Immediately after the killing frost on the night of September 11 the corn on all the plats was cut and shocked. It was allowed to stand a few weeks before husking. The results of a single season’s work are only entitled to the pub- lic attention as showing the scope of the experiment undertaken. Definite results of any practical value to the farmer can only be obtained by a continuance of the same experiment under a system of careful observations extending through a number of years. Of this a beginning has been made. Tabulated statement—In the following table that date of plant- ing is taken which shows the least number of days from time of planting to maturity.. The first seven to ten days planting came up and matured at the same time, while the coming up of the rest varied quite regularly with the time of planting. The items in the columns headed “ Ups Invtassel,””: “In silk” 326 * Matured,” and “ Days to mature ” apply only to the planting up to and including the date in the first column. columns apply to the whole piece. The per cent of corn standing and that taken by squirrels was made from actual daily counts of hills. The items in the other In computing the yield the corn was weighed instead of measured.* EHaperiments of 1888 in planting corn at Brookings, S. Dak. {First killing frost, 1888, September 12, a. m.] eine Date oe Date ve Date of Datook Variety. Spa ep ee Bee silking. Dents: | White Rustler -_-_---- May 14} June 5/| July 20 | July 30 Austin’s Calico. __--.-|----do ---|---.do--.| July 21 | July 31 Dakota Yellow: ------ May 13] June 4] July 18 |__..do--- Davis's White____....| May 14 | June 6 | July 23 | July 30 Hickory King-------- ..--do_.-| June 5 | Aug. 16 | Sept.11 Chester County Mammothe2-=os22 .---do---| June 4| July 20 | Aug. 11 Illinois Premium ~_---|----do---| June 5 | Aug. 1 | Aug. 10 Austin’s Yellow ---.-- May 16 | June 6/ July 25; Aug. 1 Davis's) WelloWeesss 4 |222-00e4|--=-d0--4|\JulyrZiale===done- Edmund’s Premium_|----do-_--| June 8 | July 25 | Aug. 4 Pride of the North_-_-|---.do-.-| June 4 | July 18 | July 27 Clearance Yellow_..-| May 12 | June 5 | July 24 | Aug. 10 Watson’s Yellow- -__-- May 16/| June 6} July 28 |__..do-__- Improved Leaming..| May 15 |....do---| Aug. 1 |.-..do--- Dakota Gold Coin____| May 16 | June 7 | July 238 | July 31 Golden Beauty ------- May 15 |_..-do---| Aug.13 | Aug. 22 Bloody Butcher------ May 16 | June 6] July 20 | Aug. 4 INOTGHIS tiheeee ose ese May 18 | June 5| July 24 | Aug. 1 Flints: SmutyNosess-c---2--= May 15 | June 4] July 14 | July 26 Compton's Early ----| May 14 | June 6| July 17 | July 31 MopiOvere sss May 12 |._.-do---| July 19 | Aug. 2 Early Canada-------- Maiyeli(G ae dores( il ya25"|2=d Or Self Husking--_-. __-- May 16 |_...do__-| July 16 | July 27 Early Six Weeks__---| May 15 | June 5| July 19 | July 26 Chad wick= 2222-52-43) Mayle suner( | oulyei6) |===doees Mandan Indian -_-_----|----do .--do---| July 11 | July 18 Hone fellow -2ee7—--- May 15 | June 6| July 23 | Aug. 2 Minnesota: White _...| May 16 |....do-...|.-..do__-|....do-_. Mencer: sss so ness .--do -.-|...-do..-| July 16 | July 26 Waushakum _______-- May 17 |_-..do__.| July 20} July 31 Silver White. _...---- May 16 | June 4 |_...do---| July 30 lrGhayes 1B ouibyey te ..--do_..| June 8} July 26 | Aug. 2 Angel of Midnight.--| May 13 | June 7 | July 23 | July 30 Date of matur- ing. Sept. 4 Sept. 10 aed Ones Sept. 11 Sept. 8 Sept. 11 Sept. 8 Aug. 20 Aug. 28 Sept. 2 Sept. 11 Sept. 2 Aug. 19 Aug. 30 Aug. 15 Sept. 10 Sept. 6 Aug. 27 Sept. 11 i KAO Les 2edoee- Sept. 1 Sums of post) Yield | Days |(T—43° erat to ma- 2 ture. plant- shelled ing to | COFn- matur- ing. SEE Bush. 113 | 2,556 243 119 | 2,692 274 120 | 2,696 24 IVAN Pall 42 Silk. | Seeeere |S op ee Milky | 2 225-0 4s Softy. |2-2:2525 |e seas 118 | 2,708 29 115 | 2,641 24 Soft y|ssses 313 118 | 2,708 214 Soft. essecee|[tecoesce Haire: {622 se3 | ieee (POOT Ss s| S222 sass eee 113 | 2,601 27 MG. |e eee | See 118 | 2,703 15 113 | 2,640 214 107 | 2,187 374 106 | 2,410 27 113 | 2,527 28 117 | 2,708 17 109 | 2,505 45 96 | 2,162 15% 105 | 2,453 244 90 | 2,071 20 118 | 2,689 18 113 | 2,601 27k 103 | 2,371 37 117 | 2,703 36 118 | 2,703 27 118 | 2,703 94 111] 2,504 d4t «JT regret not to be able to state the source whence the seed was obtained and the climatie peculiarities under which it was raised. decide as to the behavior of the seed and plant in a new climate. ; some of the varieties had been raised in previous years in the neighborhood of Brookings, Soak. —— Cleat According to Linsser’s laws this must I know, however, that In comparing the maize experiments at Brookings with the climate of that region, I shall use the record of the Signal Service station at Huron, §. Dak. (lat. 44.3° N.; long. 98.1° W.; altitude above sea level, 1,300 feet), which is 70 miles west of Brookings, and the gen- eral meteorological tables for Huron as calculated for this agricul- 327 tural usage are appended to this table of agricultural experiments. Mean Rela- Date. | tone | Dew | fine bwina|ctonds. a pera- point mid- ture. ity 1888. Oni SEE tet. || MaLesel) search. ArT el 31 23 73 303 80 2 34 26 73 144 83 3 44 34 68 97 3 4 52 44 74 441 57 5 37 26 66 287 33 6 40 27 64 127 0 Uf 46 29 58 210 13 8 53 32 55 178 43 9 45 39 81 312 67 10 45 27 55 237 33 11 35 17 52 273 7 12 48 32 59 394 40 13 52 36 7 275 0 14 58 By 44 334 0 15 47 33 63 260 3 16 53 37 59 469 60 17 39 21 55 473 13 18 34. 20 57 184 37 19 34 19 58 188 0 20 49 29 53 318 23 21 59 35 48 154 70 22 49 36 64 325 63 23 44 28 56 179 60 24 57 31 42 644 40 25 56 39 55 698 63 26 57 40 58 298 20 27 42 39 87 364 100 28 32 27 81 531 100 29 34 27 73 300 100 30 37 26 67 159 0 May 1 40 35 81) 385 100 2 42 39 90 312 100 3 40 35 84 409 100 4 45 32 62 247 0 5 51 34 56 209 70 6 46 37 73 347 100 7 48 in 70 | 259 70 8 53 32 50 186 63 9 57 31 45 195 67 Rain. Meteorological data for Huron, Dak., in 1888. Sums of tempera- tures. Tem- All Frosts. ture at ee p. | All fing all pera. 43° F, ture —43e Ia). Date. SII Maes | Sean a eee 31 0 0 sees mea| See ee 65 0 0 - eee 1 109 44 1 Ween cone 9 161 96 10 ee pel eee 198 96 10 GVizeccaas 238 96 10 7 3 284 142 13 ee oe rome 10 337 195 23 Poe OL 2 382 240 25 10 2 427 285 27 LD ere os 462 285 27 ees 5 510 333 32 mee ote tye 9 562 385 41 Bee a 15 620 443 56 he 4 667 490 60 5 eee 10 720 543 70 i 2 Sao 759 548 70 JRE a eee 793 543 70 LOG Se aoe 827 543 70 20 6 876 592 76 uae ee: 16 935 651 92 See 6 984 700 98 23 1 | 1,028 744 | 99 eS Eee 14 | 1,085 801 113 Be ees: 13 | 1,141 856 126 Pelee 14 | 1,198 913 140 Seer | Rae pee 1, 240 913 140 Tt | Mea f 1,272 913 140 SSE Pee. Sees een 913 140 SOE bese 1,343 913 140 Fae eel 2 eee 1,383 913 140 eee Se Sacee S420 913 140 Cee ts ees JS 1, 465 913 140 4 2 | 1,510 958 142 See 8 | 1,561 | 1,009 150 be ee 3,| 1,607 | 1,055 153 esis oe 5 | 1,655 | 1,103 158 pb Stel 10 | 1,708 | 1,156 168 Le 14 | 1,765 | 1,213 182 328 Meteorological data for Huron, Dak., in 1888—Continued. Sums of tempera- | tures. Mean | | Rela- Tem- All Date. ery Dew | wae Wind.|/Clouds.| Rain. | Frosts. ace Re- Hine pera- | Point. | mid- —43° ple (tem- ture, ity. F. below | Pera- Asem, || wre F.). 1888. CNH ||| SHEP ctamMaless|meiact. In. | Date. Oi ie WORE | One May 10 56 37 54 261 90 BL YAN St ee 13 | 1,821 | 1,269 195 ll 47 28 54 416 30 1 Ogi| ee Seen ‘4 1,868 | 1,316 199 12 41 23 57 352 3 AMe, a De Pc ees 1,909 | 1,316 199 18 43 18 +4 295 33 ARR 13) Seeceees | OD 2a lees G, 1 14 47 17 38 155 50 dtyes 14 4 | 1,999 | 1,363 203 15 46 30 57 321 47 A UPN See ae & 3 | 2,047 | 1,409 206 16 48 29 55 105 50 abe 16 5 | 2,095 | 1,457 211 17 42| 33 72] 189 HOO) 12 jf eee Ete 2,187 | 1,457 | 211 18 44 32 65 155 37 OFA an 2 2 1 | 2,181 | 1,501 212 19 52 43 73 430 73 22 | See ae 9 | 2,288 | 1,553 221 20 63 51 66 317 63 nil ie Soe 20 | 2,296 | 1,616 241 21 58 50 76 288 100 $845) Roa os 15 | 2,354 | 1,674 256 22 55 48 | 78 400 100 92h eae ees 12 | 2,409 | 1,729 268 23 52 44 77 391 100 AO) ewe eee 9 | 2,461 | 1,781 | 277 24 53 45 | 74 207 67 FTN? hime ee leer 10 | 2,514 | 1,834 287 25 58 44 63 79 23 Hy Ales gee 15 | 2,572 | 1,892 302 26 54 49 83 244 100 aC 030 i ee ad 11 | 2,626 | 1,946 313 27 59 44 62 375 77 OZ Se eae 16 | 2,685 | 2,005 329 28 57 40 56 290 33 rah) eee 14 | 2,742 | 2,062 3438 29 55 40 59 156 53 Ae ene se 12 |. 2,797 | 2,117 355 30 55 43 65 216 50 S605) eens 12 | 2,852 | 2,172 367 31 54 39 63 109 47 LBs Pale oe Be 11 | 2,906 | 2,226 378 June 1 51 36 60 206 0 Ra ha hae 8 | 2,957 | 2,277 386 2 57 43 62 130 7 A cel ae Soe 14 | 3,014 | 2,291 400 3 66 53 64 439 67 One eae ae 23 | 3,080 | 2,314 423 4 64 53 67 573 77 Oss See oe 21 | 3,144 | 2,335 444 5 50 41 72 78 70 02 3| seers 7 | 3,194 | 2,342 451 6 55 43 66 166 50 PT Sa eee 12 | 3,249 | 2,354 463 7 73 61 68 541 20 EA hope 30 | 3,322 | 2,384 493 8 69 60 76 496 67 Oye |e eset 26 | 3,391 | 2,410 519 9 54 49 83 508 100 el |e ark 11 | 3,445 | 2,521 530 10 63 48 62 234 17 Oz aoeess 20 | 3,508 2, 541 550 11 61 55 82 176 70 00 {he ee 18 | 3,569 | 2,559 568 12 70 56 63 182 40 On ae 27 | 3,639 | 2,586 595 13 75 63 69 | 228 37 5O0Gs| Seen 32 | 3,714 | 2,618 627 14 74 59 65 153 27 FES | asta 81 | 3,788 | 2,649 658 15 80 7 7 | 382 40 eA al Ss eee 7 | 3,868 | 2,686 695 16 81 70 71 393 3 OFS Ros Sie 88 | 3,949 | 2,724 733 17 79 65 65 180 23 SUS diets ee ae 36 | 4,028 | 2, 760 769 18 78 65 | 68 | 355 0 AO aS 35 | 4,106 | 2,795 801 19} 74) 7 67): 78). “465 PTV aS are Maa 31 | 4,180 | 2,826 | 882 20 68 56 | 68 523 73 AO seen ete 25 | 4,248 | 2, 851 857 21 59 48 66 | 615 57 Hl Dy pega eee eS 16 | 4,307 | 2,867 873 22 61 44 54 528 90 (Uf [ate oe 18 | 4,368 | 2,885 891 23 61 45 57 436 93 (1) ial Pes eree 18 | 4,429 | 2,903 909 24 62 52 val 299 90 OR ees 19 | 4,491 | 2,922 928 25 62 51 70 108 87 On| tae. =o 19 | 4,553 | 2,941 947 26 57 54 90 389 100 D2] ee 14 | 4,610 | 2,955 961 27 52 5D 81 104 97 Og Rae eee 19 | 4,672 | 2,974 980 329 Meteorological data for Huron, Dak., in 1888—Continued. | Sums of tempera- | tures. Mean Rela- Tem- All Date. re Dew aes Wind. Clouds.) Rain. | Frosts. Tees Bes ee pera- Point. | mia- —43° | ay eet (tem- ture. ity. int, : below, pee 43° F.| “Yoo F.). 1888. oR, °F. | P.ct.| Miles.| P. ct. In. Date oF, oa Cy Ge June 28 65 59 84 | 376 Ba) ea ON He Se esa 22 | 4,737 | 2,996 | 1,002 29 7 65 86} 395 ON = 022 27 | 4,807 | 3,023 | 1,029 30 82 ve 76 | 346 Biel Ole | eee 9 | 4,889 | 3,062 | 1,068 Jitlyzerlalny, 80s a. 999) |waee ee OM IRs 37 | 4,969 | 3,142 | 1,105 Oped <7aniob SAC loa le Saas Oke 31 | 5,043 | 3,216 1,136 3 66 Sane ees, ae 1501 See | Bet cee e esl) |, 28,06, 109) 8,282.11 159 CMY Bemese Foe Soe iT Ae Tr, |...-.:.-| 29 | 5,181 | 3,854 | 1,188 5 HG sees ee es eg ne. 3) ee ee Ty eileeee 38 | 5,257 | 3,480 | 1,221 G6 70) ee ©. | sei S46) (4 26 |_-...--| 27 | 5,827 | 3,500 | 1,248 7 ROMs eee 920) (Paseo. Api Roe 27 | 5,897 | 3,570 | 1,275 8 (eee eae 1 eee 5 02s|eseee 27 | 5,467 | 3,640 | 1,302 9 alee ieee 1999) 2 Mr |e 23 | 5,533 | 3,706 | 1,325 10 S| Qe | ee OCON Ie see Ut | [eee 32 | 5,608 | 3,781 | 1,357 11 a Ne eee Rhy eeeeee Te ee 39 | 5,690 | 3,863 | 1,396 12 U(r (ae Cel eee Cry eee 33 | 5,766 | 3,989 | 1,429 13 Cit See eek [ee OSIM ROO: |aomteees 24 | 5,833 | 4,006 | 1,453 14 Op eee eel 101m 025 |S: eet ee 29 | 5,905 | 4,078 | 1,482 15 CG ew Bi i Shy Weel Mie |e tes 25 | 5,973 | 4,146 | 1,507 16 Fi eee ee ea ASO) teens [ph |S eee 23 | 6,039 | 4,212 | 1,530 iff [Fin eso a (ee Bagh ness Kn | eee ee 26 | 6,108 | 4,281 | 1,556 18 Gayle se St lows oe 973) eee bi), seen ee 25 | 6,176 | 4,349 | 1,581 19 (7 a eee Ne aie 127s Eee Ts | eee 26 | 6,245 | 4,418 | 1,607 20 "gale to5¢ is aa ge ee hate aes 35 | 6,323 | 4,496 | 1,642 21 ig |e eal ss C3} wee cOGt |e ns 34 | 6,400 | 4,573 | 1,676 22 GSh ae Ee a 1243 |e Meee ses 25 | 6,468 | 4,641 | 1,701 23 ROb Mas See secs 1974 [Ese eae Og eames 27 | 6,588 | 4,711 | 1,728 24 GG cate ee 190) |keee FOG See 25 | 6,606 | 4,779 | 1,753 25 7 sl ie en 167, [bose eee Ail) ne eo 31 | 6,680 | 4,853 | 1,784 26 VER eae te ee iP iy) ee Aly (| nso 30 | 6,753 | 4,926 | 1,814 27 SHER Wal eas 15) ee Nos fl eee 35 | 6,881 | 5,004 | 1,849 28 nGilbeks A Sete Ei hat Sree rT fil| Pelee 33 | 6,907 | 5,080 | 1,882 29 et See eee tl ee AH OM ae 34 | 6,984 | 5,155 | 1,916 30 (EN deen eee Doig |e ae LOM ease 35 | 7,062 | 5,233 | 1,951 31 alae Wier nae DAR Re ee (|| eae 22 | 7,127 | 5,298 | 1,973 Aug. 1 FAC) | hs 9s pognlen Gitos ingle 27 | 7,197 | 5,368 | 2;000 2 ean Pe 7 aes {Ole |eee a 28 | 7,268 | 5,439 | 2,028 3 fg eee aol eee ORM (Bee Ty | eee 31 | 7,342 | 5,513 | 2,059 4 Gti aes goa D0 Reve = SM ee 25 | 7,410 | 5,581 | 2,084 5 (eR eee [ene ASD Wee ee Aig (tents 22 | 7,475 | 5,646 | 2,106 6 64 Sia wel eer i bee Aran seve 21 | 7,539 | 5,710 | 2,127 7 rive fee ae, | aes 2 = 14 | ere 21 | 7,603 | 5,774 | 2,148 8 GY a ena ETN AQ Ree BG |-soeaes 12 | 7,658 | 5,829 | 2,160 9 Gi hae eee | Ee ORES! IGM Mees 13 | 7,714 | 5,885 | 2,173 10 GUA toe em |e 00S 1204| Stoney 13 | 7,770 | 5,941 | 2,186 ol Eid (OR oe Fa). ok 71-3 (ere ae A) cian he 15 | 7,828 | 5,999 | 2,201 12 Md pasa 8 BE eee HA) |e tye ee 16 | 7,887 | 6,058 | 2,217 «Hours of observation changed July 15, from 7 a. m., 3 p. m., and 10 p. m. to 8 a. m. and 8 p. m. Mean D. P. and R. H. not known. 330 Meteorological data for Huron, Dak., in 1888—Continued. Date. Mean Rela- Sann, | Dew | T° | Wind \ciouds.| Rain. pera- point.) mid- 2 ture. ity. oie of. | P.ct.| Miles.| P. ct. In. G8no eas as | aeons AQ) \\i= seeae 8 sire 66a| Ss veeeas aM Cul eee 28 602 Ses eases 69 hae se 38 Giese ees Rea D4 Ae ese .10 GAG | ae. oe Sees Ce Oal Seegan o aee ys G3 i Raaeecye tee ee LOOMS ese rs Coy (ie a oe epee 4: ir eee Ears GS) Eee seers '82))| eevee eee 02 6OzlE eae ASH ies ee tbh 66/2 eee IGS Abbe ih |e eee | eee ele VSO omen cee 0 Loh ge oe | Be 199" Sema eens 0 (i Oh) ales es | ee 129) ere ee brs HCA apnea ee oe eelt = See TEN | BER oe a Ty (0; |==asee See wed: 2351) Seneeees Tr (el seco Brees tienen bee eee ry (ede eee boa ale aes .0 Gb Rees So seo roy fal a .0 5d Eee eet ial \ PL Goyal Se 0 G1 See Be | ae ae 159} Sane eee .0 GGT ees Sel area 2010 eee 0 GB Fee Sl Mak Spee DON whee Tp: Gif oR pe el LSS See Ty 68h a eaee = 501) | See 0 lp eee Bae BBB ile as -O1 (45) hee Sa eee ee 209) | eases 04 625 eae Decere PUNE Vee os 0 G3t eee Cee 2OBiEn see .0 GO} eee oe CH ONE nsec. .0 Gy eee oe. le a 286) |22-2 5S .0 AGT Eee ere! eras Gs | eee My: 657 soe See elf | ee sere 0 bate tn lee een baa Se 442) |Wooeeoe 06 Deal eee aaa Cera |) | OOS Tea. eae OG AGU ES eka 260) | ska th Areca es Sees See 153) 2aee eee ys AQWIE Es 2 sete eel OE Oia eee ani, (a0) ene a 20 t | Ae ee ee Dr: GAu ace AE eee TY ecco 02 GIS ener Besser | LOO! Geet ct: GY G) ieee edie aaa 1c) eee eee Ear: GOS see eee Eres 2565 sae Atte D8 Sees Se | aa Sa | bigs DOF | sees Se OS 2243 |e eee Eikye: 52a|at ear |eeeeees PM ex ae | .0 AS rae ack ANE ee (Beye ne ei ee a) 438 eos: | eae ae (ulsscoess .0 ZS eee om area ea 153)|e=ae ites 5: || eee a ee 250) | eee es in: Frosts. All. °F, 7,955 8,021 8,080 8, 144 8,208 8,271 8, 338 8, 406 8,472 8,538 8, 609 8, 683 8, 754 8, 826 8,896 8,970 9, 042 9,107 9,161 9, 222 9, 288 9, 351 9, 407 9,475 9,546 9,610 9, 672 9,735 9, 801 9, 853 9,901 9,966 10, 024 10,076 10,122 10, 169 10,217 10, 277 (10,341 10, 402 10, 459 10, 577 10, 679 10, 722 110, 765 10,810 11 10, 864 10,519 10, 627 | Sums of tempera- tures. —— 331 Experiments in 1890 in planting corn at Brookings, S. Dak. {Experiment Station Bulletin No. 24.] | Yield Variety. pe oot cs eeraiee per ee | corn. Dents: Bushels. MON OlaNGi ana ate see aa sags eS See aes See ee May 17 | Aug. 24 100 BS hia ELTON eee eee eee ae ade UO. Rhy ks NALS sss do _.-| Sept. 10 116 29.2 TOYS ATS NNIALOUOT EY sxc ee ples pee en ae en RP et ed doze. (@)i ees seco: 82.4 QueenronthemNorthe senso eee es ese oon a dose (QD) lessees: 30.8 IDAKOtAE DCI bere ete see ee Be 5 ON eee ee Lae aah oe 4 dome (2) ae see ee 21.8 Dako tani ose once setae one a ER Be May 19 | Sept. 12 116 33.6 Cold oinss aerate sty then ote 2 ESL eee ee ee ween don—.|h-s2 do)24= 116 34.2 Flints: SONIA Were tee errs Se oe 2 Oe ee ee ee ee May 17 | Sept. 5 111 35.4 PTIGeTO rea KO tae sete te ae eee sake ne een we oe ee Peers sealants lye 11 26.2 Man amen Gian esse eceee seen oe sete eee one eee nee May 23 | Sept. 1 101 26.4 bind sonvBaly ns eae eeee ase sa casts ee ees coe he Pes (1) aad eae ee 24.1 WEG ee bR Se REA ORES ae eee eee ae June 3} Sept.15 104 22.1 Rev ow nil i pees sete a ener ee BEN Se eee May 17 | Sept. 12 118 24.1 WOM PLOnISHWAN ly see se =e eee ee ee nese e Sea ee ae May 23 | Sept. 3 103 20.0 Das liyg SER VWVICOKS see oas oe oe a ae ae oes a eee I Tae LO |S does. 103 24.3 mandrethisph Gras Man) Ves sess oes eee a eae eae eae May 17 | Sept. 12 118 32.6 Wearlya Cana Gaye cass se ccses sass nes ie esate eee so eae May 23 |..-.do--- 112 30.5 Bln ens ad Gieaces sees ae ae ewok oe ete haa ea ee oeees Maya Lig |eae2doe-= 118 22.3 Syaagas INCA ae oe se matey he Pas ee Ske _..-do-..| Sept. 5 111 25.8 SOlfsHuskin lapses een sh as Reet Po eee new a oses May 23 | Sept. 6 106 23.8 Cha divickiemes: seta pase a ee Oe Wet hoo cooe he ede eeeae May 16 | Sept. 1 108 25.3 « Some frosted. Notes.—VFirst killing frost 1890, September 13, a. m. The data for 1890 given in this table came to hand too late to allow of preparing the corresponding meteorological table-—C. A. June 30, 1891. MAIZE. INDIANA. From experiments in planting maize, made at the Indiana Agri- cultural Experiment Station (see Agr. Sci., Vol. III, p. 192), the following results were deduced : Planting on May 1 gave a loss at harvest of 5.47 bushels per acre; planting on May 21 gave a gain of 0.31 bushels per acre. Deep plowing in 1886 and 1888 gave an increase over shallow plowing of 2.4 bushels per acre, and 0.1 bushel in 1888. Deep culture with a cultivator of 3 to 4 inches gave better results than a shallow culture of from 2 to 3 inches. As to rate of planting or density of stand, two kernels every 28 inches apart and three kernels every 36 inches apart seem to give the best results for hand planting. For machine planting, the best results were given with stalks 12 and 14 inches apart. 332 NEW YORK. Prof. C. S. Plumb states, as the result of a research made by him- self during the summer of 1886 at the New York Agricultural Experiment Station, on the growth of maize and its dependence upon climate, the following conclusions: (1) That maize makes a positive daily growth upward from the appearance of the plant above ground till the plant has reached its maximum height. (2) That the variation in the development of the plant from day to day and week to week is not controlled by meteorological condi- tions, for of two plants that one which is the most backward at the beginning of the season may eventually become the stronger, larger, and more vigorous of the two. The measures on which these conclusions are based (see Agr. Sci., Vol. III, p. 1) were made day by day upon seven individual plants, and the averages are given in the following table; the date of plant- ing was May 21, 1886, and the dates of sprouting extended from May 31 for plant No. 1 to June 4 for plant No, 7. Sums for preced: i days. rae grate Sunshine Date of observation. & Patel | a dura- | Rainfall. of 7 Air Soil Para plants. | temper- | temper- one atures. | atures. Inches. 17, oun Days. Inches. PB UL TRG hare ep eee pape et ORs RIOR Aba aces es 3 452 517 28 0.76 NUTR Al coe aie ce ers Meee re Baty eae A el ee Oe 8 475 572 60 0 JUNE ROE oe Se eee a are beet OMe Deere eee a 14 494 569 50 0 A Iku rae} 7 et ars pear, Ay ee ee a ee 23 466 553 46 -40 SPUR yA Bie Neva « See, cpm EN La 35 492 658 84 .0 SL ye es ee ae ee eee 41 523 597 50 ae AL Weal Bre Sa ee 0 ae Sey ER ih ie aces ae ae ae 47 464 610 53 a3 MLV 20) oe ae RE ne para eels ean a epee 61 472 602 50 4.93 Totals ee oe ese eee oe see ee eee | eee 3,838 | 4,678 421 7.58 The unsteadiness of the growth is very notable. There was a steady increase up to July 4 and then a drop for fourteen days, but growing more rapidly during the last period. When the greatest growth was made in the eighth or last period, the total air and soil temperatures were less than in the fifth period, when great growth was also made. During this last period of greatest growth the rainfall was large, while during the previous period of great growth the rainfall was zero. Evidently it needs a peculiar combi- nation of rainfall, temperature, and sunshine to bring about the rapid growth. According to Frear, the very rapid growth of plants observed immediately after rainfall is largely due to a simple expan- sion of the cells with water. Although a soil gains some nitrogen from the air as brought down 333 by the rain water, yet it loses a large quantity by the drainage water, which is, of course, richer in nitrogen than the rain. In 1886 and 1887 Berthelot determined by measurement that the nitrogen carried from the soil by drainage water is nearly ten times that brought to the soil by rain water. It is therefore economical to return this drainage water to the field, as far as possible, and thus return with it the nitrogen which has at great expense been given, in the shape of fertilizers, to the field by the farmer. (Agr. Sci., Vol. ITI, p- 39.) MISSOURI. Dr. P. Schweitzer, of the Missouri Agricultural Experiment Sta- tion, publishes in Bulletin No. LX an elaborate study of the chemical changes that go on in the various parts of the maize plant at differ- ent stages of growth. The plant takes up nearly all the ash ingre- dients during the first stages of growth. The more ash constituents a plant takes up over and above its needs the quicker is its develop- ment finished and the smaller is the crop. The young plant takes up nitrogen with extraordinary avidity, and contains a considerable quantity of it. The crop of corn from an acre of land removes there- from 219 pounds of ash and 135 pounds of nitrogen. The ears in this crop alone contain 52 pounds of ash and 86 pounds of nitrogen. (Agr. Sci., Vol. IV, p. 84.) PENNSYLVANIA. The relation between meteorological conditions and the develop- ment of corn is elaborately presented by Messrs. Frear and Caldwell in the annual report for 1888 of the Pennsylvania State College Agricultural Experiment Station, at Harrisburg, Pa. By testing samples of corn at various stages of its growth we obtain not only some idea of the nature of the changes going on in the plant under the influence of the climate and soil, but the records of past seasons on a given variety at a given locality should give us the means of approxi- mately estimating what will be the crop of the present year. For instance, the loss or gain of dry matter is shown in the following table for one variety of corn out of many that were tested at the Pennsylvania Station. Dry weight in 1 acre of several varieties of corn at different stages of growth. Ears | Kernels Variety. tasseled,) Alling | begin to) Narar® Pounds. | Pounds. | Pounds. | Pounds. STOUT SHE LOLIIC eee sec aae ee ee ee in ee She ee 2,735 5, 289 | 4,695 2,310 Chestarsviamim othe 2s saee sneer sare ee oak eee 3, 392 4, 337 5, 690 3,073 GoldentBeauby 62232 s--= sos eae cas tee Sees wee eee wun 2,499 3, 950 4,619 2, 835 1D eS pS ae eee RR te ae er 2,845 3, 443 | 4, 636 3, 077 ENDINGS 19/5) ie eee 2,683 | 3,825| 5,344} 2,529 334 Such tables as these show that the weight of the mature ears at harvest will not differ much from the weight of the whole plant when dried at the stage of full tasseling, the variations from this rule being about 10 per cent above or below for these varieties. ILLINOIS. The closeness with which corn or maize or other cereals may be planted depends not only upon the quantity of moisture available in the soil, but also upon the ultimate proposed nature of the crop. Thus in experiments made by the [hnois Agricultural Experiment Station, when corn is planted for ensilage one plant to every 3 inches gave the best result. When planting for the grain the thinnest planted plats gave 5,664 and the thickest planted gave 18,932 ears per acre. As to the date of planting, May 4 to May 19 gave the best harvest. As to mode of planting, hills nor drills nor fertilizers gave any strongly marked differences. As to pruning the roots, the pruned and unpruned showed no spe- cial difference in regard to size, vigor, date, or yield of harvest. (Aorasci Vols hp: 162.) The development of corn from week to week during the growing season has been -studied by Thomas F. Hunt at the University of illinois Agricultural Experiment Station, at Champaign. He states that the same 18 varieties of corn have been grown at this institution during each of the years 1887, 1888, and 1889, the same varieties being always grown on the same plats and the seed obtained from the same source. The average yield of air-dried corn per acre for the 18 varieties was 29.4 bushels in 1887, 83.2 bushels in 1888, and 66 bushels in 1889. Meteorological conditions appear to have been largely, if not solely, the causes of these differences in the yield. In 1889 measures were made weekly on three plants on each hill of Edmund’s Golden Dent, which is usually an early variety, but this year matured late, owing to the low temperature. The corn was planted four kernels to a hill on the 4th of May; it sprouted on the 20th of May, the soil hav- ing been very dry, and made slow growth to June 10, on account of the low temperature. The following table shows the weight of dried substance in a hill of three plants of uniform character : 335 Average Date of cutting. weight. Remarks. Grams. JMO MONS Me a ee eee Na) eee eoee sc Ssess 0.51 UME eee Skee ee oe eek eso see eee 2 2.48 SUNG Bosses has eee ea dtee wera een eee 10.11 ec yglleeeen eee ee een ene wee RS eee 33. 84 eUllivs Sheen seseeis eons Seek os Sos ae cause 75.46 Vg eee eee ee ag on Ss ee eee ee weaned 197.99 Dt gd 4 ncde eae tegee Soe Seee ees tee eee 322.91 | Tassels showing; not in bloom; no silk. SUT Vaio) oe eeeeee Sue ee ee oT eee ee od | 408.07 |: Allin tassel; in bloom; in silk. STU STONEL (3) gs «le eS ps ee ea 589. 10 INIDERTENH SB Se ee, eg | 681.55 | Silks dead or partly so. PATIOS TIO MAU SCOR Ne ne oe te econ once eee 724.449 | Soft milk stage. PANU OTIS Hei eens ee ee ere ee eee nes Gee 949.53 | Milk stage or passed. Septentberie asters noe el ee Weak VO Ae | 906. 22 | Mostly glazed. Sepremiberml Oss eet Seek esse oe (1,034.55 | Varies from milk stage to ripe. SeptomiberrG! a2 2 eee Sen as iI, 176.00 | All ripe except 1 ear. Professor Hunt finds that the varieties of corn that mature about September 25 give the largest yields; date of planting has little influ- ence on the yield. Depth of planting and drilling versus hill planting did not affect the yield in 1888 or 1889. The quantity of seed planted was more important than the allotment of the kernels to the hills; preventing the growth of weeds was more important than stirring the soil; pruning of roots injured the crops; shallow-working cul- tivators gave better results than deep-working; commercial ferti- hizers did not materially increase the yield, but stable manures did so. (Agr. Sci., Vol. IV, p. 184.) MAIZE AND PEAS. NEW YORK. Sturtevant (1884) gives the results of two years’ observations (1883 and 1884) at the experiment station, Geneva, N. Y., on the thermal constants of many varieties of maize and peas. He observed both the temperature of the soil and the air, and takes for his com- putations always the first plant which sprouted, bloomed, or ripened. Observations of 128 varieties of maize, four hills to each variety, gave an extreme variation of 19 days between the blooming of the first and last hill, the average interval being 4.92 days. As Sachs adopts 49.1° F. as the lowest temperature at which maize will ger- minate, and K6ppen gives 49.2° F., therefore Sturtevant adopts 50° F., and considers that any observed temperature, less 50° F., leaves a remainder that is nearly proportional to the growth of maize at that temperature. Dry. | Reet eee I8l8|sMostiabundant 22256. 2 sae. eee seme Sean omer 64.3 +3.1 1.4 —4,3 ASTO Mine! Oe BOR ATA UNE eat IER ORG) ASD aNe rads 60.3 —1.9 4.6 —1.1 18203) MProauactivel se ee see e ee Pete ry Ob Sale Aine ee ee Se 58.0 —3.2 8.2 +2.5 18250)| Hamlyian as 2OO ds seme ee see ae be see ee es 62.0 +0.8 3.3 —2.4 1826 | Remarkably early and very great.____-_--____---- 64.0 +2.8 | 5.1 —0.6 82 tl"Goode than eee Sek AE ae ee ees Eee ea 60.0 —1.2 2.9 —2.8 = 343 if Anglish wheat harvests and Greenwich weather—-Continued. I. SUPERIOR WHEAT HARVESTS— Continued. Temperature. Rainfall. Year. Character of harvest. 2 3 ee Dep. ae | Dep. SSH Canis Inches. 18330 | PAibun danbsaes cess Seco tens Awe ee sere See 59. 4 —1.8 6.7 +1.0 13345) MarlyThe winter was very mild; the spring very dry. ¢'The winter and early spring were very cold; May was very dry, with much sunshine. 4Frost occurred at blooming time. eThe spring was cold. fThe winter and early spring were very cold; May was very wet. 344 SUGAR CROP AND RAIN IN BARBADOS. Sir R. W. Rawson, as governor of the British colonies at Barba- dos, published (1874) a colonial report, printed by the house of assembly, giving an elaborate study of the dependence of the cane- sugar crop upon the monthly and annual rainfall. Barbados offers an exceptional opportunity for such study, since the cane is the only staple and is nearly all exported, so that the records of the crop are accessible in the customs’ returns. Moreover, the number of rainfall records averaged more than 1 to a square mile, being 178 for the whole island and for a period of about twenty-five years, this re- markable system of observations being due largely to the labors of Dr. R. Bowie Walcott, who still resides in the parish of St. Joseph, and was, in May, 1890, on the occasion of my recent visit to him, still active in collecting rainfall data. To his devotion and Governor Rawson’s assistance we owe this unique study of rainfall and sugar crop. It is impossible for me at present to do more than give the accompanying Tables I, II, and IIT of monthly rainfalls and annual crops. The crops, as given in Tables IT and III, in hogsheads, are credited to the years in which they passed through the custom-house. The cane is usually gathered and the sugar and molasses shipped between January and May; after the latter date the fields are newly planted and in eighteen months are again ready for cutting, so that the crop of any year has been grown under the influence of the rain of the preceding year and the latter half of the year preceding that. In the second table I give the dates of the first shipment of sugar each year, thus showing whether the crop was gathered early or late, and also the general character of the crop as credited to that year. Table III illustrates Governor Rawson’s conclusion that the crop of any year is influenced only in a slight degree by the rainfall of that year, but depends upon the rainfall of the preceding year. Thus it is arranged according to the quantity of rainfall, and the crop of the following year is compared with the rain of the current year; the wet years are followed by large crops the next year, while the dry years are followed by small crops; the increase being 10 per cent after a wet year and the decrease being 12 per cent after a dry year. The genera! development of the sugar plant is illustrated in the following extract (see p. 33, Rawson’s Report) : The influence of the rainfall in particular months and seasons upon the coming crop is generally felt and admitted, but not known with any certainty. It is believed, writes an experienced agricul- turist, that any marked excess of rain during the first six months of the year is injurious both to the crop that is being reaped and to that which is to follow. The cane plant during the early stages of its growth is very hardy and requires but little moisture; the small 345 early shoots are hard and fibrous, and very different from the large succulent shoots which are afterwards produced and which lengthen into the juicy reed whence the crop is made. In ordinary and favor- able years, with light showers during the first six months, the young canes make no marked progress, but the roots are increasing in length and strength, and in the months of July and August the plant begins to sucker, as it is called, and to put out the shoots which form the canes, but these make no great progress in length before the end of August and in’ September and October, when the rains usually come to their aid at the critical time. They then grow with extreme rapidity, are extremely tender and succulent, and a short spell of dry weather at that time usually does serious mischief. If, however, the first six months of the year are wet, and the young canes are excited to an abnormal rapidity of gr owth, they are liable to be seri- ously affected by any interval of dry weather in the middle of the year. Moreover, rainy weather in the reaping season retards the manufacture, and, especially in the black soils which contain an excess of iron variously combined, causes a great loss from the rotting of the canes at the roots. An illustration of this is afforded by the rainfall and crops. of 1860 and the two following years. 1860 was a model year; the rain fell at the right time, and’ in exactly the average quantity, 57.91 inches, of which 12.46 fell during the first six months. The crop of 1861 would undoubtedly have reached 55,000 hogsheads but for the wet reaping season of that year, in which the rainfall of the first six months was 31.93 inches—6.35 in April, 8.01 in May, and 8.01 in June. The consequence was that the crop only reached 49,745 hogsheads, and although so much rain fell throughout the year (73.82 inches), the following crop of 1862 was only 46, 120 hogsheads. In the same manner the ‘heavy rainfall of 1855 (77. 31 inches, of which 30.68 fell in the first six months) was followed in 1856 by only a moderate crop (43,077 hogsheads), although the reaping season of that year was most favorable. The result, however, is by no means constant. The sugar-crop records go back to the year 1806, but the returns are only interesting since 1847, which was the first in which the crop recovered from the effects of emancipation in 1839. Since 1847 there has been a steady increase until the crop has attained nearly twice what it was before emancipation. There has also been a slow increase in acreage of canebrake; the size of the hogsheads has been gradually increasing since 1806; there has been a decided increase in the usage of guanos and other foreign manures; there has also been a very decided improvement in the machinery and _ processes for crushing the cane and manufacturing the sugar. a Although Governor Rawson was evidently conscious of these progressive changes, and in fact, mentions most of them, yet he does not approximately eliminate their effects by taking the difference between the individual crops and a progressively increasing ideal normal, but takes the difference between the simple average and the individual years; his results, therefore, need to be computed and all the data for this purpose are given in the tables here- with.—C, A. 346 The average crop divided by the average rainfall of the preceding year shows that each inch of rain corresponds to about 800 hogs- heads in the resulting crop; the extreme limits of variations are 713 and 877 hogsheads, so that in general Governor Rawson proposes to predict the crop that will be gathered during the dry season, February to May, each year by simply multiplying the rainfall of the preceding calendar year by 800. The average uncertainties of the crop thus predicted is very small, the extreme error being 28 per cent positive following the wet year 1861 and 4 per cent negative for a certain dry year; therefore as an improvement on this method he adopts the rule of adding 7 per cent for wet years and subtracting 7 per cent for dry years, the average year being that which corre- sponds to 55 inches of rainfall. In supplementary calculations Rawson and Walcott show the chances of a good crop as calculated from a large, small, or average rainfall, respectively, for each month of the year, but I do not find that they have at any time compared the crop with the total rainfall for the whole eighteen months or growing period that immediately preceded the crop, which comparison I have therefore made and give in Table IIT. From all which it appears that large rains gives large crops, but occasionally much smaller rains do also, so that it may reasonably be suspected that here, as elsewhere, the sunshine must be considered ; probably large rains are only of advantage when they occur at such a time that they do not diminish the sunshine and in such a manner that they do not wash the soil too severely. It would have been desirable to have stated these crops as yields per acre rather than as total crops, but I find no statement of the actual acreage in cane. Rawson gives only the total areas of the six divisions of the island, which sum up 107,000 acres; probably two-thirds of this is planted in sugar cane, so that an inch of annual rainfall corresponds to ~8°°,, or one-ninetieth of a hogshead_ of sugar per acre. It is, however, more proper to reason upon this matter as follows: Eleven poor crops gave, according to Table I, an average deficit of 15 per cent; 12 good crops gave an average excess of 14 per cent; the average rainfalls were 55.15 and 58.18, respectively. Therefore an increase of 1 inch in rainfall corresponds to a gain of 2,4, or 10 per cent of an average crop. TasLEe I.—Barbados sugar crop and monthly rainfall. Average of 12 positive --_--_|_..-..---- Average of 11 negative set Oe i 429 Excess of sugar crop. Per cent. ‘ ‘ ‘ ‘ ' ‘ ' ' ' ' | i iv) 347 Inches. 4.29 3.75 3.30 4.13 i) e asi 2 & | if Feb. | Mar. | Apr. | May. | June. | July. | | Inches. Inches.| Inches. | Inches. | Inches. | Inches. 1.7 1.93 0.97) 1.68] 3.45 6.26 2.75 | 1.57] 1.26 | 2.74] 2.63 6.23 158} 1.53] 2.17| 711] 217| 2.49 2.29) 1.07) 0.56) 0.98) 271) 3.65 1.95) 1.43} 120) 1.33] 5.56] 5.68 4.49 0.88 164) 2.66 | .10.94 7.50 1.28; 140) 0.96) 223) 454| 3.69 2.18) 1.19) O.81| 2.94) 5.49 2.86 1.96) 2.761 635) 8.01) 9.31) 828 1.12| 0.81| 1.12] 3.53] 7.18 5.39 2.19 1.39) 413/) 5.89] 9.19| 7.85 2.95; 1.85| 5.49) 6.82] 6.61 8.00 3.01} 199] 1.58] 6.18] 5.31 6.63 3.94, 2.38) 3.38) 9.26| 5.21 3.89 2.8! 1.13| 241! 066| 3.13| 3.90 3.88. 2.2%) 2.26). 0.56! 1.62! 3.65 2.52 0.78 2.96 4.70| 10.48) 9.01 2.64| 122! 1.24!) 3.56] 5.68| 5.73 1.35! 0.90} 0.93) 2.80] 10.15) 5.@ 5.78| 2.02| 154] 2.64] 5.43| 7.14 2.72) 3.90) 2.69, 2.34| 6.63) 5.64 0.95) 12 2.98 1.02) 2.10) 227 2.47|~0.77| 6.63| 3.07] 2.17 7.51 2.04/ 2.66] 1.58| 6.74] 2.21 6.25 1.47| 108| 3.34| 432| 3.05| > 442 221 1.44 2.22) 3.82) 5.90| 5.62 S49) 1621) 205), 276 | 4.781 5:56 2.58, 1.47) 1.99) 3.54| 5.45| 5.70 348 TABLE I.—Barbados sugar crop and monthly rainfall—Continued. Year. Average of 12 positive_- Average of 11 negative- AMIR (25) =e ee Ss Annual— Aug. Sept. Oct. Nov. Dec. Rain. | Crop. Inches. | Inches. | Inches. | Inches. | Inches. | Inches. | Hhds. 5. 62 4.63 8.20 4,42 1.40 44.60 58, 250 11.89 4, 22 8.99 7.85 5. 80 59. 68 57, 188 7.36 3.72 6.53 14.15 6.66 58.77 | 48,611 5. 37 6.70 6.33 4.03 4.08 41.46 — 53, 907 bed: 3.97 7.03 11.19 3.79 50. 88 45, 181 9. 62 8.54 12.74 4.30 3.89 69.93 | 51, 304 4. 24 3.54 10. 46 6.13 5. 22 45. 22 | 50,788 7.80 5.98 6.15 7.25 4.21 48.49 43, 077 4.65 6.77 7.60 7.50 yenel 73. 82 | 49,745 28 4.74 11.18 7.40 2.36 59.27 46, 120 8.91 5. 07 11.00 4.53 6.58 68. 64 46, 068 12. 84 9:27 5.12 5.98 5.41 77.31 39, 290 7.00 9. 25 6.53 4.29 6.05 59.40 | 38,731 8.08 7.75 | 10.48 8.36 2.20| 68.84 38,719 7.98 fel 13.30 1.97 5.09 57.91) 42, 684 9. 34 4.99 2.89 6. 45 3.27 42.38 42,281 6.82 3.34 10.17 9.61 6.36 67.88 | 35,302 3.21 4.80 10.18 10.18 3.74 54. 22 | 39, 666 5. 61 5.03 11. 24 8.37 3.38 60.17 39, 270 6.33 7.93 6.58 9. 74 3.10 60.90 38, 798 6.82 4.74 8.53 1.42 3.73 52.77 | 338, 077 5. 26 10. 20 {fall 8.45 3.73 48.10 | 33, 703 7.37 10.77 9.14 | 6.31 6.16 59.19 | 36,199 7.53 5.41 11.78 | 5.79 7. O4 63.77 | 28, 169 6.95 4.56 6.99 5.138 5.73 48.52 32, 150 isoD 5.59 8.44 7.06 4.71 bohe Kol ee 6. 66 6.28 8.89 7. 22 4. 66 boyl5) |p 7. 24 6. 24 8.69 7.08 4.50 (ere uieeeeanss A 349 Taste II.—Barbados sugar crop and rainfall of the growing period. Year. Total rainfall of cur- | Crop. rent year. Inches. HAhds. 48.10 33, 703 63. 77 28, 169 52.77 33, 077 67.88 35, 302 59. 40 38, 731 58.77 48,611 68. 84 38, 719 50. 88 45,181 77. 31 39, 290 48.49 43, 077 60. 90 38, 798 45, 22 50, 788 54. 22 39, 666 57.91 42, 684 73. 82 49,745 59. 27 46,120 42.38 42,281 59.19 36, 199 68. 64 46, 068 59. 68 7,188 69. 93 51, 304 44. 60 58, 250 48. 52 32, 150 60.17 39, 270 41.46 53, 907 48. 36 39, 167 Total rainfall during growing sea- son of the crop of current year. Dee of ship- | allot | Latter ment. | preced- year Total. ing year! before. Inches. | Inches. | Inches. CEB a eed Le eed eee ee Feb. 18 4851 Ot (eee eee |e cece Jan. 21 63.77 37. 02 100.79 Jan. 22 52.77 43.80 96. 57 Jan. 18 67.88 30. 88 98.76 Jan. 1% 59. 40 45.31 104. 71 Feb. 12 58.77 39. 75 98. 52 Jan. 19 68. 84 40.81 109. 65 Feb. 17 50. 88 40.71 91.59 Jan. 23 77.31 36. 77 114.08 Feb. 14 48.49 46. 62 95.11 Feb. 10 60.90 34, 25 95.15 Mar. 7 45. 22 4(). 82 86. 04 Feb. 6 54.22 33. 28 87.50 Feb. 17 57.91 37.78 95. 69 cae oie 73. 82 45.50 118. 32 Feb. 14 59. 27 41.91 101.18 Mar. 9 42.38 38.30 80.68 Mar. 6 59.19 30.59 89. 7 Feb. 7 68. 64 47.26 115.90 Feb. 22 59. 68 43. 44 104, 12 Feb. 8 69. 93 44.98 114. 91 Mar. 1 44,60 46.59 91.19 Feb. 22 48.52 30.53 79.05 Feb. 21 60.17 33.78 93.95 Mar. 4 41. 46 39.25 80.71 PS Eee 48. 36 30.16 78.55 First half of year be- fore. Inches. 350 TABLE III.—Barbados sugar crop and rainfall of preceding year. | Above Above +) or (+) or elow below ; (—) the ‘ (—) the Year. Rainfall. average Year. Rainfall.| average _ of crop of crop _ of fol- of fol- lowing lowing year. year. Inches. | Per cent. Inches. | Per cent. 1855 seer eee 2 ote ee 77.31 | SIE el kone: See oe ees ee ee oS 59.19 + 2 SG free em erect nae ote nena 73. 82 | breil SD eee ae See ee Ame eee 58.77 0 ASO ieee eS een ees 69.93 | S20 | el BOO seas Sars ee eee ee ee 57.91 +10 11GG)a%s Bes Tepes pas Sear oe cee 68. 84 athe BDO ae ee Se ee 54. 22 —5 B65 ae 2 ae ae eae Pe ee 68. 64 SEACH he ot: SU oa oe, See re See eee 52.77 —9 TES 5 0 Se oe eee ee aoe ae oe 67. 88 Oli (#1854225 2 a eee 50. 88 +1 B48 Sere Sh eae N= epee oe 63. 77 == Littl fet bolts) Sea eee eR Rs A 48.52 —18 SS ee cere aie eee Aieerm ene 60. 90 ari sce holst pe ee Sees ee ake oc 48. 49 Si! S(O Ro. ee a ee Cn Sey eae 60.17 cr e7 0) | Wal Rov: leer 0 a A ai ere 48. a —27 S66 eae eee ah oe eee 59. 68 +14 | ABH See ec Sos eae rua eee 45.72 —12 FL SEE ert Sa se eh ee 59. 40 By a} || (eel bol b ss] ee Nae EN ee eres = 44:60 —28 S62 seek Sees done eo uee 59. 27 465) | 1868 S52 8 ee se ee eee 42.38 —19 Notre.—In calculating the average crop and the respective annual excesses or deficits given in Tables I and III Governor Rawson says that ‘‘ he has made an arbitrary division of the whole period into two sections marked by the introduction of the use of guano as a fertilizer.”’ For the first section, 1847-1856, inclusive, he considers 38,795 hogsheads as the average, but for the second section, 1857-1872, inclusive, he takes 45,036 hogsheads as the average. He states that this is virtually assuming that during the whole period climatic and other conditions were nearly constant and that the principal difference was in the introduction of the use of guano and the great increase of crops was due to that. During the first interval an inch of rain corresponded to 642 hogsheads of sugar in the crop of the next year, but during the second interval it corresponded to 800 hogsheads. PART III.—STATISTICAL FARM WORK. Chapter XIII. THE CROPS AND CLIMATES OF THE UNITED STATES. The ultimate object of our inquiry is to determine the exact per- centage of the effect of normal and abnormal climates upon special crops in special regions of this country and the relation to the whole crop of the United States. To this end we must first ascertain the climatic effect on the yield per acre, and this is our present special problem, leaving it to the statistician and census taker to ascertain how many acres are under cultivation and what the actual effect will be in bushels or pounds. The climatologist, or Weather Bureau, has only to determine numerically the climatic effect upon a given unit area. The tables of yield per acre for ten important crops and for all years will be given in a subsequent portion of this section, but the study of these must be preceded by several studies into matters that are not strictly climatic, but which nevertheless enter into the statis- tics of actual harvests and obscure the strictly climatic influences. Thus the statistics must be corrected in some way for the effect of the customary modes of cultivation and the quantity of seed that is sown, on which point I give statistics appropriate to the United States. Again, before comparing our climatic data with the phenomena of vegetation we must know something of the average date of seeding, with respect to which I have given the dates for seeding of winter wheat. The corresponding dates for rye will not differ very much. The dates for maize, potatoes, tobacco, and cotton have already been given for special localities, but still require to be tabulated in a general way. The necessary climatic data are given in my next section for twenty Signal Service stations, and I regret that the shortness of time has not allowed me to give more complete data for these and for all other stations, but the tables here presented will serve to show the form in which such data should be presented for the greatest convenience 1n phenological studies. But before entering upon so extensive a system of numerical com- parisons it is necessary to bear in mind certain principles which I would illustrate in the following remarks. (351) 352 VARIABILITY OF RESULTS FROM PLAT EXPERIMENTS. The reliability of the data obtained from experiments on small plats of ground, and on which we should naturally place much reli- ance in discussing the relation between climates and crops, is a matter of the first importance, and we must begin our study with an attempt to obtain a clear idea as to the extent to which such data are fit to be used as a basis for our studies. In the hght of all that has thus far been ascertained with reference to the nature of the influences at work to increase or diminish the resulting crop, we may safely say that the results obtained from two different plats will not be comparable with cach other and still less be applicable to the larger fields harvested by the farmers, unless we know for each plat or field the absolute or relative conditions as to the following matters: (1) The mechanical condition of the soil as affecting aeration, per- colation, and temperature. (2) The chemical nature of the original soil. (3) The character, proportion, and uniformity of distribution of the fertilizers and the history of the previous rotations of crops on these plats; the influence of climate, rain, and drainage on the avail- able nutrition in the soil. (4) The dates of cultivation and application of the fertilizers. (5) -The exact area of the plats. (6) The distance apart of the hills or stalks. (7) The number and quality of seeds sown per acre. (8) The moisture in the soil at the beginning and the quantity and times of rain or irrigation. (9) The chemical and biological quality of the rain or irrigation water—i. e., rain or snow water; rain with much or little nitrogenous compounds and biological germs. (10) The injury by insects and animals. (11) The temperature of the soil. (12) The remaining climatic details as to heat, sunshine, dryness, and velocity of the wind. f (13) The sterility of the soil as to the microbic life that seems indispensable to the success of certain crops or to the growth of the plants. (14) The nature of the climate in which the seed and its immediate ancestor was grown. In the total absence of knowledge as to many of these points and fragmentary knowledge on others, a simple direct comparison between the results of two plats lying side by side and that have in some few respects been treated alike must be entirely misleading. But the extent to which such comparisons are deceptive, or rather the 3538 extent to which we can rely upon them for further instruction, can only be estimated by a study of such exact experiments as have been made at the experiment stations throughout this country and Europe. Some illustrations of this matter are given by C. S. Plumb, under the title of the “ Fallacies of plat experimentation ” (Agr. Sci., Vol. II, p. 4), to which I will add the following remarks. Two sets of meas- ures are taken from the results of the year 1887 at Geneva, N. Y. The plats were arranged in two series, or two fields, but were in every respect as much alike as possible and supposed to be identical. The harvests from the respective plats were as follows: Weight of good | Weight of good Plat. ears. | Plat. ears. Series C. Series E. | Series C.| Series E. Pounds. | Pounds. | Pounds. | Pounds. CY A 8 Bie tena pe fll ge Wo SC MA Be ees Ue Uae ee 172.8 177.5 Ds ee Se ae | 224.2 PAUSE) GI a ts SS Ce BAN Ne AE Rae ee | 171.8 167.1 i St al ah ey AR a en 222.7 QUE OF) phG eae dee tern Ween eS 172.6 182.2 MRNA IR, Le 5G gs 4 Led PAPNOKA 2201 WAT eye Le eas GEE 2 rel 183. 4 150.1 io. ot Reet a eee ee earoedeoull Pe TOG IE lige re. fee acer cae en a \Patienn ts 140.2 Ge Se ee COI de AC A an a etd, ee me PAAR 128.2 gE) ama} au’s |) Averaessee ae eee ane |) peeeae 197.6 | Yield per acre_____ bushels_- 51.1 45.7 NO ceeoe asics Seenesetee Sacco 243.8 186.0 || Number of plants..._.-___-. 12,380 12, 320 WL oo sons se Seas este Sone | 224.6 168.1 | Number of good ears..__-..| 12,180 11, 400 irae teas ae Ee Saves 3 Ht tw eee 209.0 169.1 || epipets te, FD ar nd | 191.7 | 177.6 || | The individual differences between these 36 plats simply show that the conditions were not so uniform as the aythor supposed; in fact, the regular gradations from the high numbers at the top of the column to the low ones at the bottom show that there was a slight systematic difference among the plats in each series. On the other hand, the decided apparent differences between the two series, as well as between the plats, is very largely of the nature of those differences that are called accidental in the theory of exact measurements. Similar dif- erences 1n a long series of observations of the temperature or the rain- fall of any locality are spoken of not as accidental error but as the variability of the climate, and these differences in the present case may properly be treated as variability in the productive power of any plat compared with the neighboring plat without for the moment inquiring as to the cause of this variability. But the mathematical theory of probabilities, or chance, or errors of observation, is equally applicable to this question of variability due to unknown influences. According to that theory we obtain the index of variability if we take the difference between the average of a series and the individual num- 2667—05 M 23 bo4 bers in the series and treat these departures according to the following formula: Index of variability of the plats equals 40.864. / Sum of all the (Departures)? Number of departures less 1, which formula may be interpreted as meaning that from the squares of the departures added together and divided by the number of plats less 1 we derive an index called the “ probable uncertainty of 1 meas- ure,” or “the probable variability of 1 plat as compared with all the plats of the series.” Again, knowing this uncertainty of any one measure, we find the “ probable uncertainty of the average of n meas- ures” by the following formula: Probable uncertainty of the average = + mee This latter formula is to be interpreted as meaning that there is an even chance that the computed average is too large or too small by this probable uncertainty. Applying these principles to the meas- ures of plats C and E, I obtain the figures 34.3 and 22.9 as the indices of variability and 8.33 and 5.26 as the probable errors of the two averages. That is to say, so far as any internal evidence is given by the discrepancies between the measurements of the plats them- selves, there is an even chance that the crop from a plat in series C is between the lhmits 212.9 and 196.3 or outside of these limits; simi- larly, for series E there is an even chance that the crop from any plat is within the hmits 188.9 and 177.4 or outside of these limits. But the numbers within each of these two series overlap each other so much that it is perfectly possible that if we could increase the number of plats in each series sufficiently, all other conditions remaining the same, we should eventually arrive at very nearly the same average value for each. In other words, the mere difference of the two aver- ages 204.6 and 182.7 is no evidence that in this particular case there was any important constant difference between the plats of series C and those of series E, but that, on the contrary, unknown sources of influence are at work in each series and in all the plats that are more important than any that were thought of when the experimenter endeavored to make these 36 plats perfect duplicates of each other. Professor Plumb shows that this difference did not depend upon the previous crops or treatment of the plats during the previous five years. It certainly did not depend on the meteorological climate, the mechanical condition of the soil, nor on the seeds, nor on injury by insects and animals. We may possibly find a partial explanation in the irregular distribution of microbie life in the soil, but it is more likely that it depended upon the inherent variability of the 355 vitality of the seed, due to unknown causes, and which we have no means of measuring except by just such experiments as these. The elaborate measurements made by Lawes and Gilbert at Rothamsted, England, since 1850, furnish innumerable illustrations of this same principle; so, also, do those of W. R. Lazenby, at Columbus, Ohio, and many others. We shall therefore hope to derive more reliable results from the study of farming operations on a large scale, taking the averages by counties and States where the crops have been carefully measured. We may possibly eliminate irregularities in many disturbing ele- ments, and be able to clearly set forth that small percentage by which the crops of the United States as a whole are influenced by purely climatic conditions. Such influences may in extreme cases be very large, but, on the average, they are not so large as those which depend upon seed, cultivation, rotation, and fertilizers. EFFECT OF VARIATIONS IN METHOD OF CULTIVATION AND IN QUALITY OF SEED FOR DIFFERENT REGIONS AND YEARS. Among the modes of cultivation that materially affect the devel- opment of the plant and the quantity of the harvest must be consid- ered the practice of sowing seed broadcast with the hand as con- trasted with that of putting it in with the drilling machine. The drilling requires less seed, the saving being about one-half bushel per acre; the grain is buried more evenly, starts more uniformly, and stands the droughts better. Moreover, the drilled wheat fields are considered to yield more per acre, although it is difficult to state how much is due to the drilling independent of the character of the soil, because in general the fields that are drilled are most apt to be those free from stumps, stones, and steep slopes, while the broadcast sow- ing is especially adapted to this latter character of field. The census of 1879 shows that the drilled fields of winter wheat in Ohio yielded 50 per cent more than the broadcast fields of summer wheat in the Northwest; but it is not plain what proportion of this is respectively due to the drilling and to the soil. In the report for 1875 of the Department of Agriculture (p. 42) the following statistics are given as to the percentage of area drilled, the quantity of seed per acre, and the increase of harvest in drilled fields over that in broadcasted fields: The following table omits the New England States, which produce little wheat, nearly all of which is sown broadcast. The wheat area of New York is divided equally between the two methods. In New Jersey, Pennsylvania, Delaware, and Maryland the drill greatly predominates. In the Southern States the area is small, particu- larly in the cotton States, and the drill is comparatively unknown. North of the Ohio River, in the winter-wheat States, the drill is very 356 generally used, the proportion rising to 76 per cent in [llinois. In the spring-wheat region there are several reasons for prominence of broadcasting. One comes from a prevalent practice of sowing wheat on the irregular surface of a cornfield without plowing; another is found in the use of the combined cultivator and broadgast seeder, which destroys many of the weeds that would otherwise be left between the drills. * * * The result of the investigation shows that 47 per cent of the winter wheat and 30 of the spring, or 37 of both, represent the proportion seeded by the drill. The improvement by drilling is made to average 10 per cent. The average shite of seed used for seeding winter wheat is 1.35 bushels per acre; 1.24 for drilled, 1.44 for the sown. The details are as follows: Percentages for 18765. Relative area— |[necrease| Seed per acre. of prod- Ri Sown. | Drilled. duiltine. | pair Drilling. |Per cent.|Per cent.|Per cent.) Bushels.| Bushels. ING Wy WOT: ns ee Ba SE ee We a es | 50 50 13 1.80 1.60 INGwiTOrseyent nie bese etude Swan eee | 45 55 6 1.95 1.60 IBYeyob ae yeh ONY ae oe ee eo eee eee ee 30 70 12 1.74 1.49 Delaware 2 ai eee ou Ev BAG hae Sele eee oe rae 26 74 10 erie 1.50 Miers yarn Cie ee eee eee a ee ee 24 76 7 1.70 1.48 RVdaoinia te sae seas eine be vo eee eee cee | 62 38 12 1.44 1.21 INOnths Carolina a!* tessa ssn se teen Sees a oem | 97 By see seeaeee 1.07 0.83 South Caroling oss eee sees eee Pee eee see ete eee | 99 1G oe BS eee 1.00 0.70 (Creer teat Jeet oe i Soe eae = oes Seco oe aoe 99 1 ees oe 1.00 0.90 Nlahama Sa otete roar een eee bee ene deenee cosas 99 Uy Sees 1::00:) te eee Mississippi se: soe teso seen we eee eae ee | 99 se ee ee Ls 2by lee saeeees Mera Sy ote MEE Pe oe eel Wey UPR MO EIS oe] 98 Pol erga tae a 1.18 0.90 PA IKATISRS ye ene ere a ae ene eee eee Se eee | 100 CO Pees P10) 2 2 eee Tennessee-_-------- SA eo ais SoA NS ee 96 4 10 1.20 1.10 WiesteViroimia = feo 22 Cees ete ee Ses eae ee | 58 42 12 1.53 1.33 Kentucky ef 20. e te ss ees ee Un es eee Se eel 92 8 10 1.36 aa by OW OS ee ee ee en ee ee ee eee | 39 61 16 1.57 1.33 Michi ga Tie eos! yao Te ee eee ene eee ae | 49 51 9 1.62 1.40 JBM oYoS tesa enti ela ee ee need, NS kare at ee aL 24 76 19 1.52 1.24 Indianiags ssh) sembe be eee epee Shem els aag ee | 49 51 15 1.48 1.21 VEISS OUT dete ee eae ee een ae ee Eee ea 62 38 21 1.52 1,21 Kia nS eee