cent of lead) had been used, the silver coin would have contained 0° 
is the exclusive source of this impurity, for it is not at all improbable that 
a portion of the lead is derived from the leaden vats in which the reduc- 
tinct button of metallic gold was obtained in every instance, before the 
blowpipe, but the amount of gold varied to a considerable extent; it was 
abundant in the American and Spanish coin, less was observed in the 
English and Mexican, and but little in the French coin or in the American 
fine silver. Britel has remarked “that the process of separating lead and 
silver was we pe Sua in the ages of antiquity than is at pres- 
ent the case.” (Aa Ka u. Dechen’s Archiv. fiir Mineralogie, etc., 1844, 
hai 509), a in none "of the recorded analyses of ancient silver coins 
analysis—none of which are recorded—employed for separ ating lead from 
silver by other chemists, were less dehiate et those which the authors 
deseri t 
am 
metallurgists affords silver which is less strongly contaminated with lead, 
and is probably purer in other respects, than is produced by any other 
process of manufacture.—Proceedings of the American Academy, V, 52, 
Cambridge, Sept., 1860 
II. GEOLOGY. 
1. Botanical and Paleontological Report on the Geological State Sur- 
vey of Arkansas ; by Leo Lesquereux.—This is a separate issue of the 
Boiantext por diiin of A hove Geological Report of Arkansas, just pub- 
lished, from p. 297 t 9, large 8vo, with five good plates Hitega. 3 
hew species of fossil rants from the Coal formation and one of fossil-lea 
from the Tertiary. We regret that the separate title pata is not dated, 
rest and impo! P 
more thorough surveys under better aus joe especially as to what relates 
to the recent Botan: ny, and general distribution of the plants of Ar 
This part is introduced by the following we Ea 
Am. Jour. Sc1.—SEeconp Sexes, Vou. XXXI, No, 93.—May, 1861. 
56 
