320 
moisture of the air with separation of metallic silver; dry air 
does not decompose it. In the fused state it slightly corrodes 
yessels of platinum, and much more freely those of silver. The 
salt in a state of fusion with platinum electrodes conducts elec- 
tricity very freely, apparently with the facility of a metal, and 
without visible evolution of gas or corrosion of the anode; a silver 
anode was rapidly dissolved by it, and one of lignum-yits charcoal 
was gradually corroded. A saturated aqueous solution of the salt 
conducted freely with electrolysis, crystals of silver being deposited 
upon the cathode, and a black crust of peroxide of silver upon 
the anode ; no gas was evolved ; with d:/fe solutions gas was 
evolved from the anode. By electrolysis of anhydrous hydro- 
fluoric acid with silver electrodes, the anode was rapidly corroded. 
The electrical order of substances in the fused salt was as follows, 
the first-named being the most positive: silver, platinum, charcoal 
of lignum-vita, palladium, gold. In a dilute aqueous solution 
of the salt, the order found was: aluminium, magnesium, silicon, 
iridium, rhodium, and ‘carbon of lignum-vite, platinum, silver, 
palladium, tellurium, gold. ‘The chemical behaviour of the salt 
was also investigated. In many cases considerable destruction of 
the platinum yessels occurred, either in the experiments them- 
selves, or in the processes of cleaning the vessels from the 
products of the reactions. Hydrogen does not decompose the 
dry salt, even with the aid of sun-light, nor does a stream of that 
gas decompose an aqueous solution of the salt, but the dry salt 
is rapidly and perfectly decomposed by that gas at an incipient 
red heat, its metal being liberated. Nitrogen has no chemical 
effect upon the salt, even at a red heat, nor upon its aqueous 
solution. Dry ammonia gas is copiously absorbed by the dry 
salt. In one experiment the salt absorbed about 844 times its 
volume of the gas. The salt in a fused state is rapidly 
and perfectly decomposed by dry ammonia gas, and its silver 
set free. A saturated solution of the salt is also instantly 
and violently decomposed by strong aqueous ammonia. Oxygen 
has -no effect either upon the dry salt at 15° C., or at a 
red heat, nor upon its aqueous solution, Steam’ perfectly and 
rapidly decomposes the salt at an incipient red heat, setting free 
all its silver. No chemical change took place on passing either 
of the oxides of nitrogen over the salt ina state of fusion. By 
passing anhydrous hydrofluoric acid vapour over perfectly anhy- 
drous and previously fused fluoride of silver, at about 60° Fahr., 
distinct evidence of the existence of an acid salt was obtained. 
’ This acid salt is decomposed by aslight elevation of temperature. 
Numerous experiments were made to ascertain the behaviour of 
argentic fluoride in a state of fusion with chlorine, and great 
difficulties were encountered in consequence of the extremely 
corrosive action of the substances when brought together in a 
heated state. Vessels of glass, platinum, gold, charcoal, gas 
carbon, and purified graphite were employed. By heating the 
salt in chlorine, contained in closed vessels, formed partly of 
glass and partly of platinum, more or less corrosion of the glass 
took place ; the chlorine united with the platinum and fluoride of 
silver to form a double salt, and a vacuum was produced. By 
similarly heating it in yessels composed wholly of platinum, the 
same disappearance of chlorine, the same double salt, and a 
similar vacuum resulted. 
partly of gold, an analogous double salt, the same absorption of 
chlorine and production of rarefaction was produced. And by 
employing vessels partly composed of purifed graphite, a new 
compound of fluorine and carbon was obtained. 
‘“ Approximate determinations of the Heating Powers of 
Arcturus and a Lyre.” By E. J. Stone. —About twelve months 
ago the author began to make observations upon the heating- 
power of the stars. At the February meeting of the Royal 
Astronomical Society he first became aware of what Mr. Huggins 
had done upon this question: his arrangements, however, did 
not appear to the author to meet the difficulties. After some 
trials, he arranged his apparatus in the following novel manner : 
—He uses “wo fairs of plates of compounds of antimony and 
bismuth, The areas are about (0°075)* inches, and their dis- 
tance is about 0°25 inch. ‘The poles are joined over in opposite 
directions to the terminals of the pile and galyanometer. The 
whole pile is screwed into a tube of one of the negative eyepieces 
ofthe great equatorial. This completely shuts the pile up in the 
telescope-tube. A thick flannel bag is then wrapt over the eye- 
piece and terminals. The bag is prevented from actually touching 
the case of the pile, and is useful in preventing the irregular action 
of draughts upon the case of the pile and terminals. The wires 
are led from the terminals of the pile to the observatory library. 
The two faces of the pile are so nearly alike, that the currents which 
NATURE 
Also, by heating it in vessels composed | 
[| Fan. 20, 1870 
are generated by any equal heating of them are exceedingly 
feeble. The telescope is first directed so that the star falls 
between the two faces, and allowed to remain thus until the 
needle is nearly steady at the zero, The star is then placed 
alternately upon the two faces, and the corresponding readings 
of the galvonometer taken as soon as the needle appears to have 
taken up its position, which usually takes place in about ten 
minutes. The author next referred to the way in which he refers his 
results to those produced by independent sources of heat at 
known distances. The mean result of the observations on two 
nights iso°‘or98 F., as a measure of the heating effect of Arcturus 
in raising the temperature of the plate of antimony and bismuth 
when the heat is condensed by the object-glass of 12°75 inches. 
The direct effect without object-glass would be 0°‘000000685 I’. 
The author had not yet determined the coefficient of absorption. for 
the object-glass, but if it be provisionally taken at 2, the direct heat- 
ing effect of Arcturus =o”oco00127 F. The result may be 
otherwise slated as follows:—That the heat received from 
Arcturus is sensibly the same as that from the face of a Leslie 
cube containing boiling water at 383 yards. In the case of a 
Lyre the heating power is =0°70088 F. This result is so much 
smaller than those obtained from Arcturus, although the obser- 
vations of Arcturus were made under more unfavourable circum- 
stances, that the author cannot but regard it as a fact that the 
star Arcturus does give us more heat than a Lyre—a result 
probably due to the same cause which gives rise to the difference 
in colour between these stars, viz., the greater absorption of the 
red end of the spectrum in the case of a Lyrae than in the case of 
Arcturus. He mentioned that on June 25, 1869, he madea 
comparison between Arcturus and @ Lyra. The result gave for 
the heat received from Arcturus: to that from a Lyre :: 3:2; 
but on account of the observations of a Lyre having been inter- 
rupted by cloud, they were not, however, sufficiently numerous to 
eliminate mere errors of reading. From these observations the 
author concludes that Arcturus gives to us considerably more 
heat than a Lyre ; that the amount of heat received is diminished 
very rapidly as the amount of moisture in the air increases ; that _ 
nearly the whole heat is intercepted by the slightest cloud ; that - 
as first approximations, the heat from Arcturus, at an altitude of 
25°, at Greenwich, is about equal to that from the cube containing 
boiling water at a distance of 383 yards. The heat from a Lyrae 
at an altitude of 60° is about equal to that from the cube at a 
distance of 860 yards. The form given to the pile appears likely 
to be useful in many inquiries respecting differences of heating 
power. 
Ethnological Society, January 11.—Dr. Richard King in the 
chair. Col. Lane Fox read a note on the use of the mere or 
pattoo-pattoo of New Zealand, in which he showed that this 
weapon is used asa thrusting-instrument, and should not, there- 
fore, be referred to the type of the club. He regards it as having 
had its origin from the stone celt, since a series of transitional 
forms. may be traced connecting the two implements. The 
author's opinion on the use of the mere was supported by a 
letter from the Rey. J. W. Stack, of Kaiopoi, communicated to 
Dr. Hooker, C.B., in which the writer explained that the mere 
was always used for thrusting and not for striking.—A commu- 
nication was read from Dr. Haast, F.R.S., on some stone 
implements discovered in Bruce Bay, New Zealand. A polished 
stone chisel and a sharpening-stone were found by a party of 
miners in an auriferous ‘‘lead.” Advancing inland from the 
present shore of the bay, several distinct belts of land may be 
observed, each characterised by peculiar vegetation ; and it was 
in the fourth belt, at a distance of 525 feet from the present 
high-water mark that these implements were found. They 
are now deposited in the Canterbury Museum, N.Z. 
Although these polished implements are much more highly 
finished than are the roughly-chipped implements hitherto found 
in or near moa-ovens, the author does not venture to express an 
opinion on the relative antiquity of the two types: indeed, he 
considers it probable that they may have been used simultaneously 
by two races co-existing in the islands—the more highly-civilised 
using polished tools and dwelling near the coast, while the 
inhabitants of the interior retained the use of roughly-chipped 
implements, and followed the dinornis as it retreated inland. 
Mr. Bonwick referred to the great antiquity of these gold-bearing 
terrace-deposits.—At the same meeting Dr. Gustav Oppert read 
a paper on the Kitai or Kari-kitai. These are a small race of 
about 50,000 persons, dwelling near the Caspian Sea in the 
Russian province of Derbend, and in the Siberian district of 
Guldja, They are the descendants of a race which once ruled 
