22 =. H. Loughridge—Influence of Strength of Acid, ete. 
cause, in this case, still requires elucidation. Whether the 
maximum of action is exerted by acid of 17115, is niottial 
question of some interest, to be determined hereafter. 
The results of the ovestenees as to strength of acid are as 
shown in the following table 
Sp. Gr. of Acid. 
Ingredients. 
1°10 1115 1:160 
nsoluble Residue, -- ---- 71°88 70°53 14°15 
ares Silda: o. oce 11°38 12°30 9°42 
tash, 60 63 “48 
od de 09 35 
ime, “21 “27 23 
Favoebia; gris. co ost “45 “45 
ir. Ox. Manganese, -__-- 06 06 06 
rie Oride: 0 ie 5°15 5-11 5° 
! a, "84 8-09 6°22 
Sulphuric Acti; 2222.5: "02 02 02 
Volatile Matter, -.....-- 3°14 3°14 3°14 
00°02 100°69 99°29 
Amt. of gc — 24°00 27°02 22°27 
Amt. of Soluble Bases, 13°50 14°70 12°83 
Tt thus appears that in the strongest acid the amount of insol- 
uble residue is far greater than in either of the others, and that 
the difference lies chiefly in the soluble silica and alumina (i.e., 
clay), together with potash and lime. The ee ingredients 
seem to be indifferent as to the strength of the aci 
Between the acids of strength 1:10 and 1° 115 the difference 
is not so great, but the advantage is clearly with the latter, the 
amounts of silica, potash and alumina being greater, while the 
lime remains the same in bot 
As for the comparability of the analyses as affected by the 
probable variations of strength of acid, I remark that the acid 
used for distillation by Dr. Peter, as Dr. Hilgard informs me, 
was the “C. P.” of commerce, whose stren eth rarely much 
exceeds or falls below that of 1115; while “that used by us 
was usually the crude, diluted nearly to the same strength. 
The first and last portions coming over were habitually, I 
believe, rejected in either laboratory. Under these circum- 
stances, it “4 very improbable that poral of the extremes of 
sp. scussed ever actually oce |; especially as 
regards hs stronger acid, which being in small quantity, 
would always be mixed with the succeeding weaker distillates. 
It is therefore not poe that the percentage of potash or 
other important ingredients could have been so far underesti- 
mated in either of the series of analyses, as to seriously influ- 
— their comparability, either within themselves, or with each 
0} 
4 
