2 BULLETIN 288, U. S. DEPARTMENT OF AGRICULTURE. 
phate, at least 2,000,000 tons or over 56 per cent of the total sulphuric 
acid produced was thus consumed. A large tonnage of acid is also 
consumed annually in the manufacture of ammonium sulphate, a 
by-product of the coking and gas industries, and also in the produc- 
tion of what are known to the fertilizer trade as “‘base goods,” con- 
sisting of acidulated hair, wool, HSE or other nitrogenous refuse 
of tne packing industry. 
TaBLe I.—Production of sulphuric acid in the United States for the years 1911, 1912, 
1913; my grades. 
Year and grades. Quantity. | Value. | Prices 
3 
1911: . Tons. Dollars. _ |- Dollars. 
Bon BANG 6422.2 ne 1s as ee ee elo it pane Ree eRe 1, 026, 896 5, 447, 958 5.31 
GOS Banmes 2 225: oP 3c PA ae eee ea eee eee 421,165 2, 624, 042 6. 23 
662 Baume. 2a) 575522) oe w ieee speek eon ees Satie ar 751, 541 9,176, 297 12.21 
QOthererades 224 uc ses eons ce aw es ate Sees ee ae ee eee 10, 728 121,575 11.33 
Rotaliand averages. as .555-= sesagescees coset Seecesesasce 2, 210, 330 17, 369, 872 7.86 
Rotalmreaticec!to/b0 7s aAUMeCa ke Aa ee eee eee 12,688,456 | 117,313,822 6.44 
1912: e it 
BO SEES RULING aro Seis ee Ses ee asc Ne re ta eee 1, 047, 488 5,378, 411 54a 
GOSH aUMIG Se Veen! See edie n: eke Ree EN an. ely earn eng yee ” 451, 172 2, 727, 764 6.05 
GGSgi aan 64s. Soe ou eee ee Ake ge nm She coe eg pee 774, 772 9, 360, 630 12. 08 
OtherisTadesss So eas Gao eis ae ee ree et ee 66, 166 871, 214 13.17 
Totaland average Les asset sass ss cee Ae ee ee eee 2,339, 593 18, 338.019 7. 34 
hotal reducedsto SOSsBauMe sen a4 eee eee 2 2,876,000 | 217,572, 837 | 6.11 
1913: re ae 
BOM AINE, 2 ec Me Res op eck in A a er oT REE 1, 643,318 9, 212.917 5.61 
GO°RBAITNG 222218 SOS S OEP i ee ee MPs eee eee 509, 929 3, 202, 528 6. 28 
66 BaumM@ ee rae eS SOs oes Sa eC e ee a eee eee 797,104 9, 282, 422 11.65 
Other erades ste este wicacise ns wala a ectsien’s sree te cine cee ae 63, 158 986, 659 15. 62 
Wotaland average. 0.5.0 1) Aa ee ee gee ere 3,013,509 |" 22,684, 526 7.53 
Total reduced to 50° Baum. :.........-.----2-ceeceeeee-e eee 3 3,538,980 | 3 22,366, 482 | 6.32 
1 Exclusive of acids of strength greater than 66° Baumé. 
2 Exclusive of electrolyte and acids of strength greater than 65° Baumé. 
3 Exclusive of 22,947 short tons of fuming acid, not convertible, valued at $318,044. 
METHODS OF MANUFACTURE. 
There are two general methods employed in the manufacture of 
sulphuric acid, namely the ‘‘contact process” and the ‘‘lead-cham- 
ber method.” It is not within the scope of this paper to discuss 
in detail the numerous modifications of these two methods, but 
classified lists of the patents on the subject, together with short 
abstracts thereof, are given at the end of this paper. 
THE CONTACT PROCESS. 
Briefly the contact process consists In passing a purified mixture 
of air and sulphur dioxide derived either from sulphur or burning 
pyrites over some catalytic agent heated to dull redness, thereby 
effecting the further oxidation of the sulphur dioxide. The result- 
-ing sulphur trioxide is then usually absorbed in sulphuric acid, pro- 
ducing a very concentrated product. 
