1892. ] NEW YORK ACADEMY OF SCIENCES. a) 
fels, a rock, it being commonly found in granites, and not from feld, 
a field; and hence I write it thus, felspar.””. This assumption of 
Kirwan has been taken for fact by all English writers, and the cor- 
rupt form is in very general use. 
The point most commonly lacking is the reason for adopting the 
name. Where it is for some characteristic of the mineral the author 
often takes it for granted that it is as evident to others as to him- 
self. The name coracite, Le Conte, Amer. Jour. of Science, 2d 
Series, vol. iii, p. 117, is a case in point. Le Conte does not 
give any eek but it is the name of a pitch-black variety of 
uraninite, and is probably derived from xopag, a raven. A similar 
case is that of adinole; Beudaat’s Mineralogy, 1832, vol. ii, 
p. 126. No derivation is given, but it may easily be conjectured 
from the description that it is from déeos, compact. But there are 
other cases where there is nothing suggestive in the description, and 
even conjecture is at fault. Such conjectures if stated as such are 
of value, but to give them as facts, as has often been done, is cer- 
tainly a serious blunder, if not something worse. Yet this has 
often been done. In one of the large dictionaries we find the name 
acanticone derived as follows: From “ Greek dx7, point, dvi, against,» 
and xavos, cone.”” This is a mere guess. The name was given by 
d’Andrada, 1800, Journal de Physique, vol. ii, p. 240, in the form 
akanthicone, and is derived from dxav6i’s, a gold-finch, and xowa, 
powder, because the color of the powdered mineral is yellow. <A 
similar blunder is made with the name alvite, so called after one of 
its localities, Alve, Norway. In the dictionary it is derived from 
alvus, the belly. Another instance of a mistaken popular deriva- 
tion is that of coreite, an obsolete synonym of agalmatolite, from 
the name of the country Corea, probably because agalmatolite is 
from China, and Corea is close by. The name was given by Dela- 
métherie in 1795, and he derives it from yocpecos, of a swine, because 
of its greasy appearance. He at first calls it koireiite, but changed 
it to koreiite, and then to koreite, with ak, which has since been 
changed to ¢, giving the form resembling one derived from the name 
Corea. But the name ought to be choireiite, commencing with ch. 
Sometimes errors of the compositor have failed of correction, and 
the changed names have feund their way into later books as real 
ones. One of these is glorikite ; Dufrenoy’s Mineralogy, 1859, vol. 
ill, p. 326, which is an error for glinkite. Gibsonite, in the 1847 
edition of the same work, vol. iii, p. 761, is probably an error for 
gibbsite, but this is not so clear. Galadsite, galadstite, and galad- 
tite are all printer’s errors for galaktite. 
A curious case of this sort is seen in the various forms of the word 
didymite. It was announced by Schaufhautl in 1845 from &dipos, a 
twin, because it was thought to be a second silicate containing cal- 
cium carbonate as part of its composition. The form was by some 
blunder given as didrimite, but this was soon changed by the author 
himself to the correctly derived form, didymite, the original 7 being 
