i ai 
Sune 12, 1873) 
NATURE 35 
The value of v given by the experiments here described is 
293 x 10° centims. per second. The method employed was that 
of obtaining an absolute electrostatic and an absolute elec'r.- 
magnetic measurement of the same electromotive force. wv is 
defined as the ratio of the units of quantity in the two systems ; 
but it follows from the definition-of electro-motive force, that v 
is also the ratio of the units of electromotive force in the two 
systems. 
The electromotive force, or the difference of potentials be- 
tween the two poles of a constant Daniell’s battery, was mea- 
sured electrostatically by means of Sir William Thomson’s 
absolute electrometer. The absolute electromagnetic value of 
this electromotive force was giyen by the effect of the current 
which it maintained in thecircuit of an electrodynamometer. 
The determination of this value depended on the resistance of 
the electrodynamometer-circuit, which was reckoned in terms of 
the” absolute value of the British-Association standard unit of 
resistance. Any correction which may hereafter be found to be 
applicable to the absolute value of this standard coil, as mea- 
sured at King’s College by Professors Clerk Maxwell, Balfour 
Stewart, and Fleeming Jenkin, must be applied to the value of 
wv give above. 
The comparisons made in 1867 and 1868 by Mr. King gave 
as the mean value of v, 284°6x 108 centims. per second. The 
experiments made in 1870 with the new absolute electrometer 
geve as the mean result v=294'5 x 10° centims. per second. 
The result of the later observations made under much more 
favourable circumstances was v= 292'4 x 10° centims. per second. 
The latest observations (1872) furnish the most probable 
value of v7, 293 x 10° centims. per second. 
- Zoological Society, June 3.—Viscoun: Walden, F-.R.S., presi- 
dent, in the chair. The secretary read a report on the additions 
that had been made to the Society’s collection during the month of 
_ May. The following, among other objects, was exhibited :— 
The figure of a supposed new species of- Chelodina from the 
Burnett River, Queensland.—A letter was read from Dr. George 
Bennett, F.Z.S., referring to the supposed existence of a species 
of Tree Kangaroo (Dendro/agus) in Northern Queensland, some 
such animal being apparently well known to the blacks of Card- 
weil.—A memoir was read by the Viscount Walden on the 
birds of the Philippine Archipelago, founded mainly on the re- 
cent collections ot Dr, A. B. Meyer, but containing a complete 
account of all the known species of Philippine birds, and re- 
marks on their geographical range. The total number of known 
Philippine species was estimated at 215, but a large number of 
the islands remained unexplored.—A paper was read by Sir 
Victor Brooke, Bart., F.Z.S., on the antelopes of the genus 
Gazella, of which 20 species or ‘‘ persistent modifications,” as 
the author preferred to call them, were recognisable. Sir Victor 
Brooke entered at full length into the questions connected with 
the present geographical distribution of the group, and its sup- 
posed descent from pliocene and miocene forms.—Mr. A. H. 
Garrod read a paper on the pterylosis and on some points in the 
anatomy of the Guacharo (Steatornis caripensis) and showed that 
this singular bird must be constituted a family fer se, related in 
some respects to the Caprimulgidze and their allied forms, and 
in other respects to the Owls (S¢rzges), 
Chemical) Society, June 5.—Dr. Odling, F.R.S., president, 
in the chair.—Six communications were read before the society, 
the first being “On the dioxides of calcium and strontium,” by 
Sir John Conroy, Bart., in’ which the author gave the 
method of preparation and properties of these substances. —Mr. 
T. Wells then described a new form of ozone generator which 
gives abundance of ozone and has the advantage of being easily 
constructed and not liable to be broken,—The other papers, 
which contained but little of general interest, were entitled ** On 
the behaviour of acetamide with sodium alcohol,” by W. N. 
Hartley ; ‘‘ On iodine monochloride,” by J. B. Hannay ; ‘‘ On 
triferrous phosphide,” by Dr, R. Schenk ; and “ On sulphur bro- 
mide,” by J. lb. Hannay. 
Anthropological Institute, June 3.—Prof. Busk, F.R.S., 
president, in the chair.—The president exhibited and described 
anew apparatus for measuring, with ease and accuracy, the 
cubic capacity of skulls. _ Prof. Rolleston, while approving 
generally the method of Prof. Busk, differed with him in the 
nature of the material to be employed ; he thought that sand 
was objectionable as being subject to hygrometric variation ffom 
which rape-seed was entirely free.—Prof. Robinson exhibited a 
remarkable bronze sword found in the bed of the Charwell, 
_— a 
elie a. 
Oxfordshire, a bronze spear from Speen, near Newbury, and 
other implements of bronze and stone.—The president exhibited 
a series of stone implements from the Island of St. Vincent, 
West Indies, and Mr. A. W. Franks exhibited a bow and 
poisoned arrows lately used by the Modoc Indians, and found 
in Captain Jack’s stronghold in the lava beds of Siskiyon 
County, California—The Rev. Dunbar I. Heath contributed 
Notes on a Mural Inscription, in large Samaritan characters, 
from Gaza, and claimed for it a higher antiquity than the date 
of the Moabite Stone.—Mr. H. Howorth read a paper entitled, 
‘* Strictures on Darwinism, part II., the Extinction of Types.” 
The substitution of species invoived two factors; Ist, the 
extinction of certain types; 2nd, the introduction of certain 
others. The paper dealt with the former facior only. Pre- 
Darwinian naturalists, and some of those who now oppose 
Darwin, have agreed that species become extinct throvg’ the 
operation of causes, such as climatic change, &c., acting adextra 
and operating upon whole classes at once from without. Mr. 
Darwin has argued, on the other hand, that this extinction has 
arisen from the mutual struggles of individuals by which a 
certain strong and vigorous type has been evolved, and a certain 
weak and decrepit type extinguished ; the difference between 
the two theories being that one relies upon external, the other 
upon internal causes for the explanation of the extinction of 
certain types. In the present paper the author examined the 
problem and attempted to show that the old view was the 
correct one. The paper passed in review the various elements 
that have gone to destroy types of life, changes in physical 
geography, changes in climate, epidemics, &c., and showed how 
the evidence of all of these supported the old view that extinc- 
tion of type is the result of external influences, and not, as Mr. 
Darwin contends, of an internal struggle for existence. brof 
Rolleston, Mr. Boyd Dawkins, and the president, combated the 
criticisms of the author. 
Royal Microscopical Society, June 4.—Chas. Brooke, 
F.R.S., president, in the chair. The secretary read a paper by 
Mr. F. Kitton, of Norwich, descriptive of a new species of 
Navicula, with remarks on Aulacodiscus formosus, Omphalopelta 
versicolor, &c., collected in Peru by Captain Perry, of Liverpool ; 
the paper was illzstrated by specimens exhibited in the room. 
—A paper was also read by Mr. J. Stephenson, on the appear- 
ances of the inner and outer layers of Coscinodiscus when ex- 
amined in bisulphide of carbon and in air, in which the author 
pointed out the different effects obtained by mounting the diatoms 
in media of different refrangibility, and showed the value of such 
comparisons in determining the nature of the markings, as well 
as the general structure. The paper was illustrated by a number 
of very carefully executed drawings by Mr, Charles Stewart, and 
by specimens exhibited under the microscope. The meetings of 
the society were adjourned until October. 
BERLIN 
German Chemical Society, May 26.—A. W. Hofmann in 
the chair. Dr. Seligsohn investigating the origin of the oxalates 
deposited in the human body, has found that oxamide can be 
transformed into urea by ozone, and thinks therefore that 
oxamide is an intermediate product of digestion between the 
higher compounds of carbon and urea.—Dr, Riidorft has found 
that saturated solutions of chloride of ammonium and nitrate of 
potassium are not influenced in their composition by adding 
either of these salts, while saturated solutions of nitrate of ammo- 
nium and chloride of potassium are changed in their composi- 
tion by adding either one or the other to these solutions. In 
the same way behave most salts, so that the solution of one 
couple is influenced, while the other couple remains uncuanged. 
But when K,SO, and NH, NO, are dissolved to saturation, this 
solution is influenced in the way described, and solutions of the 
opposite couple show likewise the alteration mentioned. These 
changes were proved by analyses and by determination of the 
changes of temperatures occurring. Self-evident conclusions 
offer with regard to the old question, if two salts in solution 
represent two or four different compounds.—C. Bulk spoke on the 
manufacture of arsenic acid from fuchsine-residues; by subli- 
mation, as used in Elberfeld. The same chemist described a 
simple apparatus replacing spring-clamps in volumeiric 
analysis. It consists of a piece of glass-rod inserted into 
an indiarubber tube. By pressing it cautiously drop 
after drop can be let out of the burette,—J. Grosshaus 
continued his speculation on the nature of chemical ele- 
ments.—H, Vogel denied the existence of what Becquerel called 
