Feb. 9, 1882 | 
NATURE 
355 
the reptilian animals are represented only by single specimens, 
there may have been still rarer forms, which may be disclosed 
should other productive trees be exposed by the gradual wasting 
of the cliff and reef.” 
Physical Society, Jan. 28.—Dr. Stone, in the chair.—New 
Member, Mr. W. Lant Carpenter.—Mr. T. Wrightson read 
a paper by himself and Pro’, W, Chandler Roberts, F.R.S., on 
the fluid density of metals. The results were obtained by the 
process described in a former paper to the Society, on the fluid 
density of bismuth. The mean results were for copper, 8°217 ; 
lead, 10°37 ; tin, 7°025 ; zinc, 6°487; silver, 9°51; iron (No. 4 
Foundry, Cleveland), 6°88. These results are slightly less than 
those given by Mallet’s process, but they are sufficiently close. 
For bismuth tne fluid density found by the authors is 10°055, 
which is slightly more than that given by Mallet’s method (9°82). 
The authors consider their method satisfactory. It consists in 
suspending a ball of the solid metal from a spiral spring, and 
allowing it to dip into a crucible of the same metal in a molten 
state. The movements of the spring as the ball melts are re- 
“corded by a pencil on a band of travelling paper.—Mr. C. 
Vernon Boys read a paper on apparatus for calculating efficiency. 
The object of such machines is to automatically divide and con- 
tinuously record the quotient of the speeds with which two 
things are turning. If the two things are the records of two 
of Boys’ integrating machines (previously described to the 
Society), one finding work put into, and the other work sent 
out from any combination of mechanism, then the quotient gives 
the efficiency of the combination. If one measures work or 
current, and the other time or turns of a machine, the quotient 
measures the value of horse-power per hour or current per turn. 
Mr. Boys described four machines of the kind acting on two prin- 
ciples, from which he names them logarithmic and harmonic 
dividers. They all derive their actions from motions of pure rolling 
The simplest is made by hanging a magnetised steel reel on to a pair 
ofiron cones, which are turned by integrators. The reel travels 
about and continuously shows the value of the quotient.—Mr, 
Boys then read a paper ona ve current meter. The rate of a 
pendulum clock depends on gravity, and is proportional to the 
_ square root of the strength of gravity. That of a watch depends 
dies 
on the strength of the hair-spring, and is proportional to the 
square root of its strength. The force due to an electric current 
is proportional to the square of the current strength. Hence if 
part of an electric circuit is capable of vibrating under electro- 
magnetic force, the speed of vibration will be proportional 
simply to the current strenzth, for the square of the speed 
measures the force, and the force is proportional to the square 
of the current. If, then, such a contrivance takes the place of 
the balance of a pendulum-clock, the clock will measure 
electric currents instead of time. To keep the indications 
true, the maintaining power must be so contrived that the 
amplitude does not vary much, or the parts must be so 
arranged that the force is directly proportional to the displace- 
ment. Mr. Boys showed several ways of producing a controlling 
power. The first was a combination of solenoids, one passing 
through the other, and in which the force was proportional to 
the displacement. Being without iron, it applies to the case 
of alternating currents. In another a small armature is 
mounted en the balance staff, and around it are the two poles of 
an electromagnet, which forms part of the circuit. In a third 
form, which is unaffected by residual magnetism, two crescent- 
shaped pieces of iron forming the sides of the balance pass through 
two fixed solenoids. In all these cases the direction of the current 
does not matter. * The maintaining power may be any ordinary 
escapement drawn in the usual way. It may also be independent 
of clockwork, an impulse being given to the balance electrically 
at each swing. A meter of this kind was shown in which the 
controlling power depends on iron crescents and solenoids, and 
in which a portion of the main current is shunted through 
secondary solenoids when the balance is in its neutral position ; 
at which timea variation in the currents in the controlling sole- 
noids has no effect in disturbing the period of oscillation. Such 
a meter is regulated by an adjustible weight, if it goes too fast or 
slow. Being independent of gravity it will work equally well 
anywhere. Prof. John Perry thought Mr, Boys’ devices very 
promising, and mentioned that Prof. Ayr on and he had invented 
a very simple current meter not yet described. Dr. Coffin 
pointed out that electric clocks of a certain class were really 
current meters. Prof. Guthrie remarked that in Mr. Boys’ 
meter practically no work was taken from the current. Refer- 
ence was made by Dr, Stone and Mr, Lecky to Hipps’ clocks, 
the latter testifying to their efficiency.—Capt. Abney, R.E., 
then exhibited some experiments on the phenomenon of phos- 
phorescence. Balmain’s luminous paint, calcium sulphide, and 
other substances give out a violet light after having been excited 
by daylight. Capt. Abney found that when the spectrum was 
allowed to fall on an excited surface of Balmain’s paint the blue 
rays enhanced this violet light, and the red end of the spectrum 
extinguished it. This was shown to the meeting, and the red 
end of the spectrum appeared on the paint in well-defined black 
bands. Similarly, the light from an electric lamp passed through 
a sheet of red glass extinguished the phosphorescence. Capt. 
Abney’s researches further showed that there is a series of 
octaves in the blue end of the spectrum which refuse to quench 
the violet lizht. He found the mean wave-length of the rays 
exciting the phosphorescence to be 4300. Prof. Guthrie also 
showed that calcium sulphide tubes glow in violet light. 
Anthropological Institute, January 10.—Major-General 
Pitt-Rivers, F.R.S., president, in the chair.—Hugh Felvey and 
Mrs. Bathoe were elected Members of the Institute.—Mr. Bryce- 
Wright exhibited a series of sixteen portraits of the Incas, 
copied from the originals in the Temple of the Sun.—Mr. 
Worthington G. Smith exhibited some stone implements from 
the north-east of London.—General Pitt-Rivers, F.R.S., read 
a paper on the entrenchments of the Yorkshire Wolds, and ex- 
cavations in the earthwork called Dane’s Dyke, at Flamborough. 
At Dane’s Dyke the author had found flints and flint flakes, 
clearly proving that the constructors and defenders of the earth- 
work used flint, and lived not later than the bronze period. 
The whole district was the scene of the oferations of a people 
much earlier than the Danes, and therefore the term ‘‘ Dane’s 
Dyke” was a misnomer.—In the absence of the author the 
Director read a paper by Mr. J. R. Mortimer, on the discovery 
of ancient dwellings on the Yorkshire Wolds. 
Institution of Civil 'Engineers, January 24.—Mr. Brun- 
lees, vice-president, in the chair.—The paper read was on ‘f The 
Analysis of Potable Water, with special reference to the deter- 
mination of Previous Sewage Contamination,” by Mr. Chas. W. 
Folkard. 
Sypney, N.S.W. 
Linnean Society, November 30, 1881.—Dr. J. C. Cox, 
president, in the chair.—The papers read were: By the Hon. 
Secretary, for Baron F. yon Mueller, K.C.M.G., on two new 
species of New South Wales plants.—By J. J. Fletcher, M.A., 
B.Sc., on the existence after parturition of a direct communica- 
tion between the median vaginal cul-de-sac, so called, and the 
uro-genital canal in certain species of kangaroos.—By the Hon. 
William Macleay, F.L.S., on two new species of snakes from 
the western interior of New South Wales. Mr. Macleay stated 
that these new species had been discovered by Mr. James Ram- 
say, of Tyndarie, near Bourke ; they were a new species of 
Diemenia, which it was proposed to call D. fevox, and a new 
species of the genus 4sfidiotes, named A. Ramsay, after its 
discoverer.—By the Rev. Wm. Woolls, Ph.D., on the flora of 
New South Wales, being the sixth paper on this subject by this 
well-known botanist.—On the Cypreze of New Caledonia, by 
Mr. J. C. Rossiter, of Numea, N.C, ; communicated through 
Mr, John Brazier, C.M.Z.S.—On a new species of 7herapon, 
7. Macleayana.—On two new birds from the Solomon Islands : 
(1) a kingfisher, Halcyon salmonis, allied to H. chloris, but 
without the white nape patch or superciliary stripe; and 
all the under surface white, the under-wing coverts white, 
the upper surface of a much brighter blue; (2) a Rhipi- 
dura, R. ¢enebrosa.—On the habitats of Pachycephala olivacea 
and Pycnoptilus floccosus, and their occurrence near Sydney, 
by Mr. E. P. Ramsay, F.Z.S., C.M.Z.S., Curator of the 
Australian Museum, —Exhibits—Mr. Ramsay exhibited specimens 
of the following new and rare birds from the Island of ‘‘ Ugi,” 
in the Solomon groups :—1. Ptilopus Eugenia, Gould. (2) Pu- 
lopus Lewisi (Ramsay), similar to P, Eugenie, but without the 
white head. 3. Ptilopus Richardsii (Ramsay), a very remarkable 
species, having the head, neck, and breast of a light french grey, 
tinged slightly with pale olive yellow, the crown is of a very pale 
lilac, the scapulars beautifully painted wit1 rose down the centre 
of each feather. 4. Ptilopus Fohannis (Sclater), said to be 
identical with P. ceraseipectus of Canon Tristram, and of which 
P. solomonensis of Gray is the female. 5. Chalcophaps mortoni 
(Ramsay) resembles C. chrysochlora, but has no shoulder patch, 
and is larger. 6. Zvichoglossus (Charmosyne) Margarethe 
(Tristram), male and female, the female alone being previously 
