May 25, 1871] 
NATURE 
79 

_ respecting the extension of the Society’s sphere of action was laid 
before the meeting by the president; it was determined 
that the matter should be discussed at the Society’s next 
meeting. Prof. Maxwell asked for information as to the 
convention established among mathematicians with respect to 
_ the relation between the positive direction of motion along any 
_ axis, and the positive direction of rotation round it. In Sir W. 
- Hamilton’s Lectures on Quaternions the coordinate axes are 
drawn, x to South, y to West, and z upwards. The same system 
is adopted in Prof. Tait’s Quaternions, and in Listing’s Vor- 
studien zur Topologie. The positive directions of translation 
and of rotation are thus connected as in a left-handed screw or 
the tendril of the hop. On the other hand, in Thomson and 
Tait’s ‘‘ Natural Philosophy,” p. 234, the relations are defined 
with reference to a watch, and lead to the opposite system, sym- 
bolised by an ordinary or right-handed screw, or the tendril of 
the vine. If the actual rotation of the earth from west to east 
be taken positive, the direction of the earth’s axis from south to 
north is positive in this system. In pure mathematics little 
inconvenience is felt from this want of uniformity, but in 
astronomy, electro-magnetics, and all physical sciences, it is of 
the greatest importance that one or the other system should be 
specified and persevered in. The relation between the one 
system and the other is the same as that between an object and 
_ its reflected image, and the operation of passing from one to the 
other has been called by Listing Perversion. Sir W. Thomson 
and Dr, Hirst stated the arguments in favour of the right-handed 
system, derived from the motion of the earth and planets, and 
the convention that north is to be reckoned positive. The right- 
_ handed system, symbolised by a corkscrew or the tendril of the 
vine, was adopted by the society. 
Hairax, Nova Scoria 
Institute of Natural Science, March 13.—Mr. J. M. 
Jones, F.1..S., president, in the chair. D. J. B. Gilpin read a 
paper on the Mammalia of Nova Scotia, being the ninth part 
of a series on that subject delivered before the institute. The 
present paper included the common hare (Zefus americanus) and 
the cariboo (Raxgifer cariboo) or reindeer of the province. The 
author stated that whilst Newfoundland and the country around 
Hudson’s Bay were represented by the polar hare (Z. glacialis) 
which varied in colour even to pure white, and New England on 
the south by the wood hare (Z. sylvestris) which never varied, 
Nova Scotia had the American hare (Z. americanus) which 
varied to a soiled rusty-white, and which had been confounded 
with both the otherspecies. A specimen of this last species 
taken early in November, and which might be considered as in 
summer pelage, was sepia-brown with a yellow wash and coarse 
black hairs on the back, breast, belly, and inside the legs white, 
tips of ears black, and pads light rusty. One taken in December 
of the same year and which may be taken as a winter specimen, 
was soiled white with rusty streaks on the back and sides ; nose 
and circlet around the eyes rusty ; under parts, pure white ; a 
rusty streak on fore arm always, and often upon the thigh. 
The only parts which remained unchanged were the white of the 
belly, the black ear tips and the rusty pads, and that all the hair, 
both, summer and winter, had a lead coloured base. The 
change of colour takes place during the month of December, and 
is the result of the summer coat being shed and replaced by the 
winter one. The American hare abounds in the province, keeps 
close coyert, and is nocturnal. In concluding his remarks upon 
this the last of the list of rodents found in Nova Scotia, Dr. 
Gilpin stated that although the equator produced no arctic forms, 
yet we find equatorial forms side by side with boreal ones at 
the north; and that although the furryfoot of the lynx and 
ermine, and the feathery one of the day owl, the winter falcon, 
the ptarmigan, and grouse, are the true livery of the north, yet 
the shrews with satin coats and naked needle-like legs brave cold 
20° below zero, ana the red squirrel sports with naked palms 
on snow of similar temperature. Passing by the three orders 
Ldentata, Solidungula, and Pachydermata, one of which, Solidun- 
gula, was represented by the horse, an introduced species on 
Sable Island, and there allowed to assume the feral state, the 
author arrived at the Azmnantia, two genera of which only 
exist in Nova Scotia—the cariboo or reindeer (Ravgifer cariboo) 
and the moose (Aces americanus). He stated that the cariboo 
attain in Nova Scotias the enormous height of four feet ten 
inches ; that the horns differs in every individual, but agrees 
in certain typical marks, In summer they are in colour rich 
brown, with white necks and shoulders ; in winter, all soiled 
white ; legs brownish, with white fringe on he hoofs extending 

to the back hoofs. They are seen in droves of seven or eight 
usually, and now and then of a hundred, but are fast diminish- 
ing ; not, however, by the hand of man or teeth of wild beasts, 
but in that noiseless way wild creatures disappear as their range 
iscontracted by new settlements; the does producing fewer 
fawns, and the males becoming early barren. Nova Scotia is 
the most southern latitude in which the cariboo is found on the 
American continent, but there is a “permanent variety,” 
according to Richardson, one third the size of the southern form, 
with larger horns and no gall bladder, inhabiting the polar region. 
The President read a paper on the Diurnal Lepidoptera of 
Nova Scotia, being the second part of a series in process of 
delivery before the Institute. He remarked how visibly insect 
faunas differed according to the geological and botanical character 
of the districts visited by the entomologist, and more particularly 
alluded to the smaller size of certain insects inhabiting the ex- 
treme north-eastern portions of the American continent, com- 
pared with individuals of the same species taken farther south. 
This fact was first brought to his notice by the Rev. C. J. S. 
Bethune, secretary of the Entomological Society of Canada, 
three years ago, who while identifying a small collection of 
fleterocera taken in Nova Scotia, observed the smaller size of 
Nova Scotian forms when compared with those of Western 
Canada. Since that date the author has compared species of 
other orders with British types, and found a similar peculiarity, 
the British being largerthan the Nova Scotian. This specific 
change is probably owing to the difference existing in the 
botanical character of these separate districts, which is not 
far removed from each other; but he hopes to be able to 
pay a second and longer visit to the valley of Annapolis and 
the slopes of the North Mountain during the coming summer. 
VIENNA 
Imperial Academy of Sciences, March 9.—Several me- 
moirs were communicated, of which the titles only are given, 
namely, ‘“‘ On the conversion of formic acid into methylic alcohol,” 
by MM. A. Lieben and A. Rossi, of Turin; ‘‘ On the structure 
and development of the earliest plumage observed in the chicken,” 
by Dr. E. Pernitza; ‘‘ On the solution of algebraic equations of 
any degrees, even with complex co-efficients, by means of Gauss’s 
scheme for complex magnitudes,” by M. A. Raabe; and ‘‘On the 
heat equilibrium between polyatomic gaseous molecules,”’ by Prof. 
L. Boltzmann. ‘Two sealed papers were also deposited.—Dr. 
L. Fitzinger presented the sixth section of his critical revision 
of the family of the Bats (Vesfertiliones), embracing the genera 
Vespertilio and Myotis. —Prof. R. Maly communicated the results 
of some investigations made in the chemical laboratory of the 
medical faculty at Innsbruck, including an analysis of the fluid 
from an ovarian cyst, made by himself, with investigations of the 
constituents of its ash, by Prof. E. Hofmann ; a notice of Trom- 
mer’s sugar-reaction in the urine, and of a simple mode of pre- 
paring muriate of creatinine from that fluid, by himself; and re- 
searches upon the bodies containing sulphur in the urine, by 
Dr. W. Lobisch.—Prof. yon Hochstetter communicated some 
microscopic investigations on opals, by Dr. H. Behrens, in which 
the author states that most opals are mixtures of various minerals, 
including a colourless fundamental mass, containing (microscopi- 
cally discoverable) hydrophane, cacholong, quartz, hydrated and 
anhydrous oxide of iron, ferriferous silicates, metallic sulphurets 
and carbonates, and organic substances :—fire-opal, glass-opal, 
noble-opal, and hyalite are free from admixture, and the first 
two are structureless. The colours of the noble-opal are inter- 
ference-colours, caused by their lamellze, which, however, are not 
tabular crystals. The double refraction discoyered by Schultze 
in hyalite is caused by differences of elasticity such as occur in 
dextrin, amber, and compressed glass. The author also noticed 
the spheroidal structure which frequently occurs in opals.—A 
memoir on the circum-anal glands of man, by Dr. Gay, of 
Kasan, was presented by Prof. Briicke. The author describes 
these glands as having the greatest similarity to the large sudorific 
glands of the axillary cavity—Dr. Tschermak presented three 
memoirs, namely, an analysis of the meteoric iron from the 
desert of Atacama, by Prof. E. Ludwig, as a further demonstra- 
tion of its similarity to the meteoric iron of Jewell Hill ; a notice 
of the microscopic constitution of the Lavas of Aden, by M. 
J. Niedzwiedski, who distinguished three species of rocks :—an 
obsidian containing sanidine, a trachytic lava containing plagio- 
cuase and algite, and a felspathic basalt ; and a contribution of 
his own to the knowledge of salt-deposits, in which he refers 
especially to the deposit at Stassfurt, which consists of two stages 
(rock-salt and kieserite-carmallite), the upper of which appears te 
