198 
NATURE 
questions connected with the accurate comparisons of 
Standard weights and measures now require an authori- 
tative decision, with a view to their general adoption. 
These constitute the data upon which the requisite cor- 
rections of the actual results of the several comparisons 
must be computed, before an accurate determination can 
be arrived at, with reference to the circumstances under 
which the comparisons are made. Amongst these ques- 
tions may be instanced: The determination of the true 
weight of a given unit of measure of dry atmospheric air ; 
the true weight of a given unit of measure of pure water ; 
the condition of pure water employed in Standard opera- 
tions, as to its being more or less deprived of or saturated 
with air ; the rate of expansion of air ; the rate of expan- 
sion of water and of its maximum density ; the amount 
of aqueous moisture in atmospheric air and its influence 
on the weighing and measuring of Standards ; the relative 
rates of expansion generally of solid, liquid, and aériform 
bodies, and the limits of temperature within which this 
rate is to be determined ; more particularly, of the relative 
expansion of the quicksilver and glass of thermometers, 
and the constancy of the determined rates of expansion ; 
the constancy of the determined length of Standard 
measuring bars, and of their coefficients of dilatation ; 
the adoption of a uniform average rate of expansion, 
within determinate limits of temperature, of metallic and 
other bodies used in Standard operations ; and of average 
conditions of temperature of these bodies and of the 
medium in which they are placed ; the employment of an 
air thermometer, &c. &c. At the present time, different 
solutions of these questions are adopted in the several 
countries, the results being that not only is any uniform 
agreement in the results of comparisons rendered abso- 
lutely impossible, but doubts exist as to the accuracy of 
the determinations of these questions which have hitherto 
been made. It is evident that in order to obtain any 
satisfactory solution, long and varied observations and 
comparisons will have to be made, and such labours are 
proposed to form an important part of the future work of 
the International Metric Institution. It is only by such 
an authoritative determination made by the combined 
efforts of men of science in the different countries, under 
whose direction the Institution is to be placed, that 
the urgent need of uniform and accurate data for ob- 
taining trustworthy results in all comparisons of Standards 
can be expected to be supplied. 
It ought, however, to be distinctly understood that not 
only the more immediate operations of the International 
Metric Commission, but also the proposed future opera- 
tions of the International Metric Bureau, under the direc- 
tions of their permanent committee, are wholly and ex- 
clusively of a scientific character. The objects of the 
Commission are to furnish and to afford the means of 
maintaining uniform standards for all countries which have 
already adopted, or which may hereafter adopt, the metric 
system, as either a national or international system of 
weights and measures. The true sphere of the Commis- 
sion is thus limited to the investigation and accomplish- 
ment of all the best means, either in a scientific or a 
technical point of view, by which these objects may be 
attained, Whether the adoption of the metric system of 
weights and measures by this or any other country be ad- 
vantageous to it or not is a question to be determined by 
each country upon its own merits, but it is one with which 
the International Metric Commission is no way called 
upon or entitled to interfere. 
An incident which occurred at the late meeting of the 
Commission may be noticed as showing how strictly their 
objects were considered by them to be confined to pur- 
poses of science. The question of the mode of voting 
having been raised, it was referred to a committee to 
report upon. The Committee recommended, and the 
proposition was unanimously agreed to by the Com- 
mission, that on ordinary occasions each member present 
should vote personally ; but upon the demand of five 
members, the votes should be taken by countries repre- 
sented, each country having one, two, or three votes, 
according to the population. Amongst others, one vote 
was assigned to the Papal See, represented by Padre 
Secchi, who had originally been appointed delegate of the 
Papal States. Unfortunately a report of these proceed- 
ings appeared in the Y¥owrnal Officiel, though not in the 
official portion, and attracted the notice of the Italian 
Parliament then’sitting, when the Italian Government was 
instructed to insist on the cancelling of the vote fora 
nation given to the representative of the Papal See, the 
Pope being no longer a territorial Sovereign. A diplo- 
matic communication was accordingly made to the French 
Government, who declined to interfere in a matter within 
the power of the International Commission, and which 
had reference merely to the proceedings of a scientific 
body. The Italian Government then directed their repre- 
sentatives to take no further part in the Commission, so 
long as Padre Secchi continued to be the delegate of the 
Papal See, and Marquis Ricci and Prof. Govi were 
reluctantly compelled formally to announce this to the 
Commission. But the Commission felt that they could 
only deal with this communication as an accomplished 
fact, and they expressed their great regret at this seces- 
sion, in consequence of imperative orders, of two of their 
most eminent colleagues, which they trusted would be 
only temporary. They at the same time expressed their 
astonishment at so unlooked-for an interference with 
their proceedings which were of so entirely a scientific 
character. 
The extent of the preliminary work hitherto atcom- 
plished by the Commission may be estimated from the 
fact of their Minutes of Proceedings during the last four 
years filling 580 closely printed 12mo. pages. On the 
occasion of their recent meeting, when the Commission 
was found to comprehend 50 members, representing 29 of 
the principal countries of the civilised world, the subjects 
of the formal resolutions passed by them had been pre- 
viously arranged for their discussion and deliberation, and 
were referred by them to eleven different Committees. The 
Reports of these Committees, which are printed at length 
in the Procds-Verbaux of the Commission, contain the 
form of the Resolutions under each subject which was 
proposed for adoption ; and, generally speaking, they were 
unanimously passed by the Commission, with but slight 
amendments. The grounds of the conclusions arrived at 
by the several Committees are stated at length in their 
Reports, and in a future article some of the more im- 
portant of them of tke highest scientific interest will be 
specified. 
H.W. C 
