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MFTAL EDGE. INC. 2007 PH 7.5 TO 9.5 RA.T. 
 
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 CHEMIST TO THE DEPARTMENT OF AGRICULTURE, 
 
 THE OFFICIAL CONTROL 
 
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 THE OFFICIALCOMTROL OF COMMERCIAL HAHURESIN SOUTH CAROLINA. 
 
 BY CHAELES U. SHEPAED, Jr., M. D., 
 
 Chemist to the Department of Agriculture. 
 
 The Department of Agriculture of the State of South Carolina pro- 
 tects the purchaser of commercial manures by compelling manufac- 
 turers of and dealers in these articles "to state what they sell and to 
 sell what they state." 
 
 It demands that a notification of the claimed amount of the essential 
 constituents of plant-food contained in each brand of commercial ferti- 
 lizer, of whatever nature, shall be forwarded to the Department, where 
 these returns are preserved for subsequent use ; and that every pack- 
 age of manure shall bear a plain statement of what it jnirports to con- 
 tain. Consequently there can be no excuse for a misunderstanding as 
 to the claims of the dealer in respect to the composition of the article 
 exposed or advertised for sale. He is allowed to make use of a gener- 
 ous margin in his figures ; which, however, must not exceed one-fourth 
 (}) of the lowest guaranteed amount. If the dealer knows, as the 
 result of chemical investigation, that his article contains (saj^) three 
 per centum of ammonia, he is able to almost absolutely protect him- 
 self against complaint and prosecution, in consequence of the accidental 
 deterioration or inferiority in respect to this ingredient, of any lot 
 which may fall vmder inspection, by limiting his guarantee to from 
 2.40 to^S.OO per cent, of ammonia. This margin is suificient to cover 
 differences in analytical results and such losses or short-comings as 
 may (in spite of i-easonable care) occur in the manufacture and hand- 
 ling of commercial manvires. But it is not advisable for the dealer to 
 state as his minimum guaranteed amount, the very highest figure which 
 he believes that he has reason to claim, or which he hopes may be 
 found in his article. The latter course is apt to give rise to consider- 
 able annoyance and loss, as it not infrequently happens that such ex- 
 aggerated claims are not confirmed by the results of an accurate 
 chemical investigation. 
 
 The security afforded the planter, that he actually receives what the 
 packages are claimed to contain, consists in a systematic inspection of 
 the various brands exposed for sale throughout the State, which takes 
 place at the depots of purchase, and not at the factories, by a regular and 
 responsible agent of the Dejiartment. This official draws his samples 
 in a prescribed and uniform manner, in accordance with directions 
 issued from the Department of Agriculture, and forwards them to- 
 gether with his re|3ort to the Commissioner for future use. 
 
 The samples are numbered by the Inspector, and these numbers 
 
 D. ox 
 
 7 1^0/ 
 
^ 767 
 
 {^ 
 
 '^ refer to the names of the brands as enumerated on his returns. They 
 are otherwise without name or mark, and consequently unrecogniz- 
 able except by those having access to the key in the possession of the 
 Commissioner of Agriculture. 
 
 Such samples as the Commissioner may select, are forwarded to the 
 Chemist of the Department for examination, with a specification of 
 the constituents to be determined, but without mention either of the 
 amounts which it is claimed that thej- contain or of the names of the 
 articles. They are known to the Chemist, simpl^:^ and solely, by the 
 numbers attached to them, and his instructions are to determine this 
 or that constituent. (Thus, he may receive sample No. "55," Avith 
 instructions to find the content of potential ammonia; or No. "90,'' 
 with directions to determine soluble, reduced and undecom]>osed phos- 
 phoric acid). 
 
 On the completion of his work, the Chemist reports to the Com- 
 missioner the results of his examination, and the .Department becomes, 
 thiis, apprised to what extent the investigation, by its Chemist, has 
 borne out the claims of the dealer. The chemical analyses of the vari- 
 ous brands inspected and examined by the authority of the Commis- 
 sioner of Agriculture, appear from time to time in the Bulletins of the 
 Department. 
 
 In almost all of the samples examined by the Chemist of the Depart- 
 ment, the investigation is directed to the determination of one or more, 
 or all of the following constituents : 
 
 A. — Phosphoric Acid. 
 1. Soluble in icater. 
 
 2. ^'' Reduced'^ or '■'■reverted.^' ^ 
 
 3. Undecomposed, i. e., insoluble in water and in the solvents which 
 are supposed to approximate to the action of the soil, hence, unavail- 
 able at the time of the chemical examination. 
 
 4. Total. 
 
 B. Potential Ammonia. 
 
 C. Potash. 
 
 With reference to the determination of soluble and iotal -plwsjjlioric 
 acid there is at present among chemists no material difference of 
 methods or results on the same samples; but difference in the time of 
 the examination may cause considerable variance in the results bv 
 reason of the "reversion" of some of the previously soluble phosphoric 
 acid. It is. hovever, in the estimation of the ^^reduced" or "reverted" 
 phosjjhoric acid, and consequently in that of the 'hmdecomposed" or. 
 as it is sometimes termed, the 'Hmolidile' phosphoric acid that the 
 greatest lack of uniformity appears; audit will be well to bear the fol- 
 lowing facts in mind : 
 
 1. That the object of the chemist is to detennine how much of the 
 
768 
 
 phosphoric acid which is insoluble in water, can be regarded as avail- 
 able plant-food at the time of Ms investigation. Obviously, he is unable 
 to ascertain how much of it may be available six months or a year 
 afterwards, more especially because he is ignorant of the intensity of 
 the various natural and artificial forces to which it may be subjected. 
 2. That practically it makes no difference whether such phosphoric 
 acid has actually undergone a reversion (or ])recipitation) from a pre- 
 viously soluble state, or is by reason of its physical condition or chem- 
 ical composition possessed of an equal solubility. The difficulty under 
 the circumstances, lies in the ]5reparation of a method for the deter- 
 mination of that part of the available phosj)ho7'ic acid which is insoluble 
 in water ; and as there are various conceptions as to what constitutes 
 such phosphoric acid, both yyhysicall}^ and chemically, there ensue dif- 
 ferences of method, and, consequently, discrepancies in the results ob- 
 tained by them. 
 
 Pending the solution of this important question, or at least until 
 more definite information has been obtained, the great majority, if not 
 all, of the American official chemists, who have especiallj' to examine 
 phosphatic manures, have signified their intention to conduct the esti- 
 mation of the ^'reduced" phosphoric acid on the plan adopted last j^ear 
 at the Washington conference, viz., the so-called neutral citrate of 
 ammonia method. 
 
 It may be added that the utmost interest exists among agricultural 
 chemists, both at home and abroad, on this question ; and that our know- 
 ledge cannot fail to be largely and speedily augmented by the multitxi- 
 dinous researches now l)eing prosecuted alike in the laboratory and 
 on the experimental field. Until further notice, therefore, " Reduced " 
 phosphoric acid, as returned by the Chemist of the Department, will, 
 mean that phos]dioric acid which, while it is insolvible in water, is 
 soluble in the neutral citrate of ammonia, under the conditions pre- 
 scribed by the Washington Convention of Agricultural Chemists. 
 
 ^^ Potential ammonia'' means the equivalent in ammonia (N Hg) of 
 all the nitrogen contained in the article examined, as determined hj 
 the absolute nitrogen method. This very expensive and somewhat tedi- 
 ous, but most reliable process for determining the total amount of 
 nitrogen, has been duiing the past year, and will continue to be, the 
 only one employed for the estimation of ammonia in the laboratorj^ of 
 the Chemist to the Department. For the estimation of the nitrogen 
 contained in many high-grade nitrogenous materials, such as dried 
 blood and meat, (which are extensively used in " ammoniating " phos- 
 phatic manures), it gives much more satisfactory results than any 
 modification of the soda-lime process ; and since the adoption of the 
 European practice of incorporating nitrate of soda in commercial fer- 
 tilizers, its use has become indispensable. 
 
769 
 
 " Potash " refers to the content of jjotassa (K^O) in the fertilizer 
 analysis, and is determined by a modification of Dr. J. Lawrence 
 Smith's method. 
 
 It should be distinctly understood that the Chemist of the Department 
 does not undertake to detei-mine the relative efficiency of the commer- 
 cial manures submitted to him. What the practical results of the 
 use of a particular fertilizer may be, is a question beyond the scope of 
 his usual methods, except so far as he can judge from the compari- 
 sion of his analytical results with the comjiosition of manures which 
 have proven successful under similar circumstances. It lies in the 
 function of the experimental station to settle th.Q agricultural value of 
 each manurial constituent, and it would redound to the benefit of 
 every planter to carefully test the applicability of several commercial 
 manures to his soils and ci'ops. 
 
 The Chemist of the Department simply reports the content of each 
 of the claimed constituents in the fertilizers sent to him for investiga- 
 tion. This information enables the Commissioner to determine 
 whether the dealer is delivering to his customers w^hat he adA'ertises 
 on the packages of the article. 
 
 The commercial value of the various inanures off'ered for sale in this 
 State, and analyzed by the Chemist of the Department, is, by direc- 
 tion of the Board of Agriculture, determined in conformity with the 
 price at which the several essential constituents can be purchased /or 
 cash in the city of Charleston. The valuations for this season will be 
 the following : 
 
 Soluhle Phosphoric acid 12? cents per pound. 
 
 Reverted or reduced acid 10 cents " " 
 
 Potential ammonia.. 25 cents " " 
 
 Pot2Lsh {Potassa) 6 cents " " 
 
 The Act establishing the Department of Agriculture fails to take 
 cognizance of undecomposed (i. e. unavailable) phosphoric acid ; conse- 
 quently whatever phosphoric acid is insoluble in water and neutral 
 titrate of ammonia, (Washington method,) does not enter into the calcu- 
 lation of the commercial value.In the ordinary ground phosphate it 
 is to-day worth about three cents per pound, and in the condition in 
 which it occurs in superphosphates (especially those containing ani- 
 moniacal matter or potash salts) or in the so-called phosphate 
 "dust" — which has been floated in air — it is worth at least four 
 cents per pound. 
 
 " Eeverted " or " reduced " phosphoric acid receives a lower valua- 
 tion than that which is soluble in water, because it costs less to produce 
 it, and entirely aside from the agricultural question whether it is 
 equally valuable. Ammoniating materials have so advanced in price 
 
' f iMniiiiiin 
 
 020 948 389 
 
 770 
 
 during the past few months as to justify a higher valuation than that 
 obtaining during the past season. 
 
 The phmter is thus enabled to compare the cost at which the con- 
 stituents of commercial manures can be procured for cash in the city 
 of Charleston, with the price demanded for the articles themselves. 
 The commercial value of a complete fertilizer is obtained by multiply- 
 ing the percentum of each essential constituent by 20 (the number ol 
 pounds to each percentum or 1-100 lbs of a short ton), and that re- 
 sult by its value per pound ; and subsequently adding together the 
 values of the several constituents. 
 
 Thus for a fertilizer containino; — 
 
 P. C. Value per lb 
 
 Soluble phosphoric acid....... 6 12^ cts. 
 
 Eeduced " ... 3 10 cts. 
 
 Potential ammonia..... 2J 26 cts. 
 
 Potash...... 2 6 cts. 
 
 The calculation lor valuation is — 
 
 Soluble phosphoric acid 6x20xl2^=$15 0( 
 
 Eeduced " 3x20x10 = 6 0(s 
 
 Potential ammonia... 2^x20x25= 12 5(: 
 
 Potash.......................... 2x20x6 = 2 4( 
 
 Total commercial value per ton $36 9( 
 
 The analytical work performed during the past year for the Depart 
 ment of Agriculture b}^ its Chemist, comprises : 
 
 Phosphates 4 
 
 Acid Phosphates 6 
 
 Acid phosphates with potash 9 
 
 Ammoniated superphosphates 14 
 
 Ammoniated superphosphates with potash..... 32 
 
 Potash salts • — • •• 2 
 
 Other analyses .- • 3 
 
 Total analyses........... .....70 
 
 Several papers on Agricultural Chemistry, embracing much analy 
 tical work, have been necessarily delayed in their publication by rea 
 son of the chemist's long detention at the Atlanta International Cottot 
 Exposition, where he had charge of the exhibit of the South Carolins; 
 Phosphate Industries. These papers will be prepared for publicatioi 
 at an early day. 
 
 Laboratory for Analitical Chemistry, 
 
 Charleston, November 18th, 1881,