reheat vit bel bat ; t YEH ee iy pote ekh Hye Be) iNet Ha AE BE AF sh Sit ae , cee 4 hs , : iy Wht dl | t ah 10 peeled iy ahaa i A lathe rite ih " abe # put ry agi yy r ie j aon # et att Bi 47 4 i it a Ces cae) ae +! Batt peeing at 3 4 ays} ride f hyn di hstew ELPA Ty f 1 4 A Hit iH Ne byt ri y $ ‘ rec ba tea ' il taht agaehk ry Iseasud sat elias ee ’ yin | t F . AN uh ne Litt: jeitegs (ths) iar ’ , u Car FEY ou na hi ni 5 A He ia! ahaha) sha they ed ea nia uerieeneaett ice art ih ‘ acini b rayon ; : : q its eit rtniiaks wit RE ROry Chat \ ‘ 1 Taudiagnsatas fh Mad bt Hot: ait abt aaa mn Mi Bite Ht aiy 1}, MRRERISUSE TE LICR Ea aD Ue rarng hit dp} wit ’ \ t Harare etek dir sth. H i Hrork 4 lvinthl eit seit wy aan ct ah ; Resa fiat ieraunesnie the ik 1 Chto Nt ae te Soar metal ah itint HN oh Bsa i! tee Vet Fi » a ay vi laage a 4 qoieiant thts eh (Ri tinge tates ; Soh 1a fish! | tu! nity h $ hada gas balay hh etn evga eid te ua Ge +t si gr fegpes AEE Bt yan ay Tyineny Fhe Ah t hase Uitinati 4 Maidan ares an RGAE BS . iat t ’ iParEte es Wi Ray 4 Ah y ant aL yt yee yen EDM DDST UN LELER OUTED AR bonis Hitt : yeaa - 4 Ha Warrants BRR? PAVED CR Mrs RUC Dos DS fA. ath f a bitortet Hatsy ae ee VE We ct ty pa? Wa ded stag uy Mt ead G8 bias 6 i # fe iy gacits FABIAN Se : Hgts i ‘yt ate vied qe Rita Vite Hid teth PRR UL A Be Mi seat ry} ; Panay ue ee nie PUSCAR ECL ELE EE! ats Shins ty % : the CHa aay; phi PETS EIA eerie aia seine } i Hin ms 9 ding indi renga yy dnd ee fos ben Lia tes Be ESSE Aza ee gayi be b33 rehettaagsda dh : bat att hd utatyts: LUE Thee ety } ui} as one $atag ral bay lazne ahmiaey es ee Ba MAyt Wahl thay? % : Je ean tt Pt, ft ‘ viet te hit Feed Jr ei t fan reds : eh 4 a esa aie Ut ahh nas Ae lage drt aatiey itd nalhs ee eisdtl te ieee is 14 Sthitgheestncaar ts Pei gilt Maisy bisa yee $ hh ero at rity Rie Hy o alivent Sih aa EecyroaD 3 4 PMLAe SEs » f nab iie ah 1 Gaestoinag Mad j PEAT Ads chp Aly fitiies te SNIRE TUMOR ett t MS hota? noe rhe oS ord tt Birks ayer aae 108 RT HE tees 1284 He wh gad Biers Oe ae VATA Ae. Are iterain ys Pye ! 7 erst] uy * aD ate Sts | Hae ek AR HiaNy gaunt 4 SER TE Bae caus (Wiehe Hae th hy Bye R? * Pp. 4 i BBO eee Yee Fret we i Vi pevaibha tits pkaa ties Latta yids peeved wre eso Sen Peer ‘ tet st Per he THR So a (Eta biited “ ly i IPs Fe Sig Brats 2 SR ee ey TA hoe ees Mary he 7h i ip ha Paes PAD G Mae AS Aa Y Tae | AGRICULTURAL QUALITATIVE AND QUANTITATIVE CHEMICAL ANALYSIS. —- = r ZB 7 AFTER EK. WOLFF, FRESENIUS, KROCKER, AND OTHERS. EDITED BY eoaea Oe CALDWELL, PROFESSOR OF AGRICULTURAL CHEMISTRY IN THE CORNELL UNIVERSITY. NEW YORK: ORANGE JUDD AND COMPANY, 245 BROADWAY. Entered according to Act of Congress, in the year 1869, by ORANGE JUDD & CO., In the Clerk’s Office of the District Court of the United States for the Southern District of New York, PREFACE. The purpose of this work is to supply a complete manual of chemical analysis, for the use, especially, of agricultural students. The qualitative and quantitative processes that are de- scribed refer only to such substances as are found in soils, plants, animals, fertilizers, or other materials or products of agriculture ; and, moreover, in order to reduce the size, and consequently the cost of the book as much as possi- ble, except in two or three instances, only those methods of analysis are introduced which are most commonly used by good chemists, and have been tried and found reliable, with such improvements as have been made in more recent practice. The chapters on Special Analyses consist, in the main, of a translation of the “ Anleitung zur Chemischen Un- tersuchung landwirthschaftlich-wichtiger Stoffe, von Dr. Emil Wolf, 2te Auflage, 1867,” a work of the first au- thority in Germany ; two or three unimportant matters have been omitted, the arrangement has been somewhat altered, and some additions have been made to the original. The other chapters, on reagents, manipulation, etc., are 3 = LY PREFACE. made up largely from the “ Anleitung zur Quantitativen Chemischen Analyse, von Dr. C. RR. Fresenius, 5te Aufiage, 1866.” Concerning late improvements in methods of analysis, the Zeitschrift fir Analytische Chemie, by the same au- thority, has been frequently consulted. The scheme of qualitative analysis has worked well in my own hands, and with my own students, but, neverthe-. less, I would have preferred to give it a more careful trial before publishing it. Valuable assistance in testing this and other methods of analysis has been received from Mr. T. B. Comstock, while a student in my laboratory. The use of the old system of atomic weights, and of the old nomenclature, would doubtless have made the book more simple to the majority of students at first, but, nevertheless, it seemed more expedient to follow the com- mon usage in the best recent works on chemistry. The same may be said in regard to the use of the centigrade thermometer and the metric system of weights and measures. Although the work has been somewhat hastily prepared to meet a pressing want in my own laboratory, I trust it may yet be found to answer a good purpose in other lab- oratories where agricultural chemistry is made a specialty. GoGe. Cornell University, College of ) Agriculture, August, 1869. J TABLE OF CONTENTS. CHAPTER I.—The Reagents. List of the reagents needed, with directions for preparing them, when not more readily obtained otherwise, and for testing their purity. 7 CHAPTER Il.—Amalytical Manipulation. Determination of specifie gravity, solution, evaporation, precipita- tion, filtration (including Bunsen’s new method), weighing of residues and precipitates, measuring and dividing solutions, and calculation of results..........:<.. CHAPTER III. —8eactions and Methods of Quantita- tive Estimation. Potassium, sodium, ammonium, barium, calcium, magnesium, alumin- ium, iron, manganese, zinc, lead, copper, and arsenic; silicic, sulphuric, carbonic, phosphoric, nitric, hydrochloric, hydrocyanie, hydroferrocyanic, hydrosulphuric, hydriodic, hydrofluoric; oxalic, acetic, tartaric, citric, malic, lactic, uric, hippuric, and tannic acids; cellulose, starch, gum, the sugars, albuminoids, urea, fat, i Cr ie) (0) i ee i CHAPTER IV.—Special Methods of Amalysis. Course of qualitative analysis, estimation of water, of organic mat- ter, of sulphur and chlorine in organic compounds, special methods of separation of bases and acids, schemes of analysis...128 CHAPTER V.—Amalysis of Soils and Rocks. Mechanical and chemical analysis, and examination of physical prop- erties, of soils, and examination of marl, limestone, and clay... ..165 Va TABLE OF CONTENTS. CHAPTER VI.—Fertilizers. Farm-yard manure, urine, solid excrements, bone-meal, bone black, bone-ash, phosphorite, guano, superphosphate, gypsum, salt, potash compounds, ‘and Chili saltpetre............ceceeessseenne 213 . CHAPTER VII.—Ashes. Ashes of plants, of animal substances, and of fuel................6. 241 CHAPTER VIIl.—Fodder and Food. Fodder plants, beets, turnips, potatoes, seeds, meal, flour, milk, butter, icheese, and Vinegar: ..0'. 4.0620 <0 san see aeepiee eee 251 CHAPTER IX.—Wool and Bark. Hxeamination-of woolvand tanners” bark-2....--.- see eee 269 CHAPTER X.—Beverages. Water and. wine. ..c..6 sce obs oces bees oe be Rb Oe a erciate © tisk 271 CHAPTER XI.—Vables. Metric system of weights and measures, atomic weights of elements, factors for calculating analyses, estimation of tannin in bark, etc.284 AGRICULTURAL SUALATATIVE AND QUANTITATIVE CHEMICAL ANALYSIS. ee ee CHAPTER I. REAGENTS. The following list contains all the reagents used in the - various courses of analysis described in this book, arranged in alphabetical order. Most of them can be procured of the druggists, or the dealers in apparatus and. chemicals. Directions are given here for the preparation of such reagents only as cannot be thus obtained conveniently. The chemical tests to which each reagent should be sub- jected, in order that the analyst may be assured of its purity, and the strength of the solutions to be made, are also given, when it is necessary. Most of this information is taken from the works of Fresenius. The new system of nomenclature and the new formulas being adopted in this work, the new name and formula of each reagent are given first, and, for the benefit of those who are less familiar with these, the old name and formula are afterwards enclosed in parentheses, whenever there is any essential difference between the new and the old. f 8 § 1. REAGENTS. 1, a—Acid, acetic.—HC,H,O,. (HO,C,H,O,. HO,A.) —This should leave no residue on evaporation, and should emit no empyreumatic odor when evaporated after saturation with sodic carbonate; neither hydrosulphuric acid, argentic nitrate, nor baric chloride should produce any change in it, nor ammonic sulphide, after neutraliza- tion with ammonia. 6. Acid, citric.—H,C,H,O,. (8HO,C,,H,O,,.)—Reerys- tallize it, unless clean and colorless. 7 c. Acid, hydrochloric.—HCl. | (Chlorhydric acid. Mu. riatic acid.)—This must be colorless, and it should leave no residue when evaporated on platinum foil, nor should it attack the foil; it should give no blue color to starch- paper, nor should it bleach starch that has been faintly colored blue with iodine; it should give no turbidity with baric chloride, after having been considerably diluted, nor should it be colored by hydrosulphuric acid or potassic sulphocyanate. For the dilute acid, add the concentrated acid to 4 parts of water. _ | d. Acid, hydrosulphuric.—H,S. (HS.)—Pour dilute sulphuric acid through a funnel tube over fused ferrous sulphide, in a common bottle, and conduct the gas that is evolved, first through water in a small wash-bottle, and then into distilled water. The solution should emit a strong odor of sulphuretted hydrogen, and should be freshly made. e. Acid, nitric HNO, (HO,NO..)—This should be colorless, and should leave no residue when evaporated on platinum foil; after having been considerably diluted, it should not be made turbid by argentic nitrate or baric chloride. For the dilute acid, add the concentrated acid to 4 parts of water. jf. Acid, nitro-hydrochleric, Aqua regia.—Mix to- gether 1 part of pure nitric acid, and 3 or 4 parts of pure hydrochloric acid. § 1. REAGENTS. 9 g. Acid, oxalic.—H,C,O,. (2HO,C,0,.) This should not present the least appearance of efflorescence ;_ it should give a perfectly clear solution with water, and should fea no residue when ignited in a platinum dish. If the_acid does not meet these requirements, it should be purified by repeated recrystallization. Stolba (Fresenius, Zeitschrift 8, 63) recommends subli- mation as a convenient method of purifying oxalic acid. Dry the acid thoroughly by keeping it in a warm place for a considerable time, with occasional stirring; when a small portion of it, Denies heated in a test tube, gives off but little water before subliming, it is sufficiently dry. Put it, then, in a large beaker to the depth of 15-20 mm., cover the beaker with a hollow cone of paper, and im- bed it in iron turnings in an iron dish, to the same depth as that of the acid inside, and heat it cautiously, raising the temperature very gradually. Scrape off the outside of the cone of sublimed acid, separate the more solid yel- lowish outer part from the white inner portion, and purify each by itself by crystallization from solution as usual. h. Acid, sulphuric. — H,SO,.. (HO,SO,). — Common sulphuric acid usually contains lead, which is precipitated as a fine white powder, when the acid is diluted with con- siderable water, or when mixed with 4 or 5 parts of alcohol ; it sometimes gives a red color with a solution of ferrous sulphate, where the two liquids come in contact (§ 62), and, when diluted, gives the reaction for chlorine with argentic nitrate (§ 63), and for arsenic by Marsh’s test ($57). The pure acid should give none of these reac- tions, nor any blue color after dilution with 20 parts of water, when a little starch paste and potassic iodide are added to the cooled liquid; it should be volatilized com- pletely when heated. The dilute acid is prepared by adding the concentrated acid to 5 parts of water, slowly, and with constant. stir- ring, letting the mixture stand a long time if any plumbic 1% 10 § 2, REAGENTS, sulphate is precipitated, and then decanting the clear su- pernatant liquid for use. a Acid, silicic.—See Quartz. k. Acid, tannic, needs no testing. 2. Alcohol.—C,H,O. (C,H,O,.)—This is used both in its pure state (absolute alcohol), and mixed with water until its specific gravity is 0.83 or 0.84, corresponding to about 90°|, of pure alcohol, by volume. It should be volatilized completely, and leave no odor of fusel oil when rubbed between the hands; it should burn with a pale blue, barely visible flame, and should not redden blue litmus-paper. 3. a.—Ammonic acetate.—NH,C,H,O,. (Acetate of ammonia. NH,O,C,H,O, NH,O,A.)—This should be colorless, free from empyreumatic odor, and inorganic acids, and should be completely volatilized when heated. 6. Ammonic carbonate.—(NH,),CO,. (Carbonate of ammonia. NH,O,CO,.)—This should be completely volatilized when heated, and, after supersaturation with nitric acid and heating, should give no reaction with solu- tions of silver, barium, or ammonic sulphide. Dissolve it in 4 parts of water, and add 1 part of ammonia, Keep some of the salt also in the dry form. ce. Ammonic chioride.—NH,Cl. (Chloride of ammo- nium.)—This should be completely volatilized when heated on platinum foil, and should give no reaction with am- monic sulphide, baric chloride, or litmus. Dissolve in 8 parts of water. Keep some of the salt also in the form of a dry powder. d. Ammonic fluoride.—NH,F. (Fluoride of ammonium.) —This, when heated in a platinum dish, should leave no residue; if impure, it may be purified by sublimation between two platinum dishes, It should be kept in gutta percha bottles, § 3. REAGENTS, 11 e. Ammonic hydrate.—NH,HO. Ammonia NH,.— This should be colorless, and leave no residue when evap- orated in a watch-glass: after dilution with its volume of water, it should give no very marked turbidity with lime- water, and, after supersaturation with nitric acid in slight excess, it should give no precipitate or color with argentic nitrate, baric chloride, or ammonic sulphide. J. Ammonic molybdate.— (NH,),MoO,. (Molybdate of ammonia. NH,O,MoO,.)—Dissolve 1 part of molyb- dic acid in 8 parts of ammonia-water, pour the solution into 20 parts by weight of nitric acid (Sp. Gr.=1.2), let the mixture stand several days in a warm place, and decant the clear liquid for use. When moderately heated with excess of nitric acid, it should give no yellow pre- cipitate. g. Ammonic nitrate.x—NH,NO,. (Nitrate of ammonia. NH,O, NO,.)—This should give no reaction with baric chloride or argentic nitrate, and should be completely volatilized when heated. h. Ammonic oxalate.—(NH,),C,O,. (Oxalate of am- monia. 2NH,O,C,O,.)—This should be completely vola- tilized by heat, and should give no reaction with hydro- sulphuric acid, or ammonic sulphide, or with baric chloride in a solution acidified with hydrochloric acid, Dissolve in 24 parts of water. z. Ammonic sulphate.—(NII,),,SO,. (Sulphate of am- monia. NH,O,SO,.)—This may be readily prepared by neutralizmg ammonic hydrate with dilute sulphuric acid. k. Ammonic Sulphide. — (NH,),S. (Sulphide of am- monium, NH,S.)—Conduct sulphuretted hydrogen (§ 1, d) into 3 parts of ammonic hydrate as long as the gas is absorbed, and add 2 parts of fresh ammonic hydrate. The reagent should evolve sulphuretted hydrogen freely when mixed with strong acids, and should give at least only a white precipitate with them; it should give no re- 1 § 4. REAGENTS. action at all with solutions of lime or magnesia; when evaporated in a platinum dish, the fexidng should be vola- tilized completely on ignition. Dissolve some flowers of sulphur in a small portion of the reagent, and label this solution, ammonic sulphide with excess of sulphur. 2. Ammonic tartrate.—(NH,), C,H,O,. (Tartrate of ammonia. 2NH,O,C,H,O,,.) — Neutralize tartaric acid with ammonic hydrate, and then add more ammonie hy- drate, so that it shall be in excess over the acid. m. Ammonic-ferrous sulphate. — (NH,), Fe (SO,).. (Sulphate of protoxide of iron and ammonia. NH,O, TeO, (SO,),.)—Divide a quantity of sulphuric acid into two equal ‘parts; heat one of them with an excess of small clean iron nails free from rust, as long as the evolu- tion of hydrogen continues. Neutralize the other portion of the acid accurately with ammonic carbonate, and then add a few drops of sulphuric acid. J ilter the solution of ferrous sulphate, obtained by the action of the acid on the nails, into the ammonic sulphate, evaporate the mixture a little if necessary, and let it crystallize. Let the erys- tals drain in a funnel, dry them by exposure to the air on filter-paper, and keep them in a well stoppered bottle. The solution of the salt in water acidified with sulphuric acid should give no red color with potassic sulphocyanate, 4. Argentic nitrate. — AgNO,. (Nitrate of silver. AgO, NO,.)—After the solution of this reagent has been ‘completely. precipitated with hydrochloric acid, the fil- trate from the precipitate should leave no residue when evaporated, and the same filtrate should give no color with ammonic sulphide. Dissolve in 20 parts of water. All the silver refuse, consisting of precipitates contain- ing silver, and solutions to which argentic nitrate has been added, should be thrown into a bottle containing dilute hvdrochloric acid. When a sufficient quantity of the § 5. REAGENTS, 1s precipitated chloride has accumulated, separate it from the liquid by decantation of the latter, wash it well with water, pour dilute sulphuric acid over it, and put some pieces of zine in contact with it. When the whole is changed to a gray metallic powder, and the zinc is all dissolved, filter out and wash the pow- der well, dry, and ignite it. Dissolve the silver thus ob- tained in nitric acid, add water, filter if necessary, evap- orate the filtrate to dryness on the water-bath, and dis- solve the residue in 20 parts of water, and subject the solution to the tests above described. 5. «a.—Baric acetate, — Ba(C,H,O,),. Acetate of baryta. BaO,C,H,O,. BaO,A.)—This should be colorless and should have no empyreumatice odor, and it should give no reaction with ammonic sulphide or argentic ni- trate; after complete precipitation with sulphuric acid, the filtrate should leave no residue on evaporation, Dis- solve in 10 parts of water. b. Baric chloride.—BaCl,. (Chloride of barium. BaCl.) —This should not affect litmus-paper, nor give any reaction with ammonic sulphide; after complete pre- cipitation with sulphuric acid, the filtrate from the precipi- tate should leave no residue when evaporated. Dissolve in 10 parts of water. ce. Baric hydrate.— Ba(HO),. (Hydrate of baryta. Baryta water. BaO,HO.) — After precipitation of the barium from the solution by sulphuric acid, the filtrate should remain clear when mixed with alcohol, and should leave no residue when evaporated. Dissolve in 20 parts of water. In determinations of urea in urine, a mixture of one volume of a cold saturated solution of barie nitrate and two volumes of a cold saturated solution of baric hydrate is used. d. Baric nitrate.—Ba(NO,),. (Nitrate of baryta. BaO, NO,.)—This should be completely precipitated by sul- 14 § 6. REAGENTS. phuric acid so that the filtrate from the precipitate leaves no residue when evaporated, and it should give no reac- — tion with argentic nitrate. e. Calcic chloride.—CaCl,. (Chloride of calcium. CaCl.) —This should not affect litmus-paper, should give no reaction with ammonic sulphide, nor any ammonia when heated with sodic hydrate. Dissolve the erystals in 5 parts of water. The crude, impure, fused chloride answers for desicca- ting purposes. J. Caleic fluoride.—CaF,. Fluor spar.—To save trouble, buy the powdered fluor spar. g. Calcic hydrate.—Ca(HO),. Lime-water. (CaO, HO.)—Digest slaked lime with cold water with occasional stirring, let the mixture stand quietly for a time, and de- cant the clear liquid for use. It should give a dark color to turmeric-paper, and a considerable precipitate with ammonic oxalate. for many purposes milk of lime is used in preference to lime-water; this reagent is simply lime-water mixed with an excess of undissolved calcic hydrate. It should be made with lime from white marble, and should be kept in well stoppered bottles, and shaken up when used. h. Caleic sulphate.—CaSO,. (Sulphate of lime. CaO, SO,.)—Digest powdered, crystallized gypsum a long time with cold water, with frequent agitation, let the mixture stand quietly at last, and decant the clear liquid for use. 6. Chlorine.—Cl.—Nearly fill a flask with manganic binoxide in pieces about as big as peas, and then add so much common, concentrated hydrochloric acid, that about half the oxide will be immersed in it. Conduct the gas, by a glass tube passing through the cork with which the mouth of the flask is closed, through a cylinder or wash- bottle containing concentrated sulphuric acid. The evo- § 7% REAGENTS. 15 lution of the chlorine begins at common temperatures, but _ a little heat must be applied after a time. 7. Cobaltic nitrate.—Co(NO,),.—Dissolve the salt in 10 parts of water. 8. Cochineal solution.—Boil cochineal with water. The solution will keep better if about half its volume of alcohol is added to it. 9. a—Cupric acetate.—Cu (C,H,0,)CuO. (Acetate of copper. Verdigris. 2CuO,C,H,O,.)—To prepare the solution of this salt for washing the precipitate of baric sulphate, dissolve the commercial salt in water contain- ing a little acetic acid, add 2 drops of sulphuric acid, if this acid is not already present, then a few drops of baric chloride until the liquid gives a faint reaction for barium, boil a short time, and filter. The solution should be sufti- ciently concentrated to deposit crystals on cooling. Use the supernatant saturated solution, 6. Cupric sulphate. — CuSO, (Sulphate of copper. CuO,SO,.)—This should be recrystallized once or twice. 10, Curcuma-paper.— Zurmeric-paper. — Digest pul- verized curcuma root with 6 parts of weak alcohol, color slips of unsized paper with the yellow extract, and dry them. 11, Ether.—C,H,,0O. (C,H,O.)—This is sufficiently pure as obtained of the druggist. 12. a.—Ferric chloride.—Fe,Cl, (Perchloride of iron. Fe,Cl,.)—Its solution should give a permanent precipi- tate with a drop or two of ammonic hydrate; it should give no blue color with potassic ferricyanide. Dissolve in 20 parts of water. b. Ferric oxide.—Fe,O,. (Sesquioxide of iron.) —This is also known as colcothar. c. Ferric nitrate,—Fe(NO,),. (Nitrate of sesquiox- ide of iron, Fe,0,,3NO,.)—Dissolve iron in nitric acid, 16 § 13. REAGENTS. evaporate the solution to expel excess of acid, and dis- solve the residue in 10 parts of water. d. Ferrous chloride.—FeCl,. (Protochloride of iron. FeCl.)—Dissolve pianoforte wire in concentrated hydro- chloric acid; the solution should be made as it is wanted. e. Ferrous sulphide.—FeS. (Sulphide of iron.)—Get the fused sulphide of the druggists. 13. Hydrogen.—H.—This is made by the action of di- lute sulphuric acid on granulated zine. To purify the gas conduct it through a U tube, or a calcic-chloride cylinder, containing freshly ignited charcoal, and in order to dry it, through another cylinder containing calcic chloride. 14, Indigo solution.—This may be prepared by treat- ing 1 part of finely powdered indigo with 5 parts of fuming sulphuric acid 48 hours in the cold, and pouring the mixture into 20 parts of cold water. 15. lodine.—I.—This needs no testing. 16. c.—Iron Turnings.—These should be clean and free from grease, 6. tron Wire.—Get the finest pianoforte wire, free from rust. 17, a.—Lead-paper.—sSoak slips of unsized paper in a solution of plumbic acetate, dry, and keep in a well stop- pered bottle. 6. Litmus-paper (blue).—Digest irae with 6 parts of water, filter, divide half of the filtrate into two equal parts aa eutehiie saturate the free alkali in one of these parts with sulphuric acid, until the liquid has taken a red color that does not disappear after standing a few min- utes; add the other part to this, color strips of unsized paper in the blue liquid, dry them, and keep in a dark place. The strips should have a fee color. c. Litmus-paper (red).—Add sulphuric acid to hie other half of the extract of the litmus until a permanent § 18. REAGENTS. jb? red color is just obtained ; color slips of unsized paper in this solution, dry them, and keep in a dark place. The strips should have a distinct red color. 18, a.—Magnesia (calcined).—Mg0O.—This should be freshly ignited before being used. b. Magnesia mixture.—Mix together 1 part of mag- nesic sulphate, MgSO,, 1 of ammonic chloride, 4 of am- monic hydrate, and 8 of water; let the mixture stand several days in a moderately warm place, and decant the clear solution for use. 19, Malt.—Get good brewer’s malt. 20. Manganic binoxide.—MnO,.—The commercial, na- tive, crystallized binowide of manganese is generally suf- ficiently pure. 21. a—Mercuric nitrate,x—Hg(NO,),. (Nitrate of mercury. HgO,NO,.) — Dissolve mercury in its own weight of nitric acid (Sp. Gr.=1.4), heat the mixture to- wards the close of the cperation, and, finally, add to it twice its bulk of water. 6. Mercureus nitrate.—Hg,(NO,),.—(Subnitrate of mercury. Hg,O, NO,.)—Pour 1 part of pure nitric acid (Sp. Gr.=1.2) over 1 part of mercury, let stand 24 hours in a cool place, separate the crystals from the undissolved mercury and the mother-liquor, dissolve them in water mixed with *|,, of nitric acid, by trituration in a mortar, filter, and keep the solution in a bottle with metallic mer- cury covering the bottom. Microcosmic salt.—See sodic ammonic phosphate. Milk of lime.—See calcic hydrate. 22. Oxygen.—O.— Mix ‘together in a mortar 100 grms. of potassic chlorate and 0.1 grm. of ferric oxide, half fill a retort with the mixture, and heat over a coal fire, at first gently. As soon as the contents of the retort are partly fused, mix them together by gentle agitation. Collect 18 § 23, REAGENTS. the gas in the gasometer; for use, conduct it from the gasometer through a solution of caustic potash (Sp. Gr.= 1.27) ina Liebig’s potassa-bulb, then through a U tube containing pumice-stone soaked in sulphuric acid, and finally through a tube containing calcic chloride. Phosphorus salt.—See sodic ammonic phosphate. 23. Platinic chloride.—PtCl,; (Bichloride of plat- inum. PtCl,.)—Its solution, evaporated to dryness on the water-bath, should leave a residue entirely soluble in alcohol. Precipitates and solutions containing platinum should be thrown into a bottle containing a solution of ammonic chloride. When a sufficient quantity of the precipitate has accumulated, separate it from the liquid by filtration, wash, dry, and ignite it strongly. Exhaust the residue thoroughly with hot nitric acid, wash the insoluble part in water, dissolve in aqua regia with the aid of a gentle heat, adding fresh portions of nitric acid until the plat- inum is completely dissolved, evaporate the solution on the water-bath, with the addition of hydrochloric acid, and dissolve the semi;fluid residue in 10 parts of water. 24. a—Plumbic acetate.—Pb (C,H,O,),. (Acetate of lead. PbO, C,H,O, PbOA.)—The basic acetate, Pb (C,H, 0,), 2 PbO, is prepared by treating 120 grms. of crystallized common acetate (sugar of lead) with 60 1 : germs, of gently ignited, and then finely pulverized plumbic — oxide (litharge), and 400 c.c. of water; let the mixture stand some time in a warm place with frequent agitation, and finally filter the liquid for use. b. Plumbic binoxide.—Pb9O,,. c. Plumbic oxide.—PbO. Litharge. 25. a—Potassic acetate.—KC,H,O,. (Acetate of po- tassa. KO,C,H,O,.)—This should be white and free from empyreumatic odor. Dissolve in 5 parts of water. ; § 95. REAGENTS. 19 6. Potassic bisulphate.—KHSO,. (Bisulphate of po- tassa. KO,HO,SO..) c. Potassic chromate.—K,CrO,. (Chromate of po- tassa. KO,CrO,.)—This should give no turbidity with argentic nitrate, after acidification with nitric acid. Make a cold saturated solution. d. Potassic chlorate.—IKCl1O,. (Chlorate of potassa. KO,CI1O..) e. Potassic dichromate.—K,Cr,O,. (Bichromate of potassa. KO,2CrO,.)—This should be recrystallized. Dissolve it in 12 parts of water. J. Potassic ferricyanide.—K,Cy,Fe. K,Cfdy. (Fer- ricyanide of potassium. K,Cy,Fe,.)—This should give no blue color with ferric chloride. g. Potassic ferrocyanide.—K,Cy,Fe. K,Cfy. (Fer- rocyanide of potassium. K,Cy,Fe.)—Dissolve in 12 parts of water. h. Potassic hydrate.——KHO. (Potassa KO,HO.)— This should not be changed by ammonic sulphydrate, and should effervesce but slightly if at all with hydrochloric acid; the solution obtained with hydrochloric acid in excess, when evaporated to dryness should give a residue that is at least almost completely dissolved by water; the same solution should give, at the most, but a very slight reac- tion for phosphoric acid with ammonic molybdate, and should give but a slight flocculent precipitate with am- monia in excess, after long standing in a warm place. Pure potassa prepared from an alchoholic solution of the hydrate should give none of these reactions. Dissolve in 10 parts of water. z. Potassic iodide.—KI. (Iodide of potassium.)—This is sufficiently pure as obtained from the druggists. k. Potassic permanganate.— K,Mn,O,. (Perman- ganate of potassa. KO,Mn,O.,.) 20 § 26. REAGENTS. Z. Potassic sodic carbonate.—KNaCO,. (Carbonate of potassa and soda. KO, NaO, 2 CO,.)—Recrystallize some potassic sodic tartrate, ignite the salt in a silver dish until completely charred, exhaust the black residue with water, filter, evaporate the filtrate to dryness in the silver dish, and keep the salt in a well stoppered bottle ; when it is fused with a little pure sodic nitrate, and the residue is dissolved in water and nitric acid, and then am- monia added, each in slight excess, no flocculent precipi- tate should appear after long standing in a warm place. m. Potassic sodic tartrate.—KNaC,H,0,. (Seign- ette salt. Tartrate of potassa and soda. KO, NaO, C.H,O,,.)—This should be recrystallized once or twice. It should give a colorless solution with water. | n. Potassic sulphocyanate.—-KCyS. (Sulphocyanide of potassium. KCy §,.)—Dissolve in 20 parts of water. 26. Quartz, powdered.—SiO,.—Drench red-hot quartz with cold water, and reduce the friable mass to a very fine powder. 27. a.—Soda lime.—Na,CaO,.—This should not effer- vesce much with acid, and, when mixed with pure sugar and heated to redness, it should evolve no ammonia. in order to have the reagent perfectly free from nitro- gen, Lawes and Gilbert found it necessary to mix it intimately with 1-2°|, of sugar or some other non- nitrogenous substance, and ignite the mixture in a muffle, then to moisten it, and heat it again gently. 6. Sodic acetate.—NaC,H,O,. (Acetate of soda. NaO, C,H,O,.)—This should be colorless and have no empyreumatic odor, and should give no reaction with ammonic molybdate or baric chloride. Dissolve in 10 parts of water. c. Sodic ammonic phosphate—NaNH,HPO, Phos- phorus salt. (Phosphate of soda and ammonia. Na0O, § 28. REAGENTS, 21 NH,O,HO, PO,.)—This should give a colorless bead when fused on platinum wire. d. Sodic bisulphite.—HNaSO,. (Bisulphite of soda. Na0O,HO,SO,.)—This should give a residue when heated with sulphuric acid, whose solution is not changed by hydrosulphuric acid or ammonic molybdate. Dissolve in 10 parts of water. e. Sodic carbonate.—Na,CO,. (Carbonate of soda. NaO,CO,.)—This should be perfectly white, and the solu- tion obtained after supersaturation with nitric acid should give no precipitate nor color with baric chloride, argentic nitrate, or potassic sulphocyanate, nor any reaction with ammonic molybdate, nor any insoluble residue of silicic acid when evaporated to dryness. Dissolve the crystal- lized salt in 3 parts of water, or the anhydrous salt in 5 parts. Keep some of the ignited salt in the dry form. f. Sodic hyposulphite.x—Na,S,H,O,. (Hyposulphite of soda, NaO,HO,S,0O..) g. Hydric di sodic phesphate.—Na,HPO,. (Phosphate of soda. 2Na0O,HO,PO,.)—This should not be made turbid when heated with ammonia, and the precipitate produced by argentic nitrate, or baric chloride, should be dissolved completely and without effervescence by dilute nitric acid. Dissolve in 10 parts of water. | h. Sodic nitrate.x—NaNO,. (Nitrate of soda. NaO, NO..)—This should give no reaction with argentic nitrate or baric chloride, nor with sodic carbonate. 28. Starch-paper.—Boil starch with 25 parts of water, saturate strips of paper with the liquid, and dry them. Tannin.—See acid, tannic. 29. Tin.—Sn.—Get the best tinfoil of the druggists, or pure tin in small sticks. Turmeric-paper.—See curcuma-paper. 30. Uranic acetate.—(U,O) C,H,O,. (Acetate of 22 § 31. REAGENTS. uranium, (U,O,,C,H,O,.)—Heat uranic nitrate until a small part of the uranic oxide is reduced, digest the yellowish-red residue with acetic acid, filter the liquid and set the filtrate aside to crystallize; the crystals are composed of uranic acetate, while uranic nitrate remains in solution. The solution of the acetate should not be changed by sulphuretted hydrogen after acidification with hydrochlo- ric acid, and should give a precipitate with ammonic car- bonate that is entirely soluble in an excess of the reagent. 31, Urea.—Recrystallize it from its solution in alcohol. 32. Water, distilled.—H,O.—This can be prepared by the analyst himself, if necessary. Dealers in apparatus can supply small stills of copper and worms of block-tin, put together and ready for use. ‘The water must be colorless and tasteless, and it should leave no residue when evaporated in a platinum dish. Ammonic sulphide should give no color to it, nor should basic plumbic ace- tate make it turbid, nor should ammonic oxalate or argentic nitrate make it turbid after long standing. 33. Zinc,—Zn.—This should give no reaction for arsenic with Marsh’s test, and, when dissolved in nitrie acid with the aid of heat, it should give no red color with potassic sulphocyanate. Fresenius recommends that before using zine for reducing ferric to ferrous oxide in the estimation of iron by the permanganate process, it Should be tested by the same process. Dissolve a piece of the zine in di- lute sulphuric acid in the small, long-necked flask, as de- scribed in § 52, 5, and, after the flask is filled with water and its contents are cold, add a drop of a very dilute so- lution of potassic permanganate, and at the same time add another drop to the same volume of pure water, and stir both mixtures well. The depth of color communica- ted to both liquids should be precisely the same. § 34. DETERMINATION OF SPECIFIC GRAVITY. 23 CHAPTER 11. ANALYTICAL MANIPULATION. DETERMINATION OF SPECIFIC GRAVITY. 34, By the specific gravity of a solid-or liquid is un- derstood its weight as compared with the weight of an equal volume of water. a. The most obvious method of determining it is to weigh equal volumes of the substance and of water. This is easily accomplished in the case of liguids, with the aid of the so-called specific-gravity bottle or piknometer, an instrument made of thin glass and provided with an ac- curately ground stopper; the stopper is sometimes per- forated. The weight of the empty bottle is ascertained, then its weight when completely filled with water, or filled toa mark on the neck, and finally when filled to the same extent with the liquid under examination; be- fore weighing, in each case, all adhering particles of liquid should be carefully wiped off with blotting paper; both weighings should be made at as nearly the same tempera- ture as possible, or at about 15° C.,the usual temperature of the working room. Divide the weight of the liquid by that of the water, for the specific gravity of the former. b. The specific gravity of liquids is also determined with great facility, though with less accuracy, by means of the areometer or hydrometer; this is a glass tube closed at both ends, considerably enlarged towards one end, and loaded with mercury to make it take a vertical position in the liquid, but not with enough to cause it to sink under the surface. The use of the areometer depends upon the principle, that the less the specific gravity of a liquid is, the less its buoyant power. The specific gravi- 24 § 35. ANALYTICAL MANIPULATION. ties corresponding to the different depths to which the in- strument will sink in liquids of different densities, are marked on a scale in the upper, slender part of the tube. The temperature of the liquid whose specific gravity is to be determined with the hydrometer should be as nearly 15° C. as possible. ce, As there is a fixed relation between the degree of concentration and the specific gravity of a solution of any given substance, areometers are constructed, upon whose scales the amount of the substance in 100 parts of its solution is given, instead of the specific gravity of a solution of that particular degree of concentration. Thus, we have alcoholometers for mixtures of alcohol and water, saccharometers for solutions of sugar, acetometers for so- lutions of acetic acid, lactometers for milk. 35. a.—To determine the specific gravity of a solid, we may weigh it first in the air, and then while immersed in water, and suspended from the arm of the balance by a fine thread or hair. The difference between these two weights, divided into the weight of the body in the air, will give its specific gravity. b. Or, if the substance is in the form of a powder that is insoluble in water, we may weigh it first by itself in the specific-gravity bottle, then fill the bottle with water, as in § 34, a, and weigh again. The difference between the weights of water that the bottle will hold, with and without the substance in it, which is the weight of a vol- ume of water equal to that of the solid substance, divided into the weight of the substance itself, will give its spe- cific gravity. e. Or, taking advantage of the fact that a cubic centi- metre of water weighs very nearly one gramme at com- mon temperatures, we may make a rough determination of the specific gravity by fillmg a 500 c.c. graduated cyl- inder exactly up to the 250 cc. mark, then putting a § 36. SOLUTION. 25 weighed quantity of the substance (100 or 200 grms.) in the cylinder, shaking the mixture well so as to disengage bubbles of air, and observing the volume occupied by both the substance and the water; the increased volume, which represents that of the substance added, expressed in cubic centimetres, divided into the weight of the sub- stance taken, expressed in grammes, will nearly equal the specific gravity. d. If the substance is soluble in water, some other liquid, like alcohol or naptha, must be used. Determine the specific gravity of the substance with reference to this liquid, by the same rules as above, and then multiply the result by the specific gravity of the liquid used, with ref- erence to the common standard, water; the product will be the specific gravity of the substance with reference to the same standard. é. The specific gravity of a substance may be deter- mined roughly, but very expeditiously, as, for example, of potatoes, by putting several samples in a shallow dish containing a saturated’ solution of common salt, and add- ing water with constant stirring, until the buoyant power of the liquid is diminished to such a degree that half the samples swim at the surface, and half sink to the bottom; it can then be assumed, with sufficient accuracy for some purposes, that the average specific gravity of the article under examination is the same as that of the solution, and this can be determined with the aid of the hydrome- ter (§ 34, 0). SOLUTION. 86. In order that a substance may be analyzed accord- ne to the methods described in the following pages, it ust be brought into solution if not alneady. dissolved. The solvents most commonly used are water, hydrochloric acid, and nitric acid, for inorganic substances, and water, 9 ° 26 § 36. ANALYTICAL MANIPULATION. alcohol, and ether, for organic matters. As the manner of making the solution is described in each case, when spe- cial directions are necessary, but little need be said on the subject here. As a general rule, heat increases the sol- vent power of the dissolving agents to a considerable ex- tent, and hence it should always be applied, unless the solution is very easily accomplished without, or unless di- rections are given to the contrary. Time is often an im- portant element in effecting solution, and hence long con-_ tinued digestion at a moderately high temperature may be useful, or even necessary. A great excess of strong acid in a solution to be analyzed often causes much _ trouble ; hence, as little acid as possible should be used, — and in case a large quantity has been added to the sub- stance, it should, in most cases, be removed subsequently by evaporation almost to dryness. Unless a substance is readily and completely soluble, it is essential that it should be as finely divided as possible, and, to this end, it should be ground to a fine powder in © a porcelain mortar, or, better still, an agate one. j In order to reduce a substance to a sufficiently fine © powder, it is sometimes necessary to levigate it, which means simply to grind it in the agate mortar with the addition of water enough to make a thin paste, until no — grittiness can be felt under the pestle, nor any grating © sound heard. Then rinse the contents of the mortar into an evaporating dish, dry the substance thoroughly — over the water-bath, and mix the dry residue together — carefully by further grinding in the mortar. | _ In making a solution for quantitative purposes, when — the loss of even a minute part of the substance would impair the accuracy of the results obtained, if the mixture of substance and solvent is to be boiled, or if the sub- stance is a carbonate, and is to be treated with an acid, it is best to operate in a flask placed on its side, or with its — mouth loosely stoppered by a small funnel, or in a beaker — } : § 87. EVAPORATION. 27 covered with one of the large watch-glasses now so much used for this purpose. The flask with the funnel in its mouth is better for the solution of carbonates, since fresh _ quantities of acid can be conveniently added from time to time. When the solution is finished, carefully rinse the funnel or watch-glass into the flask or beaker. Heat is most conveniently applied to a mixture of sub- stance and solvent with the aid of the water-bath, or sand- _ bath, in making solutions for quantitative purposes, and often in qualitative analysis also. When it is necessary to boil the mixture of substance and solvent for a consid- erable time, and the solvent is more or less volatile, it is best to connect the flask with the Jower end of a Lieb- ig’s condenser; the vapor of the liquid as it is condensed flows back into the flask, and it is unnecessary to renew the solvent until it is quite saturated. See § 389, c. EVAPORATION. ad. A liquid may be evaporated either to get rid of a superabundance of water, that makes the solution too di- lute, or to expel an excess of acid, or for the purpose of weighing what it has in solution. In the first and second cases, the operation may be performed in porcelain dishes, unless the solution is strongly alkaline. a. In the third case, if the quantity of the liquid is large, it may be evaporated to a small bulk in a porcelain dish, and then carefully transferred to a platinum dish or crucible. Or the original solution may be put into the platinum dish in small quantities at a time; if, however, the solution contains free chlorine, or nitric and hydro- chloric acids together, it must be evaporated in a porcelain dish until no more fumes of chlorine are evolved; the residue may then be transferred to the platinum vessel, _and the evaporation continued. When a considerable quantity of a liquid is.to be evap- 28 § 37. ANALYTICAL MANIPULATION. orated, the operation may be performed at first directly over the lamp; but in quantitative work the evaporation should be completed on the water-bath in all cases; if the original quantity of the solution is small, it is better to conduct the whole evaporation on the water-bath. If the evaporation is connected with quantitative work, the dish should never be more than three-fourths filled, and the solution should not be allowed to boil at any time in an open vessel; evaporation will, however, proceed quite rapidly in a flask placed partly on its side, and in this case gentle boiling may be allowed. Unless the evaporation is performed in aroom set apart for the work, and entirely free from dust, solutions should be kept covered with filter-paper during the operation ; the paper should be supported by glass rods, or a glass triangle, laid over the dish in such a manner that it cannot come in contact with the liquid; if the solution is strong- ly acid, the paper should have been well washed with acid, as directed for washing filters § 39, a; otherwise, drape of acid, that have eoudomeatl on ne glass cade and come in contact with the paper, may fall eam into the liquid and carry with them inorganic substances that were dissolved out of the paper. To prevent the salts in solution from being deposited on the sides of the dish above the liquid, and even over the edge, smear the rim of the dish, just below the edge on the inside, with the thinnest possible coat of tallow. Or, fit the dish in a little jacket of fire-clay, im such a manner that the part of it above the liquid shall be kept very hot. Or, turn the crucible on its side, and apply the flame of the lamp just above the surface of the liquid. b. When, as is often the case in agricultural analysis, potassa or soda is to be estimated in a solution containing a large quantity of ammoniacal salts, and from which these salts are to be removed by evaporation to dryness and ignition, Fresenius recommends to evaporate the so- y =] § 88. PRECIPITATION. 29 lution to dryness in a porcelain dish on the water-bath, dry the residue thoroughly at a temperature a little above 100° C., transfer it to another dish with the aid of a spatula, rinse the porcelain dish with a little water into the crucible in which the residue is to be finally ignited, evaporate these washings to dryness, then ignite the dry residue, obtained above, in small portions at a time, and finally rinse the dish that contained it into the crucible, with the aid of a little finely powdered ammonie chloride, and ignite again. The dish with the residue should be kept in the desiccator while waiting for the ignition. PRECIPITATION. 88. Precipitation is usually resorted to in order to sep- arate certain substances from others in the same solution, or simply from the solution itself; it consists in adding some reagent to the solution, which causes the substance or substances in question to enter into an insoluble form. The operation is usually performed in beakers, because, from these, the precipitate is more easily transferred to the filter. Care must be taken not to use too large an excess of the precipitant, and yet there must be no doubt at all that enough has been added ; if the precipitate does not settle speedily, so that the effect of the addition of a few more drops of the reagent can be observed, a small portion of the mixture should be thrown on the same filter that is finally to receive the whole of the precipitate, and the necessary test can be applied to the filtrate; this small portion that has been separated from the main part of the liquid should then be mixed with it again, before more of the precipitant is added. The solution and the reagent should always be well mixed by stirring, and, in most cases, the solution should be so dilute that, when the precipitate settles, it will not 30 § 38. ANALYTICAL MANIPULATION. occupy more than one-third or one-fourth the space taken up by the liquid above it; and, moreover, for convenience in filtration, the beaker should not be more than two- thirds or three-fourths filled by the mixture. A few precipitates may be filtered out at once, in quan- titative analysis, but in most cases digestion In a warm place for a longer or shorter time, is required. The beak- er should be carefully covered during the digestion, so that no particle of dust can get in, and the operation is most conveniently performed on the sand-bath. a ct as as When about to transfer the contents of the beaker to ~ the filter, smear a very little tallow under the lip of the former, wet a glass rod in the liquid, and hold this wet rod against the lip of the beaker in such a manner that the liquid will run down the rod and against one side of ~ the filter. Of course every particle of the precipitate must be transferred to the filter if the two are to be weighed together, with or without ignition. Most of the preci- pitate can be rinsed out of the beaker by means of the jet from the washing-bottle; if any particles re- main adhering to the glass, they may be loosened with a stiff feather; or, when the precipitate is to be ignited before being weighed, a quarter ora half of a filter, of the same size and kind as that in the funnel, may be moistened slightly and rubbed over the sides and_bot- tom of the beaker with the aid of the glass rod, or of glass-pointed pincettes, and then transferred to the filter, with most of the remainder of the precipitate adhering to it; a little subsequent rinsing with the wash-bottle will leave the beaker thoroughly cleansed; or the precipi- tate that adheres obstinately to the sides of the beaker may be dissolved in very dilute acid, and re-precipitated on neutralization of the acid with ammonia or soda, and the addition of a little more of the precipitant. If the second method of cleaning the beaker is followed, remem- § 39. FILTRATION. 3h ber to subtract the weight of 1'|, or 1'|, filter-ash from the weight of the ignited residue instead of 1 as usual. FILTRATION. 39. a@.—Solid particles are separated from the liquids with which they may be mixed by the process of filtra- tion, referred to in the preceding paragraph, which con- _ sists simply in passing the liquid through porous unsized paper, that intercepts the solid. Paper, already cut in convenient sizes, can be had of ‘ apparatus dealers. For quantitative purposes, filters of Swedish paper should be used, or common white filters that have been washed in dilute acid; to wash filters, pour over them, in layers of moderate thickness in a large evaporating dish, a mixture of one part of hydrochloric acid and nine parts of water; digest for several hours at a moderate temperature, wash with distilled water by de- cantation until the washings no longer redden litmus, transfer the bunches of paper to blotting paper, and leave them undisturbed until the filters can be separated from each other without being torn. These washed filters are more suitable for filtration by Bunsen’s process than those of Swedish paper, as they are stronger and less lia- ble to be torn. To make the filter, fold the circular piece of paper twice in directions at right angles to each other, and through the centre; open the quadrant thus formed in such a man- ner as to make a conical cavity, put it in a glass funnel, which should be at least 8-5 millimetres larger than the filter, wet the latter with a little water from the washing- bottle, and press it closely against the glass throughout with the finger. The filter should never be filled with the liquid to within less than 6 mm. of the top, and should not ordi- narily be much more than half filled with- the precipitate when the liquid has drained off. 32 § 39. ANALYTICAL MANIPULATION. Most liquids may be filtered much more rapidly when hot, and many precipitates are much less liable to pass through the filter, or to choke it up, when formed in nearly boiling hot solutions by hot reagents. When possible, it 1s best to let the solid matter settle to the bottom of the vessel containing the mixture of liquid and precipitate, then to decant as much as possible of the clear, supernatant liquid on the filter, pour fresh distilled water over the contents of the beaker, stir well, and perhaps heat almost to boiling, let the precipitate set- tle, and decant the liquid again; this may be repeated a — number of times before putting the solid substance on the filter. If the precipitate is to be dissolved without weighing or ignition, it is generally best to wash it altogether by decantation, and then to pour the solvent over the filter through which the decanted liquid was passed, and collect it in the beaker containing the main portion of the washed precipitate; the precipitate may then be digested with the reagent if necessary, and, afterwards, the filter well washed out with water, that is added to the solution just made; in this way we may avoid any considerable dilu- tion of the solvent before it has had time to act on the substance to be dissolved. If the solvent is one that, in its concentrated state, would attack the paper, it may be poured at once over the precipitate in the beaker, while another portion may be diluted somewhat, and passed re- peatedly through the filter, to take up the small quantity of the substance on that. The thorough washing of precipitates and residues, that is so essential in quantitative analysis, and is often not unimportant in qualitative work, may sometimes be greatly facilitated by this process of decantation, particu- larly if the solid is one that settles readily; but if Bun- sen’s process of filtration is followed, decantation may be dispensed with. § 39. FILTRATION; BUNSEN’S PROCESS. 33 In washing precipitates on the filter, the washing-bottle is an indispensable aid. This consists simply of a flask of a capacity of 150-1000 c.c., according to the purpose for which it is to be used, closed by a good cork that is pierced with two holes; through one of these holes passes a glass tube, 8 or 10 cm. long, that extends just beyond the cork on the inside, and, outside, is bent at an angle of about 110°; the tube that passes through the other hole extends nearly to the bottom of the flask, and, out- side, is bent at an angle of about 70°, and drawn out to a small jet at the end; water in the flask is forced out at this jet on blowing air in at the mouth of the shorter tube. Each portion of water with which a precipitate on the filter is washed should be allowed to pass through com- pletely before another is added, and the precipitate should be stirred up as much as possible by the jet from the wash-bottle with each fresh addition. Insoluble residues and precipitates must be washed, particularly in quantitative operations, as long as the wash- water carries off any notable quantity of matters in solu- tion; the washings are tested by evaporating a drop to dryness on platinum foil, to see if any residue is left, or by a chemical test, as, for example, when washing a pre- cipitate of baric sulphate that was formed by adding baric chloride to a solution of a sulphate; as long as any ef the soluble chloride remains in the pores of the filter, or adheres to the precipitate, and is taken up by the water, the washings will give the usual reaction for chlorine with argentic nitrate (§ 63). When the contents of the filter are to be weighed or ignited, dry the whole together in the drying-chamber or air-bath, with the funnel well covered with filter paper. b. A method lately devised by Bunsen (Annalen der Chemie, 148, 270. American Journal of Science and Art, 2d Series, 47, 321) for increasing the rapidity of fil- o4 § 39, ANALYTICAL MANIPULATION. tration, and of the washing of precipitates, promises to be very useful. He supports the filter by a hollow cone of thin plat-— inum foil in the throat of the funnel, and then rarefies the air in the funnel-tube; the excess of pressure on the liquid in the filter causes it to flow through very rapidly, while there is no danger of tearing the paper. To make the platinum funnel, a cast of the glass funnel — must first be taken. Select a funnel with perfectly smooth — and straight sides, and opening at an angle of 60°, fit in it a piece of oiled writing paper in such a manner that it shall touch the glass everywhere, like an ordinary well- fitted filter, and fasten the paper in place with two or three drops of sealing-wax around the rim. Half fill the fun- . nel then with gypsum paste, into which, before it hardens, a plug of wood is inserted, to serve as a handle. When the gypsum cone has hardened, remove it from the funnel, oil the paper again, and plunge it, with the paper still adher- ing, into a large porcelain crucible filled with another por- tion of gypsum paste; when this mould has hardened, take the cone out and rub off the paper with the fingers. Now, cut out a piece of thin plat- inum foil weighing about 0.154 grm., of the precise shape and size repre- sented in the adjoining figure, with a é a slit running from 0 to a, the centre \ of the circle of which the are, ce d, c b ad forms apart; ignite it in the flame of SIE the lamp to make it perfectly flex- ible, lay the gypsum cone on it so that the apex of the cone shall coincide with a, bring up the edge, a 6 d, and press it well against the cone, and then do the same | with the edge, a6 ¢ ; after fitting the foil to the cone as perfectly as possible with the fingers, put the whole in the mould in the crucible, and revolve the cone back and forth until the platinum has taken the exact shape of the § 39, FILTRATION; BUNSEN’S PROCESS. 35 plaster casts, and retains its form when removed from the mould ; if found necessary, it may be ignited once more and shaped in the mould with the cone. It may be sol- dered at its upper edge by a grain of gold and borax, so that it will be less liable to get out of shape, but this is not necessary. If properly made, the light should not be visible through the point of this platinum funnel when it is held before the window. With the platinum funnel in the throat of the glass: funnel, adjust the paper filter, which may be much small- er than would be used in the ordinary way of filtering, in the usual manner, with specia/ care to secure perfect con- tact between the filter and the funnel at all points. Con- nect the tube of the funnel with a large, strong glass flask, by means of a rubber cork pierced with two holes, so that the tube extends about 6 cm. beyond the cork; through the other hole pass a short glass tube so that it extends just to the lower surface of the cork; this tube should be bent once at a right angle outside of the flask; it may be connected with a small brass stop-cock by means of a short rubber tube with a small bore and very thick walls ; all the rubber tubing used in the apparatus should be of this kind. Now, pour the liquid to be filtered on the filter, rarefy the air in the flask, and keep the former full as long as any of the liquid remains. The precipitate may be al- lowed to come within 1 mm. of the edge of the filter. In washing the precipitate, pour the water from a flask, fill up to about a centimetre above the rim of the filter, with care not to disturb the precipitate, and let each por- tion of water drain off completely before adding a fresh quantity ; thus the washing may be thoroughly effected in a wonderfully short time; if the vacuum in the flask is nearly perfect, or the pressure on the filter is nearly an atmosphere, three or four washings suffice, even in the case of precipitates that are the most difficult to wasb. 36 § 389. ANALYTICAL MANIPULATION. Moreover, the precipitate is so completely deprived of its water, that it may be easily removed from the filter, or can be ignited at once without further drying. To ignite the precipitate at once, Bunsen directs to wrap the filter around it, put the whole in the crucible, set the latter on its side as usual, apply the heat at the top of the crucible first, and eradaully carry it towards the bot- tom as the filter is burned. The rarefaction of the air may be produced in various ways. The flask may be connected with the upper end of a water-pipe 30 feet high in such a manner as to make a Sprengel’s air-pump. Desaga, of Heidelberg, furnish- es a complete apparatus for this purpose. Or, an air-tight connection may be made between two large glass bottles, or demijohns, by means of a long piece of thick walled rubber tubing ; then put one bottle filled with water on a high shelf, w hile the other is put on the floor, connect the filtering-flask with a tube leading just through the cork of the upper bottle, allow the water to flow from the upper bottle to the lower one, while pro- vision is made for the escape of the air from this lower bottle; the rarefaction of the air in the filtering-flask will follow. When all the water has flowed from the upper to the lower bottle, their relative positions may be re- versed, the proper connection made between the filtering- flask and the upper bottle, and the filtration continued. Or, a small demijohn may be closed by a rubber cork through which passes a glass tube, connected with a small brass stop- -cock; connect the demijohn with an air- pump, exhaust the air, close the stop-cock, connect the demijohn with the filtering-flask, and open a stop-cock when all is ready for the filtration. In order to prevent acid fumes or ammonia coming from the filtered liquid from injuring the stop-cock, a wash-bottle, containing sodic hydrate or sulphuric acid, may be interposed. (J. M. Crafts.) § 89, FILTRATION. OV For fuller details in regard to this mode of filtration we refer to the original articles. c. When several portions of a solvent, such as water, alechol, or ether, are to be made to act on a substance, each portion can be readily separated from the substance by the following contrivance. Close the flask with a rubber -cork pierced with two holes; through one of these pass a short bent tube, like the shorter tube of the common washing-bottle, and in the other hole fit a tube which is widened out, funnel-like, » at one end, but not so much as to prevent its being put into. the flask easily ; near the other end, this tube is bent at an acute angele, and the end is drawn out to a point and left with a pretty large opening, after the fashion of the other tube of the washing-bottle; the long arm of the tube should reach nearly to the bottom of the flask, and have a piece of fine linen firmly bound over its mouth. The substance and the solvent having been digested in the flask, when the solvent is supposed to be saturated, and it is desired to replace it by a fresh quantity, force air into the flask by the shorter tube and the solution will be expelled, and at least partially filtered on its way through the muslin; then, if the end of the longer tube is immersed in a fresh quantity of the solvent, this may be drawn into the flask by suction at the mouth of the short tube. If heat is used, the mouth of the short tube may be connected with the dower end of a Liebig’s condenser ; then the vapors of the solvent are condensed, and the liquid flows back into the flask, and the ebullition can be maintained as long as is desired without the necessity of adding fresh quantities of the solvent to replace what is lost by evaporation; when it does become necessary to replace this portion of the solvent by a fresh one, the rub- ber tube that connects. the flask with the condenser may be closed with a clamp, and, the application of heat being 38 § 40. ANALYTICAL MANIPULATION. continued, the liquid will be forced out through the mus- lin filter; on immersing the open end of the longer tube in a fresh quantity of the solvent, and removing the lamp, this liquid will flow in. The solution may not be perfectly clarified in passing through the linen filter, in which case it will have to be filtered again through paper. To effect more perfect filtration, a thick mat of gun- cotton may be bound over the linen; this layer of cotton should not be anywhere less than 14 mm. thick. WEIGHING OF RESIDUES AND PRECIPITATES. AQ, When it is possible, residues or precipitates are ig- nited before being weighed. This ignition may be performed in two ways. a. If the substance is not altered in its chemical com- position by contact with burning organic matter, or at the somewhat high temperature that is sometimes neces- sary to effect the complete incineration of the filter, roll the well-dried filter together around the precipitate, put the whole in the previously ignited and weighed crucible, cover and heat, at first very gently ; when the filter is completely charred and no more smoke is given off, turn the crucible on its side, lay the cover partly on the edge of the crucible and partly on the triangle, and heat the contents of the crucible until the ash is quite white. 6. If the filter may not be burned in direct contact with the precipitate, crush and work it gently between the fingers over a sheet of glazed paper, to loosen the pre- cipitate as much as possible, place the crucible on the glazed paper, and empty the contents of the filter into it. Put the crucible on the porcelain plate belonging to the Bunsen’s burner, open the filter on another piece of glazed paper, fold its edges up so as to make a little tray, with a soft feather carefully brush into this tray any § 40. WEIGHING OF RESIDUES AND PRECIPITATES. 39 particles of the precipitate that may have fallen on the first piece of paper, roll the filter up, enclose it in a short spiral on one end of a platinum wire that was weighed with the crucible, hold it over the crucible, and set fire to it; by applying the charred filter to the flame of the lamp two or three times it may be almost completely in- cinerated ; finally, either let the ash and the wire drop into the crucible and ignite the whole four or five minutes, _or until the ash is white, or, in case the filter-ash must be kept entirely separate from the precipitate, let the two drop into the hollow lid of the crucible, and ignite the precipitate and ash separately. The glazed paper used above should be of a light color if the precipitate is dark-colored, and vice versa, and the whole operation should be performed in a place free from currents of air. e. If the quantity of the precipitate is very small, and yet is of such a nature as to be partly reduced to a i er degree of oxidation if ignited with the filter, the ignition may be performed as in@, when it is ee put a piece of dry ammonic nitrate in the crucible, cover well, and ignite again, but very gently at first. Ferric oxide or baric sulphate may be ignited in this way when nothing better can be done. Sometimes, when a portion of the filter is very difficult to incinerate completely, the combustion may be facilita- ted by adding a little ammonic nitrate as above. After ein subtract the weight of the filter-ash, which has been determined once for all for the par peuiar kind and lot of paper and size of filter used, by the incin- eration of half a dozen or a dozen together, and dividing the total weight of the ash thus obtained by the number of filters burned. d. If the substance to be weighed cannot be ignited, a filter should be previously thoroughly dried in the steam or air-bath at the same temperature to which it is after- AO § 41. ANALYTICAL MANIPULATION. wards to be exposed with the precipitate, and weighed, either between two watch-glasses with ground edges and fitting well together, or in a stoppered glass tube; after careful drying with the precipitate, it is again weighed in the same manner. It should then be dried an hour longer and weighed again, and this ‘should be repeated until a constant weight is obtained. Swedish filter-paper or washed filters should always be used in this operation. e. The substance that has been dried or ignited, and is to be weighed, should always be allowed to cool under a bell-glass over concentrated sulphuric acid, or in the des- iccator more commonly used for this purpose; this desic- cator consists simply of a short and wide glass cylinder, with a ground edge upon which a ground glass plate will fit closely, particularly if the edge is smeared with a litte tallow. The pair of watch-glasses containing the dried filter, or the crucible with the ignited precipitate, rests on a tri- angle in the cylinder over, fused calcic chloride, with which the bottom is covered. No object should be weighed until it is entirely cold. f. Platinum vessels, after having been heated by gas, should be rubbed with a little sand on the moistened fin- ger. The sand should be fine, and all its grains should be rounded. The crucible should also be cleaned from time to time by fusing a little potassic bisulphate in it. The crucible should be supported over the lamp on stout platinum wire, which is stretched from side to side of a larger iron-wire triangle, in such a manner as to make a second triangle inside of, and about 6 mm. smaller than, the iron triangle. MEASURING AND DIVIDING SOLUTIONS. 41, For these purposes graduated pipettes and eylin- ders, and *|,, *|,, and 1 litre flasks are used. § 41, MEASURING AND DIVIDING SOLUTIONS. 41 The analyst should test the correctness of the gradua- tion of his instruments before using them, by comparing them with each other; the *|, litre flask should require just as much water to fill it twice up to the mark on the neck as is required to fill the *|, litre flask once up to the mark on its neck. In the same way the ’|, litre flask should be compared with the 1 litre flask, and these with the graduated cylinders, and the pipettes with each other and the graduated cylinders. When a certain quantity of any standard or titrated solution is to be measured out with a pipette or flask, the instrument should either be dry on the inside, or it should be rinsed out with a little of the solution to be measured, and the last drop of the solution that remains in the point of the pipette should either always be allowed to remain there, or it should always be blown out into the vessel containing the measured solution; the same course should be followed in testing the graduation of the pipettes. To read off the height of a solution in a burette or other graduated instrument, be sure, first, that it is in a vertical position, so that the surface of the liquid in it will be horizontal ; then place the cylinder between the eye and a brightly illuminated white wall, and read the height of the lower surface of the dark zone that is read- ily seen under these circumstances just beneath the sur- face, while the eye is in the same horizontal plane. In filling a Mohr’s burette, fill up to above the zero mark with the solution, and quickly open wide the clamp for a moment so that the rubber tube and the glass tube below the clamp will be completely filled; then open the clamp a little and allow the liquid to flow out, drop by drop, until the dark zone, mentioned above, reaches the zero mark. The temperature of all measured liquids should be as nearly 15° C. as possible. When the quantity of a solution to be divided is not 42 § 42, ANALYTICAL MANIPULATION. too large, the division may be more accurately made by weighing than by measuring. Get the weight first of the whole amount of the liquid, in a small flask, pour out about the quantity desired for a particular analysis, and weigh the flask again with the remainder of the liquid ; pour out another quantity and weigh again, and so on until the division is completed. For this purpose, a flask with a little spout, attached just below where the neck widens out into the body, will be found very convenient. CALCULATION OF RESULTS. 42, The results of an analysis are usually calculated so as to give the per cent composition of the compound analyzed. If the substance determined is weighed or estimated in the form in which it existed in the compound, and it was determined in the undivided solution of the same, noth- ing remains to be-done but to estimate the percentage by a simple rule-of-three calculation, in which the amount taken for analysis is the first term, the amount of the sub- stance found the second, and 100 the third. If the substance was determined in a fractional part of the solution, the same fractional part of the weight of the compound taken for analysis must be made the first term of the proportion; or the amount of the substance found may be estimated for the whole amount of the original solution by multiplication by the proper number, and this product is then made the second term of the proportion, the first term being the weight of the whole amount taken for analysis. In gravimetrical analysis the substance is usually weighed in the form of some insoluble compound that did not exist at all in the compound analyzed, and the amount of the substance in the weight that was found of this insoluble compound must first be calculated. § 42. CALCULATION OF RESULTS. 43 This may be effected by a rule-of-three calculation also, in which the molecular weight of the insoluble sub- stance is made the first term, the weight of the substance sought in a molecule of the insoluble substance the second, and the weight of the insoluble compound found the third. For example, in a determination of sulphuric acid, SO,, 1.15 grm. of baric sulphate was found; then we have BasO,. ;: SO, = BasO, : SO, 233 : 80 =1.18 : 0.8879 orm, The same result can be more expeditiously obtained, however, with the aid of Table III, where for each special case a part of this calculation has already been perform- ed, namely, the division of the second term by the first ; nothing is left to be done, therefore, but to multiply the weight of the insoluble compound found, whose name is given in the first column, by the decimal in the second column against the name of the substance sought in the third column. In the above-mentioned case we find, on consulting the table, the proper decimal against the names sulphuric acid and baric sulphate is 0.3433, which multiplied into 1.13 grm. = 0.3879. 44 § 43, BASES AND ACIDS WITH REAGENTS. CHAPTER — Alt. BEHAVIOR OF THE MORE COMMON BASES AND ACIDS WITH REAGENTS, AND THEIR QUANTITATIVE ESTIMATION. 43. The substances for whose qualitative detection or quantitative estimation directions are given in the follow- ing pages, are as follows. 1. Lnorganic, basic elements.—Potassium, sodium, bari- um, calcium, magnesium, aluminium, iron, manganese, zinc, lead, and copper. 2. Volatile, basie radical. Ammonium. 8. Acid elements and inorganic acids.—Arsenic, chlo- rine, iodine, fluorine, sulphur, and sulphuric, phosphoric, carbonic, silicic, and nitric acids. 4. Compound, acid radicals.—Cyanogen and ferrocy- anogen, 5. Organic acids.—Oxalic, acetic, tartaric, citric, malic, uric, hippuric, lactic, and tannic acids. 6. Indifferent organic substances.—Cellulose, starch, sugar, gum, albuminoids, urea, fat, and alcohol. POTASSIUM. K. 39.1 44,.—Salts of potassium, with all the acids mentioned in § 43, except tartaric, are easily soluble in water. The tartrate is soluble in free alkali or mineral acid, or in considerable water. Reactions. —In tolerably concentrated, neutral or slightly acid solutions of potassic salts, containing hydro- chloric acid or a soluble chloride, platinic chloride, PtCl,, gives a yellow, granular, crystalline precipitate, K,PtCl,, which is sparingly soluble in water, and nearly insoluble in alcohol, Its solubility is slightly: increased by the § 44, POTASSIUM. 45 presence of free hydrochloric acid. No precipitate will be given by the reagent in a very dilute solution of the potassic salt, but if such a solution is evaporated nearly to dryness with a little platinic chloride, and alcohol is added to the residue, the yellow double salt remains un- dissolved. If a drop of a solution of a potassic salt is evaporated to dryness in the platinum-wire loop, and the loop with the residue on it is held at the end of the inner blowpipe flame, or in the corresponding part of the flame of the Bunsen gas-burner, a violet color is communicated to the flame beyond the wire. Viewed through thick blue glass, this color has a more reddish appearance, but the light is not entirely absorbed; the presence of sodium, barium, calcium, and copper, may interfere with this reaction. In a silicate, this reaction for potassium may be ob- tained by fusing it, in a fine powder, with pure gypsum, treating the fused mass with water, filtering, and testing the filtrate. Quantitative estimation.—Potassium may be deter- mined as potassic chloride, KCl, potassic sulphate, K,SO,, or potassic platinic chloride, K,PtCl,. The first two salts are soluble in water, and therefore cannot be obtained by precipitation; other metals and acids being removed from the solution by methods here- inafter described, the pure salt is then left as a residue on evaporation to dryness. a. Determination as potassic chloride.—The solution being freed from other metals and acids, evaporate it to dryness over the water-bath, and ignite the residue in a well covered platinum crucible, very gently for a consid- erable time at first, to avoid the decrepitation and conse- quent loss that might result from too rapid heating ; finally, heat the crucible to a dull red for a short time. The residue contains 52,41°|, of potassium, 46 § 44. BASES AND ACIDS WITH REAGENTS. b. Determination as potassic sulphate.—The solution - being freed from other metals and from non-volatile acids, as fvecreds in each special case, evaporate it to dices and ignite the residue in a platinum crucible, as directed for the ignition of potassic chloride, except that it may be more strongly heated at the close of the operation. If volatile acids, such as hydrochloric, nitric, or acetic, are present in the solution containing the potassium to be determined, suflicient sulphuric acid must be added before evaporation to expel them; in order, however, to avoid the disagreeable operation of expelling a large excess of sulphuric acid also, it is well toadd but little at first; the evidence that enough has been used will be found in the evolution of abundant white acid fumes towards the close of the evaporation; if these fumes do not appear, of course a little more acid must be added, and the evapora- tion continued. After igniting the residue in the platinum crucible gently for a little while, put in a small fragment of well dried ammonic carbonate, and ignite again while the crucible is loosely covered, very gently at first, and then gradually raise the heat toa fullred; repeat this addition of ammonic carbonate and the subsequent ignition as long as there is any change in weight. The ignition with ammonic carbonate facilitates the ex- pulsion of the second equivalent of sulphuric acid from the potassic bisulphate, and it should be used in the man- ner indicated whenever free sulphuric acid was present in the solution that was evaporated. The residue of potassic sulphate contains 44.89°| potassa. e. The determination of potassium as potassic platinic chloride depends upon the insolubility of this compound in alcohol. The solution being freed from all except potassic and sodic chlorides, and, according to Stohmann, ecalcie and 0 0 of potassium, or 54.08°|, of © — : a § 44. PorassiuM. 47 magnesic chlorides also, and highly concentrated, add platinic chloride in excess, until the liquid has a_ bright yellow color, and evaporate the mixture nearly to dryness - over the water-bath, with care not to heat the water quite to boiling. Pour alcohol of 84°|,, mixed with *|, its volume of ether, over the residue, let stand several hours in a well covered vessel, with occasional stirring, transfer the in- soluble double chloride to a dried and weighed filter, wash it with alcohol and ether mixed as above directed, dry at 100° C., and weigh. If great accuracy is required, evaporate the filtrate from this first portion of the chloride nearly to dryness, at a temperature not above 75° C., after addition of some water and more platinic chloride, and some sodic chlo- ride if but little of this is supposed to be present, and treat this almost dry residue with the mixture of alcohol and ether as above; if a second quantity of insoluble chloride is thus obtained, collect it on a filter, wash, dry, and weigh it, and add the amount so found to the first quantity. The salt contains 16°|, of potassium. If the quantity of the precipitate is quite small, less than 0.03 grm. or thereabouts, it is better to collect it on a small filter, incinerate the filter, add a little pure oxalic acid to the cooled residue, cover the crucible, and ignite again gently at first, and more strongly afterwards ; after this ignition nothing but platinum and potassic chloride remains; dissolve out the salt by washing the residue with water until the washings give no turbidity with ar- gentic nitrate, and dry, ignite, and weigh the platinum. d. In some cases, as in the analysis of wood-ashes, potassium or potassa may be determined by a volumetric process, which consists in ascertaining the amount of a solution of sulphuric acid of known strength, that is re- 48 § 45. BASES AND ACIDS WITH REAGENTS. quired to combine with it and form a salt which is neutral to test-papers (§ 45). PREPARATION OF THE STANDARD ACID AND ALKALINE SOLUTIONS. 45. a.—Sulphuric acid.—To about 1100 ec.c. of water add nearly 68 germs. of concentrated sulphuric acid, mix the whole well together, let the mixture cool to the tem- perature of the working room, and then estimate sulphu- ric acid with baric chloride ($ 59) in two or three portions of 20 c.c. each, with the utmost care; having in this way determined the strength of the solution; dilute it so that one litre shall contain exactly one equivalent of the acid expressed in grammes, or 40 grms. Supposing that the mean of three satisfactory determinations, as above, gives 0.84 orm. of sulphuric acid in 20 ¢.c.: then we learn from the proportions, 20 : 0.84 = 1000 : 42,and 40 : 42= 1000 : 1050, that 50 ¢.c. of water must be added to one litre of the acid that we have made, in order that it shall be of the proper strength; to cffect this further dilution, measure out 1000 ¢.c. of the acid in the litre flask, pour it without any loss into the bottle in which it is to be kept, rinse the walls of the flask with exactly 50 c.c. of distilled water, pour this water likewise into the same bottle without loss, and mix the acid and rinsings together well; finally pour about half the contents of the bottle into the flask, rinse off the walls of the flask with the liquid, and pour it back into the bottle. The bottle containing this standard acid should be kept well stoppered ; each time that a portion is to be taken out, the contents of the bottle should be shaken up in such a manner as to rinse down the water that may have evaporated in the space above the liquid and condensed on the glass. (Fresenius. Quantitative Chemische Analyse.) Since 40 is the equivalent of sulphuric anhydride, SO,, a § 45, PREPARATION OF THE STANDARD SOLUTIONS. 49 and this standard or normal solution contains an equiva- lent of the anhydride expressed in grammes, in a litre, ( = 1000 cubic centimetres) it contains, then, an equivalent, expressed in milligrammes, in one cubic centimetre = 40 mer. or 0.04 grm. The quantity of acid in one cubic centi- metre will combine with exactly one equivalent of potassic oxide or potassa, K,O, expressed in milligrammes, = 47.1 mer. or 0.0471 grm., and form a salt whose solution is neutral to test-papers ; ima like manner, the acid in one cubic centimetre of the standard solution will combine with or neutralize one equivalent of sodic oxide or soda, Na,O, expressed in miligrammes = 31 mer. or 0.031 grm., or with one equivalent of ammonic oxide, (NH,),O, = 26 mer. or 0.026 grm. The neutrality of the solution may be determined by its effect on paper that has been colored by litmus, or by adding a small quantity of a solution of litmus, or of cochineal or curcuma root. Litmus is colored blue by free alkali, and red by free acid ; cochineal under the same circumstances is colored purple and light reddish-yellow, while curcuma or turmeric is colored brown by free alkali, and yellow by acids. If, then, to a solution containing any one of the alkalies just mentioned, cither in a free state or combined with the weak carbonic acid, we add a little cochineal solution, and then the standard acid from a burette or a graduated pipette, with constant stirring, until the purple color sud- denly disappears, and a reddish-yellow one takes its place, that remains permanent throughout the whole liquid, we may know that, for each cubic centimetre of acid added, there were 0.0471 grm. of K,O, or 0.031 of Na,O, or 0.026 of (NH,),O in the solution; the whole amount of the al- kali in the quantity of its solution taken for analysis will be given by the product of the number of cubic centime- tres of acid required, into the corresponding equivalent 3 50 § 45, BASES AND ACIDS WITH REAGENTS. of the alkali, expressed in milligrammes or fractions of a gramme as above. b. Standard oxalic acid.—Put 63 grms. of pure erys- tallized oxalic acid in a litre flask, fill the flask up to about two-thirds with water, and, after the acid is entirely dissolved, add more weter until it rises nearly to the mark on the neck of the flask; bring the water to a tempera- ture of 15° C., and then, holding the flask by the rim, so that it will take a vertical position, carefully add water up to the mark on the neck, Mix the whole well together by shaking, transfer the liquid to a well stoppered bottle, and keep it ina dark place. As 63 is the equivalent of crystallized oxalic acid, expressed in grammes, this nor- mal solution contains, like the standard sulphuric acid, one equivalent of the acid expressed in milligrammes, —63 mer. or 0.063 grm., in one cubic centimetre. c. A standard soda solution is often wanted in connec- tion with the use of the standard acid, and for other pur- poses, and its preparation may be described here. It is made of such a strength that one cubic centimetre of it will be exactly neutralized by one cubic centimetre of the standard acid, or will contain 0.031 grm. of sodic oxide, Na,O. To prepare it, put 5 ¢.c. of the standard acid in a small flask with a very little cochineal solution, and then add a diluted solution of sodic hydrate, of which a considerable quantity has been previously made, from a 5 e¢.c.- pipette graduated into twentieths of a cubic centimetre, very slowly and with constant shaking of the flask, until the reddish-yellow color is just changed to purple; suppose that 2 ¢.c. have to be added; then evidently 3 ¢.c. of wa- ter must be added to 2 ¢.c. of the soda solution, in order to make 5 ¢.c. of the latter that shall exactly neutralize 5 ¢.c. of the standard acid; or ?%'°°* = the amount,of oa water to be added to one litre of the sodie solution, to § 46. soprum. 51 make it of the normal strength. When the solution has been prepared according to these directions, and the water and alkali are well mixed, it should be tested, to be sure that the equality between the acid and the alkaline solution is perfect. Keep the solution in a bottle closed with a cork, through which passes a calcic-chloride tube that is stopped at its lower end with a plug of cotton and then filled with soda-lime; by this arrangement the free ex- pansion of the air in the upper part of the bottle with changes of temperature is permitted, while no carbonic acid can enter; it is well to bend the slender part of the calcic-chloride tube at a right angle just above the cork, so that no soda-lime can possibly fall into the bottle, and to fill the burette by means of a small siphon passing through the cork to the bottom of the bottle, the longer arm of which may be closed at the end by a clamp on a rubber tube. To 100 c.c. of this solution add 900 ¢.c. of water, mak- ing both measurements with the utmost care, mix well, and test this solution with the standard acid; 1 cc. of the latter should require exactly 10 c.c. of the former to neutralize it ; keep this solution in the same manner as de- scribed for the other standard soda solution, and labeled, *|,, standard soda solution. SODIUM. Na, 23. 46, Salts of sodium, with all the acids named in § 48, are soluble in water. The double chloride of sodium and platinum is also soluble in both water and alcohol. When this solution is very slowly evaporated to dry- ness, slender, rosy, prismatic crystals are formed, while the crystals of the corresponding potassium salt are octa- hedral and granular. Reactions.—When a drop of a solution of a salt of so- dium is evaporated to dryness in the platinum-wire loop, 52 § 46. BASES AND ACIDS WITH REAGENTS. and the loop is then held at the end of the inner blow- pipe flame, or in the corresponding part of the flame of a Bunsen’s gas-burner, a yellow color 1s communicated to the flame beyond the wire. These yellow rays are completely absorbed by blue glass of sufficient thickness. This test for sodium is very delicate, and is not masked by even a considerable pro- portion of any other metal, except copper and calcium. The presence of avery large proportion of potassium may conceal the sodium reaction. In that case, green glass will absorb the violet rays of the potassium flame, but will not affect the colored rays produced by the sodium. Quantitative estimation.—ca. Sodium, like potassium, may be weighed as chloride or as sulphate, on evaporat- ing the solution to dryness, from which all other acids excopt hydrochloric or sulphuric have been removed by the methods described in each special case, The operations of evaporation and ignition may be conducted precisely as directed for the treatment of the corresponding potassium compounds (§ 44), except that no provision need be made to guard against loss by the decrepitation of the sodic sulphate. Sodic sulphate, Na,SO,, contains 32.39°|, of sodium or 43,66"|, of soda, Na,O. Sodic chloride contains 39.32°|, of sodium, 6. If potassium is present, the two metals being con- verted into chlorides, ascertain the amount of the same by evaporation to dryness and weighing the residue after gentle ignition, as directed for the treatment of potassic chloride (§ 44, a), and then determine the amount of po- tassic chloride in this mixture, with the aid of platinic chloride, as directed under potassium (§ 44, c). The dif- ference between the sum of the two chlorides and the amount of potassic chloride will give the sodic chloride. In this separation, enough platinic chloride must be § 46. sopium. Dd added to convert both the potassium and the sodium into the platinic compounds, and the evaporation with platinic chloride should not be carried to complete dryness, so as to avoid expelling the water of crystallization of the so- dic salt. The filtrate from the potassic salt should have a deep yellow color, and the salt, when examined with the magnifier, should be seen to consist only of yellow octa- hedral crystals or a yellow granular powder. e. If sulphuric acid is present in the solution containing sodium and potassium, the conversion of these metals into chlorides may be effected by gentle ignition with powder- ed ammonic chloride. Evaporate the solution of the sul- phates to dryness, mix-the residue with a little more than its weight of pure ammonic chloride, heat the mixture gently as long as fumes are evolved, and weigh; add more ammonic chloride to the contents of the crucible, ignite, and weigh again, and repeat this operation as long as there is any change in weight. d. In case the quantity of one metal in the mixture of the chlorides is not very much larger than that of the other, they may be estimated with accuracy by the indi- rect process. Determine the chlorine in the known weight of the mixture by the volumetric process (§ 63, 5), and then calculate the amount of potassium and sodium in it by the following formulas, in which 8 = the weight of the mixture of the chlorides, and A = the amount of chlorine contained therein. [(S-A) x 1.54]-A. P i = otassium 0.63 A-[(S-A) « 0.91] al i — Sodium 03 e. If it is more convenient to weigh the metals as sul- phates, the sulphuric acid may be determined in the usual ~ D4 § 47. BASES AND ACIDS WITH REAGENTS. manner ($ 59), and the respective amounts of sodie and potassic sulphate estimated by the following formulas, in which X = the amount of the sodic sulphate, Y that of the potassic sulphate, A the weight of the mixed sul- phates, and 5 that of the sulphuric acid contained therein. 2 (AZ, x 0.45919) oe os 0 ae: ve ee In determining potassium and sodium by either of these indirect methods, it is absolutely essential that all other metals be carefully removed. AMMONIUM. NH, 18. AMMONIA. NHs. 4%, All the salts of ammonium are either volatilized by heat or decomposed with expulsion of the ammonia, and their solubility is the same as that of the potassium salts, except that the tartrate is more soluble. Reactions.—Salts of ammonium behave like salts of potassium, with platinic chloride, except that when am- monic platinic chloride is ignited, nothing but metallic platinum is left behind. When salts of ammonium are gently heated with baric or sodic hydrate, ammonia is expelled and gives a blue color to a piece of moistened red litmus-paper held in the tube above the liquid, or a brown color to a piece of tur- meric-paper. To make this reaction as delicate as possi- ble, put the substance to be tested in a small beaker, with baric or calcic hydrate in 4 dry form, moisten the mixture with water, cover the beaker with a watch-glass on the under side of which is a slip of the moistened test-paper, and heat the whole gently. Sooner or later, the presence of ammonium will be manifested by a change in the color of the paper, if any is present in the substance. The test is a delicate one, as thus performed, and none of the metals interfere with it, if present. _——e a a § 47, AMMONIUM. 55 A still more sensitive test is that known as Nessier’s, When a mixture of solution of mercuric iodide in potassic iodide, and potassic. hydrate, is added to a solution con- taining ammonium, a light or reddish-brown precipitate is obtained, NHg,I. To make this test still more delicate, as in the case of an exceedingly dilute solution of the am- moniacal salt, add 25 ¢.c. of baric hydrate to a litre of the water to be examined, distil off "|, of the mixture, and test the distillate with the Nessler solution. If the solution is not too dilute, a good reaction is ob- tained on holding a drop of the Nessler solution, sus- pended on the end of a glass rod, in the test-tube just above a mixture of the substance tested and baric hy- drate; if ammonium is present, the drop is colored red- dish-brown. To make a litre of the solution for this test, and a solu- tion that can also be used for quantitative purposes, dis- solve 62.5 grms. of potassic iodide in 250 c.c. of water, and add to this a concentrated solution of mercuric chlo- ride, until the precipitated mercuric iodide ceases to be dissolved on agitation; then dissolve 150 grammes of caustic potassa in its own weight of water, and add it gradually to the iodized mercurial solution, and finally the necessary amount of water to make one litre; let the mixture stand 8-10 days, decant the clear and nearly colorless liquid, and keep it in well stoppered bottles in a dark place. Quantitative estimation.—a. Ammonium may be de- termined in the form of the ammonic platinic chloride, (NH,),PtCl,, when all metals except sodium (and calcium and magnesium, Stohmann,) are absent. The course to be followed is precisely the same as that described for the determination of potassium in the corresponding manner (§ 44, c). The double chloride contains.7.64° |, of ammonia (NH,), or 8.07°|, of ammonium. 56 § 47%. BASES AND ACIDS WITH REAGENTS. 6. Ammonia may also be determined by expulsion from the mixture containing it by a strong base, and col- lecting the product in a known quantity of standard acid. (Schléssing’s process.) The solution to be examined, which should not be more than 385-¢.c. in bulk, nor con- tain more than 0.3 grm. of ammonia, is put in a shallow vessel, A, about 5 cm. in diameter, which, in its turn, 1s put ona plate about 10 cm. in diameter, the bottom of which is covered with mercury. Put 10 ¢.c. of the nor- mal sulphuric acid in another, and rather smaller, shallow vessel, B, that is supported over A by a glass triangle; then put about 10 c.c. of milk of lime or sodic hydrate in A with the ammoniacal solution, by means of a pipette, and finally invert a bell-jar or a weighted beaker over the whole, and be sure that its rim is completely immers- ed in the mercury. After 48 hours, the ammonia will usually be entirely expelled from the substance, and absorbed by the acid; in the analysis of animal and vegetable liquids, Schulze found that three or four days were required, but that after the expiration of that time the ammonia was completely liberated. To test the matter, lift the edge of the bell- jar or beaker, or take out the stopper of the tubulure, if the bell-jar has such an appendage, and introduce a piece of moistened red litmus-paper ; this should retain its red color even if left for a considerable time in the jar. If the operation is finished, titrate the acid in the vessel B, with the standard solution of soda; the difference be- tween the number of cubic centimetres of acid put into B in the beginning, and the number of cubic centimetres of soda solution required to neutralize what acid remains free, multiplied into 0.017 grm. will give the amount of ammonia (NH,) in the substance analyzed—or, multiplied into 0.026 grm. will give the amount of ammonic oxide (NH,),0. If albuminoids are present in the substance examined, | § 47. AMMONIUM. oT it is better to use freshly ignited magnesia, instead of milk of lime, to set free the ammonia, so as to avoid the forma- tion of the compound out of a portion of the albuminous matters ( Vogel). c. When the substance does not contain, besides am- monia, nitrogenous organic matter that would yield more ammonia on being heated with an alkali, the de- termination may be more expeditiously performed as fol- lows. Weigh the substance out in a small tube about 10 mm. in diameter and 5 cm. long, put it in a small flask, A, containing a moderately concentrated solution of sodic hydrate which has been previously boiled for a consider- able time to expel all traces of ammonia, and allowed to cool again, Freshly ignited magnesia is sometimes used in the place of the alkali, Put the flask in an inclined position on the wire gauze over the lamp, and connect it quickly with the tube of a small cooling apparatus; con- nect the other end of this tube by a good cork with a tubulated receiver, £, through the tubulure of which passes another small tube that is bent twice and carried to the bottom of a small flask, C. Put into the receiver, 4, the larger portion of 50 ¢.c. of standard sulphuric acid and the remainder in the flask C, and color the acid in both vessels with a little cochineal; neither tube that “passes into B should dip into the liquid contained in it. Be sure, now, that the apparatus is tight throughout, boil the contents of the flask A gently, and continue the boiling for a little while after the drops of condensed liquid as they fall into the receiver have ceased to change the color of the acid as they come in contact with it. Then remove the lamp, and allow the contents of the flask C' to flow back into B; rinse C several times with cold water, and allow these rinsings to flow into B also ; finally disconnect the receiver B from the rest of the apparatus, transfer its contents to a beaker without any 2% D8 § 47. BASES AND ACIDS WITH REAGENTS. loss, titrate the acid remaining free with the standard so- dic solution, and estimate the amount of ammonia in the substance analyzed, as directed in 0. ( Hresenius.) d. If the standard acid in either of these processes, 6 or e, should contain but avery small amount of am- monia, instead of titrating with soda, the determination may be completed more satisfactorily with the aid of the Nessler solution, by preparing a solution containing an accurately known quantity of ammonia, of such a strength, that about equal volumes of it and of the solution con- taining the unknown amount of ammonia, will give the same shade of color with equal small quantities of this reagent. The color observations in this process are best made in narrow glass cylinders of such a diameter that 100 ¢.c. of the water to be tested form a stratum about 18 cm. deep, and by placing these cylinders upon a sheet of white paper near a window and looking at the surface of the liquid obliquely. The amount of ammonia present in the solution to be examined should not be great enough to give a precipi- tate with the reagent, but only a coloration; the best re- sults are obtained when there is not more than one milli- gramme of NH, in 100 .c. of the solution, but even if the solution is ten times stronger than this, the results are more accurate than those obtained by titration; it is im- portant that the temperature of the solution tested should be nearly the same as that of the other solution contain- ing a known quantity of ammonia, which is made the standard of comparison, and that neither free potassa or soda, nor calcic or magnesic carbonate should be present. To estimate the ammonia in a solution by this:method, first make a standard solution of ammonic chloride con- tainng 0.3147 grm. in one litre, which is equal to 0.1 grm. of ammonia (NH,) in the litre; add 1 ec.c. of the § 48. Barium. § 49. cancruM. 59 standard iodized mercurial solution to 100 or 150 c.c. of the distillate, obtained in 0 or c, or to any clear and color- less solution containing ammonia; put in another test- tube, containing about 100 ¢.c. of water, as much of the standard solution of ammonic chloride as is thought nec- essary to give the same shade of color with the test- liquid, make the volume of this mixture the same as of the other, by addition of water, add 1 «ec. of the iodized mercurial solution, let stand ten minutes, and then compare shades of color; if not alike, make another more or less diluted portion of the standard ammonié solution, according as the shade of color of the first was too dark or too light, and repeat the test. (W. A. Miller.) BARIUM. Ba... 137. 48, Compounds o. barium with sulphuric, oxalic, car- bonic, phosphoric, tartaric, and silicic acids, and with flu- orine, are insoluble or sparingly soluble in water. The sulphate and silicate are insoluble in acids. Reactions.—Sulphuric acid and all soluble sulphates produce, even in very dilute solutions of barium salts, a finely pulverulent precipitate of baric sulphate, BaSO,, insoluble in acids, except when hot and concentrated, and even then but very sparingly soluble. This sulphate is slightly decomposed when boiled with a solution of sodic carbonate, but is not changed at all ifasoluble sulphate is mixed with the carbonate. CALCIUM. Ca. 49. 49, Compounds of calcium with oxalic, carbonic, phos- phoric, tartaric, and silicic acids, and with fluorine, are insoluble or sparingly soluble in water. The tartrate dis- solves in 352 parts of boiling water. The silicate and fluoride are insoluble in acids. Both water and acids dis- solve the sulphate in small quantity. . 60 § 49. BASES AND ACIDS WITH ‘REAGENTS. Reactions.—If dilute sulphuric acid or ammonic sul- phate is added to a not too dilute solution of a calcic salt, free from a large excess of strong acids, a white precipi- tate of calcic sulphate, CaSO,, 2H,O, is formed immedi- ately or after standing some time, which is soluble in an excess of mineral acid, and slightly soluble in acetic acid and water. This sulphate being much less soluble in alcoho. than in water, the addition of a quantity of this reagent about equal to the volume of the solution, will often cause the for- mation of a precipitate, at least after standing some time, that would otherwise not appear. This precipitate is readily decomposed when boiled with a solution of sodic carbonate, calcic carbonate and sodic sulphate being formed. Ammonic oxalate gives, even in very dilute solutions of calcic salts, if they contain no free mineral acid, a white crystalline precipitate of calcic oxalate, CaC,O,, soluble in hydrochloric or nitric acid, and insoluble in acetic acid or a solution of ammonic chloride. If the so- lution of the ecalcic salt is very dilute, a precipitate may not appear until after the mixture has stood some time. Quantitative Estimation.—Calcium is usually deter- mined as carbonate, CaCO,, by precipitation with am- monic oxalate and conversion of the oxalate into carbon- ate by ignition. a. 1,—If the salt is soluble in water or the acid is one that, like carbonic acid, may be expelled by hydrochloric acid, or can be removed by evaporation to dryness, like silicic acid, or the solution gives no precipitate with am- monia, add ammonic oxalate to the hot solution free from any great excess of acid, and then ammonic hydrate until the liquid, after being well stirred, gives off an ammoni- acal odor, let the mixture stand in a warm place 12 hours, decant the clear liquid into a filter, wash the precipitate » § 49. CALCIUM. 61 several times by decantation, and finally rinse it into the filter with hot water. Ignite the precipitate and filter separately ($ 40, 4), keeping the filter-ash on the crucible cover. Keep the crucible at a faint red heat 5 or 10 minutes at the close of the ignition; at no time should it be heated to a higher temperature than this; during this short ignition lift the cover of the crucible a few times, After weighing, moisten the contents of the crucible with a little water and apply a piece of turmeric-paper to the moist mass ; if the paper is turned brown, rinse it off with a very small quantity of water, put a small lump of ammonic carbonate into the crucible, heat the crucible over the water-bath until its contents are dry again, ignite gently, and weigh again; repeat this opera- tion with fresh portions of ammonic carbonate, and igni- tion, as long as there is any change in weight. The change of color in the turmeric-paper showed that the first ignition was carried too far, so as to expel some of the carbonic acid, and leave calcic oxide. (Avresenius.) The residue of calcic carbonate contains 40 °|, of calci- um or 56 °|, of calcic oxide or lime. 2. If a blast-lamp is at hand, or a gas blowpipe, it is best to ignite the precipitate of calcic oxalate 10 minutes to an incipient white heat, after the usual ignition to a red heat over the common lamp; in this way all the calcic carbonate will be converted into calcic oxide, which may be weighed as such; no testing of the ignited residue is necessary, and moreover the filter may be burned with the precipitate. 3. Instead of igniting the precipitate of ammonic oxa- late, after it has been well washed in the usual manner, dissolve it in dilute hydrochloric acid while yet moist, add water in such a quantity that the ratio between the oxalic acid and the water will be about 1 : 400 or 500, add to this 6-8 c.c. of concentrated sulphuric acid, and then estimate the oxalic acid in this solution with the aid 62 50. BASES AND ACIDS WITH REAGENTS. of the standard permanganate solution, as directed in § 69, a. This method yields results that are hardly less accurate, if any at all, than the other two already de- scribed. For each equivalent of oxalic acid found, ex- pressed in milligrammes, reckon one equivalent of lime, similarly expressed, or 0.028 grm. If the amount of ealcic oxalate in the filter is very small, it may be converted into sulphate by ignition with pure ammonic sulphate, and the lime weighed as sulphate, containing 41.18 °|, of lime. b. If the acid in combination with the lime is one that, like phosphoric acid, cannot be readily removed, add am- monia until a permanent precipitate just begins to appear, dissolve this: by adding a few drops of hydrochloric acid, add ammonic oxalate in excess, then sodic acetate, and proceed as in @ with the precipitated calcic oxalate. MAGNESIUM. Mg. 24. 50. Compounds of magnesium with phosphoric, car- bonic, oxalic, and silicic acids, and with fluorine, are in- soluble or sparingly soluble in water. The silicate and fluoride are insoluble in acids. Reactions.—The carbonate is not precipitated from so- lutions of magnesic salts containing much ammonic chlo- ride, on addition of an alkaline carbonate. — Hydric disodic phosphate produces a white precipitate of ammonio-magnesic phosphate, MgNH,PO,, in solutions of magnesic salts containing ammonic salts. The precipi- tate, at first flocculent, if at all abundant, becomes more granular and crystalline after standing some time, or after violent agitation of the liquid containing it. If the solu- tion of the magnesic salt is very dilute, the precipitate may not appear for some hours, and then it is crystalline and adheres to the sides of the tube; if, before the solu- tion was set aside, it was stirred with a glass rod, and the 50. MAGNESIUM. 63 walls of the tube rubbed here and there with the rod, the precipitate is deposited along these lines, producing the appearance of white streaks on the glass. Even in concentrated solutions containing magnesium and ammoni¢ chloride and sodic phosphate, the whole of the ammonio-magnesic phosphate is not deposited until after long standing; hence, if the first precipitate pro- duced on adding the reagent is filtered out, and the clear filtrate stirred and set aside, a fresh precipitation will take place, and partly on the walls of the tube in the manner described above. Quantitative estimation,— Magnesium is usually deter- mined as pyrophosphate, Mg,P,O.. : a. To the solution of the magnesic salt add a consider- able quantity of ammonie chloride, and then ammonia in slight excess; if this ammonia causes the formation of a precipitate, add enough more ammonie chloride to dis- solvé it; then add hydric disodic phosphate, as long as a precipitate is formed, stir the mixture well, with care not to touch the sides of the beaker with the rod, cover the beaker carefully, and let it stand with its contents 12 hours without applying heat; decant the clear liquid through the filter, rise the contents of the beaker into the filter with portions of the first filtrate, and wash the contents of the filter with a diluted ammonia water containing one part of ammonia water of 0.96 Sp. Gr. and three of water, until the last five drops of the wash- ings give no opalescence with very dilute nitric acid con- taining argentic nitrate. Ignite the precipitate and filter separately. Rose rec- ommends to ignite the precipitate for a short time in a porcelain crucible over the blast-lamp; in this way it is obtained quite white. Add 0.002 grm. to the residue of magnesic phosphate for every 110 c.c. of the filtrate from the precipitate (but 64 50. BASES AND ACIDS WITH REAGENTS. not the washings), to compensate for the solubility of the salt in the ammoniacal solution in which it was precipi- tated. (Lresenius.) The residue contains 36.04°|, of magnésic oxide or magnesia, MgO. If the solution containing the magnesium is strongly acid, Rose recommends that the sodic phosphate be added first, and then a suflicient-quantity of ammonia to super- saturate the acid; thus he prevents the formation of any hydrated magnesic oxide that is liable to be precipitated with the phosphate and make it impure. 6. Separation of Calcium and Magnesium.—This is effected with ammonic oxalate in the presence of am- monic chloride, and ammonia in slight excess. Add the ammonic chloride and ammonia as directed above in «, and then ammonic oxalate; this last reagent must be added in slight excess, after it has ceased to give any further precipitate of calcic oxalate, in order to convert all the magnesium into oxalate. Let the mixture stand 12 hours in a moderately warm place, decant the clear liquid into the filter, wash the precipitate in the beaker once with water, decant the washings, dissolve the pre- cipitate in a little dilute hydrochloric acid, add ammonia in slight excess, and ammonic oxalate; let the mixture stand until the precipitate has completely subsided, then filter through the same filter as before, and wash. The first filtrate has the larger portion of the magnesium in it; the second, the rest. ieaiy the second filtrate, and concentrate thet and the washings by evaporation, add the residue to the first filtrate, and precipitate magnesium in this solution as phospaate. Treat the precipitate of calcic oxalate on the filter as directed in § 49. If, in the filtrate from the calcic oxalate, there is a great excess of ammonic salts, it will be safer to evapo-| rate the solution to dryness and expel them by ignition, § 51. ALUMINIUM, 65 dissolve the residue in water acidified with hydrochloric acid, filter if necessary, and then to precipitate the mag- nesium in the usual manner with hydric disodic phosphate. e. If but little calcium is mixed with considerable mag- nesium in the substance to be analyzed, evaporate the solution to dryness, and ignite the residue gently to ex- pel ammoniacal salts completely, dissolve this residue in a very little water mixed with a few drops of hydrochloric acid, add strong alcohol and a slight excess of pure con- centrated sulphuric acid, and digest the mixture in the cold several hours. Collect the precipitated calcie sul- phate on the filter, wash it first with almost absolute al- cohol and finally with alcohol of about 40 °|,, dry, ignite and weigh. Expel the alcohol from the filtrate and washings by heat, and determine magnesium in the usual manner with sodic phosphate. ALUMINIUM. Al. 27.5. 51, Compounds of aluminium with phosphoric and silicic acids, and fluorine, are insoluble in water. The silicate is insoluble in acids. Reactions,—Solutions containing aluminium give a pre- cipitate, Al,O,,38H,O, or Al,H,O,, with ammonic or sodic hydrate ; the precipitate is dissolved in an excess of the latter reagent, but not in the former. When a compound of aluminium is fused on platinum foil with four or five times its bulk of sodic and potassic carbonate, the fused mass dissolved in a very little water, and the solution filtered if necessary, nitric acid added to the filtrate carefully until effervescence ceases, and then a few drops of ammonia until the solution emits a faint odor of the reagent, a white flocculent precipitate appears, at once, or after standing some time; it will appear soon- er, or be more readily perceived, on heating the liquid gently for a time. 65 52. BASES AND ACIDS WITH REAGENTS. Quantitative estimation.—Aluminium is always weigh- ed as sesquioxide, AL,O,,. To the not too dilute hot solution add a fourth or a third of its volume of ammonic chloride, if not already present, and then ammonic hydrate until a faint odor of ammonia is perceptible after vigorous stirring; heat the mixture almost to boiling until no more ammonia is given off, let it stand a few hours in a moderately warm place, decant the clear liquid through the filter, wash the pre- cipitate two or three times with hot water, by decanta- tion, transfer the whole to the filter, and wash it until the washings leave no fixed residue on platinum foil; if the solution contained sulphuric acid in notable quantity, it will be best to dissolve this first precipitate in dilute hy- drochloric acid, and re-precipitate the aluminic hydrate with ammonia, as above. Dry the precipitate very thor- oughly, and ignite it gently at first, and carry the heat to a full red, finally. The residue is pure alumina. IRON. Fe. 56. 52, Compounds of iron with carbonic, phosphoric, oxalic, and silicic acids, and sulphur, are insoluble in water ; the silicate is insoluble in acids. Ferric salts give a yellowish-red color to solutions con- taining them in notable quantity. Reactions,—Solutions of ferrous and ferric salts give precipitates, FeO, H,O, or FeH,O, and 2Fe,0,, 3H,0 or Fe,H,O,, with ammonic or sodic hydrate ; the ferrous salts, however, give no precipitate with ammonia in the presence of ammonic salts. These precipitates are insoluble in ex- cess of the precipitant. The precipitate produced in so- lutions of pure ferrous salts is white; in solutions of ferric salts, reddish-brown, Solutions of ferrous salts give a blue precipitate with § 52. 1R0N. 67 potassic ferricyanide; ferric salts give no precipitate with this reagent. Ferric salts give a deep red color with potassic sulpho- cyanate; this reaction is exceedingly delicate. Nitric acid causes the color to disappear after a while, and am- monic hydrate destroys it immediately. Ferrous salts give no color with this reagent. Ferrous salts are converted into ferric compounds when heated with nitric acid. Quantitative estimation.—Iron may be determined by a gravimetric or a volumetric process. In the former ease It is weighed as sesquioxide, Fe,O.,,. a. Add ammonic hydrate in excess to the hot solution, in which the iron has been completely oxidized by heating with nitric acid, if any ferrous oxide was present, heat the mixture almost to boiling, and then Ict it stand until the larger part of the liquid can be decanted into the fil- ter; wash the precipitate several times by decantation, and afterwards on the filter, until a drop of the washings leaves no residue on evaporation on platinum foil, and ignite the precipitate and filter separately. The residue is pure ferric oxide, and contains 70°|, of iron. If the substance analyzed contained silica, this precipi- tate is liable to be contaminated with it, and should be digested with concentrated hydrochloric acid, after hav- ing been gently ignited ; if silica is present, it will remain undissolved, and may be filtered out and weighed. 6. The volumetric process, with potassic permanganate, is particularly convenient for the determination of iron in the presence of aluminium, The iron is converted into a ferrous salt, and then it is ascertained how much of a solution of permanganate of known strength is required, to oxidize the ferrous to a ferric salt. To make the solution of permanganate, dissolve about 8 grms. of the crystallized potassic permanganate of the 63 § 52. BASES AND ACIDS WITH REAGENTS. druggists in one litre of water; as this solution is changed by exposure to the air, its strength must be determined from time to time, and the oftener, the more imperfectly it is protected from such exposure. To determine its strength, weigh out accurately about 1.4 grms. of ammonio-ferrous sulphate, dissolve the salt in about 200 c.c. of distilled water, to which about 20 ¢.e. of dilute sulphuric acid have been added. To protect the salt more completely from oxidation while the solution is taking place, heat it with a part of the water in a small flask closed by a cork through which two short glass tubes pass; fasten the flask in an inclined position in a retort-holder, and heat its contents while a slow current of carbonic acid is conducted through the upper part of it. When the solution is completed, let the liquid cool in the current of carbonic acid, transfer it quickly to a beak- er or a larger flask, rinse the flask out with the rest of the water, set the vessel over white paper, and immedi- ately begin to add the solution of permanganate from a burette, with constant stirring of the liquid. At first, the red drops disappear the instant that they come in contact with the solution, and the latter gradually takes a yellowish tint; add the permanganate more and more carefully as the drops begin to disappear less readily, and stop when the last drop gives an unmistakable reddish color to the whole liquid. Ammonio-ferrous sulphate contains just one-seventh of its weight of iron, and hence the amount of permanganic solution used in this trial will convert a weight of iron from ferrous to ferric oxide, equal to one-seventh of the weight of the salt taken. . The concentration of the solution of permanganate should be such, that from 20 to 30 ¢.c. is required for 1.4 germs. of ammonio-ferrous sulphate, or 0.2 grm. of metal- lic iron. Now, to determine iron by this process the ferric salt § 52. IRON. 69 must be in the form of a sulphate or a chloride, and the solution should contain about 0.5 orm. of iron and an excess of free sulphuric or hydrochloric acid and as little nitric acid as possible; heat the solution in a small, long- necked flask placed in an inclined position, drop in a few pieces of pure zinc, and conduct carbonic acid through the flask in the same manner as described above, for dis- solving the ferrous salt; the ferric compound is reduced to a ferrous salt by the zinc, with the evolution of hydro- gen. When the solution is decolorized, and all the zine is dissolved, cool the liquid as quickly as possible by im- mersing the flask in cold water, while carbonic acid is still passing through, transfer the solution to a beaker, rinse the flask into the beaker with a considerable quanti- ty of water, and dilute the solution until it contains about 200 ¢.c. for every 0.2 grm. of iron supposed to be present ; the solution must be more largely diluted if the salt was a chloride, or was dissolved in hydrochloric acid, instead of sulphuric. To this solution add the solution of permanganate in the same manner as directed above, for the treatment of the ferrous salt. The amount of iron im the quantity of solution taken will be given by the proportion Cee. =e) x ss in which C = the number of cubic centimetres of per- manganic¢ solution used in the trial with the known quan- tity of ferrous salt, F = the weight of the ferrous salt taken, C’ = the number of cubic centimetres of perman- ganic solution used in the trial with the substance exam- ined, and X = the amount of iron therein. The solution of potassic permanganate is most con- veniently kept in a bottle provided with an ordinary washing-bottle arrangement for filling the burette from it: then the bottle need not be opened until empty, no 70 52. BASES AND ACIDS WITH REAGENTS. dust can get into it, particularly if the open end of the. shorter tube is closed with a plug of cotton, and its strength will not change perceptibly in two or three months. c. The following volumetric method of estimating fer- ric oxide has given satisfactory results (Oudemans, Fre- senius’s Zeitschrift, 6, 129), and is very easily executed. Prepare a standard solution of sodic hyposulphite, by dissolving 24.8 grms. of the pure crystallized salt in one litre of water; this gives a'|,, normal solution, since 248 is the equivalent of the crystallized salt. Determine the streneth of a solution of ferric chloride containing no traces of free chlorine, as carefully as possible, by precipi- tation with ammonia (a). To a quantity of this solution, accurately measured, containing about 0.2 grm. of iron, add a little hydrochlo- ric acid, one or two drops of a concentrated solution. of cupric sulphate, and the same quantity of potassic sulpho- cyanate ; heat this blood-red liquid to about 40° C., and allow the standard solution of hyposulphite to flow from a burette into it with constant stirring, until the red color disappears, leaving a clear, colorless liquid; towards the end of the operation, when the color of the solution has become quite pale, wait a few seconds between each ad- dition of a few drops of the hyposulphite. Divide the quantity of ferric oxide corresponding to the amount of ferric chloride taken, by the number of cubic centimetres of the solution of hyposulphite required in this trial, and the quotient will give the amount of ferric oxide which the sodic hyposulphite in oné cubic centimetre of the standard solution is able to reduce to protoxide. Having in this way determined the value of the solu- tion of hyposulphite with reference to ferric oxide, this oxide may be determined in any solution containing it or the corresponding chloride, in the manner described § 53. MANGANESE. re | above; the solution should contain no free chlorine or ni- tric acid. The standard solution of hyposulphite should be care- fully protected from the light, and the determination of its strength should be repeated from time to time by com- parison with a portion of the solution of ferric chloride of known strength, as above. MANGANESE. Mn. 55. 53. Compounds of manganese with phosphoric, car- bonie, oxalic, and silicic acids, and sulphur, fluorine, and cyanogen, are insoluble or sparingly soluble in water. The silicate is insoluble in acids. Reactions.—A solution containing manganese gives a precipitate, MnO,H,O, or MnHi,O,, with scdic or ammonic hydrate; the presence of ammonic chloride prevents the formation of the precipitate by ammonic hydrate; in this way manganese may be partially separated from iron for qualitative purposes. When a compound of manganese is fused with potassic and sodic carbonate and sodic nitrate, the fused mass takes a bluish-green color, which can be masked only by the presence of a very considerable quantity of iron. In ease this large proportion of iron is present, it may be precipitated by ammonia after adding considerable am- monic chloride, filtermg it out quickly, and evaporating the filtrate; then test a few drops of the concentrated liquid by fusion, as above. Quantitative estimation.—The manganese is usually precipitated as carbonate; when ignited, this carbonate is converted into manganous manganic oxide, Mn,O,, which is weighed. Heat the solution, free from any great excess of mineral acid, nearly to boiling in a capacious flask, add sodic carbonate very slowly until it is in excess, boil a few minutes, and wash the precipitate by decantation and on @2 § 54. BASES AND ACIDS WITH REAGENTS. the filter; ignite the filter and its contents separately. The ignition should be carried to a full red heat. The residue contains 72.05°|, of manganese. ZINC. Zn. 68. 54, Compounds of zine with phosphoric, carbonic, ox- alic, and silicic-acids, and sulphur and cyanogen, are in- soluble or sparingly soluble in water, The silicate is insoluble in acids. Reactions.—Solutions of zincic salts give a white pre- cipitate, ZnO, H,O or Znf,O,, with sodic or ammonic hydrate, soluble in excess of the precipitant, and re-pre- cipitated from this solution on dilution with considerable water and boiling. Solutions of zincic salts give a white flocculent precipi- tate, Zn,Fe,Cy,, with potassic ferrocyanide, that is diffi- cultly soluble in acids, LEAD Pie 20% 55. Compounds of lead with sulphuric, phosphoric, car- bonic, oxalic, and tartaric acids, and sulphur and fluorine, are insoluble, or sparingly soluble in water. The sulphate and sulphide are insoluble in dilute acids. Reactions.—Solutions of salts of lead give a white pre- cipitate, 2PbO, H,O or Pb,H,O,, with sodic or ammonic hydrate, insoluble in excess of the precipitant. If free from avery large excess of strong acid, they give a white precipitate, PbSO,, with dilute sulphuric acid, which appears at once, or after some time if the so- lution is very dilute ; this precipitate is insoluble in dilute acids, and is more insoluble in dilute sulphuric acid than in pure water; it is soluble in a solution of ammonic tar- trate containing an excess of ammonia; if this solution is acidified with acetic acid and potassic dichromate add- § 56. coprpER. § 57. ARSENIC. 73 ed, a yellow precipitate of plumbic chromate, PbCrO,, is formed. Lead is precipitated from its solutions by metallic zinc in the presence of free acid, COPPER. Cu. 63.5. 56. Compounds of copper with phosphoric, oxalic, car- bonic, tartaric, and silicic acids, and sulphur and cyanogen, are insoluble, or sparingly soluble in water. The sulphide and silicate dre insoluble in dilute acids. Cupric salts give a blue or a greenish-blue color to so- lutions containing them. Reactions.—Solutions containing copper give a green- ish precipitate, CuO, H,O or CuH,O,, with sodic or am- monic hydrate. This precipitate is dissolved by an excess of ammonic hydrate, giving a deep blue solution; the reaction is very delicate. Solutions of copper give a red precipitate with potassic ferrocyanide, Cu,Fe,Cy,. Copper is precipitated from its solutions by zinc in the presence of free sulphuric or hydrochloric acid ; jiree nitric acid hinders the reduction, but does not prevent it. ARSENIC. As. 70. 57. When a solution containing arsenic is treated with dilute sulphuric acid and metallic zine, in a small flask closed with a cork through which passes a glass tube drawn out to a small jet at the end, and the escaping gas is lighted, after it has been evolved long enough to expel the oxygen from the flask, a bluish flame is produced, which deposits black, shiny spots on a cold porcelain sur- face. The arsenic was evolved as arseniuretted hydrogen, AsH,. This reaction is very delicate, and is known as Marsh’s test. 4 74. § 58, BASES AND ACIDS WITH REAGENTS. ACIDS. SILICIC ACID. H,SiOs. 58, All silicates are insoluble in water and dilute acids, except those of potassium and sodium. Silicates may be decomposed, and the metals contained in them brought into a soluble form, by means of concen- trated hydrochloric or sulphuric acid, by hydrofluoric acid or ammonic fluoride, or by fusion with an alkaline carbon- ate, and subsequent treatment with dilute hydrochloric acid. Reactions.—If a solution of a soluble silicate is evapo- rated to dryness, after addition of hydrochloric acid, the residue gently ignited and treated with dilute acid, the silica remains undissolved in the form of a white, gritty powder. When a silicate in powder is fused in a bead of sodic carbonate, on platinum wire, the carbonic acid is expelled by the silicic, and its evolution causes the bead to froth. If a very small fragment of an insoluble silicate is fused in a bead of phosphorus-salt, on platinum wire, the bases are dissolved out, and the silica remains floating about in the bead, retaining the form of the original fragment. Quantitative estimation.—Silicic acid is always weighed as such. a. 1.—If the acid is to be determined in a solution or a soluble silicate, add an excess of hydrochloric acid to the solution, or the very finely powdered solid, and evaporate the mixture to dryness on the water-bath with frequent stirring to break up the lumps. If, as is sometimes the case, the solution analyzed con- tains organic matter, or ferrous oxide, add a few drops of nitric acid towards the close of the evaporation. If a solid is being treated, the digestion should be continued, with § 58. SsILICIC ACID 7) the addition of fresh quantities of acid if necessary, until no gritty particles can be felt under the end of the stirring rod. Heat the residue to a temperature somewhat above 100°, in an air-bath, made by suspending the dish on wires inside of an iron dish, so that there shall be a space of about 12 mm. between the two at all points; when the whole is completely dry and no more acid fumes escape, moisten the residue with concentrated hydrochloric acid, let it stand half an hour, add water, and digest the mix- ture awhile, wash the insoluble residue two or three times by decantation, wash well on the filter, dry, and ignite. The residue is generally pure silicic acid. All the bases with which the silica was combined can _be determined in the filtrate from it. 2. Sometimes this residue is mixed with sand which it may be desired to estimate. In this case collect the mixture on a dried and weighed filter, dry it at 100° C., and weigh it; then separate it from the filter as completely as possible without tearing the latter, and boil it with several portions of a concen- trated solution of sodic carbonate, or with sodic carbonate to which about *|, of sodic hydrate has been added, or with sodic hydrate alone; dilute each portion of the liquid if it contained much free alkali, let it cool, and throw it on the same filter from which the mixture of silica and sand was taken; finally, transfer the insoluble sand to the same filter, wash it well, dry, and ignite, If the extraction of the silica was performed in a silver dish, the amount taken into solution by the alkaline liquids may be estimated also; for this purpose, evaporate all the filtrates and washings to dryness, after having added an excess of hydrochloric acid, and determine the silica as In a. 3. Sometimes, in agricultural analyses, this residue con- tains, besides silica and sand, free carbon, or coal. In this case, dry the whole at 100° and weigh it, separate it 76 § 58. BASES AND ACIDS WITH REAGENTS. from the filter as above, treat it with the alkaline solu- tions also in the same manner, cullect the residue that is insoluble in the alkali on a dried and weighed filter, dry and weigh it, and finally ignite and weigh again. The first of the three weighings gives the total amount of silica, sand, and coal, the second the sand and coal, and the third the sand alone. b. If the silicate is insoluble in water or acids, pulverize it until an impalpable powder is obtained, mix a weighed quantity of it, in a platinum crucible, with four parts of finely powdered potassic sodic carbonate, as intimately as possible by stirring with a glass rod; wipe the glass rod with a little more of the carbonate on a slip of glazed paper, and transfer this from the paper to the crucible ; the latter should not, with all its contents, be more than two-thirds filled. Cover it well and heat at first moder- ately over a blast-lamp, or, after imbedding it in calcined magnesia in a Hessian crucible, in a furnace; carry the heat gradually to an intense red; after about 20 minutes the mass will have ceased to boil and bubble, and the operation is finished. Put the crucible, when cold, into a beaker with considerable water, and add hydrochloric acid gradually, as directed for the solution of carbonates, § 86; when the mass is entirely loosened from the cruci- ble, take the latter out, rinse it carefully into the beaker, transfer the contents of the beaker to a platinum or a porcelain dish, evaporate to dryness, and eliminate silicic acid, as in a. ce. Of course potassium and sodium cannot be deter- mined in the filtrate from the silica in 6, since both metals have been added to the substance in a large and undeter- mined quantity. : For the determination of these elements the silicate must be decomposed with the aid of hydrofluoric acid or a fluoride, § 58. smIcrc ACID. ve 1. Decomposition with hydrofluoric acid.—Provide a leaden cup about 16 cm. in diameter and 16 cm. deep with a close-fitting cover, with projections on the sides about 8 cm. from the bottom, supporting a perforated shelf, and with a shallow tray in the bottom about 12 cm. in diameter and 3 cm. deep, all made of lead; spread a layer of finely powdered fluor spar about 12 mm. deep, over the bottom of the tray in the cup, and mix it with enough concentrated sulphuric acid to make a thin paste; put the shelf in its place and on the shelf a shallow plat- inum dish, such as a crucible cover, containing 1-2 grms. of the very finely pulverized and carefully weighed sub- stance, spread over the surface of the dish in as thin a layer as possible and moistened with sulphuric acid; put the cover on the cup, and set it in a warm place where the temperature is about 60° or 70° C., and lift the cover a few times in the course of the digestion ; the evolution of the hydrofluoric acid should be main- tained all the time. After 48 hours take the substance out, expel most of the sulphuric acid by heat, boil the residue with dilute hydrochloric acid, and, if anything remains undissolved, treat this residue with hydrofluoric acid in the same manner as above described. The alkaline metals can be determined in this solution by hydrochloric acid. 2. Decomposition by ammonic fiuoride.—This method is considered by many to be easier of execution and more certain in its results than the other. Mix the very finely pulverized silicate with 4-5 times its weight of ammonic fluoride in a platinum dish, moisten the mixture thorough- ly with concentrated sulphuric acid, and heat the whole on the water-bath in a place where the fumes of hydro- fluoric acid will be carried off speedily; after a time, when the evolution of acid fumes has ceased, moisten the residue again with sulphuric acid, and heat it, directly over the lamp at last, until it is completely dry and all 78 § 59, BASES AND ACIDS WITH REAGENTS. the sulphuric acid is expelled; digest the residue with hydrochloric acid; it should be dissolved completely, although, if calcium is present, considerable time may be required. If the solution is not complete, the insoluble part should be treated again with ammonic fluoride. SULPHURIC ACID. H,S0O,. 59, The sulphates of lead, barium, and calcium, are in- soluble, or difficultly soluble, in water and dilute acids; the last of the three is much the most soluble. Reactions.—Sulphuric acid and solutions of sulphates give a finely pulverulent precipitate, BaSO,, with baric chloride, insoluble in water or dilute acids; the reaction is very delicate. Quantitative estimation.—This acid is always de- termined as baric sulphate, BaSO,. Heat the slightly acid solution nearly to boiling, and add a hot solution of baric chloride as long as a precipitate is formed ; let the mixture stand until the precipitate settles, and wash the latter by decantation, until the washings give no reaction for barium with sulphuric acid; then pour 40 or 50 cc. of the solution of cupric acetate (§ 9) over the precipitate in the beaker, add some water and so much acetic acid that, after digestion for 10 or 15 minutes at a temperature very near to boiling, no basic cupric salt separates from the solution; if any does appear, dissolve it by adding more acetic acid; stir the mixture constantly during the digestion. Filter, wash the precipitate with hot water, and, if the filter is still colored blue, moisten it with a little dilute hydrochloric acid and wash with more water, until the washings give no reaction for copper with potassic ferrocyanide. Ienite the precipitate and filter separately. The residue con- tains 34.31°|, of sulphuric anhydride, SO,, or 13.73°|, of sulphur. § 60. CARBONIC ACID. 79 Unless the precipitated baric sulphate is washed, as above directed, with a solution of cupric acetate, the re- sult of the analysis may be very unreliable, particularly if notable quantities of nitrates or alkaline salts were present. CARBONIC ACID OR ANHYDRIDE. CO, 44. 60. Carbonates of all except the alkaline metals are insoluble, or sparingly soluble in water; all carbonates, without exception, are dissolved by dilute acids, with the expulsion of carbonic anhydride, CO,,. Reaction.— When dilute nitric or hydrochloric acid is added to a carbonate, whether a solid or in solution, the anhydride is expelled with effervescence, and if a drop of lime-water, suspended on the end of a glass rod, is held in the tube just above the liquid, it is made turbid by the formation of insoluble calcic carbonate. Quantitative estimation.—Carbonic acid is usually estimated by the loss of weight suffered by the carbonate on treating it with a stronger acid, or by collecting and weighing the expelled anhydride itself. a. For the first method a convenient form of an ap- paratus is represented in the adjoining figure. The carbonate is weighed in the flask A and water is added. B is nearly filled with nitric acid; C contains fused calcic chloride to absorb the moisture from the carbonic acid as it passes out, and so retain it in the appara- tus. The apparatus being put to- gether, with water enough in the flask A to cover the mouth of the tube leading from B, close the mouth of the tube at e with the finger, and suck a very small quantity of air out at d,; on letting air in 80 § 60. BASES AND ACIDS WITH REAGENTS. again at d, the water will rise iu the tube leading from A to B, and, if the apparatus is tight, will remain at a stationary level above that of the water outside of the tube. Now, weigh the whole apparatus, apply suction at d to cause a little nitric acid to flow over into A from time to time, and in this manner keep up a slow evolution of carbonic acid; when all the carbonate is decomposed, and all the nitric acid transferred to the flask, apply a little heat to the latter; then, by suction at d, draw air through the apparatus as long as any acid taste is per- ceived in the gas, let the apparatus cool, and weigh it. The air should be caused to pass through a calcic chloride tube before it goes into the apparatus, in order to dry it thoroughly. The loss of weight suffered by the whole apparatus equals the carbonic anhydride, CO,,. This method, otherwise very convenient, is, according to Prof. 8. W. Johnson, (American Journal of Science and Arts, Second Series, 48, 111) liable to the objection, that in freeing the apparatus completely from carbonic acid, some vapor of water escapes the desiccating materi- al. He therefore proposes to fill the apparatus with car- bonic acid gas before weighing it, and then to weigh it again as soon as the decomposition of the carbonate is completed ; it is essential only, that the substance under examination dissolve freely in cold acid, and that the analysis and weighings be conducted in an apartment not liable to changes of temperature. His apparatus may be closely imitated by substituting for the acid reservoir in the above figure, another one consisting of a bulb of sufficient size blown on a tube of which one end, that passes just through the cork in the flask, has an internal diameter of 7 mm., is cut off oblique- ly, and bent so that, on inclining the whole apparatus when put together, the acid can be made to flow from the bulb into the flask; the other end of this tube is turned § 60. CARBONIC ACID. 81 upwards. Short pieces of thick-walled rubber tubing that will fit snugly on the outer termination of the calcic chlo- ride tube and the acid reservoir, at d and e¢, are slipped over them, and these rubber tubes are then provided with well-fitting stoppers of glass rod; all these joints must be air-tight. The carbonate is weighed as usual in the flask, A, bet- ter in the form of smali fragments than of a powder, the acid reservoir is nearly filled with hydrochloric acid (Sp. Gr. = 1.1), the apparatus is put together, and, after the glass-rod stoppers are removed, it is connected with a generator of carbonic acid, and a rather rapid current of washed gas is passed through for about 15 minutes, or until the acid in the reservoir is saturated, and the air displaced in the flask; then stop the opening at d, discon- nect the apparatus from the generator, and close the open- ing at e, with care in this and all subsequent operations to handle the apparatus so as not to change its temperature. Weigh it immediately, loosen the stopper at d, and in- cline the whole so that the acid will flow over, little by little, and produce a slow decomposition of the carbonate. Close @ again when the decomposition is ended, let the apparatus stand about 15 minutes, to be sure that it is cool, pass well-dried carbonic acid gas in again for about a minute, in the same manner as at first, and finally weigh it after closing d and e. 6. For the second method the following form of ap- paratus is highly recommended by Fresenius. In the apparatus represented by this figure e contains soda lime or caustic potash in pieces, @ is a flask of about 300 c.c. capacity, the arm f of the first U tube is filled with fused calcic chloride, and the arm,/” with pumice-stone that has been soaked in a concentrated solution of cupric sulphate, dried, and gently ignited so as to drive out the water of crystallization of the salt; g contains pieces of glass, 6 to 10 drops of concentrated sulphuric acid in the Ae 82 § 60. BASES AND ACIDS WITH REAGENTS. bottom and plugs of asbestos in the upper parts of both arms; / is ‘|, filled with about 20 grms. of coarse grained soda lime, and the remaining ‘|, at /’ is filled with coarse-. Fig. 3. ly pulverized calcic chloride; the arm & of the last U tube contains calcic chloride, and the arm k’ soda lime. The carbonic acid evolved in a is deprived of its water and hydrochloric acid in ff” ; g enables the operator to observe the rapidity of the flow of the gas, while the acid is absorbed and weighed in g and AA’; the contents of kk’ prevent carbonic acid and water from reaching the U tube, hh’, from the atmosphere. Weigh out the substance in a, add water, weigh g and | hh’ together, connect the various parts of the apparatus | with each other, and the little funnel d with J, and put a few drops of mercury in at d so as to close the tube at 7. Pour the usual quantity of dilute nitric or hydrochloric acid in at d, and, by suction at J, cause a little of the acid to flow over into the flask ; regulate the flow of the gas by slowly transferring fresh quantities of acid from 6 to a, and applying a gentle heat to the contents of the flask. When the carbonate is completely decomposed, fill d several times with hot water and transfer the same to a; then, substitute the calcic chloride tube e for the funnel d, § 61. PHOSPHORIC ACID. 83 bring the contents of the flask to a gentle boiling, and continue the application of the heat until the bulb on f becomes hot; draw about 1800 c¢.c. of air through the apparatus, by means of an aspirator connected with J, then immediately separate a from jf, and weigh g and hh’ again when they have become cold. The increase in weight gives the carbonic anhydride. The tube g can be used several times if it is carefully closed when not in use. If the tube hh’ is used a second time, it will be safer to connect another with it on the outside, filled in the same way; if this second tube does not gain in weight, the first one may be used a third time, with the same precaution ; if it does gain notably, use it alone in the third analysis, and re-fill Ah’. c. It often happens that carbonic acid and chlorine are to be estimated in the same substance; in this case, after making the determination of the acid by either of the above methods, using, of course, pure nitric acid to set it free, filter the contents of the flask if not perfectly clear, and precipitate the chlorine in the filtrate and washings with argentic nitrate. PHOSPHORIC ACID. H;PO,. 98. 61, All phosphates except those of the alkaline metals are insoluble in water, but all are soluble in acids. Reactions.—When a solution of a phosphate is added to one of magnesia containing an ammoniacal salt and an excess of ammonia, a white flocculent precipitate, MgNH,PO,, is produced, which, after standing for a time in a warm place, becomes more granular and crys- talline ; in very dilute solutions the precipitate does not appear until after long standing, and is then crystalline, and adheres to the sides of the tube in the same manner as described under magnesium. 84 § 61. BASES aND ACIDS WITH REAGENTS. When avery small quantity of -a solution of a phos- phate is added to a considerable quantity of a solution of ammonic molybdate, containing an excess of nitric acid, a lemon-yellow, pulverulent precipitate is formed, at once or after long standing; a portion of the precipitate ad- heres strongly to the sides of the tube. This precipitate is soluble in a solution of a phosphate and in ammonia, but is insoluble in dilute nitric acid in the presence of excess of the molybdate. The reaction is exceedingly delicate. Quantitative estimation.—c. In cases where the acid is free or combined with an alkaline metal only, the deter- mination of it may be made as magnesic phosphate, Mg,P,0.. Neutralize a quantity of the solution of the substance containing not more than 0.2 grm. of the acid with am- monia, if it is acid, and add magnesia mixture (§ 18, 8) as long as a precipitate is formed; 12-15 ¢.c. of the re- agent will be required for 0.2 grm.of P,O,; then add diluted ammonic hydrate containing one part of ammonia- water of 0.96 Sp. Gr. and three of water, until the vol- ume of the mixture is about 110 ¢.c., and proceed further as directed for the treatment of the same precipitate un- der magnesium (§ 50,a). It contains 63.96°|, of phos- phoric anhydride, P,O.. If in any case the precipitate has a somewhat suspi- cious flocculent appearance, and does not become erystal- line after long digestion, it had better be dissolved in dilute hydrochloric acid on the filter; evaporate the solu- tion to dryness on the water-bath, treat the residue with dilute hydrochloric acid, and precipitate the phosphoric acid again with magnesia mixture as before. Neverthe- less it is best to avoid the necessity of this re-solution and re-precipitation if possible, by careful attention to the di- rections for removing silicic acid and other substances from the solution at the proper time and in the proper 0 § 61. PHOSPHORIC ACID. 85 place; according to Kubel ( Versuchs Stationen, 10, 123) there is a loss of magnesia when the precipitated phos- phate is dissolved and re-precipitated. 6. In the presence of alkaline earths, alumina, ferric oxide, and manganous oxide, phosphoric acid is best de- termined indirectly, by precipitation as ammonic phospho- molybdate. If silica is present, it must first be removed by evaporation to dryness in the usual manner (§ 58, a, 1). To the solution, free from silicic acid, add the solution of ammonic molybdate containing an excess of nitric acid, whose preparation is described in § 38, 7, and which, if made as there directed, contains 5°|, of molyb- dic acid, in such a quantity that the amount of molybdic acid added shall be from 40 to 60 times as great as that of the phosphoric acid supposed to be in the solution ; since the molybdic acid must be so largely in excess, it is well to take a quantity of the solution of phosphate that contains not over 0.1 grm. of the acid, and the solution should be tolerably concentrated. Digest the mixture from 12 to 24 hours at a temperature of about 40° C.; then take out a small sample of the clear liquid with a pipette, mix it in a test-tube with its volume of ammonic molyb- date, and heat the mixture gently for an hour or more. If more of the precipitate appears, rinse the test-tube into the beaker again, add more ammonic molybdate, digest 12 hours longer, and repeat the test. Not until the mix- ture remains perfectly clear in this test may the precipita- tion be considered as finished. Collect the precipitate on a small filter, rinse the beaker out with portions of the filtrate, and wash the contents of the filter with a mixture of 100 parts of the solution of ammonic molybdate, 20 parts of nitric acid (Sp. Gr. = 1.2), and 80 parts of water (/ires. Zeitschrift 6, 405), until, in case lime was present, the filtrate gives no turbidity in strong alcohol to which sulphuric acid has been added. Dissolve the precipitate in the smallest quantity of am- 86 61. BASES AND ACIDS WITH REAGENTS. monia (Sp. Gr. = 0.96), wash out the filter with a mix- ture of 8 parts of water and 1 of ammonia, and wash off what remains adhering to the walls of the beaker, in which the phospho-molybdate was precipitated, with a little of the same ammonia water, or clse collect this so- lution of the whole precipitate in that beaker; add di- lute hydrochloric acid to the strong ammoniacal solution, until the yellow precipitate, that appears with each drop of the acid added, begins to dissolve again with some dit ficulty, showing that the ammonia is nearly neutralized, then add the magnesia mixture as long as a precipitate is produced, and the proper amount of the diluted ammonia, and proceed as in a. Latschinow (Lres. Zeitschrift 7, 215) asserts that this precipitate of ammonio-magnesic phosphate must be fused with potassic sodic carbonate, the fused mass extracted with water, and this solution precipitated again with the macnesia mixture in the usual manner, after addition of a little citric acid. c. In the absence of at least all but small quantities of iron and aluminium, phosphoric acid may be determined with sufficient accuracy for industrial purposes by a volu- metric method that depends upon the following reactions. First, when a solution of uranic salt is added to one of a phosphate containing no other free acid than acetic, the uranic oxide is immediately precipitated in combination with phosphoric acid. Second, a solution containing the least traces of urani¢ oxide gives a brown precipitate with potassic ferrocyanide. Preparation of the standard solutions. 1, Dissolve 12.6056 grms. of pure crystallized hydric disodic phosphate, that does not show the least signs of | efflorescence, and has been thoroughly dried in powder by pressure between folds of bibulous paper, in about 300 c.c. of water, and, when the temperature of the solution is 15° C., make the volume up to exactly 500 ¢.c. with dis- 61. PHOSPHORIC ACID. 87 tilled water. One cubic centimetre of such a solution con- tains 0.005 grm. of phosphoric anhydride, P,O.. 2. Dissolve 100 grms. of sodic acetate in 900 c.c. of water, and add 100 ¢.c. of concentrated acetic acid. 3. Dissolve about 33 grms. cf uranic acetate in about 1 litre of water, and proceed to titrate this solution with reference to the standard solution of phosphate so that 1 cubic centimetre of it shall exactly precipitate 0.005 grm. of phosphoric anhydride, as follows. Put 25 ¢.c. of the standard phosphatic solution in a small flask, add 5 c¢.c. of the solution of sodic acetate, heat to about 50° C., add 5 or 10 ¢.c. of the uranic solution from a burette or graduated pipette, heat to boiling, and let the mixture stand a few minutes; the precipitate wiil settle quickly, and a drop of the clear supernatant liquid can be taken out on the end of a small glass rod, and tested with the solution of potassic ferrocyanide for ex- cess of uranic oxide; this test is best made by letting the drop fall gently in the middle of a small shallow pool of the solution of ferrocyanide, on a white porcelain plate, when the slightest excess of the uranic oxide in the solu- tion will be manifested by the formation of a brown zone where the two liquids come in contact; the color soon spreads throughout the entire liquid. If no color appears, add 5 c.c. more of the uranic solution, boil again, let set- tle, and test a drop of the supernatant liquid in another little pool of the ferrocyanide, and so proceed until a brown color is produced in the test drop. Suppose that this brown color was obtained after adding 20 c.c. of the uranic solution, but not after adding 15; repeat the trial now with a fresh quantity of the standard phosphatic so- lution, adding 16 ¢.c. of the uranic solution at once, be- fore making the test, and repeating the test after each addition of a cubic centimetre at atime. If, in this trial, we find that a brown color is obtained with 17 cc. but not with 16, we may make a third trial with another por- 88 62. BASES AND ACIDS WITH REAGENTS. tion of the standard phosphatic solution, and locate the. point of saturation more accurately between 16 and 17 cubic centimetres, beginning with 16.1 c.c. and so on, If we find, finally, that 25 cc. of the standard phos- phatie solution requires 16.5 ¢.c. of the uranic solution for the complete precipitation of the phosphoric acid, then, evidently, to every 16.5 c.c. of the former, 8.5 c.c. of pure water must be added, in order to make a standard uranic solution, each cubic centimetre of which shall be exactly equivalent to 0.005 grm. of phosphoric anhydride. The respective quantities of uranic solution and water being carefully measured out and mixed, for making half a litre or a litre of the standard solution, this solution should be tested, in order to be sure of its value with respect to phosphoric acid. Dilute 5 ¢.c. of the standar 1 phosphatic solution, add 1-2 cc. of sodic acetate, and then add the uranic solution from a burette graduated into ‘|,, Cubic centimetres ; exactly 5 c.c., not a tenth more or less, should be required before the reaction with the ferro- cyanide is given. The method of determining phosphoric acid volumet- rically, with the aid of this standard uranic solution, is the same as that just described for the determination of the strength of this solution as originally prepared. The amount of phosphoric anhydride in the quantity of the solution taken is then given, by the product of 0.005 into the number of cubic centimetres of standard uranic solution required to precipitate the acid. NITRIC ACID « HNOg 63. 62, All nitrates are soluble in water. Reactions.—If a nitrate is heated with concentrated sulphuric acid and copper turnings, red fumes of nitric peroxide, NO,, become visible in the upper part of the 62. NITRIC ACID. 89 tube, particularly if it is held over white paper and looked through lengthwise. If a nitrate is mixed in a test-tube with strong sul- phuric acid and the mixture is allowed to cool, and a con- centrated solution of ammonio-ferrous sulphate is then poured slowly down the sides of the tube so as to float on the surface of the liquid in it, a colored ring is formed, the tint of which may range from a rose color to a dark brown, according as little or much nitric acid is present. If a solution of a nitrate is poured into a test-tube con- taining 2-3 grms. of a mixture of clean iron filings and granulated zine, or of sodium amalgam, and 5-6 c.c. of a strong solution of potash or soda are added, and the mix- ture is heated to boiling, ammonia is set free ; 1ts presence in the tube may be detected by moistened turmeric-paper, or by holding in the tube a drop of Nessler’s solution, suspended on the end of a glass rod; this solution will be colored reddish-brown. A delicate test for nitric acid in rain-water consists In acidifying 100 ¢.c. of the water with 2 or 3 drops of con- centrated sulphuric acid, adding 2 or 38 pieces of pure zinc, and, immediately, a freshly prepared mixture of potassic iodide with a little boiled starch paste ; the pres- ence of nitric acid is indicated by a blue color. The re- agents used should be tested by mixing them together without the water. If the water contained nitrous acid, it will give a blue color with potassic iodide and starch paste alone. Quantitative estimation.—a. Of the numerous meth- ods of determining nitric acid, that of Schléssing has proved the most satisfactory in all cases. Friihling and Grouven have simplified Schléssing’s apparatus somewhat. (Die landwirthschaftlichen Versuchs-Stationen, 9, 13.) The dissolved nitrate is introduced into the flask A, of about 400 cc. capacity, whose mouth can be perfectly closed by a rubber cork, through which passes a glass 99 62. BASES AND ACIDS WITH REAGENTS. tube, a ; the rubber tube bc should be about 8 em. long, and have a clamp on it; d is another narrow caoutchoue tube, 15 cm. long. The neck of the jar B is ground on the outside so that’ a rubber tube slipped over it will more readily make a tight joint; a small glass tube, g, is connected with the jar by the stop-cock & and rubber tubing ; another glass tube, 7, bent at an obtuse angle, and reaching above the level of the stop-cock 4, is fastened im the tubulure m of the jar by a good cork. This last- mentioned tube being in place, open the stop-cock 4, pour a little boiled water into the jar through the tube 7, and then pour in mercury until it rises to the lower rim of the rubber tube 7 on the neck of the jar; close the stop-cock, put the jar in the mercury trough so that the mercury rises above the tubulure, and remove the glass tube 7 and the cork; now, by means of a pipette, the lower end of which is bent so that it can be inserted in the tubulure, introduce 50 c.c. of well-boiled milk of lime, and then cover the mercury in the trough with water to the depth of about 3 cm. | The solution of the nitrate in A, which must be neutral or alkaline, is boiled down to a small volume, while the open end of @ is immersed in water; when the bubbles of gas escaping from A are completely condensed in passing through the water, showing that all the air has been ex- pelled from the liquid in A, close the clamp on 6c, and Fig. 4. § 62. NITRIC ACID. 91 dip d in a glass containing a solution of ferrous chloride in hydrochioris acid, remove the lamp from A, and open the clamp just enough to allow this solution to flow into the flask rather rapidly; when about 200 c.c. of the fer- rous solution have passed in, replace this solution by dilute hydrochloric acid, and allow three or four portions of this to flow in also, and thus wash all the ferrous salt out of the tube; finally rinse the tube into the flask with a little dis- tilled water. Now, close the clamp on bc, and, without allowing any air to enter the tube, insert d in the tubulure of the jar B, replace the lamp under A, immediately open the clamp on dc, while holding the rubber tube tightly compressed between the fingers until a pressure is felt from within; then remove the fingers and allow the nitric oxide gas that is generated in the flask to pass into the receiver B. The reaction is generally terminated in about 8 minutes; so long as nitric oxide is escaping it bubbles up through the milk of lime in B, but as soon as nothing but water and hydrochloric acid pass over, both are absorbed by the milk of lime, and the bubbling of the gas through it ceases. If the receiver B is filled with gas before all the nitric acid in A is decomposed, close the clamp on dc, remove the lamp immediately from under A, take the rubber tube d@ out of the tubulure and let it lie in the water over the mercury, while the receiver is emptied in the manner de- scribed below; then fill the receiver again with mercury and milk of lime as directed above, insert @ in the tubu- lure again, apply heat to A while the tube dc is closed with the fingers only, and proceed as before, until the de- composition of the nitric acid is finished. When the evolution of gas finally ceases, close be, re- move d@ from the tubulure, and proceed to empty the gas from b. To this end, mount another flask, C, in the same manner as A was arranged, put about 100 c.c. of distilled water in it, attach a rubber tube about 12 cm. long to the 92 62. BASES AND ACIDS WITH REAGENTS. glass tube that passes through the well-fitting rubber cork in the mouth of the flask, and put a clamp, y, on the end of the tube. Fasten this clamp open and boil the water in C until the air is completely expelled from the flask, and, while steam is still escaping from the end of the rub- ber tube, slip it over the glass tube g on the receiver, and at the same moment open the stop-cock & ; the aqueous vapor, from the water that continues to boil in the flask, condenses at first in the neck of the receiver and washes the milk of lime out of the upper part of it and out of the glass tube; if any milk of lime is carried into C in the operation that follows, the analysis is worthless. Now, remove the lamp from C, and a current starts in the opposite direction, which carries the nitric oxide into C; the rapidity of the flow can be regulated by compress- ing the rubber tube between the fingers ;\ as soon as the milk of lime in the receiver has reached the rim of the rubber tube /, close the stop-cock & and conduct 20 or 30 c.c, of pure hydrogen into the receiver, open the stop-cock and allow this gas to flow into C; repeat this two or three times, thus carrying the last traces of nitric oxide from Bto C. Now, close & again and also the clamp y near this end of the tube, connect the rubber tube with a small gasometer containing oxygen, open the cock of the gasometer and the clamp y again, and oxygen will pass into C and convert the nitric oxide into nitric acid ; when all the oxygen has passed into the flask that will, close the gasometer cock, disconnect the rubber tube from it, and, after about 15 minutes, determine the nitric acid in the liquid in C by means of the *|,, standard solution of soda; each cubic centimetre of the sodic solution, con- taining *|,, of an equivalent of sodic oxide (Na,O), will combine with ‘|, of an equivalent of nitric anhydride N,0,, expressed in milligrammes = 5.4 mgr. or 0.0054 orm. 6. Nitric acid may be very conveniently estimated in nitrates, as, for example, when it is desired to test the § 62. NITRIC AcID. 93 purity of nitre or of Chili saltpetre, by its expulsion at a high temperature by another acid, as silicic or chromic, that is not volatile at such a temperature. Fuse a quantity of the salt, free from carbonic acid, ammonic salts, or organic matter, at the lowest possible temperature, pour it on a warm porcelain plate, pulverize the cake, and dry the powder thoroughly; then put 2-3 grms. of finely powdered quartz in a platinum crucible, and ignite it strongly; add to this about 0.5 grm., care- fully weighed, of the nitrate prepared as above directed, mix the two substances carefully with a dry glass rod, wipe off the rod with a little more of the quartz powder, and weigh the whole; ignite the well-covered crucible with its contents, for half an hour, at a barely visible red heat, weigh, and count the loss as nitric anhydride. Sul- phates or chlorides are not decomposed under these cir- cumstances, but, if carbonates are present, they must be removed by previous treatment of the salt with hydro- chloric acid in slightest possible excess, and evaporation to dryness on the water-bath. ce. A very convenient method for determining nitric acid in nitrates is given by C. Noellner. (Fires. Zeitschrift 6, 875). It depends upon the solubility of ammonic nitrate in absolute alcohol, and the insolubility of other salts of the alkalies and alkaline earths. Heat a quantity of the salt containing not more than 0.2 grm. of the nitre with a small quantity of a solution of ammonic sulphate; ammonic nitrate is formed, and this remains in solution while all other salts are precipitated, when absolute alcohol is added to the liquid ; let the mix- ture stand a few minutes, filter it, wash the precipitate, add an alcoholic solution of potassa to the filtrate, collect _ the precipitated potassic nitrate on a dried and weighed filter, wash it with alcohol, dry it at 100°, and weigh it. 94. 63. BASES AND ACIDS WITH REAGENTS. HYDROCHLORIC ACID. HCl. 36.5. 63. Chlorides of all the metals in the list in § 48 are soluble in water. Plumbic chloride is sparingly soluble in cold water but readily soluble in hot. Reaction.—When argentic nitrate is added toa solu- tion containing a chloride or hydrochloric acid, a white precipitate is produced, AgCl, which, if at all abundant, is collected together in curdy flakes on violently agitating the mixture. This precipitate 1s blackened on exposure to the light, 1s insoluble in dilute nitric acid, but is solu- ble in ammonia; from this solution it is re-precipitated unchanged, on addition of nitric acid in excess. It can be fused without decomposition. In contact with metal- lic zine in the presence of sulphuric acid, it is decomposed, metallic silver being set free. Quantitative estimation.—Hydrochloric acid or chlo- rine is most easily and accurately determined by precipi- tation as argentic chloride, and the estimation may be made either by a gravimetric or a volumetric process. a. Gravimetric Process—Add the solution of argentic nitrate, containing a slight excess of nitric acid, to the so- lution of the chloride, heat the mixture and stir or shake it vigorously to cause the precipitate to settle more read- ily, let it stand until the supernatant liquid is quite clear, decant the liquid through a small filter, agitate the pre- cipitate with hot water, transfer it to the filter with the aid of a little water acidulated with nitric acid, wash it at first with the same acidulated water and afterwards with pure water, until the washings give no turbidity with ammonic chloride. Dry the filter and its contents, separate the latter from the filter as completely as possible, burn the filter on the crucible cover, add the ash to the precipitate in the cruci- ble, heat the whole some time with a little nitric acid, add a little hydrochloric, evaporate carefully to dryness on the 63. HYDROCHLORIC ACID. 95 water-bath, ignite the residue until it begins to fuse, and weigh it. When this precipitate of argentic chloride is produced in the presence of much organic matter, it, together with the ash of the filter, must be fused with 3 or 4 parts of pure sodic carbonate, and the fused mass exhausted with water, the insoluble residue well washed, and the solu- tions and washings re-precipitated with argentic nitrate, and the precipitate treated as directed above for washing and ignition. The precipitate contains 24.74°|, of chlorine. 6. Volumetric Process.—To prepare the standard solu- tion of argentic nitrate, dissolve 18.75-18.8 grms. of the pure fused salt in 1100 cc. of distilled water, filter the solution if necessary, and mix all parts of it well together. Weigh out accurately four portions of pure sodic chloride of 0.1-0.18 grms. each; the salt should have been pre- viously gently ignited, pulverized while warm, and kept in a well stoppered bottle until wanted for use. Dissolve each portion of the salt in 20-30 c.c. of water, and add 2 or 3 drops of a cold saturated solution of potassic chromate. Now, allow the solution of argen- tic nitrate to flow from a burette, graduated into ‘|,, cc, into one of these solutions, slowly and with constant stir- ring; each drop as it comes in contact with the liquid produces a red precipitate, which, at first, disappears when mixed with the rest of the solution, but finally the addi- tion of a single drop causes the red color to remain per- manent; all the chlorine has united with the silver. A solution of argentic nitrate is to be made, one litre of which will exactly precipitate the chlorine in '*|,, of an equivalent of sodic chloride expressed in grammes, or 5.85 grms. If the amount of sodic chloride in the solu- tion tested in this first experiment was 0.11 grm., and 96 63. BASES AND ACIDS WITH REAGENTS. 18.% c.c. of argentic nitrate were required, we learn by the proportion, 0.11 : 18.7 = 5.85 ; 994.5, how much of the argentic solution that we have made would be required for the desired purpose; we must therefore add 5.5 c.c. of distilled water to 994.5 c.c. of the argentic. solution, to make a litre of a solution that shall be exactly equivalent to 5.85 grms. of sodic chloride, or 3.55 grms. of chlorine; or, since it is more convenient to measure out one litre of the solution, and add a small quantity of water accurately measured with the pipette, we may learn. from the proportion, 994.5 : 4.5 = 1000: x, how much water will be required for one litre. Repeat the test made with one portion of the salt with two of the remaining three portions, keeping the first at hand as a standard of comparison, substitute the mean of the quantities of salt taken and of the three correspond- ing results in the place of the first and second terms in the first proportion given above, and make the standard silver solution accordingly ; then, in order to be sure that the work has been correctly done, rinse the burette out with a little of the solution last prepared, fill up to the zero mark with this solution, and make a fourth trial with the last weighed portion of the sodic chloride. The num- ber of cubic centimetres of the standard solution required, multiplied by 0.00585, should give a product exactly equal to the amount of salt taken. One cubic centimetre of this solution corresponds to 0.00355 grm. of chlorine. The solution in which chlorine is to be determined with the aid of this standard solution must not be acid in the slightest degree, but should be neutral, or at the most very slightly alkaline. If strongly alkaline, it should first be neutralized with nitric acid; if acid, with sodic § 64. WYDROCYANIC ACID. 97 carbonate. Of course, neither of these reagents should contain any chlorine. Greater accuracy is secured, more- over, by using the same volume of a solution containing about the same amount of chlorine as in determining the standard of the argentic solution in the beginning—that is, about 25 ¢.¢c. containing about 0.15 grm. of chlorine. It is well, also, to have on hand an accurately titrated solution of sodic chloride, containing exactly 5.85 grms,. of sodic chloride in the litre, and which, therefore, is ex- actly equivalent, cubic centimetre for cubic centimetre, to the argentic solution. Then, if it is feared in any case that too much argentic nitrate has been added, a cubic centimetre of this solution can be put in, when the red coloration will disappear, and argentic nitrate can be add- ed again more cautiously ; finally, when the desired result is obtained, subtract one from the number of cubic centi- metres of argentic solution used. HYDROCYANIC ACID HCy. 64, Cyanides of manganese, zinc, and copper, are in- soluble in water. Reactions.—Cyanides give a white precipitate, AgCy, with argentic nitrate, insoluble in dilute nitric acid, and somewhat difficultly soluble in ammonia; when heated, it is decomposed, metallic silver being left behind. If a cyanide is treated with dilute sulphuric acid ina watch-glass, and another watch-glass, with a drop of ammonic sulphide charged with excess of sulphur in its ‘centre, is quickly inverted over the first glass, the hydro- cyanic acid evolved from the cyanide is absorbed by the ammonic sulphide, and on evaporating the drop in the upper glass to dryness at a very gentle heat, ammonic sulphocyanate is left, which, if moistened with a drop of ferric chloride, gives a deep red color. 5 98 65. BASES AND ACIDS WITH REAGENTS. HYDROFERROCYANIC ACID. HCfy. 65. Ferrocyanides of iron, zinc, manganese, lead, and copper, are insoluble in water; ferrocyanides of iron and copper are insoluble in dilute acids. Reactions,—F errocyanides give a deep blue precipitate of Prussian blue, Fe,Fe,Cy,,, with ferric chloride, which is not soluble in dilute hydrochloric acid, but is decom- posed by sodic hydrate, the blue color being changed to red, HYDROSULPHURIC ACID. H.S. 66. Sulphurets of arsenic, lead, copper, iron, manga- nese, and zine, are insoluble in water; the first three are insoluble in dilute acids. Reactions.—Sulphurets give with argentic nitrate a black precipitate, Ag,S, insoluble in dilute nitric acid and in ammonia. When sulphurets are treated with hydrochloric or sul- phuric acid, sulphuretted hydrogen, H,S, is evolved with effervescence ; the gas may be recognized by its disagree- able odor, and the property of blackening lead-paper. HYDRIODIC ACID. HI. 67, Plumbic iodide is sparingly soluble in cold water, but readily soluble in hot ; other iodides are soluble. Reactions.—lIodides give a yellow precipitate, Agl, with argentic nitrate, which is very sparingly soluble in ammonia and in dilute nitric acid. If enough potassic dichromate is added to a solution of an iodide to give it a pale yellow color, and then a lit- tle hydrochloric acid, iodine is set free, which, if it is present in notable quantity, gives the solution a darker § 68. wyDROFLUORIC acID. § 69. oxazic Act, 99 color; a drop of this solution on starch paper colors it blue; the latter reaction is very. delicate. HYDROFLUORIC ACID. HF. 68, Calcic and magnesic fluorides are difficulty soluble in water and acids. ~ Reactions.x—When a fluoride in powder is moistened with concentrated sulphuric acid, in a leaden or platinum cup, and gently heated, hydrofluoric acid is evolved; if the cup is covered with a piece of Bohemian glass that is protected with a coating of wax, except along a few lines where the wax has been removed with a sharp point, the glass will be corroded on these lines, in a few hours at the most. If but a small quantity of hydrofluoric acid is present, the marks may not be seen until all the wax is carefully cleaned off and the glass is breathed upon. To be sure that these faint marks are produced by traces of hydrofluoric acid in the substance, wipe the glass off carefully with water, and see that they can be developed again by the breath—and be sure, also, that the sulphuric acid used does not contain traces of hydroflu- oric acid, as it sometimes does. If a silicate is present, this reaction may not take place; in this case mix the substance with strong sulphuric acid in a watch-glass, heat until the mass is dry, and wash the residue off with water. If fluorine was present, the glass will be found to be corroded where it came in contact with the substance. OXALIC ACID. H.C.0,. 90. 69. Oxalates of barium, calcium, magnesium, iron, manganese, zinc, lead, and copper, are sparingly soluble, or insoluble, in water, but soluble in dilute acid. Reactions.—Oxalates. are decomposed, but not black- ened when heated. 100 § 69. BASES AND ACIDS WITH REAGENTS. When an oxalate is heated with plumbic binoxide and concentrated sulphuric acid, a brisk effervescence ensues, carbonic acid being set free; if a drop of lime-water, on the end of a glass rod, is held in the tube above the liquid, it is made turbid by precipitation of calcic car- bonate. A solution of an oxalate in which no free acid except acetic is present, gives a fine white precipitate, CaC,O,, with calcic sulphate, insoluble in acetic acid. Quantitative estimation.—c. Oxalic acid may be ac- curately determined by a volumetric process with potassic permanganate. First make a ’|,, standard solution of oxalic acid, by mixing together 10 cc. of the standard acid already made and 90 ¢.c. of distilled water. Put 50 c.c. of this new standard solution, containing 0.315 grm. of the acid, in a beaker, add about 100 c.c. of water and 6 to 8 ¢.c. of concentrated sulphuric acid, and heat to about 60° C.; put the beaker on a sheet of white paper and add the standard solution of permanganate with constant stirring, in the same manner as directed for the determination of iron (§ 52). When the reaction is completed, make another trial with the other 50 ¢.c. of the *|,, standard acid. The standard of the permanganic solution with refer- ence to oxalic acid being determined, to estimate the acid in any substance, whether free or combined, the substance must be freed from all other compounds that act in the ‘same manner on the permanganate, such as ferrous oxide, or organic matter; dissolve it in water or hydrochloric or sulphuric acid, add 400 to 500 ¢.c. of water for every gramme of oxalic acid supposed to be present, and 6 to 8 c.c. of concentrated sulphuric acid, and proceed to titrate with the permanganic solution in the usual way. Let m = the amount of permanganate used to oxidize 0.315 grm. of crystallized oxalic acid, or 0.18 grm. of oxalic an- hydride, and m’ the amount required to oxidize the acid ’ S %0.. ACETIC ACID. 101 in the quantity of substance taken. Then from the pro- portion, 2 O88" =. mos x we may learn how ies oxalic anhydride, C ,0,, Was con- tained in the substance analyzed. b. Oxalic acid may be estimated in any substance con- taining it and free from carbonic acid, by converting it into carbonic acid with the aid of manganic oxide and concentrated sulphuric acid, and determining this car- bonic acid. Weigh the substance in the flask A, Fig. 1, § 60, add about the same weight of manganic oxide free from carbonic acid, fill B with concentrated sulphuric acid, weigh the whole apparatus, and proceed further as in the estimation of carbonic acid with this form of ap- paratus (§ 60, @). Each equivalent of oxalic anhydride, C,O,, yields two equivalents of carbonic anhydride, CO,,. ? ACETIC ACID. HC.H;O:2. 60. 70. All acetates are soluble in water. Reactions.—Acetates are blackened when quickly heat- ed to a high temperature, carbon being set free. | If a neutral acetate is mixed with a solution of ferric chloride, a deep red liquid is produced; on boiling the mixture a red precipitate is formed. If an acetate is heated with concentrated sulphuric acid and alcohol in about equal volumes, acetic ether is disen- gaged, the pleasant aromatic odor of which is best distin- guished from that of common ether, which may be formed from sulphuric acid and alcohol alone, after the liquid has become quite cold. Quantitative estimation.—F ree acetic acid may be es- timated by a volumetric process, with the aid of the standard sodic solution. | . Since neutral sodic acetate has a slightly alkaline re- action, It is best to ascertain first, the relation between 102 § V1. BASES AND ACIDS WITH REAGENTS. this standard solution and one of acetic acid of known strength. or this purpose add a measured quantity of the standard sulphuric acid to a solution of sodic acetate, but not enough to decompose the whole of the acetate. Each cubic centimetre of the sulphuric acid, containing 0.04 grm., will set free an equivalent quantity of acetic anhydride, = 0.051 grm., or of the hydrated acid, 0.06 grm. Knowing, then, how much acid has been set free, we can titrate the mixture with the standard sodic solution, and learn how much acetic acid each cubic centimetre of the sodic solution will neutralize. Merz recommends the use of a tincture of turmeric as a coloring matter that is not affected by neutral sodic ace- tate ; the addition of a single drop of the soda solution to a solution of sodic acetate colored yellow by this tincture produces a brown color, while a drop of acetic acid re- stores the yellow color. ( Wagner's Jahresbericht, 13, 498.) TARTARIC ACID. H,.C,H,0,. 150. @1. Tartrates of barium, calcium, zinc, and copper, are difficultly soluble in water. Reactions,— W hen tartrates are heated, they are ie ened, and an odor of burnt sugar is given AG If a solution of free tartaric acid, that is not too dilute, is mixed with a solution of potassic acetate, a crystalline precipitate, KHC,H,O,, is formed at once, or after some time, or after violent agitation, or addition of an equal volume of alcohol. If the two solutions are very concen- trated, and are stirred in a watch-glass, a deposition of crystals marks the track of the rod over the glass. Calcic chloride gives a white precipitate, CaC,H,O,, in solutions of a neutral tartrate, the formation of which is hastened by violent agitation; the presence of ammonic chloride only retards the appearance of the precipitate, > § 72. CITRIC ACID. 103 but does not prevent it. The precipitate is soluble in boiling sodic hydrate, but re-precipitation follows on cooling. With lime-water in large excess, so as to turn red lit- mus-paper blue, tartaric acid gives the same white precipi- tate. With calcic sulphate, tartaric acid in tartrates gives no precipitate, thus distinguishing it from oxalic acid. With argentic nitrate, neutral tartrates give a precipi- tate that is turned black when the mixture is boiled. Quantitative estimation,—An approximate determina- tion of tartaric acid may be made by adding potassic acetate to its moderately concentrated solution, and con- siderable alcohol, collecting the precipitate on a weighed filter, washing it with alcohol, and drying it at 100° C., and weighing. : The residue of potassic tartrate, KHC,H,O,, contains 70.18"|, of tartaric anhydride, C,1,0,. CITRIC ACID. H;C,.H;0;. -”9, Citrates of barium, calcium, and aluminium, are sparingly soluble in water. Reactions.— When citric acid is heated, it fuses at first, and then carbon is separated with the evolution of pun- gent acid fumes. Citrates are blackened when heated. Citrates give no precipitate with potassic salts. With lime-water in excess, at ordinary temperatures, they give a very slight precipitate, which, on boiling, be- comes quite abundant, but 1s mostly dissolved when the mixture is cooled. Calcic chloride gives a precipitate Cx (CO) 2; im solutions of neutral citrates, which, if obtained without heat, is soluble in ammonic chloride; it is re-precipitated from this solution on boiling, and is not then soluble in ammonic chloride ; it is insoluble in potassic hydrate. 104 § 73. BASES AND ACIDS WITH REAGENTS. MALIC ACID. H,.C,H,0;. 194. 73. Malate of lead is difficultly soluble in water Reactions.— When malic acid is heated, it froths, pun- gent acid vapors being set free, and crystals of maleic and © fumaric acids are condensed in the colder parts of the tube. Malates give no precipitate with potassic salts, nor with calcic hydrate or sulphate, even on boiling. With calcic chloride no precipitate is formed unless the solution is concentrated and the mixture is boiled; if this precipitate, CaC,H,O,,2H,O, is dissolved in a very little hydrochloric acid, ammonia added, and the mixture boiled, the calcre malate is re-precipitated ; but if it is dissolved in considerable acid, no precipitate is formed on adding ammonia and boiling; alcohol will precipitate the salt from this solution. Quantitative estimation,—An approximate determina- tion of malic acid may be made by adding calcic hydrate In excess to its highly concentrated solution, free from citric, tartaric, or sulphuric acid, and then adding consid- erable alcohol, collecting the precipitate on a dried and weighed filter, washing with alcohol, drying at 100° C., and weighing. The residue contains 67.44°|, of malic anhydride, CHO. LACTIC ACID. HC3H;03. 90. 74, All lactates are soluble in water ; only zincic lactate is somewhat difficultly soluble in cold water. Reactions,—Lactates are blackened when heated. If a liquid containing free lactic acid is boiled with zin- cic oxide or carbonate, the filtered solution will deposit a erystalline crust on its surface, or acicular crystals, on cooling. § 75. URIC ACID. 105 Quantitative estimation.—This acid in the free state may be determined by a volumetric process, the same as for the determination of acetic acid. The solution, free from acetic or other free acid except lactic acid, is titrated with the standard sodic solution. Each cubic centimetre of sodic solution required corresponds to 0.81 grm. of the anhydrous acid, C,H_,,O.. To remove acetic acid as well as carbonic from the so- jution, before estimating the lactic acid, evaporate a por- tion of the liquid in the water-bath with the addition of pure quartz sand and with constant stirring towards the end of the operation; continue to heat the dry residue until no more acid odor is given off, then treat it with water, filter, and wash the sand on the filter as long as the washings are acid, and determine lactic acid in the filtrate with the standard sodic solution as above. URIC ACID. HeC;H2N,O2 + 4aq. 304. 75. This acid is but slightly soluble in water, and is insoluble in alcohol. Alkaline urates are soluble in water ; others are insoluble. Reactions.—If uric acid or a urate is heated with mod- erately strong nitric acid, the mixture filtered if not clear, the filtrate carefully evaporated to dryness, and the resi- due moistened with ammonia, a beautiful purple color (murexide) appears. In urinary sediments, uric acid may often be recognized under the microscope by the rhombic six-sided plates, or right-angled four-sided prisms of a brown to a golden yel- low color, which it forms. Quantitative estimation.—Precipitate the uric acid- from the solution containing it by the addition of hydro- chloric acid, if no albumen is present; in case it is pres- ent, use acetic or phosphoric acid instead of hydrochloric. Let the mixture stand 36-48 hours, and collect the pre- 5* 106 %6. BASES AND ACIDS WITH REAGENTS. cipitated acid on a dried and weighed filter, and add 0.045 mgr. to the amount of uric acid found, for every cubic centimetre of wash-water passed through the filter. If hippuric acid was present, it must be dissolved out of this precipitate by treating it several times with alco- hol of 83°|.. HIPPURIC ACID. HC,H,NO;. 179. 76, This acid is slightly soluble in cold water, but readily soluble in boiling water and in alcohol, and slight- ly soluble in ether. Ferric and plumbic hippurates are quite insoluble in water; all others are soluble. Quantitative estimation.—Precipitate the concentrated solution of the acid with hydrochloric acid, and let the mixture stand in the cold 48 hours; collect the precipitate on a dried and weighed filter, wash it with small portions of very cold water, until the washings are colorless and give only a faint turbidity with argentic nitrate, dry at 100°, and weigh. For every 6 c.c. of wash-water that passed through the filter add 0.01 grm. to the amount of hippuric acid found. If uric acid is present, the precipitate, after being weighed, must be treated with alcohol, and the residue of uric acid weighed again. The difference between the two weights will be the hippuric acid. For a better method of separating the two acids see urine, § 113, A. TANNIC ACID. 77. Tannic acid is soluble in water, alcohol, and ether; alkaline tannates are soluble in water, but others are diffi- cultly soluble. Reactions.—Tannic acid gives a violet-black precipi- “7. TANNIC ACID. 107 tate with ferric salts. It also gives a white precipitate when poured into a solution of gelatine; as long as the gelatine is in excess, this precipitate is soluble in the su- pernatant liquor when heated, while if the acid is in ex- cess, it is much less soluble. If a piece of fresh skin, deprived of its hair by caustic lime, is left for several hours in contact with a solution of tannic acid, the latter is completely absorbed, so that the liquid will give no color with ferric salts. Quantitative estimation.—The tannic acid in a solution may be determined with considerable accuracy by com- paring the specific gravity of the solution before and after it has been in contact with powdered skin. The solution must be as clear as possible and not too dilute; such a one will answer, for example, as may be obtained by exhausting 20 to 40 grms. of tanner’s bark with water, and diluting to 400 or 500 c.c. Determine the weight of the extract obtained from a weighed quantity of the bark, and then determine the specific gravity of the solution accurately with the pik- nometer, or specific-gravity bottle (§ 34, @). Then weigh out 100 ¢.c. of the solution in a flask, and weigh out also a quantity of finely divided skin, equal to about four times the amount of tannic acid that is supposed to be in this quantity of the solution; this amount can be ascer- tained approximately from Table IV, taking as the per cent of tannic acid that which is found against the number representing the specific gravity of the original solution, just determined. Soften the skin by soaking it in water, enclose it in a linen bag and press out the water, add it to the weighed solution in the flask, close the flask and shake the mix- ture vigorously, filter through a linen cloth and determine the specific gravity of the filtrate. To the difference be- tween the specific gravity before and after treatment with the skin, add one, seek for the number so obtained in the 108 78. BASES AND ACIDS WITH REAGENTS. column headed specific gravity at 15° C.,in Table IV, and against that will be found the per cent of tannic acid in the solution examined. A simple calculation will then give the per cent of the acid in the bark. To prepare the powder of skin required in this analy- sis, wash a piece of skin, that has been prepared for tanning by treatment with lime and other agents, with water, stretch it on a board, dry it with the aid of a gentle heat, and rasp it with a coarse file. Keep the powder in a well stoppered bottle. CELLULOSE. Cy,2Heo)ho. O24. 78, Cellulose is insoluble in water, dilute acids or al- kalies, alcohol, ether, or oils. It is soluble in an ammonic solution of cupric oxide, and is precipitated from this so- lution in the form of colorless flakes. Strong sulphuric acid, composed of four parts of acid and one of water, disintegrates it at ordinary temperatures without coloring it, and, after a time, changes it into dextrine. With iodine solution this disintegrated cellulose, before its passage into dextrine, gives a violet-blue color. Quantitative estimation.—Cellulose is estimated quan- titatively by freeing it as completely as possible from all other substances, and weighing the residue as pure cellu- lose; the best method yields results, however, that are about 1°|, too high. A quantity of 3 to 4 grms. of the substance is exhaust- ed with water, alcohol, and ether, successively, as long as each of these solvents takes anything into solution, and is then macerated 10 or 12 days in a glass-stoppered bot- tle, at a temperature not above 15° C., with 12 grms. of nitric acid (Sp. Gr. = 1.1), and 0.8 germ. of potassic chlo- rate; water is then added, the mixture is filtered, and the filter is well washed, first with cold and afterwards with hot water: the contents of the filter are then rinsed “9. STARCH. 109 into a beaker and digested about an hour, at 60° C., with ammoniacal water containing 50 parts of water to one of common ammonia; the mixture is filtered through a dried and weighed filter, the contents of the filter washed with the same ammoniacal water until the washings are color- less, then with pure water, with alcohol, and finally with ether, dried at 100° C., and weighed. This cellulose often contains as much as from 0.5 to 0.7 °|, of albuminoids, and a very small per cent of inorganic matters, STARCH. C,sHssO in: 824. 79, Starch, as long as it retains its natural form, is in- soluble in water, alcohol, and ether. In contact with hot water the starch grains swell up, and, if a larger quantity of water is then added, a small portion of the starch re- mains in solution. Starch may be converted into a soluble modification by boiling it with water under pressure, by heating it a short time with dilute sulphuric acid, or by the action of dias- tase at ordinary temperatures. Dry starch is colored blue or black by a solution of iodine in potassic iodide. The color is destroyed by alco- hol, potassa, or hydrosulphuric acid, or by heat; if not heated too long, the blue color reappears as the solution cools. Quantitative estimation,—Starch is usually determined by conversion into glucose, either by malt or sulphuric acid, and the subsequent determination of the glucose with Fehling’s solution. 1. By malt.—To prepare the extract of malt, crush 6 germs. of fresh malt in a mortar, digest with lukewarm water, filter, and wash the filter with water of 60° or 70°, and divide the clear filtrate, after mixing it well with the washings, into two exactly equal parts. Mix a quantity 110 %9,. BASES AND ACIDS WITH REAGENTS. of the substance to be examined containing about 2.5 grms. of starch with water, heat to 70° C., add one of the portions of the extract of malt, put the other portion into another flask, and digest both precisely alike 8 or 4 hours on the water-bath, at a temperature of about 60° or 70° C. Then bring both liquids to about 200 ¢.c. by addition of water, add 20 ¢.c. of a solution of basic plumbic ace- tate (§ 24, a) to each, shake vigorously, add water again until the volume of each liquid is exactly 500 ¢.c., ata temperature of nearly 15°, let the mixture stand until the solid matters settle, and then determine the glucose in an aliquot part of each liquid with the aid of the standard Fehling’s solution (§ 81). 10 ¢.c. of that solution corres- pond to 0.045 grm. of starch. The two liquids will con- tain equal quantities of glucose, produced from the malt ; therefore, the difference between the amounts of glucose found in the two, or the corresponding difference between the amounts of starch, will be the amount of starch in the substance analyzed. 2. a. By sulphuric acid.—Dry the substance thoroughly, and digest a quantity of it, supposed to contain about 2.5 grms. of starch, 2 hours on the water-bath, with 50 times its weight of a dilute sulphuric acid, containing 1°|, by volume of concentrated acid, then filter, and wash the residue on the filter carefully. This residue is composed mostly of cellulose. Dilute the filtrate and washings to 200 ¢.c., add about 16 ¢.c. of concentrated sulphurie acid, and digest again 7 or 8 hours on the water-bath, at 95°, or until a drop of the solution gives no blue color with a solution of iodine. If the solution is highly colored, add 20 c.c. of plumbic acetate, shake vigorously, make the volume of the liquid up to 500 ¢.c., let the mixture stand if it is necessary to clarify the solution, and determine the glucose in the clear supernatant liquid with the standard Fehling’s solution, 10 c.c. of which correspond to 0.045 grm., of starch (§ 81).. 79. STARCH. 111 The process of previous digestion with a more dilute acid separates the starch more completely from the cellu- lose, the former being converted into the soluble modifica- tion, while the latter remains unchanged. (Arocker.) b. Wolff's process.—Digest 2.5 to 4 grms. of the sub- stance with 100 c.c. of water, and 12 to 16 drops of con- centrated acid, 24 hours on the water-bath, then seal the liquid up in glass tubes and heat 12 hours in an oil-bath to 120° C., then dilute, decolorize with plumbic acetate, and so on as directed in a. 3. Dragendorff gives the following method for separat- ing and determining starch and the other matters with which it is usually associated. Pulverize about 2.5 grms. of the substance that has been dried at 100°, mix the powder with about 80 grms. of a solution of about 6 parts of potassic hydrate in 95 parts of absolute alcohol, and digest the mixture 24 hours at 100° C. in a sealed tube, or in a flask that can be closed air-tight ; filter the contents of the flask, while hot, through a dried and weighed filter, wash the residue thoroughly, first with hot absolute alcohol, then with cold alcohol of ordinary strength, and finally with distilled water, mixed with a little alcohol if gummy substances are present in notable quantity, dry the filter, first at 50°, and then at 100°, and weigh. The difference between this weight and that of the substance taken gives the amount of albuminoids, fat, sugar, and a part of the mineral salts. The insoluble residue, with the filter torn in shreds, 1s heated with water containing 5°|, of hydrochloric acid until a drop of the liquid gives no blue color with solution of iodine, the mixture is filtered. again through a dried and weighed filter, dried at 100°, and weighed. The sec- ond loss of weight gives the amount of starch; it was converted into dextrine by the acid and dissolved out; a very small quantity of mineral matters might pass into solution also, and, if great accuracy is required, the 112 § 80. BASES AND ACIDS WITH REAGENTS. amount of these can be determined by evaporating the solution of starch and inorganic salts to dryness, and in- cinerating the residue at a low red heat (§ 91). Or, the starch may be extracted with a concentrated solution of malt instead of with acid, in which case no in- organic salts will be taken into solution. Prepare the solution of malt and perform the operation as directed above. If much mucus is present, a concentrated solution of sodic chloride mixed with 5°|, of hydrochloric acid should be used instead of pure water and acid. GUM. 8. The gums, which abound in the juices of plants, are very soluble in water, forming thick, viscid solutions; they are insoluble in alcohol. Quantitative estimation.—This depends upon their in- solubility in alcohol. A quantity of from 500 to 1000 c.c. of the aqueous extract of the substance in which the gum is to be determined is evaporated almost to dryness on the water-bath, and the moist residue is digested with al- cohol of 80 to 85°|, until it is no longer colored by mat- ters taken into solution. Sugar is dissolved, while gum, albuminoids, and some inorganic salts, remain unaffected; collect the insoluble substance on a dried and weighed filter, dry at 100° C., and weigh. Then incinerate this residue at a low red heat (§ 91), and subtract from the total weight of the residue insoluble in alcohol, the sum of the weights of the ash just determined, and the albuminoids, which are deter- mined by another process (§ 85). The remainder may be considered as gum, mixed with some vegetable acids. GLUCOSE. GRAPE SUGAR. C,Hi2.0,H,0. 180 +18. 81, This sugar is soluble in water, and somewhat solu- ble in aqueous alcohol. § 81. GLUCOSE. 113 It is colored dark brown when heated with a strong so- lution of sodic hydrate. If triturated with cold concentrated sulphuric acid, it is dissolved without being blackened. If a concentrated solution of glucose is mixed with co- baltic nitrate and a small quantity of fused caustic soda, the solution remains clear on being boiled. If baric hydrate is added to an alcoholic solution of sugar, a white precipitate is formed. If a little caustic soda is added to a solution of glucose, and then, drop by drop, a dilute solution of cupric sul- phate, a deep blue liquid is formed; but after a few mo- ments a yellowish or red precipitate of hydrated cuprous oxide is separated. Cosas eee eee : a ane And so on, as in the statement of the analysis of the = |2>| 2°98) ~ solution ‘in cold acid, with the exception of Chlorine, = a 2oS8 1 and the addition of Silica, (dissolved out of the resi- iB a a due insoluble in hot acid, by boiling sodic carbon- 8 JE 2S | ate) et a = SEES . 15.24 & = ie bot a yemmataa matter expelled on ignition......... 1.82 he Ss ny S Limes; . oon oad. va kek 6 er 0.21 & Z F @ya | Maemesiajcd. 0). WSR bases nent ee 0.381 3 Cue 5 728 Ferric oxide .....i..00..0000s er 1.08 a Rs; & TS ot | AIUMIMA. . ooo. oe eee eens een oles ees ALAS aa tes = B22 S IPOH: .5.. sieseeds 65h ocecloee la ee 0.12 OS a. tee y Soda l fo.c. ce. een 0.20 S SH jive |S | Phosphoric acid... 2.1.01 aos» duis ao eee 0.15 Tl Gi) eS. 8S | Silica) insolution..- 7... -. 2222p eee 0.14 H og a ae ‘** (dissolved out of the residue insoluble OU ee tel. appro in H2SO4 by boiling NagCO3..... 4.56 2 js | 3 |F “10.30 a 5 re = {8 = Sob 40 ( Sime: v5.45... eee trace ar S) BR 2 Suns MaSOnesla. . 5. iesa coanev eu 6 sce peepee 2 B 4 A 10 GaSc Ferric 0xid@). 0... ..4..2ayecc enn 0.00 lens ls Oe Se | Alama. 3 oo) = 2110s ois 6.91 ot Begs etl) Seta F A POtRssA\y. ...00..---0> eh eee eee 3.20 5 = Sin @4"bpei S| SOd@s..0. 0.0.2.0: -+- +40 + +a 2.11 oe BS Silica, Coes. a0... 44.00 6 PT as 56.22 rf (ee Lae o-oo ll Sx 2 bsiay es aes ae eye. er ne § 107. THE PHYSICAL QUALITIES OF THE soIL. 191 100 parts of soil dried at 100° C. contain of clay Al,O3 2810.2, 2H.,0, estimated from the aluminaand silica dissolved by acids (See Table III). qt poaslivdrochloric Acid sOlutions. 2. 2002. bos oe eee ce eee 4.56 Gee SUL TIG: ACG SOLUTION . sos ne « fds sid bate leie, SMe dew dain bode 4.41 100 parts of soil dried at 100° contain of a. Potassa feldspar, K,O,8S8iO2, Al,O3,08i0O2, estimated from the potassa in the solution by hydrofluoric acid. (See Table IIL. ).18.94 b. Soda feldspar, Na,O,d8iO., Al,03,58i0O2, estimated from the sedaan the solution-by hydrofluoric acid 3225 esses see 17.85 ce. Clay, undecomposed by the previous treatment with sulphuric acid, estimated from the alumina in the solution by hydro- fluoric acid in excess of what is required for the feldspars.... 0.50 d. Pure quartz sand, estimated from the silica in excess over what ic required jor the feldspars: amd. Clay... k, to neutralize the total free acid in 10 c.c. of wine; this second remainder represents the quantity of acid that was removed from the wine by treatment with alcohol; for each cubic centimetre of this remainder calculate 0.1881 grm. of tartar. Griffin estimated tartar by evaporating 100-200 c.c. of the wine to dryness, incinerating the residue, determining potassic carbonate in the ash with the aid of the standard acid, and allowing one equivalent of tartar for every equivalent of potassic carbonate thus found in the ash. He estimated it also by adding 25 ¢.c. of aleohol and as much ether to 10 c.c. of wine, letting the mixture stand 24 hours, collecting the precipitate on a dried and weighed filter, drying it at 100° C., and weighing it; all but about 0.002 grm. of the tartar will be precipitated in this way. m. Total tartaric acid.—Evaporate 100 c.c. of the wine to about half its volume, precipitate the acid by lime- water in slight excess, filter the precipitate out, boil it with a solution of potassic carbonate, filter the liquid, evaporate the filtrate somewhat, acidify it with acetic acid, precipitate the potassic tartrate with considerable alcohol, and collect and treat the precipitate as directed in § 71. 2. Malic acid.—This is contained in the filtrate from the calcic tartrate in m. To determine it, evaporate this filtrate down to one-third, and precipitate the calcic malate with alcohol, as directed in § 783. As this precipitate will contain also the sulphuric acid, if any is present in the Wine examined, a determination of this acid should be made in a portion of the wine, in the usual manner ; then estimate the amount of calcic sulphate, CaSO,, 2H,O, in i § 142. wine. 283 the precipitate obtained as above with alcohol; the re- mainder, after subtracting this, may be reckoned as calcic malate, although it may contain a little succinate. The acetic acid, malic acid, and tartar, taken together, correspond very nearly to the amount of soda used in /, to determine the free acid, each equivalent of tartar neu- tralizing one equivalent of soda. o. Free sulphuric acid, if present in the wine under examination, may be detected and determined in the same manner as directed in § 188, 0. p. Total alkalies.—These may be estimated in the ash obtained in ¢c, or in the following manner. To the remaining. 30 c.c. of the filtrate from the pre- cipitate by alcohol in /, add 5 ¢.c. of an alcoholic solution of tartaric acid, whose strenvth is accurately known, let the mixture stand several days, and titrate 25 ¢.c. of the clear supernatant liquid with the standard sodic solution ; the rest of the potassa, not precipitated in /, and the soda, have crystallized out, with an equivalent quantity of the tartaric acid that was added; this quantity of acid will be represented by the difference between the amount of sodic solution used in this trial, and that which would be re- quired to neutralize the free acid already in the solution (see Z), plus the 5 c.c. of tartaric acid added. For each 2 c.c. of this difference estimate 0.0471 grm. of potassa and add it to the amount in the tartar obtained in J, The average composition of wine, according to Nessler, who examined a large number of European wines, is as follows: Alcohol, 7 — 10°|,; Sugar, 0.1 — 0.2°|,; Free acid, estimated as tartaric, 0.4 — 0.8°|,; Malic acid, 0 — 0.3°|,; Acetic acid, 0 — 0.3°|,; Tannic acid, 0.02 — 0.05°|,. Total dry substance in solution, 1.5 — 2°|.. 284 TABLES. TABLE I. THE METRIC SYSTEM OF WEIGHTS AND MEASURES. 3 MEASURES OF LENGTH. 1 Metre ite I PR ies Nitin naam ane Ry Metre. leDecimetre. =» Od rs See cs L@entimetre i; (O.0lveeeaeee eee we 1 Millimetre === O00 eee cee de 1 Metre a Ray Ge aie RAE PRA ere Inches iCentimetre sa) Soa imieeee ee ot eee Inch. 1 Foot == (OONAS ae eevee ene Centimetres. 1 Inch =e Bi el oA te nahn We Millimetres. The accompanying scales, copied from Professor H. A. Newton’s little pamphlet (The Metric System of Weights and Measures, with Tables. Prepared for the Smithsonian Institution), ex- hibit the relative magnitude of the divisions of the metre and inches. 9 te MEASURES OF VOLUME. 1 Cubie metre == 1000: tire eee Litres. 1 Cubic decimetre = IS Sgn oer fee Litre. 1 Cubie centimetre = O00 2 esc eee Litre. 1 Cubic centimetre = 0.06103..... Cubic Inch. 1 Litre == O S80 6G wee ob Quart. 1 Gallon (imperial) = AEBS Te Ses ee eos Litres 1 Gallon (wine) = Ab eae Ai a SS Litres 1 Hectolitre a O:0k ee tet eee eee Bushels 3. THE WEIGHTS OF THE METRIC SYSTEM. a I Kilosramme «= R000: 960 52's Grammes. a 1 Hectorramme = 400... ©. o5Se - peas 1 Decagramme SNES Re pt = 1 Gramme a 5 ans PE ee Gramme 1 Decigramme Dale ac orene es : 1 Centigramme OOM OLS Sh eee ie 1 Milligramme 0. ie x 1 Kilogramme 2046. P’ds (avoirdupois.) Ho MU hth a 1 Gramme = 0353. Ounce 1 ae GAS PSA ee Grairs. 1 Pound 3s a oe Grammes 1 Ounce io i ae SORE eS ae 1 Grain SES Soot Milligrammes, 4. ABBREVIATIONS. WGMUIICHI GS, winches cin va pyre ja vrebade's sieeO ers 6.5 vie ba scifi ee Cm. PRUMLCDT CS sree ors ale = wis «5.4 ein a sie yale, CF diosa sce Vs ces Te Mm. Obie Gentimeire o:.05 wees oa de weir ee vem es sas be ae he ee C.c. FEMOSTAMUME, £55 2 )sini005te o-< Seciae Rin bos 4m (0 3 ao ie Kilo AGETMATIG os. wiehe Bh iareie ee x aavere tars eevee wins + she, «dea 2 SBE Grm. Milligramme...... a sie \si’ule $ia. vie WPlpiniaialp « woe 60 »'s «site pee Mgr a ee | TABLES, 285 TABLE IL THE ATOMIC WEIGHTS OF THE ELEMENTS CONCERNED IN THE QUANTITATIVE PROCESSES DESCRIBED IN THIS BOOK. eens Alek ee tek Pico’; Mitromen:. Nae; a eaeree ees 14.0 oy Sy 2g] 7 eee co SO! Oxyorny ON). 2 er ee 16.0 BRS TITINS OTT Ps. ais kas oe actors ale va 40.0’ Phos phorass Ps. ads. ccpate c 31.0 SUC e Clean ey 120i) Plats Piss yn set eaaets 197.1: Ss Sal a Soid)| Potassinm« Koy .52.250% 40.8208 39.1 Oc ToAe BE ae ee Gai SLLLCON s lcs,. orca were Scares oes ren 28.0 PRIME Fries ob s< 2a ciste aw bit See ws DOIG SAL Ver eA sii oon a cinsiein oe ae 108.0 muponesivm, Me... oeciia cee 24.0) :Sodinm> Nas .scists ts eicgeee 23.0 Mancanede: Mnie.. iseceaees Boh! SalPMME oes senses vee ee ie 32.0 TABLE ITI. FACTORS FOR ESTIMATING THE SUBSTANCE SOUGHT FROM THE COMPOUND OBTAINED. Compound obtained. SANs Oo sec ate Ammonia... 2... Ammonio -platin- ic chloride Ammonio -platin- ic chloride..... Ammonio -platin- ic chloride..... Argentie chloride Argenticsulphide seers Baric sulphate... ‘a9 ‘79 Calcic carbonate. Calecie malate..,. (79 66 Calcie sulphate... Carbonic acid.... 4c (74 6 “a Formula. Al,O3 NH; (NH,)PtCle |(NH,)2PtCle (NH,4)ePtCl, AgCl AgS BaSO, ee CaCO, 66 6c CaC,H,0; CaSO, CO. i 66 | Substance soucht. Nitrogen eevee eceeoe AMMTONIDs . 2-6 < Ammonie oxide. Nitrogen Chlorine Sulphur Sulphuricanhy- } dride eee eeecece SES ecco nee Calcium Calcic (lime) fvacaes Caleic sulphate CeGVSis) cs cee « Malic acid Malic anhydride. Calcie. (lime) Caleic Carbonate. seer eree Calcie hydrate.. | Humus ewer eeoreee Formula. Al,Os. 28102 20 w NH; (NH,).0 C20 CaSO,,2H.O H.C,H,0; CHi04 CaO CaCO; CaH.0, lacie 2.5150 0.8235 0.0762 0.1165 0.0628 0.2474 0.1481 0.8455 0.1873 0.4009 0.5609 )1.7200 0.7791 0.6744 0.4118 2.2730 1.6820 0.4702 286 Compound obtained. Ferric oxide oo 66 Ferric ph osphate. ce oe Ferrous oxide... oe 6b Glucosears za, .4 a9 Lactic anhydride. Magnesic pyro- phosphate Magnesie pyr phosphate..... Magnesic pyro- phosphate:..:; Manganous man- ganic oxide.... Manganous man- ganic oxide.... INIEEOUEI cdi cae “eo eeeee Qride ea a 6b Potassie chloride. oe (79 Potassie oxide (potassa)<=:... Potassic sulphate ce oe Potassic tartrate. <9 b Potassio - platinic Chloride... ss Potassio - platinic ehloridé,, “ages Potassio - platinic ehloride.... a. 2 Sodie chloride... (<5 66 (a9 Sodic oxide(soda), Sodic sulphate... (7 6 Sulphuric anh y- dride TABLES. TABLE III.—( Continaed.) Formula. Fe,O3 FesP303 (4 ‘FeO a9 Ci2Hs10i2 | C,H 1005 Mg»P.0, MgeP.0, Me.P.0, ‘Mn;0, ‘Mn,0, KHC,H,0, ce K.PtCl, K,PtCl, K.PiCl, NaCl iad Na,O Na.SO, SO; H,.0,H,0, | | Substance sought. Ferrous oxide... Phosphoric an- hydride, . 2%: Ferric oxide see ee ewe se etes eeeee Stareh ey Magnesic oxide.. Phosphoric anhy- Formula. FeO Fe Fe Fe.03 Fe . CyoH 2011 CoH 90, 0 H2CeH 10. MgO AVIdeE o3 ccna P.O; Tricaleic phos- PHA: ose Ca,Es0¢ Manganous oxide MnO Manganie oxide. Mn,O; Ammonia....... Hy Protein com- POURGSL 5 cas Tricaleic phos- phate. shal slaisisloieie CasP20% Ammonia. 43.2 NH; Potassium... 5 Potassiuin: ;. ~| Total” ||Sp area Sugar. dry sub-|| at |Sugar./drysub-|| at | Sugar. stance. |} 18° C stance. || 18° C. 73004. 42 70 4 A OS88<1 00200 =| ilies 1.060 | 13.75 750415 1225 a 040 9 ale a6 1.062 | 14.00 8.00 | 13/0 =||'1.042 | 11.50°1/18.0 -4| 12064." as 8.25 | 18.5 || 1.044 | 11.75 | 18.25 4! 1.066 | 14.50 C275 1014700) 120469 127007) 48.5 1.068 | 14.75 9300 | 14:5°|| 12048: | 12.25-| 18.75") 1-070, ta Ge 9250 «| 15709) 12050 | 12.502) 19200 OP | 25%). 4) 10521 12.75 419,225 10.00 | 16.0 || 1.054 | 13.00 | 19.50 10.26.) 1658 |) 1.056°}°13225° 7°19. 75 10.50 | 16.6 || 1.058 | 13.50 | 20.00 LO Tat V7 ON TABLE VIL. - Total dry sub- stance. 20.25 20.50 20.75 21.00 21.25 21.50 ESTIMATION OF STARCH AND TOTAL DRY SUBSTANCE IN POTATOES, BY THE SPECIFIC GRAVITY OF THE TUBER. np. Gr. Total ||Sp. Gr. Total ||Sp. Gr. at /Starch.|dry sub- at |Starch.|dry sub- at |Starch. 18°°C stance.|| 18° C stance. || 18° C. 1.060 | 9.54 | 16.96 || 1.082 | 14.50 | 22.07 || 1.106 | 20.18 1.062 | ‘9.98 | 17.41 || 1.084 | 14.96 | 22.54 |) 1.108 | 20.61 1.064 | 10.42 | 17.87 || 1.086 | 15.42 | 23.02 || 1.110 | 21.09 1.066 | 10.87 |-18.33 ||-£.088 | 1o<88 +) 23.50°7|) 2. bbe eee 1.068 | 11.32 | 18.79 || 1.090 | 16.35 | 23.98 || 1.114 | 22.05 1.070 | 11.77. | 19:26 "| 1.092 4.16.81 |-24.46°)| 1 AiG (eee ee 1.072 112.22 | 19.72 |) 1.094 | 17.28 | 24°94 71) 2 11S) seas 1.074 | 12.67 | 20.18 || 1.096 | 17.75 | 25.42 || 1.120 | 23.52 1.076 | 13:12 | 20.65 || 17098 | 18.23 | 25.91 || 1.122 \o2 or 1.078 | 18.58 | 21.13 |} 1.100 | 18.70 | 26.40 || 1.124 | 24.50 1.080 | 14.04 | 21.60 || 1.102 | 19.17 | 26.88 || 1.126 | 24.99 1.104 | 19.65 | 27.87 || 1.128 | 25.49 1.130 ' 25799 TABLE IX. HARDNESS OF WATER. | C.C. of | Hard- || C.C. of | Hard- || C.C. of | Hard- || C.C. of soap |ness or|| soap |ness or|| soap |ness or|| soap solution| Mgr. |\solution|] Mgr. |jsolution| Mer. |/solution used. CaO. used. CaO used. CaO used. 3.4 0.5 bse S20 26 .2 6.5 36 5.4 1 17.0 4.0 28.0 7.0 38 7.4 5 hea 18.9 4.5 29.8 fj) 40 9.4 2.0 20:3. -\-° S20 31.6 8.0 41 41.3 2.5 22.6 a wale 8.5 43 13.2 3.0 24.4 6.0 35.0 9.0 45 Total dry sub- stance. 27.86 28.36 28.86 29.35 29.85 30.35 30.85 31.36 31.86 32.36 32.87 33.98 33.90 Hard- ness or TABLES, 289 TABLE VII. PER CENT OF BUTTER IN MILK, BY VOGEL’S OPTICAL MILK TEST. C.C. of | |, of || C.C. of | |p of || C.C. of | lo of || C.C. of | %, of milk re-} butter. milk | butter. mill | butter. milk | butter. quired. used. used, used. 2.50 9.51 4.50 5.38 6.50 3.80 8.50 2.96 2.75 13 4.75 5.13 6.75 3.66 8.75 2.88 8.00 7.96 || 5.00 4.87 7.00 3.54 9.00 2.80 3.25 7.41 5.25 4.66 4.25 3.45 9.25 2.73 3.50 6.86 || 5.50 4.45 || 7.50 3.32 9.50 2.67 8.75 6.44 || 5.%5 4.26 vss 3.22 9.75 2.61 4.00 6.05 || 6.00 4.09 8.00 3.138 4.25 pote bi) 6.25%.-| 38.94 Sig, | - 3.0£.- || TABLE X. COMPOSITION OF AGRICULTURAL MATERIALS AND PROD- UCTS IN 1000 PARTS OF THE SUBSTANCE. From this Table the student may gain some idea of the chemical composition of the more important substances relating to agriculture; although since this composition varies so widely with varying circumstances, no great degree of precision can be claimed for statements of so general character, with whatever care they may be pre- pared, The extreme and the average composition are given; the latter is to be taken, however, as indicating not the real mean of all the reliable analyses of the substance that have been made, but rather as an approximation to the proportion of each clement or compound that is gen- erally found in the substance; in some cases the propor- tion of a component ranged too evenly from one limit to the other of the extremes to admit of estimating any average of this kind. Fuller details may in some cases be found in the admirably arranged tables at ime end of Prof. Johnson’s “ Wow Crops Grow.” 13 290 TABLES. TABLE X, - — cf, . oO as a ro) & o ms O1Se1-O) 3) 2) 4 O8. | eee eee = ff «fe ee = fa Qe |= A I mh cF wa Ashes, coal 22 14. 2.) 350. 52.) 437. (anthracite). 87. 57.| 80.) 430.) 180.) 545. 50.*| 23.| 15.) 380 80.| 500. Ashes, coal 15S. 0 0 10. bol ee 23.| 269. (bituminous). 147. Roel) eae 230.} 14.) 350.] 258.) 624 70.*| 30.| 10.| 293.| 60.| 4st. Ashes, peat. 20. Te) 10.) ORE aaO: 0| 10. 920. | 200.) 95. 580.| 160.) 1%0.| '%30:) %60. 70.* 8. 4. 2005) 20: 30. Ashes, wood. Dee) 25") + 20). 0 270 16. 6. 5. D3 2202 GOS! alae 500:| 245 80.| 60 tis.) 2 | 7 380.| 70. a9.| 32. 0 510 8 Bone ash. 2.5] 0.3 550 14. f 530. |10.6 Bone-black. | 30.| 58. W5.| 5. 42. 8s0 q q 430.| 9. 5.—10. 52: 40.| S00. 400.| 8.5 {fp 50. Bone meal. 4%.| 520. 260. 28° 167. | 680 q q | 360. |11.6 bee bts %5.| 600. 625-1 Ore 10. Cement (hy- ils 0 550.| 0 53,| -4.5.| 229% draulic). EP Siallatre 628. |22. 94.) 61. 260. He 6.3 602.|10.4 Todos 240. Cheese. 95 5) 520.) 67 6.(?) 380.) 43. | 2.5 eel (0).S 0.1_ (2)| 0 0 0 0|0 100.| 0 150. Clay. 330. Ooaatl wee 4 183. |40. 890. |250. 770. 130 19. 9. 20./10. 280.| 90. 480. (3)| 20. 3 5. 40.| 5. 10. Coprolites. 100. 58. i 460.|15. 20.—60. 50. 35. 360. 40. 30. Excrements, |565.| 11. | 0.77/0.26 |U0.009 1.4/1 0.43 | 16. solid(Herbiy).|906.| 58.7) 4.8 |1.9 |0.08 108% os 124 ->|> 20u4 R64 deed ee Lose lO O20D 4.6 | 2.5 1.0 21 Excrements, |708.| 22. | 2.5 |1.4 |0.18 B28 | a2e0 0.6...) 9129 solid (Man).|330.| 34. yA 12 R22) wSaG 2.4 800.| 28. ite 67 0.6 (eek oe Mask * In 1000 parts of the fuel.—{_ Possibly present.—(1) Fluorine 36 — 40, average 33; Fluorine, 0—50; average 30. K,O and Na,O usually 0.—(2) Mn, 0—0.3; K,O and Na,O mostly 0.—(8) 1 a ‘ r ne a el ts et ee ie ae ee ee een ce TABLES. 291 TABLE X.—[ Continued. lepta = (5) re et ae | os cs lg me ab Seca # BSS 3 &E| = on ay | & 5 w| 5 (zo IHelocln & bel Ashes, coal (an- 0 | thracite). tr. Ashes, coal 0. 0. (bituminous), 84 66 | 50. | 10 | Ashes, peat. 0. 0 0 0 370 80 306 65 50. | 30. 10. ri Ashes, wood. MeSr ils. 57 48. SS WS + 4 50. pie; Bone ash. 380. 14. tr. | 400 40. 390. 30. Bone-black. 100. 105). 5. | 40 380. | 27 32. | 300. 17. cf ch Bone meal. 180 ? 28. | 280. 60 Oe a q 220. jas. | Cement (hy- 0. draulic). 18.8 10.2 Cheese. 80. 100. 440 600. t + |—— a 11.5 240. 310. 3 | | | | | | | | | Coprolites. 7.6 | 30. ie 0 10.6 | 380. 67. traces}25. 9.0 | 230. 30. Excrements, 0.47| 2.2 2 DA SGa ISO (P10: solid (Herbiy). 1.58}. 5.5 ai + 9.0} 23.)110.} 110. | 18. 0.87 3.6. 4.7| 20.| 95.| 95. | 10. Excrements, 0.3 | 8.5 , solid (Man). 0.9 |10.9 t t tol: t ok t 0.6.| 9.9 4, | + Present.—{ Possibly presert. 292 o| 82 a om im | ad Flesh. 446.| 10. 590.| 3 524. 22. Fodder, dry, {118.| 24. graminacese. |180.{ 111. 1503] 2366: | Fodder, dry, |116.| 45. leguminose. |200.| 80. GOES 10) Fodder,green,} 690. 1(e graminacese, |S70.| 21. 445.) 18. Fodder,green,|740.| 10. leguminose. |850.| 20. 804:| 12. (1)|760. 2. Fruits. 880. 9: 820. 4. (2)/100.| 380 Guano, 200.) 400. ammoniacal, |——|——— 140.| 344. (3)| 10.) ‘780. Guano, 140.| 950. phosphatic. |—— 00.) S90. Gypsum. 188. 205 197 Limestone. 3. 21 Manure, fresh|660.| 34. farm-yard. LOR 20S: 680.| 58. Manure,rotted|750.| 0. farm-yard. (905 a8. OE FOR (4 13. Marl. 100. 30 * In the dry substance. and sand, 50—S50, TABLE X.—[ Continued. NaCl. “aw ee { Possibly present. (1) Free acid, esti- | mated as malic acid, 1.0—20.0; average 8.6.—(2) Oxalic acid, 58—S80; average 60. Uric acid present.—(3) Fluorine, traces. Sand 8—47—(4) Insoluble silicates — 298 TABLES, TABLE X.—[ Continued. = a: : a) 3 Sala jee <2 S - 3 Hera easy [eS ere S) a ce fe) . Comm — al n Ss ons n A |G oO |wul 5 |w eelde [2 mm bp S Flesh. 0 4.3 0.1 123. 210. 0.41 5.8 iy | RORG t |1%4. 397. 5.0 0.4 144. 299. ¥odder, dry, 3.3 TG 30./1'70.| 225. |12. graminaces, q 3.3 t |180.|400.| 514. |56. 3.4 | 4.1 enti) alta: 90. |260. 410. 28. Fodder, dry, £5 | 4.7% 0 OE9e eS Ps. le E/ESO. |) 150m as leguminose, 5.3 | 9.0 |0.081 Patel! peed 190.|}400.| 480. |55. oe a OF D- IRS sled 140.|}280.| 330. |80. Fodder, green, 0.2) | 1.3 0.3 | 0.4 EE SOs ie Sone nos graminaceze. Qe eee Ne ots 0.8 | 1.9 fF OGOR EOS | 2308 ite CEPA 025s |EIEO 30.} 90.} 129. |10. Fodder, green, 0.2 | 0.9 {0.007 0.3 | 0.2 22.) 30.[- 60. |4. leguminose. 2.2 | 2.0 [5.0 0.8 | 1.0 te | M22 160.1 140.192 0.8 | 1.4 025) | OE: 295) GOR etos 0% Fruits. 0.4 0.1 S22 | 29.| 14: 0.7 0.4 Sante 120. ———— || So sr 0.2 | 0.5 Net) Or2 5.0 | 49 64. Guano, 6U. 80. ammoniacal. 137. 170. ff: * | 00. 110. | Guano, 0 170. |0 0 0 tr ere phosphatic. 270. 420.5 15. 8 40. 6 340. |3.2 f 125 Gypsum. 418. tr 160. | 30. | | 140. Limestone. 0.3 | 0.03 310. 0.32 |0 are Ont, (L250 440. 1.76 |1.6 2.0°| os | 400. Manure, fresh IGOR | ae 0.6 {4.0 farm-yard. 3.0 | 3.0 feb BO! ieee le eels th ti + 2.0 | 2.8 0.8 |6.0 | Manure, rotted 1.2 | 3.4 0.2 farm-yard. 2.4 | 4.5 oh 1.6 |6.0 it 3.9 0.9 Marl. rea Ae: 30. (fe 15): 5 450. * Sugar.—t Present.—{ Possibly present. 294 TABLES. TABLE X.—[Coniénued. Sysa) o} [6]. lsd eee ae Gi on a a 3 ll S he La o — milas hs A Z ad oD = < ey oD} Milk. 860.] %. 875. 8.5 SHOEI Hees ie alee i Weir 1) |p Maz (4)| 4. 0 | 0 200. | 0 |———| 0 Phosphorite | 25. 12.6] 5.0 550. | 2.8 | 0.387—90. |66. (Apatite). —— | | —— | —— | | ——_ | |-_-—— — 15. 5.6] 3.0 449. | 1.8 50. Plants, cereal;|126. Rel wae O52 tra) Onda ates 0 0.3 grain. 148. 39.| 5.5) 1.0 3.4 |10. 2.2 0.6 | 12. 142. 20 | 4.6] 0.5 0:6 jo1e9 0.18 Plants, cereal:| 90. 40.| 4.9] 0 irs 2.3 | 0.4 02 | 18. straw. 22580 etob ||| AGG edo 15 7 |ebe0 “1256 2.11 | 34. 150. 45.| 6.0) 2.5 3.6 4 10m hear Plants, com- |100. 28 5.2) 0.9 Be 2.0 08 | 0.8 mercial. 300.) 198 | 54.1] 7.3 Teo ites -l20Sa Be UF ties (ops, tobac-|——|-———-| ——-| —- co, etc.) 220. 50.}| 15.0) 1.6 8. 3.0 1.74 Plants, 128. 17.| 6.3] 0.4 0.6 | 0.4 0 0.2 legume ; 148. 35.| 12.0] 6.0 q Ori | eek 0.48 | 0.4 seeds. —— —— —- 144. 2oe| POEs |e Leo ites) abet 0.15 | 0.3 Plants, 160. 30, |) 2 aaiotel 9.6:] 1.9 0.09 | 2.4 legume ; 190.} 584.} 25.9] 3.9 7 258 4.6 0.2 3.1 straw. — -——-|-—— -— | - — 150 50.| 18.9} 2.6 | | AS | BROS Oa ee 3.0 0.18 2.7 Potatoes ; TOO) os One eso NAO eeL > (Og2. | One | nae ann tubers. 300.| 46. 6.7%| 0.4 gq 0.4] 0.4 0.06 | 0.2 |7%5.| 10. 6.10.25 0.25] 0.35 0.05 Potatoes; 770 Tel 08% 6.1 | 2.6 0.5 tops. 820. 1GR S 2eeime) CT Bedi eek 8.5 7o7.| 14. 4.5 5.3 | 2.65 0.21. Root-crops; |754. Gs], 290.8 0.4 | 0.1 O.Qie |. s0nt roots. 920. 10.| 4.3] 2.0 q 0.9 | 0.7% 0.29 |. 0.38 é 875. Ss] v8.0] 160 0.%7 | 0.4 0.09 | 0.2 Root-crops; | 765 15, | 8.2) 025 1.7 | 0.4 0; 17h Oe tops. 920. 33.) 6.0] 6.0 q 8.6 | 3.3 0.28 |. 2.6 85 1s. FALE 4.8 | 1.3 0 26-| 1.0 (2)| 12 937 0 890. | > loins 0 0 : Salt. 63.) 983.) 2.3] + . (994. OMT Leos ar brs tr. | 53.0 34.) 963 22 Maps jet) a 8.0 4820 | ie a er Saltpetre ite 330. (Chili). 20. siael) oslsh. 10.} 980. 340. 1.0F/51 0 29.0 + Present.—{ Possibly present.—(1) Fluorine 0—49; average 28.—(2) N.O,, usually 0. TABLES. TABLE X.—[ Continued. m = 8 a & Spier a ce te Sl poipl oe oe SSIS SER E| os i o Gi (eo) A | ._ (S @ai\s SE Bape deo lias bepldsioclas ale Milk 24. Pa PP 68 83. |60. 0.1 | 1.9 ORT 38. 47.* 35. Phosphorite. 300.0 3. 0. (Apatite). tr. |460.0 43. 5.0 360.0 DAV Plants, cereal ; 0.1) 5.5) tr 0.4 | 0.18 [19. |526:|: %.| 500.) 5. grain, 0.5 | 10.0; 6.8 1.7 | 0.27 |42.5/270.|165.} %65.|70. 0.36 8.0 1.0 0.2— 20.0)120.| 60. ~ 640. Plants, cereal ; 0.9 1.4] 0 O29e en 1.%| 6./290.| 180.] 6. straw. mole aco O22 4.0 | 1.3 | 4.2/100.|550.| 455./25. TA | B25 2.0 3.0] 87.|460.} 300.]18. Plants, commer- | 0.8] 3.3) | 0 0.7 cial. (Hops, to- Kae he 930) Fi 4.8] 8.8 Te) oo" 48 bacco, etc.) — —— —|—_—— — — 2.0 Gal a24'| 1:8 672. Plants, legume ; 0 5.2] 0 0 0.2 200.) 37.| 270.)12. seeds. 2.5 |eBeli tr. 2.5 | 0.6 + |350./145.| 600./76. 1.3 | 8.0 2.4 | 0.5 250.| 97.} 400.82. Plants, legume ; Oa [sony Ont,| Zate (5s |) 48a 250s | aLOs LOE straw. 228 aw Galles T 2.2 | 8.1 18. |100./5380.} 400.|50. 2:0: (eros 1.5 | 4.5 | 9. | 80./390.| 800.]18. Potatoes; tubers.| 0.8 | 1.6 0.2 Si, 52) 235-120: 10:5 0.6 | 2.0) 0.94) + 3.0] 40.} 27.} 160.|8.0 0.45) 1.7 0.9 2.0} 18.] 10.| 190. |3.0_ Potatoes; tops. 0.6 | 0.6 0.5 | 0.4 O29." 220). OLS 0.6 | 0.% eteont tal F 0.75] 0.8 | 0.55] 0.55 | 5.5 Root-crops ; 0.3 0.5| 0.12 0 0.1 5. ioe 23.|0.8 roots. ich ach -2e6 4.4/2.5 + | 26.) 45.) 155./8.0 0.6 | 1.0) 0.67 3.9 | 0.38 ill lal. 85.1.0 Root-crops ; Hak [ORS 0.5 | 0.3 12) Gh. 21s ['3: tops. a0 230) Ff 1.4] 10. 8. | 38.} 34.) 129.|10. Terie |e 0.6 26: || 25. 60.| 6. Salt. 1.4 0 0.5 10.6 tr. 3.7 6.0. 1.9 Saltpetre ot. (Chili). 620. | 10. 596. 8.0. |170 * Sugar.—t Present.— Possibly present. 296 TABLES. TABLE X.—[ Continued. ° = ° fe) a a 5 x o Ss io) Sq jo) a o ian) jo) 2 ct cl ca 3s 3 = on a) iS) mied| M1 | oe | a | oO eee et ee (1) O22! abI3. al ae 0.00231) ir. Sen: 8 15. Soils. 990.| 28. |20.7 0.102 170. |14.0 }140. 110. t 950.| 4.0] 2.0 0.0485 | 5.0 | 3.0 | 50. | 30. | Sugar-beet. |800. 3 2.5| 0.15] 0.4 0.4 | 0.16 0.1 900. 62) 23825)" 053) | 0.9 q 0.7 | 0.21 0.2 815.| 3b |. 8201 022) 70% 0.5 | 0.2 | 0.12] 0.1 (2)| 94.| 576 159. | 0 0 Superphos- [223.| %28.| q 820. 122. 3.0 phate. ==> == 155.| 665. 230. | 1.0 } a (3)/860.| 17. | 6.0 | 2.0 0.31 Urine. 925 4. 0 OE AT 0.16 Herbivora. SS SS |= == si5.| 30. [18. | 8.0 4.2 (4)|934.| 10.3 | 1.7 | 1.0 | 3.6 |0 0 0 Urine. 970.| 14.5 | 5.0 | 3.0 | 8.0 0.9 0.33 |0.23 Man. ——|—_—_ —$— |—_— SS |S 948.| 13.5 | 2.5 | 2.0 | 6.0 0.26 |0.2 | ] Water, rain. 0 0 .0001 |0 0 a) 5) tr tr. J. 004 a pe eee ain 9.0014 (5) 0 0 0.00009]0.007|0.002]0 0 0°. 001 Water, river. 0.013) 0.024 0.005 {0.1 |0.082)0.007 |0.012 |0.013 y 0.001 |0.061/0.01 9.006 (6) 0) 0 0) 0.002]0 a) ‘) 0 Water, spring. 0.41 |0.58 9.0006 |0.23 |0.104)0.0128)).0045/9.14 | ‘Joie 4 ae + Present.—{ Possibly present.—(1) Mn, traces to 17; average 0.8. SiO, and insoluble silicates 240—930; average %70.—(2) Fe.O.3, usually traces. Sand and insoluble silicates 29—178; average 48. Soluble P.O; in older and foreign phos- Chlorine, usually 0.--(8) Hippuric acid, phates, 120; in recent American, 33. 1.8—60. Urea, 18—‘0; average 28.—(4) Urea, 23—33; averave 29. Uric acid, 0.5—1.1; average 1.—(5) Mn. 0—0.003.—(6) Al,03, NH, Fe.O3, P2O;, and NO; usually 0. MgO, K,0,Na.O, S03, COg, and Cl, rarely 0, Organic matter 0—0.07; average 0.03. TABLES. 297 TABLE X.—[ Continued. ~~ ial OT . 2 ‘ B w| oo ns) o o ro} a aL = 3 | ag q a ro) has rier br iss ce — a|lae|e |S |e! 8 |e esi8sezel a Soils. 0.070.001; 0.001, 0 0 0.5 ‘11.0 15.00 | 0.12 |220. 14. |50. ai 1.5 |1.0 | 0.03| 5 0.3 | 2 Suvar-beet. 0.18|0.37 | 0.3 6.| 10.| 66.| 6. 0.28/1.0 1.7 + # | + lh98) | Se aes 9? of Pee) |, a, | 0.2 |0.7 | 1.0] 0.1 s.| 13.| 100.| 8. Superphosphate. |121. |126. 0 3.9 314. [2838 | 59 7. 210. 170. 20. Urine. 0 Salts 0 4.4 Herbivora. 1.6 14.0 3.3 )26. 10.8 15. Urine. Or4- eG 2.0 G | Man. St Ae 5.0 18 P50 3.6. |14.5 Water, rain. 0 0. 0.0001 tr tr. |0.006 0.0005 | Water, river. 0.002 0.001 |0.0017 0 0.079 0.01 |0.08 0.089. 0.022 0.046 |0.01 Water, spring. 0 0 0 0) ) 0.5 |0.006|0.67 |0.97%0 0.560 0.2 * Sugar.—t Present. INDEX. Acctic acid, as reagent, S—estima- tion, 101—in vinegar, 268—oc- currence of, 145—reactions..... 101 AC CTOIVELED Sea Ue ee ie On setae ee 24 Acids ireessim “wine saee... cence 280 Albumen, 11%7—in milk............ 263 Albuminoids, see protein com- pounds. Alcohol as reagent, 10—estimation, 1 2G-——TM WATE 5. aa aioe tec heiee ere = 279 Alcoholometersi.iseneneenieceere 24 Alkalies, elimination by milk of lime, 157—by oxalic acid, 15S— estimation as chlorides, 53, 157 —as sulphates, 53—in gypsum, 238—in limestone, 209—in marl, 20%—in wine.......... BR Hee 283 Alumina, hydrated, in soil......... 186 Aluminium, elimination of, 153—es- timation of, 66—reactions...... 65 Ammonia, estimation of by distilla- tion with sodic hydrate and ti- tration, 57—by distillation and Nessler’s solution, 58—platinic chloride, 55—Schléssing’s proc- ess, 56—in beets, 260—in fodder, aqueous extract of, 254—in gua- no, 232—in manure of the farm-yard, 214—in soil, 183—in superphosphate, 285—in urine, 219= im Wael. sinrrereieceis Ce er 202 Ammonia, reactions of............. 54 Ammonic acetate as reagent, car- bonate chloride, fluoride, 10— hydrate molybdate, nitrate, oxa- late, sulphate, sulphide, 11— RAL GEAUC a2 clicis ote lerep potest deem cists 12 Ammonio-ferrous sulphate, as re- ACCU. ae eee es aoe e svete o cesiee 12 Ammonium, see ammonia. Analyses, calculation of............ 42 Analysis, qualitative, course of for acids, 180—for bases, 136—table BOE ss sess 00 Vis Sana Mears one eee 144 oe ee Analysis, quantitative, schemes for, 161—special methods for separa- TON ANS wah ceo, 146 Animal substances, ash of.......... 248 Aqua regia, a8: reagent. ©2222 eee 8 Argentic nitrate as reagent, 12— standard solution of............ 95 Arsenic, occurrence of, 145—reac- TLONSs «05 sheet ta eae eee Oo Artichokesn. 3.532 Geos eee eee 262 Ash analysis, preparation of ash for, 241—statement of results. ..247 Ash, elimination of carbon and car- bonicacidan:<2 4. ce eee ore 150 Ash of animal substances, 248-—of bone-black, 230—of bone-meal, 228—of coal, 248—of flour, 262— of fodder, aqueous extract, 253 —of green fodder, 251—of fuel, 249—of guano, 232—of manure of the farm-yard, 213, 216—of milk, 263— of peat, 243 — of plants, 241—of seeds, 262—of superphosphate, 235, 2386 — of urine, 218, 219—of wine, 278—of Ash of plants, carbonic acid, chlo- rine, 243—coal, sand and silica, 248 Ash of plants, Reichhardt’s method of preparing, for estimation of sulphur and chlorine........... 246 Ash rich in carbonates, 243—rich in BUCA |. .<\- :c\0/5 + eteaaisleintiealeeeeiee 244 ‘Ash. sulphurine. 2. poses 246 Ashes of fuel, carbonic acid, chlo- rine in, complete analysis of, POtASsaAUN ee ee eee eee ee 249 Baker @uanGs sc a. nese eee 284 Baric acetate as reagent, chloride hydrate, mitrate. 22 622 see eee 13 Barium, occurrence of, 145—reac- TODS .”, 5. . ashes eee eee ee 59 Bark, tanner’s, tannic acid, water in, 270 Beets (and turnips), ammonia in, ios , INDEX. 258—ash of, 258—crude cellulose in, fat, 258—nitric acid 260—ni- trogen, pectose, 258—starch 260 —sugar, 258—water...........-- 257 LOW IGEN 'S] 07 Oiloe dep Gn Re rece abe canbe 281 Bone-black, ash of, 280—calcic hy- drate in, carbonic acid, chlo- rine, nitrogen, phosphoric acid, CLG EE WRLC M eta See syste: A. sce gies 230 Bone-meal, ash of, 228, 229—fat in, fineness of division, gelatine in, 229—nitrogen, phosphoric acid, DEAS aaa eT eos ae es ack 228 Bunsen’s method of filtration...... 33 Butter (and cheese), casein in, fat, 267%—salt, 26S—water....... ... 267 Butter in milk, estimation of, 264, 266—by Vogel’s optical milk- RESbe oy oasis « Lepr esetcs © Seine’ 265 Calcic chloride as reagent, hydrate, MNOTIOE. SUPA. (32.62 =e. rer 14 Calcic hydrate in bone-black....... 230 Calcium, elimination of, 157—esti- mation of as carbonate by igni- tion of oxalate, 60--as lime by ignition of oxalate, 61—as oxa- late by titration of oxalic acid, 61—as oxalate in presence of phosphoric acid, 62—as sulphate by conversion of oxalate into sulphate, 62 — reactions, 60 — separation from magnesium.... 64 Calculation of analyses.... ........ 42 Carbon eliminated from residue left after incineration, 150—in urine.223 Carbonic acid, estimation of, 79— by Fresenius’s apparatus, 81— in ash left in the determination of volatile matter, 150—in ash of plants, 248, 244—in ashes of fuel, 249—in bone-black, 230— in gypsum, 238--in manure of the farm-yard, 213, 215—in marl, 206—in soils, 178--in urine, 218 —reactions of, 7)—separation ACOMMNGMIOTING S255 b05 4.5/5.0 .-\5 oa 83 Casein, 11S—in butter and cheese, DBT ao crops stare ore aie 263, 266 Cellulose, 108—in excrements of animals, 228—in fodder, 252, 256 —in seeds, etc., 262—in roots, Q5S—=TEAChOUS sacs csios eta oss: 108 299 Cement, hydraulic, analysis and VES AMOR Olas 2. 5 creo oie rescore nets 211 Cheese, (see also butter)............ 267 Chili saltpetre, adulterations detect- ed, 240—complete analysis of, 239—nitric acid in, 240—potash, soda, water in. . een Coo Chlorine, estimation of by gravime- tric process, 94—by volumetric process, 95—in ash of fuel, 249 —in ash of plants, 243, 244—-in bone-black, 230—in farm-yard manure, 215—in organic combi- nation, 152—in the plant, 245— in soil, 186--in urine, 220—reac- tions of, 94—separation from CALDOMICH ACI as sare aac teres gael 83 Citric acid, as reagent, S—-occur- rence of, 145—reactions........ 103 Clark’s method of determining hardness of water.............- 274 OF ae ee ne Oo etna tor oe 212 Coal (carbon) in ash of plants...... 243 CoalaAshe scorn ctso> «fain ois ateran = Seveie ste 250 Cobaltic nitrate as reagent......... 15 Cochineal’asreacentit2.% 202. --a.- 15 Copper, occurrence, 145—reactions. 73 Coprolites, complete analysis of— phosphoric acid in.... ......-. 231 Cupric acetate as reagent, sulphate, 15 Curcuma-paper. o. 2.22 ee ee 15 Cyanogen, occurrence, 146—reac- [NOMS Rabestoece copddsosdooude 97 Meeiccabon theta san esse er 40 Desiccation of substances.......... 147 Division of solutions in quantita- TLVCs ANALYSIS: an ee esas ete 40 Dragendorff’s process for estimat- TNOASTALC He ate m reteset is a -ie 111 Dung Of animals... 02. vss. 2.3 223 Bther as: reagent: 205% e226 ese = 15 Evaporation, 27—of solutions con- taining excess of ammonic salts, when the residue is to be ignit- CUS hate ea Ns aces adee taeda: e's 28 Hixcrements, SOldesoan. 22-75 - 223 Fat, 125—in beets, 25S—in bone- meal, 229—in butter, 267—in flour, 262—in fodder, 252—in milk, 264—in seeds............ 262 Fehling’s solution............-..++5 113 Ferric chloride as reagent, 15—ni- 300 INDEX. eatrate, (Oxides. asec: snseles Ge ame 5 VAMC eee cr ais «v2 se 209 Ferric oxide, elimination, 153—esti- mation, 67— hydrated, with aluminic hydrate in soil, 186— and other substances in farm- yard manure, 216—reactions, 66 —separation from phosphoric ACs: Se hsb haa Se eter 153 Ferrocyanogen, occurrence, 146— PEACTLONS!. acunlieee ae fee 98 Ferrous chloride as reagent, 16— Sulphide. sc 5 ne Aes Veen eee 16 Ferrous oxide in soil, ‘estimation, 1Si——reactions sews. Aae.-be ete 66 Fertilizers, 213--commercial, tariff of prices for valuation of...... 226 Fiber, see cellulose. IDLING hy. crevice eee eter er or Oe: Filters, incineration of, 38S—wash- ing of with dilute acid.......... 31 Filtration, 31—by Bunsen’s process, 33—by the wash-bottle arrange- me TG = aie he tite ett On Fleck’s method of determining hardnessiofpwater: ai... eel 276 Flour, (see also seeds)...........-.- 262 HIVOvNCAreAachlOns eee eee e eee 99 Fodder, aqueous extract of, estima- tion, 253—-ammonia in, eg of, 253—gum, nitric fed in, —-nitrogen, 254—sugar.......... 955 Fodder, dried, 251—ash, 251—cellu- lose in, fat, protein compounds, 252—starch, 257--water.........251 Fodder, green, ash of, water in, preparation of sample for analy- Siseuuppn ecco abhi canuosgousod 251 Gelatine in bone-meal.............- 229 Glucose, estimation, reactions...... 113 Graduated instruments, testing and USC [OL seieae See ee RRO ee Meee 40 Guano, ammoniacal (Peruvian), ash of, and ammonia in, 232—com- plete analysis of, 233—marks of a good article, 233—nitrogen in, 232—oxalic acid, 938 —phosphor- ic acid, etc., 232—solubility in water, 2338—uric acid in, 233— WALLET D1) sOrek Re eea ts See we 83s ae 232 Guano, phosphatic (Baker, etc.)... .284 Gum, estimation of, 112—in fodder, aqueous extract of, 255 —in Gypsum, alkalies in, and carbonic acid, 288—complete analysis of, 237—solubility in acid, water Heat, absorbent power of soil for, and conducting power, 197—re- taining power... 25: 2a. eeeeeee 198 Hippuric acid, estimation, reac- tions, separation from uric, 106 =in-urine. 3. Get eee 221 Hops, s eieumed of analysis of ash Of... Viei..tn) Ree 238 Humus in marl, 208—in soil........ 183 Hydric disodic phosphate as re- acent,).....)Siohes Ben eee 21 Ilydriodic acid, reactions of.... ... 98 Hydrochloric acid as reagent, S—es- timation, see chlorine — reac- tiONS.... 4:05, Ae eee 94 Hydrocyanic acid.2..... fees 97 Hydroferrocyanic acid......... ss 298 Hydrofinoric acidicg2-2-e.e8 989 Hydrogen as reagent, 16—in urinc, 223 Hydrosulphuric acid as reagent, 8— estimation, see sulphur—reac- tions icses-ie Ae Be 98 Ilygroscopic moisture, estimation..147 Ignition of precipttates, 388—of resi- dues containing excess of am- monic salts.:: 2i: :ageoee see 28 Incineration of filters, 88—to deter- mine organic matter........... 149 Indigo solution as reagent........ aly Iodine as reagent, 16—occurrence, 146—reactions..... Bo RELI Seis: Iron (see also ferric oxide), estima- tion by precipitation, 67 — by volumetric process with potas- sic permanganate, 67—by volu- metric process with sodic hypo- sulphite, %0— reactions, 66 — separation from alumina and phosphoricacid........ sis, 153 Tron turnings as reagent, 16—wire.. 16 Lactic acid, estimation, 105—occur- rence, 145—reactions:.......55. 104 Mactometer:.. cn... eee adeno eee .. 24 Lacto-protein in milk.............. 266 Lactose, 117—in milk... ........ +.266 Lead, occurrence, 146—reactions... %2 Lead-paper as reagent.......5....6. 16 INDEX. 301 Teevigation...................:.... 26 | Milk, albumenin, ash, casein, 263— Levyulose:. =... Seog bodice sian ae ee oe 115 fat, 264, 265—lacto-protein, etc., GAC EU CCL Sp. F 27 at aies aletice: die si aisretsisio c+ 209 266—protein compounds, 263— Lime in marl, 206—in water, 273-- reactions and estimation, see value for mortar lime, 210—for bydranlic Cement, ./5.. =....1o5211 Litmus-paper, blue and red........ 16 Magnesia (calcined) as reagent, 17 MASA ESTANMIR LUNG st h:s/-1.06 siale « 17 Magnesium, elimination from mix- ture of metals, etc., 157—esti- mation as pyrophosphate, 63— reactions, 62—separation from calcium as pyrophosphate, 64— by Sulphuric acid... ........:. = 6D Malic acid, estimation, 104—in wine, 282—occurrence, 145—re- 0100 oo oe a Shcisiete 104 Previt, As TEAC OM ts 055 ce: aslo 2 92% ee AlrG Manganese, climination from mix- ture of substances, 156—estima- tion, 7i—occurrence, 146—reac- PIGIATON CS ae AS Bales ee ae TL Manganic binoxide as reagent..... BEY Manures, commercial, general con- siderations, 224—nitrogen in, 225—phosphoric acid, 224—po- tassa, 225—statement of analy- sis, illustrated, 225—tariff of prices for valuation of.......... 226 Manure of the farm-yard, 213—am- monia in, 214—aqueous extract of, 214—ash, carbonic acid, 213 —insoluble part, 214, 216—nitro- gen, organic matter, 213—state- ment of analysis, illustrated, 217—sulphur, sulphuric acid in, 2i4—water......... eae Se ee 213 Marl, alkalies in, 207 — carbonic acid, 206—humus, 20S—lime and magnesia, 207—nitrogen, 208— phosphoric acid, 207—silt analy- sis of, 205—water..... ........-206 Manly burnedeesizipecks. ssi: Sb Hee 208 Meal (see also seeds)..............-262 Measurement of solutions. ........ 40 Mercuric nitrate as reagent, 17— standard solution of............122 Mercurous nitrate as reagent... . . 17 sugar (lactose) 266—Vogel’s op- tical test, 265—water........... 263 Milk of lime as reagent............ ile’ Nessler’s solution as reagent, 55— estimation of ammonia with... 53 Nitric acid as reagent, S—estima- tion of by fusion of nitrate with silica, 92—by insolubility of am- monic nitrate in alcohol, 93— by Schléssing’s process, 89—in beets 260— in Chili saltpetre, 240—in farm-yard manure, 215— in fodder aqueous extract, 255— TM SOU A iiz.d aoe HSS ye eee 185 IND iriciacid: reactions=. 5.4.0 00eeeee 88 Nitrogen in beets, 258—in bone- black, 230—in bone-meal, 228— in commercial manures, 225— in fodder, 252, 254—in guano, 232—in manure of the farm- yard, 213,215, 216—in marl, 20S— in soil, 173—in superphosphate, 250 == ULIICT ae ates oe ake 219 Nitro-hydrochloric acid, see aqua TEST AE Ml ete woes 23 ae Nitrousticid aniwaterssss scot eee 273 Organic matter, estimation by igni- tion in muffle, 149—ignition in platinum dish, 149—by titration with potassic permanganate, 151—in manure of the farm-yard, 213, 215—in soil, 188—in urine, 21S in wateres.tc saseeeseee 272 Oxalic acid as reagent, 9—estima- tion by conversion into carbon- ic acid, 101—by titration with potassic permanganate, 100—in guano, 233—reactions of, 99— standard solution of............ 50 Oxygen, preparation of............ MG Pea, as fodder plant, statement of analysisiot st. susedvaeen. y~ 25% Peatiasheshicis.cucktoe oggetemer sa. 200 Pectose dmupbects: te... 0 ameriesee 205 Pernvignspuano, aise «2. sictoaa aoe Phosphate, see superphosphate. ... Phosphaticspuanor. 2s o224/ 505s 23 Phosphoric acid, 88—climination by ammonic molybdate, 85, 157—by ferric chloride, sodic acetate, magnesia mixture, and citric acid, 159—by metallic tin, 155— in presence of large excess of ferric oxide, 160—when it alone is to be estimated, 159—estima- tion as magnesic pyrophosphate 84— by volumetric process, 86—in Done. -black, 280—in bone- meal, 228—in commercial ma- nures, 224—in coprolites, 281— in guano, 232—in marl, 207—in phosphorite, 231—in superphos- phate, insoluble, 286—soluble, 250—— I ELN Cee msee aoe eee = 2.222 Phosphoric acid, reactions of....... 83 Phosphorite, complete analysis of, 231—phosphoric acid in........ 2381 Phosphorus salt, as reagent....... 18 Piknomeferssce Jf) amie trees Sele 23 Plant ash, see ash of plants... Plant, chlorine in, 245, 246—sulphur- ic acid (ready formed), 245—to- talsulphurs occ... . 245, 246 Platinum crucibles, care of......... 40 Platinic chloride, as reagent........ 18 Plumbic acetate, as reagent, binox- ides Oxadle. ss Per) ae ee 18 Potash compounds, commercial... .239 Potassic acetate as reagent, 18—hi- sulphate, chromate, chlorate, dichromate, ferricyanide, ferro- cyanide, hydrate, iodide, per- manganate, 19—and sodic car- bonate, and sodic tartrate, sulphocyanate...steecent sasriue oe 20 Potassium, elimination from mix- ture of metals by milk of lime, 157— by oxalic acid, 158 — by platinic chloride, 159—from sili- cates, 76—estimation as chlor- ide, 45—as potassic platinic chloride, 46—sulphate, 46—by titration with standard acid, 47 —in ashes of fuel, 249—in Chili saltpetre, 239 — in commercial manures, 235—in water......... Ae Potassium, reactions, 44—separa- tion from sodium by indirect determination as chloride, 53— as sulphate, pened platinic Chloride: << ayn. sates tas enee. 252 INDEX. Potassium and sodium, conversion of mixed sulphates into chlor- Potatoes, dry substance in, soluble in water, protein compounds in, 261—starch, 262—water......... 261 Precip tatin =.= eee sidatl eee eae 29 Precipitates, ignition of, with filter, 388—after separation from filter, 38—transferring of to filter, 30— washing of, 32—weighing of.... 38 Protein compounds, estimation - 118—in fodder, 252—in milk, 26 —in potatoes, 261—in seeds, 3 —in wine, 278—reactions of....117 Qualitative analysis, course of...... 130 Quantitative analysis, schemes of...161 Quartz powdered, as reagent....... 20 Residues, ignition and weighing of, 38 Results of analyses, calculation of.. 42 Rocks, and products of their weath- CrINS. 64.445 1 1d 205 Saccharose, estimation, 116—reac- TIONS J sd eee i. scale Saccharometer...... oie WE 24 Salt, complete analysis of, 238-—esti- mation of in butter and cheese. .268 Saltpetre, Chili, see Chili saltpetre. Sand in ash of plants, 248—in soils, 182—separation of from silica.. 75 Schléssing’s process for estimating ammonia, 56—nitric acid........ 89 Seeds, ash, etc., dry substance solu- ble in water, in starch, water. . .262 Silica and sand in ashes............ 243 Silicates, fusion of with sodic and potassic carbonate, 76—solnution of, 74—treatment of with ammo- nic fluoride, 77—with hydrofiu- OTIC. ACId. 245.22 e see ee eee Fes sk Silicic acid,.estimations and reac- tions, 74—separation of from coal and from sand........ Hove Silt analysis of marl, 205—of soils, Dietrich’s method, 172—Noébel’s methode.i sine ae Sone 169 Silver refuse, to work over...:..... 12 Skin, powder of, as reagent... ose 118 Soda-lime as reagent............... 20 Soda, standard solution of.......... 50 Sodic acetate as reagent, 20—sodic and ammonic phosphate, 20—bi- ee ae ee ee ee ‘=... INDEX. 303 sulphite, carbonate, hyposul- phite phosphate, nitrate........ Pal Sodium, elimination of from sili- cates, 76—climination with milk of lime, 157 — with oxalic acid, 15S—estimation of as chloride, or as sulphate, 52—by indirect processes, 53—in Chili saltpetre, 239 Sodium, reactions, 51—separation ™ from potassium by indirect meth- od, as chloride or as sulphate, 53 —by platinic chloride........... 52 Sodium, sulphate of converted into PLOT Cee aI Toes cheep eh. gee 53 Soil, absolute weight of, 198—ab- sorptive power of for salts, 1SS— adliesive: power. of..2).5 22385 200 Soil analysis, experiments to be combined with, 200 — general considerations in regard to, 165 —preparation of sample for....166 Soil analysis, chemical part, prepa- ration of solutions for, 174— with carbonated water, 177— with cold hydrochloric acid, 174 —with hot hydrochloric acid, 179—with hydrofluoric acid, 181 —with phosphoric acid, 182— Soil analysis, mechanical part, 16S— silt process by Dictrich’s meth- od, 172—by Noébel’s method, 169 Soil analysis, physical part, in rela- tion to heat-absorbing power, 19%7—to heat-conducting power, » 197—to heat-retaining power, 198 —consistency, 199-—power of ab- sorbing water-vapor, 192 — of retaining liquid water, 193—of retaining water-vapor, 192—rate of evaporation of water from, 194 — readiness with which water moves downward in, 197 —readiness with which water moves upward, 196—readiness with which water percolates through,196—volume when com- pletely saturated with water, 199 —porosity, 199—specific gravity, | apparent and real, 198—tenacity,199 Soil analysis, statement of results pinsirateds: SF 5 22t. feecl eee 188 Soil, estimation of ammonia in, 188 —of carbonic acid, 173—chlo- rine, 186—ferrous oxide, 187— hydrated alumina and ferric ox- ide, 186—humus, 183—nitrogen, total in, 173 — nitric acid, 185 — organic matter, 183—sand, by phosphoric acid, 182 — sulphur, 1S6— waters nc..tesik eee: 173 Solutions 225 ses cen eee ee 25 Solutions, division and measure- MEN ENOLS AM sok sowle tia Aeroee he Be 40 Solutions standard, preparations of, 48, 55, 67, 70, 86, 95, 100, 1138, 122, LOTT QOGE fen i ca dole. tet setelsle oye 274 Solutions, estimation of solid mat- terin by simple evaporation on water-bath, 14S—after mixture with gypsum, 149—by evapora- tion in vaccuo on hot sand, 148 —to save ammonia that may be AVENE Olin ee casera ies ioers oe Meisels 148 Specific gravity of liquids, with the areometer,23—with the piknome- ter or specific-gravity bottle, 23— of soil apparent and real, 198— of solids by specific gravity of liquid of the same density, 25— if soluble in water, 25—by vol- ume of water displaced, 24—by weight of water displaced in piknometer, 24—of urine, 217— of wine, 278—of wool .......... 270 Starch, 109—estimation by conver- sion into sugar by malt, 109—by sulphuric acid, 110 — Dragen- dorft’s process,111—in beets, 260 —in fodder, 257—in potatoes, 262—in seeds, 262—reactions of,109 Starchipapers. de \ccs sciences es vee 21 Sugar (see also saccharose, glucose, etc.) estimation in beets, 258— in fodder, aqueous extract, 255 —milk, 266, 267—in wine....... 209 Sulphur, estimation in organic com- bination, 152—in manure of the farm-yard, 214—in plant, total, 245—in soil, 286—in urine, 223— REO HUONG - ine Golan p woobcdcoecor’ 9S Sulphuric acid as reagent, 9—elimi- nation of, 157—estimation, 78— in gypsum, 237—in manure of 304 the farm-yard, 214—in plant, 245 —in urine, 223—in vinegar, 268 —in wine, 283—reactions of, 78 —standard solution of.......... 48 Superphosphates, ammonia in 235— ash, 235—complete analysis of, 236—nitrogen in, 285—phosphor- ic acid, insoluble, 286—soluble, 235—water...2s...: Pee erin hiaiae 23 PADIES vac terde acne Natron citer et ene 2984 TAUHerS Datln ven see ese eae 270 Tannic acid, as reagent, 10—estima- tion, 107—in bark, 270—in wine, 280—occurrence, 145—reactions.102 Tin, as reagent, 21—use to elimi- nate phosphoriciacid..:......--- 155 MinmericuassredSenieee sete nee ere al Uranic acetate as reagent, 21—stand- ard esolution Olas cere aee rer 78 Urea as reagent, 22—estimation, 122 —in urine, 221—reactions....... 122 Uric acid, estimation, 105—in gnano, 235—in urine, 221—reactions, 105 —separation from hippuric..... 106 Urine, ammonia in, 219—ash of, 218, 219— carbon in, 223—carbonic acid, 218—chlorine, 220—dry sub- stance in solution, 218—hippuric acid, 221—hydrogen, 228—nitro- gen, 219—phosphoric acid, 222— sulphur and sulphuric acid, 228 —urea, 220—uric acid, 221— SPCCHICROTAvT hy mOlm se amos eee oly Valuation of manures.............. 226 Vinegar, acetic acid in, 268—free Sulphurievaerd ees cee. ste bisterc sete 268 Vogel’s optical milk test............ 265 Washine Wotiler. 4 occ csc eeee meee 33 Water distilled as reagent........-. 22 Water, hygroscopic, estimation of by simple desiccation on the water-bath, 147 — estimation when ammonia is present, 147— INDEX. estimation by simple ignition, 147— estimation of in bark, 270 —in beets, 257—in bone-black, 230—bone-meal, 228—butter and cheese,267—Chili saltpetre,239— fodder,251—green parts of plants, 241—eypsum, 287—guano, 232— marl, 206—milk, 263—potatocs, 261—roots, 241—salt, 288—seeds, 262—soil, 173—superphosphate, 234-—WOOlt 2 on. sac acer ee 270 Water, estimation of ammonia in, 272— of dry substance in solution in, 271—of hardness, Clark’s method,274—hardness byFleck’s method, 276—of lime in, 273—of nitric acid, 272—of nitrous acid, 273—organic matter, 272—the same by titration with potassic permanganate, 151—potassa in..272 Water, expulsion of from solutions, see evyaporation—relation of to soil in liquid form, 195—as va- Wine, alcohol in, 279—alkalies in, 288—ash of, 27S—average com- position of, 283—dry substance in solution, 278—free acids in, 280—gum and sugar, 279—malic acid, 282—protein compounds, Q78—specific gravity of, 278— sugar, 279—sulphuric acid free, 988—tannic acid, 280 — tartaric VCM:.456.%3.5 ee eee sina ROW Wolff's process for converting starch into SUGAal. sce: eee ee eee 111 Wool, estimation of ash of, 270—of effect of washing at the factory, 270—water in, 270—preparation of sample for examination..... 269 Zinc as reagent, 22— occurrence, 146—reactions...5.i/csaeaeeens Oe ADDENDA FROM PERIODICALS RECEIVED WHILE THE FOREGOING MATTER WAS IN PRESS. BUNSEN’S FILTRATION PROCESS; page 33. R. §. Dale (Chem. Neus, Eng., Hd. 20, 108) states, that more rapid filtration can be obtained by substituting platinum-wire gauze, for the foil in the funnel, without any more danger of tearing the paper; and the gauze funnel can be fitted in the glass one with sufficient accuracy, by means of a cone of wood turn- ed to the proper angle. Undoubtedly, this gauze funnel can be advan- tageously used in cases where the pressure on the liquid in the filter is much less than an atmosphere, as when the rarefaction of the air in the filtering flask is effected by means of the flow of water from one bottle to another. STANDARD ACID AND ALKALINE SOLUTIONS; page 48. Dr. Fleischer (Chem. News ; Am. Repr., 5, 83) gives some good reasons for preferring a standard hydrochloric acid, instead of sulphuric; it forms soluble salts with all the alkaline earths, is readily obtained pure, is estimable with great aceuracy by a standard solution of argentic nitrate as well as by an alkali, and its constancy is unimpeachable. The standard of the acid can be determined by means of a weighed amount of pure calcic carbonate, that has been slightly heated, or by the standard argentic so- lution. For a standard alkaline solution, ammonia has many advantages over soda; it is more easily obtained pure, and has so slight a tendency to absorb carbonic acid from the air, that no special provision need be made against it. As some neutral ammonice salts have a slight acid reaction when the solution is hot, the liquid to be tested should be cold. A solution con- taining half an equivalent of ammonia in the litre, is recommended. Both of these standard solutions should be kept in a cool place, free from dust. If the ammonic solution is exposed to hot summer weather, the bottle containing itshould be placed in cold water that is renewed every day; by exposure toa temperature above 25° C., the standard of the solution will be very slightly altered. ESTIMATION OF IRON BY THE PERMANGANATE PROCESS; page 67, M. Moyaux (Revue Universelle des Mines, etc., Chem. News, Am. Repr., 5, 179) states, that the use of ammonio-ferrous sulphate to determine the stand- 305 306 ADDENDA. ard of the permanganic solution is unsafe, for the reason that the com- position of the salt is not constant, and that, consequently, metallic iron or oxalic acid must be used. Fresenius also, gives the preference to the use of metallic iron as the most accurate, although perhaps less conyven- ient, method; he gives the following directions for executing the proc- ess. Weigh out about 0.2 grm. of the finest piano-forte wire, free from rust, and add to it in the long-necked flask (p. 68) 20 c.c. of dilute sul- phuric acid, and as much water, and proceed with the solution in the current of carbonic acid, and the subsequent titration, as directed in tlie case of the use of the ammonio-ferrous sulphate. Instead of F, 7 in the proportion on page 69, substitute F x 0.9973 this product is taken as the weight of pure iron in the weight F of iron used, since the purest wire contains about 0.5°|, of impurities. In the text (pp. 69, 154) the preference is gfven to a sulphuric-acid so- lution of the ferrous salt for titration rather than a solution in hydro- chlorie acid. In an appendix to his Quantitative Analyse, Fresenius states, that the titration of a hydrochloric-acid solution is unreliable unless con- ducted as follows. Make the volume of the solution up to a quarter of a litre, add 50 ¢.e. of this solution to a considerable quantity of water acidified with sulphuric acid, titrate this mixture with permanganate, add to it 50 ¢c.c. more of the ferrous solution, titrate again, and so on with athird and fourth portion of the same solution; finally use the last two results, the mean of which multiplied by five will give the amount of permanganic solution that should be required for the whole amount of the ferrous solution. THE PRECIPITATE OF AMMONIO-MAGNESIC PHOSPHATE, IN THE ESTI- MATION OF MAGNESIUM, PAGE 64, AND OF PHOSPHORIC ACID, PAGE 87. As the results of experiments by Kubel and by Kiesel (Fes. Zeitschrift 8, pp. 125, 164), itappears that the solubility of this precipitate in the jiquid in which the precipitation takes place, in the presencé of con- siderable ammonie chloride and a not too great excess of magnesie sul- phate, is very nearly compensated for by the minute quantity of basic magnesic sulphate, or of magnesia, that is precipitated at the same time; hence the correction for the imperfect insolubility of the precipitated phosphate seems to be unnecessary. ORGANIC MATTER IN WATER, page 272. R. Angus Smith, who is a strong andearnest champion for the permanganate process, in the ex- amination of water with respect to the presence of hurtful organic matter, uses a stronger solution than Kubel (see page 151). He adds 2 germs. of the salt to a litre of water, and gives the following directions for the titration: To not less than a litre of the water add a drop of this permanganate solution; stir the liquid well, and wait until the color disappears, and proceed in this manner as long as the color disappears quickly, say in a minute or two; generally, considerable permanency of color is obtained ~ ADDENDA, 307 in 10-15 minutes. Then add 3 germs. of sulphuric acid to the liquid and proceed to add more permanganate in tlhe same manner as before, According to Dr. Smith, the oxygen of the permanganate used before adding the acid, was taken up by products of putrefaction in solution in the water, such as sulphuretted hydrogen, and that required after the addition of the acid, was consumed by easily oxidizable organic (animal) matter; all matters that thus act speedily on the permanganate are the most harmful in « sanitary point of view. Aecording to this writer and to W. A. Miller also, the results obtained can be expressed more accurately, by giving instead of the number of cubic centimetres of permanganic solution used, the wnount of availa- ble oxygen therein—of which each eubic centimetre contains 0.005 grm. Dr. Smith estimates the nitrous acid in the water roughly, by di- luting a measured quantity of it until iodized starch paper (paper dipped in a solution of potassic iodide containing a little starch) is no longer colored blue by it, even after a contact of several minutes; this diluted solution then contains about one part of nitrous acid in 100,000 of water, and upon this basis the proportion in the water before dilution ean be estimated. (Chem. News Am. Repi. 5.141, Hay. Hd. 20.118). VALUABLE AND BEAUTIFUL WORK. HARRIS’ Insects Injurtous to Vegetation. BY THE LATE THADDEUS WILLIAM HARRIS, M.D. A New Edition, enlarged and improved, with additions from the author's manuscripts and original notes. fllustrated by engravings drawn from nature under the supervision of PROFESSOR AGASSIZ. Edited by CHARLES L. FLINT, Secretary of the Massachusetts State Board of Agriculture. CO WARE Nass CHAPTER i. INTRODUCTION.—Insects Defined—Brain and Nerves—Air-Pipes and Breath- ing-Holes— Heart and Blood—Metamorphoses or Transformations— Classification ; Orders and Groups. CHAPTER il. COLEOPTERA.—Beetles—Scarabeians—Ground-Beetles—Tree-Beetles—Cock- chafers—Flower, Stag, Spring, Timber, Capricorn, Leaf-mining, and Tor- toise Beetles—Chrysomelians—Cantharides. CHAPTER Ill. ORTHOPTERA.—Earwigs — Cockroaches - - Soothsayers — Walking-sticks or Spectres—Mole, Field, Climbing, and Wingless Crickets—Grasshoppers— Katydid—Locusts. CHAPTER IV. HEMIPTERA.—Bugs—Squash-Bug—Clinch-Bug—Plant Bugs—Hervest Flies— Tree-Hoppers—V ine-Hoppers—Plant-Lice—American Blight—Bark-Lice. CHAPTER V. LEPIDOPTERA.—Caterpillars*— Butterflies — Skippers — Hawk-Moths—Aize- rians or Boring Caterpillars—Moths—Cut-W orms—Span-W orms—Leaf- Rollers—Fruit, Bee, Corn, Clothes, and Feather-Winged Moths. CHAPTER VI. HYMENOPTERA.—Stingers and Piercers--Saw-Flies and Slugs—Elm, Fir, and Vine Saw-Fly — Rose-Bush and Pear-Tree Slugs — Horn-Tailed Wood-Wasps—-Gall-Flies—Barley Insect and Joint Worm. CHAPTER VII. DIPTERA.- Gnats and Flies—Maggots and their Transformations—Gall Gain essian, Wheat, and Radish Flies—Two-Winged Gall-Flies, ang Fruit-Flies. APPENDIX.—The Army Worm. Published in two beautiful editions; one plain, with steel engravings, 8vo, extra cloth, $4; the other in extra cloth, beveled boards, red edges, engrav- ings colored with great accuracy, $6. Sent post-paid on receipt of price. ORANGE JUDD & CO., 245 Broadway New-York (City 3477 ts eos pei a ig ne ae ane he oe is i - her fhe 4 2 4 rtbey i | es Lg -" Gb pwereaegreg ACEP Eel by + | Peleeed re ay yeteb tefl 4 YIoe fh . ae pale has as ead hig oe Cohan e a Ch L th! Un sted ral i ie fasceareteteett ranteiel pee eee R { c byt : ! . Hh ete ee tpl ¥ RTS sca a a Pe ee Pa hparucl , ean i f ; j ey ee. Ae peru ‘ : , bi peisrhts way bad eh 2 44 soe tet We he ‘ bi 2 Agawee hele nee i Bad t vt awe atte Gah OT a eee died Oe kere ait LET toe ‘ f vi an fs te Syke aun rer Lg uote ei pes Parra ary a i E ‘ ee rte Wat Ehyt Fe De ee Ea seh dedieded Staal Let fobs ’ ; i p Re paty aires peices Penbabg deh te VC wibite ra a CA ee gia aye ¥ ‘ eye f HA ee Re ea ; ete aH ble wri ‘ Cas aie t a ae Me! Pea PF ybe ' pipes ' ‘ alts Chg RSE 4 2 { ¥ t Grete Wet A ro? i) ’ ‘ tet beast Le TET herd ’ ; Wan vie i ns he ' “ HE Vbel Rat arephabeuley! g pebseatae rr , vor $ ys i Lib retldyer | em Pade hate Paar al Ah F A gai reir oe 5 agi , Fi i i Huber vest eine ata é arts < ; F ; K Sen cliveg apepet : Has baie real ; i seth ted £ ; Ne ub elie efit nea ee eee ae Fak at j ; ’ 1 . HEU hese fore ¢ ; 4 ’ wie pePerceined ' ' 1 Hy i L obits ? BH Ore ss ; Pr peeksait ' Capibetelet sohaye ts Oey Fer Eth elareye ts ioe ie ct CNV TA el oOebed Aeey Aan }H ae bf { Havel Beste rs Ket i Webi ds yee a vi 1 ¢ A LIBRARY OF CONGRESS rer eS iiminm | OO0er?h0r S449 ip # Pd Ah te trie hh hey Mig bd aR ott, Fe OF * : ¥ Hi Sata: Lett 4 rey bs ¥he ‘ H 4 4 y \ ' ) A Wey aya: : Sete ey thaetal ‘ } *' F Kacseeegeree: ‘ t f A . . Bit Fist bry abd 5h argue i \esg 4 § she : a HEH ting H r F f f ; } oh a3 abe H Wait 1 1 ‘3 ; ' $ wee arya! ' ah Cote j i peetren ett ae 4 Abt 4 $ abi usa Vay } i oat pepegewenss Selah ateer bent Y . f vit i F Tpepive pears fee Fes EL ea) } bebe f { i : } i S ana ier’ PY paees B UAE pk: fe ree ; bees} i j jE ate iy bee f rai i fat LY J IEF i \ f Tepeb sees ie it Laie we eer ' 5 | | a3 aie 4 4 Tey ieah ‘ \ : i ! naan Lita : iti ' ' iva qhae yd pee sbhad AA DBE Whe) H y 1 ' ; | ois wl ; ‘ i 1 \ ey ied Arete | 1 | ‘ie f { H “f t tPue| yy Ba 2 a oe | arret ' } ‘ f 3 } ern ‘ t ty 2A { 1 hate ah beyet i ante tae tata ea (egepetay ehihey i H i ' i i) hua ee gi i4 He ee ee ! yyy i ‘ ‘ tet j H { , Liadieyear bce ould at bapspeeehiryg Fit hepys eh ees eben 4 } H . ' ? henta aya tris ' H etree tarts ee aa) gh urea 5 out ‘ ' i H 7 4 WAS AIR babs Page aa Sana ek ot tle ; fegkes ' , ‘ epee ae eta te in] ipseee t t { Paeaca st! i l ee i H H ‘ , ; ‘ jdyeadbg oe! besepr' i adel ayeun La ee f } PAN St pete eeep bet Bey Hag ee pur yu ‘ ; ¢ Weasel aight rere ha ea 4 i ? Prati HE eee | j grea 4 baushee Ahura? F j beett gE PeRevEg? beget HOE a ks a { ied meUt hat ; ‘ i \ Uvysare Pabopls het ha ; ‘ j ‘ ! j ' PERSE Hy : ' NeChaT pie HEMEL CI 5 ba She OA eur H i ‘ iv! ! : ‘ ' Sie PA Ay oa DAE ye (3 hia ‘ Aare } i ? beged i jai peeeh Ly ta hiinute: t é UY, : i tiara pref ' 4 : Re usues “beh ‘ yt Wehner { $i ares Oh) t ‘ ee | ‘ : B lide pee e ed ’ { ceisheh ‘ a Ree OF ley yee bay Psa ¢ 4 { Pea { » Ls vie 1 ‘ . y We wadbiraae ey u 4 7 ‘ H bibnese ‘ : i Peel rugend ‘ i A rat; ree hey aled | hoa Retired vy r ‘ Ai pbk ray ch i Yh ee We bea f { H ‘ i { : yeu Fes Geicheur t H eee lee ‘ at ’ wt) ee bee Tea et eat ee i mata) Vaaiut | ' \ : 4 rpregutes GMAT Ube he RAUL oR , : pe) ea) ' ‘ i