REPORT OF THE CHEMIST OF THE DEPARTMENT OF AGRICULTURE. WASHINGTON, D. C., July 1, 1866. SIR: I have the honor to submit to you the following report of analyses made during the year, and the kind of work performed in the chemical laboratory of the department. 1. QUANTITATIVE ANALYSIS OF A MARLY SOIL FROM VIRGINIA. The juice was expressed with a hydraulic press. The method of determination employed was that by Fehling's copper test, a short description of which will be appended to the analysis. The proportion of sugar in beets varies. First, it is greater in some varieties than others; second, it is greater in small than in large beets; third, in dry climates, especially where the climate is dry after the roots have begun to swell; fourth, in light than in heavy soils; fifth, in the part above than that under ground; sixth, when the manure has not been directly applied to the crop. The physical characters which serve to show that a beet-root is of good quality are its being firm, brittle, emitting a creaking noise when cut, and being perfectly sound within; the degree of sweetness is also a good indication. The 45th degree of latitude appears to be the southern limit of the successful growth of beet, in reference to the extraction of sugar. (Ure.) The beets in question were sent by Gennet Brothers, of Chattsworth, Illinois. They yielded Dry residue... Cane sugar. Total.. 4.00 11.40 84.60 100.00 Fehling's method depends upon the property of grape-sugar, at an elevated temperature, and in the presence of an alkali to deprive oxide of copper of onehalf of its oxygen; thus converting it into sub-oxide, characterized by a brown. ish red color. The test liquid is prepared as follows: 34.45 grammes (a gramme is equal to *15.434 grains, English) of pure crystallized sulphate of copper are dissolved in about 200 cubic centimetres of distilled water. (A c. c. or cubic centimetre of pure water is in weight equal to one gramme or 15.434 grains, English, or a little over half a drachm fluid measure.) A concentrated aqueous solution of 173 grammes neutral tartrate of potassa and soda (Rochelle salts) is then prepared and mixed with 480 cubic centimetres of a solution of caustic soda having a specific gravity of 1.14. The copper solution is then poured into this alkaline liquid by small quantities at a time. The whole is finally diluted with distilled water until it measures 1 litre, (=1000 cubic centimetres,) at 17.5° Centigrade (63. 5° Fahrenheit.) Ten cubic centimetres of this clear violet blue copper liquor require exactly 0.05 grammes (or 0.77 grains, English) of sugar for its decomposition, or, which is the same, its discoloration. It will keep for a long time unchanged if the bottle is well stoppered. Suppose we fill a burette, graduated into cubic centimetres, with the sugary liquid to be tested, and add it gradually, drop by drop, to ten cubic centimetres of the blue test liquor till the latter has lost its color; what is wanting to make up the original measured quantity of the sweet juice corresponds to 0.05 grammes or 0.77 grains of sugar. The principle involved is this: One equivalent of glucose or grape-sugar is able to decompose ten equivalents of copper vitriol. The equivalent of glucose is 180 (its composition being C12 H12O12) Ten equivalents of copper vitriol 1247. The numbers 1247 and 180 are in proportion as 34.65 to 5. Hence one litre (to 1000 cubic centimetres) of copper liquor containing 34.65 grammes of copper vitriol would be decomposed by 5 grammes of sugar, or, as we take Too part to 10 cubic centimetres of it for our experiment, 5 centigrammes (or 50 milligrammes) of sugar represents the quantity necessary to reduce the copper liquor. To obtain accurate results very dilute solutions must be employed. Under no circumstances ought the sugar solution to contain more than one per cent. of sugar For example, we bring ten cubic centimetres of copper solution into a new porcelain dish, and after diluting it with forty to fifty cubic centimetres of distilled water, we heat over a spirit lamp nearly to boiling. From ten to twenty cubic centimetres of fresh juice are mixed with ten to twenty times their bulk of distilled water, and by the drop added to the copper liquor until complete reduction takes place, i. e., until the supernatant liquor is colorless. To reach this point accurately requires some practice; it is therefore advisable to remove the dish from the fire as soon as the precipitate (at first yellow) turns intensely red, and to suffer the same to settle, when the slightest blue tint of the clear liquid is strongly contrasted with the white walls of the porcelain dish. Should we still have our doubts whether to add more sugar liquid or not, we pour a little of the clear liquid into a test-tube, add a drop of juice and apply heat. If there is any undecomposed copper left, a red cloud appears. In that case the tube is emptied into the dish and more juice supplied. Still greater accuracy may be attained by the use of acidulated prussiate of potash, but as those who desire it will probably guide themselves by some more extended directions it will be omitted here. The result may be calculated as follows: Of course that quantity by volume of the sugar solution poured out of the burette into the copper solution *480 grains equals 1 ounce Troy. 5,760 grains equals 1 pound, Troy. +Chemists use the French decimal system in weights and measures as a ready means of simplifying calculations. which it decomposes, contains exactly 0.05 grammes, or 0.77 grains of sugar. Now it is evident that the less of sugar juice required, the greater will be the percentage of sugar, or, in other words, the amount of sugar stands in an inverse ratio to the volume of sugar liquor consumed. If m (quantity sign) cubic centimetres of juice contain 0 05 grammes of sugar, how much do 100 cubic centimetres contain? Equation: m 100 :: 0.05 : x. x= 100 X 0.05 5 m m It follows, then, that we obtain the percentage of sugar in the juice analyzed, by dividing 5 by the number of cubic centimetres necessary for the complete reduction of the test copper liquor. If the juice was diluted, say with twenty times its volume of water, we have to divide 20 × 5 by the number of cubic centimetres used. Assume that ten cubic centimetres of original juice were required, and that this was likewise mixed with twenty times its bulk of water, then we have: These brief hints are designed to apply to the determination of cane-sugar alone, previously inverted into grape sugar. The simplicity of the process and the slight difficulty attendant upon the procuring of very correct results induced me to insert it for the benefit of manufacturers and others. 3. SUGAR FROM SORGHUM, OR CHINESE SUGAR-CANE. This cane is now generally raised by farmers for home consumption, especially in the western States. From carefully conducted analyses by Dr. Charles Wetherill and others, it appears that native sorghum stems contain usually from two to ten per cent. of cane-sugar, associated with more or less of glucose, which may be the result of the action of an acid inverting a portion or all of the cane-sugai Contrary to my expectations, I found that the expressed sorgho juice of ripe cane, whether neutralized by lime or not, refused to crystallize, for what solidified or granulated after long standing of the sirup was grape-sugar. This fact has been established by the largest and most skilful farmers and experimenters, and admitted at the western sorghum conventions. The result might be ascribed to the total inversion previously of the cane-sugar by the influence of acid, or of a ferment, but this is not the case, as I have repeatedly been able to prove. The following extreme case may suffice for illustration of this fact: In the sugar determination which is here given, cane-sugar was found, and yet the most persistent efforts failed to produce a single crystal in the concentrated liquid. Determination of cane-sugar and glucose in the sorghum juice.-The cane, somewhat dry, submitted to a pressure of about 10 tons, yielded in 100 parts 39.9 residue and 60 parts juice. Specific gravity of latter 1.0719. (1.) Determination of glucose.-The filtered juice was diluted 20 times with distilled water, and the burette filled. C. 10 cubic centimetres of copper tartrate were heated in a porcelain dish to 63° to 145° Fahrenheit,† and there was required for reduction— 1st trial, 27 cubic centimetres. 2d trial, 27.2 cubic centimetres. Mean 27.1 cubic centimetres. 5 x 20 = 100 27.1 3.69 per cent. The juice from unripe cane readily crystallizes. This temperature must never be exceeded, that the action of cane sugar upon the copper liquor may be prevented 3.69 × 100 100 cubic centimetres of juice weighs (having a specific gravity of 1.0719) 107.2 grammes; 107.2 grammes juice hence contain = 3.45 per cent. of sugar. Then, since the cane yielded 40 per cent. residue and 60 per cent. juice, the cane contained 3.45 X 100 60 =2.07 per cent. of glucose. (2.) Determination of cane-sugar.-Fifty cubic centimetres of juice were mixed with some 50 drops of sulphuric acid, and boiled for about one hour to convert the cane sugar into glucose. The liquid was carefully neutralized with carbonate of soda, and then, after being diluted 20 times, brought in contact with the boiling copper solution: 1st experiment, 4.8 cubic centimetres was required. Mean = 100 4.7 21.28 per cent. of glucose. The specific gravity of the sugary juice being 1.0719, 100 cubic centimetres sugar liquor weigh 107.2 grammes; hence one hundred cubic centime 21.28 X 100 tres of juice contain 107.2 19.85 per cent. of glucose. Again, since the cane furnished 40 per cent. residue, and 60 per cent. juice, the cane must originally contain 19.85 × 60 11.91 per cent. of glucose; deducting the quantity of glucose first obtained, 2.07, from 11.91, we have 9.84 per cent. of glucose, which, as 100 parts of glucose correspond to 95 parts cane-sugar, represents 10.31 per cent. of cane-sugar. A series of experiments was instituted soon after this determination, in the hope of removing the hindrance to crystallization. Although unable thus far to report any method which can be deemed practical, it was demonstrated that the basic acetate of lead, and several other metallic salts, will remove the medium member between sugar and gum which causes this hindrance. 4. ASSAY OF SILVER ORE FROM THE "ISAAC NEWTON LODE," UTAH TERRITORY. $70 78 This silver-bearing quartz was plentifully flecked with malachite, (carbonate of copper,) and yielded, upon assay, to the ton of 2,240 lbs.... Another specimen, evidently inferior to the first, gave.. 56 64 5. ANALYSIS OF SAND ROCK, IMPREGNATED WITH THICK AND LEUM, SAID TO COME FROM MECCA, OHIO. Calculated from the specific gravity of the oil, (.9,) compared with that of water,(1,) it follows that one ton (2,000 lbs.) of the above sand contains about 20 gallons of lubricating oil. A practical distillation gave the following results. One hundred parts by weight yielded— Oil... Coke. Quartz Loss.. 4.26 1.00 92.85 1.89 100.00 The oil obtained by distillation was also measured, and the amount contained in one ton of sand calculated. The result showed 11.28 gallons of oil. It will be perceived that by the process of distillation we sustain considerable loss, partly in the form of coke deposited in the retort, and partly by the decomposition of the heavy paraffine oils at a high temperature. Hence, it would appear advisable to procure the oil by an extractive process, such, for instance, as has recently been patented by H. P. Gengembre, of Pittsburg, Pennsylvania, using for that purpose the cheap light petroleum naphtha, which, after having dissolved out of the rock all the heavy oil, can be driven off, recondensed and used again. An analysis later made from a similar specimen from Leavenworth, Indiana, by this process, gave for this rock, by the ton, 39.4 gallons. 6. ANALYSIS OF CALIFORNIA WINE. This is in some respects a superior specimen of the California wines, containing but a trace of free sugar, and having evidently passed through all the stages of fermentation. Flavor good, though somewhat earthy, a peculiarity which can be removed by the improvement of the soil. Bouquet marked, showing complete fermentation. Color, reddish pale brown. It will be observed that the amount of extractive matters exceeds that of the majority of continental wines; a good property, since in well-cellared wines all the substances found in the extract add to their excellences. It contained Alcohol, by volume.... Alcohol, by weight. Acid, calculated as dry tartaric. Extract, at 212°, consisting of sugar, salts, coloring matter, non-volatile free acids, &c.... Free sugar.... a trace. 7. ANALYSIS OF A MAGNETIC IRON ORE, FROM WEST VIRGINIA. A. DETERMINATION OF OXALIC ACID AND MALIC ACID IN THE PETIOLES OF THE GARDEN RHUBARB (RHÈUM RHAPÓNTICUM.) The root yields tannin, gallic acid, malate, gallate and oxalate of lime, starch, sulphate, and muriate of iron, and extractive and coloring matter containing oxide of iron, &c., &c. DETERMINATION OF THE PHOSPHORIC ACID AND ALKALIES IN THREE SOILS FROM LAND OWNED BY W. D. SHEPHERD, ESQ., OF WASHINGTON, D. C., AND SAID TO BEAR NEITHER GRASSES NOR CLOVER. |