1883. | Botany. 873 
characters of some feldspars. More than 400 determinations of the 
optical constants of feldspars from numerous localities were 
made, including sixty-four varieties of oligoclase and ande- 
site and thirty-seven varieties of albite. Only mineralogists who 
have been engaged in this kind of work can appreciate the labor 
involved. The results will be of importance in showing how far 
feldspars can vary from the type form while preserving their iden- 
tity, and in distinguishing between such variations and the mix- 
ture or alternation of different species. Among the specimens 
examined is the moonstone from Mineral Hill, Penna., which is 
determined to be a peristerite, containing probably certain admix- 
tures of oligoclase. Some very beautiful transparent groups of 
apatite crystals have been found in the Untersulzbachthal, in Salz- 
burg. They have a white color with a delicate tint of mauve. 
The largest of the specimens, so far found, has been deposited in 
the South Kensington Museum. They are beautifully terminated 
by a number of planes, and have an unusual luster——The Ore- 
gon nickel ore is found in two varieties, which analysis has shown 
to be almost identical with the ores from New Caledonia—gar- 
nierite and noumeite. They also occur under precisely the same 
geological conditions. Garnierite has a pale apple-green color, 
adheres to the tongue, is not unctuous and falls to pieces in water. 
Noumeite is darker, does not adhere to the tongue, is unctuous, 
and does not fall to pieces in water. Noumeite contains more 
water than garnierite. 
BOTANY.’ 
and a few days later Mr. W. C. Stevenson’s Alphabetical Index 
to Centuries 1 to x. By means of the latter we are able to make 
sented .by but a single species. Under Helvellacee the genus 
Peziza is represented by sixty-eight species, while of Pyreno- 
mycetes there are of the principal genera as follows: Diatrype 
14 species, Dothidea 13, Hypoxylon 13, Hysterium 11, Nectria 
16, Sphzria 68, Valsa, 39. In the Uredinee, Æcidium has 14 
species, Phragmidium 4, Puccinia 19, Uromyces 15, and in Usti- 
l Edited by Pror. C. E. Bessey, Ames, Lowa. 
