1889.] Psychology. 529 
with iron pyrites and organic calcium carbonate, as to leave 
no doubt' that they have been produced by the action of these 
two substances upon each other. — Messrs. Clark and Catletf 
have discovered small quantities of platinum in a mass of sul- 
phide of nickel, iron and copper from the copper mines at 
Sudbury, Ontario. The principal sulphide in the mass is the 
rare mineral polydymite (NiFe^jSj. — Mallard'' has measured 
the index of refraction for yellow light in the rare mineral 
sellaite from the vicinity of Montiers, and finds e = 1.389 and 
to = 1.379. — Cruciform twins of tJienardite from Borax Lake, 
Cal., are stated by Mr. Ayres' to have Poo' as their twinning 
plane. — Jannash and Calb^ have analyzed a large number of 
specimens of tourmaline, and have reached the same conclu- 
sion with reference to the composition of the mineral as was 
reached by Riggs^ about a year ago. 
PSYCHOLOGY. 
The Sense of Smell in Dogs. — Under this title Dr. 
George J. Romanes read a paper at the meeting of the Lu- 
mean Society of London, December 16, 1886. After prelim- 
inary observations on the faculties of special sense generally, 
and in particular that of smell, as enormously developed in 
Carnivora and Ruminantia, the author related his own experi- 
ments with a setter bitch. His conclusions are that in the 
case of this animal she distinguished his trail from that of all 
others by the peculiar smell of his boots, and not by the 
peculiar smell of his feet. " No doubt the smell which she 
recognized as belonging distinctively to my trail, was com- 
municated to my boots by the exudations of my feet ; but 
these exudations required to be combined with shoe leather 
before they were recognized by her. Moreover, it may be in- 
ferred that if I had always been accustomed to hunt without 
boots or stockings she would have learned to associate with 
me a trail made by my bare feet. The experiments further 
show that although a few square millimetres of the surface of 
" Bull. d. L Soc. Franc. O. Min., xi., p. 295. 
2 Atner. Jour. Sci., May, 1889, p. 372. 
3 Bull, Soc. Franc, d. Min., xl., p. 302. 
« Amer. Jour. Science, March, 1889, p. 235. 
^ Ber. d. deutsch. Chem. Ges., 1889, p. 216. 
American Naturalist, 1888, p. 250. 
