306 
Observations made in the upper vault, five 
metres under ground, show that the daily vari- 
ation of temperature is insensible, and that the 
annual range is only a few degrees. As it is 
apparently water-tight, it will serve as a safe 
place of deposit for the standards. In the 
lower vault, ten metres under ground, the tem- 
perature is steady at 11° C. throughout the 
year. At present there is trouble from moisture. 
Steps are taking to overcome this difficulty ; 
and, when they are complete, the chamber 
will be ready for the reception of the proto- 
types. 
The examination of the universal compara- 
tor has been completed, and all values deter- 
mined save the final errors of division of the 
two-metre scale. Certain auxiliary scales need- 
ed for this work were ordered, and have just 
been received. 
Modifications are being made on the Brun- 
ner comparator to admit of comparisons of 
metres under water. 
The report for 1882 showed that the balance 
for vacuum-weighings had been received ; but 
certain defects of construction were found to 
exist, and it was returned to the makers to have 
them remedied. It was again received last 
autumn, and now appears to maintain a vacu- 
um in a satisfactory manner. Its examination, 
and the determination of its instrumental con- 
stants, will be immediately begun. 
The manufacture of the standard metres 
and kilograms by Johnson, Matthey, & Co., is 
progressing. Analyses of the alloy show it to 
fill all requisite conditions. Up to the present 
time the progress has necessarily been slow, as 
the important questions of alloy, refinement, 
and mechanical execution, had to be provided 
for. These matters have now been satisfacto- 
rily settled, and the delivery of the bars and 
ingots may be expected soon to begin. 
In the report of the operations during 1882 
was given an account of the copies of the 
metre des archives and of the kilogramme des 
archives, which, on April 26, were confided to 
the care of the director of the bureau. Although 
rigorously compared, and the relation to the 
standards of the archives accurately deter- 
mined, these were not adopted as international 
prototypes, but were deposited as witness-cop- 
ies of these standards. The kilogram, Kj, 
elaborately compared with the kilogramme des 
archives in 1882 and 18838, was found to be 
identical in value thereto ; and on Oct. 3, 1883, 
it was formally adopted as the international 
prototype of the kilogram. 
During the year, changes have taken place 
in the personnel of the international committee 
SCIENCE. 
‘Peet eee ed, 
and the bureau. The Turkish member of the 
original committee having taken no part in its 
deliberations since its organization, and repeat- 
ed attempts to ascertain his future intentions 
in the matter having failed, his place has for- 
mally been declared vacant. ‘The vacancy as 
yet has not been filled. The resignation of 
Mr. Marek as a member of the international 
bureau took effect from March 1, 1883. Dr. 
Max Thiesen of Berlin was chosen as his suc- 
cessor, and is charged with matters relating to 
weighing. 
The second volume of the Travaux et mé- 
moires has appeared, and contains a number of 
important papers relating to comparisons and 
to determination of coefficients of expansion. 
The third volume is in press, and in great de- 
cree printed. It is expected to appear in a 
few months. The material for the fourth vol- 
ume is in large degree prepared. 
Although the comparison of the internation- 
al standards has not yet begun, a number of 
national standards have been compared, and 
important physical investigations made. 
Comparisons of much interest to Americans 
are those between the British platinum kilo- 
gram and a platinum-iridium and two brass 
avoirdupois pounds and the prototype kilo- 
gram, as through them our own weights are 
brought into more direct relation with the 
international standards. Also a steel metre 
belonging to the U.S. lake survey has been 
compared for length and coefficient of expan- 
sion. 
Experiments with the Fizeau expansion ap- 
paratus have given a new and elaborate re- 
determination of the change, with temperature, 
of the index of refraction of atmospheric air; © 
and the coefficients of expansion of many 
minerals have been determined. An elaborate 
redetermination of the wave-length of the so- 
dium-ray is in progress. 
Correspondence is in progress with Mexico 
with a view to the adoption, by that govern- 
ment, of the articles of the metric convention. 
H.-W .. : Brame 
A QUESTION OF EXPOSURE. 
Tue extraordinary depressions in tempera- 
ture, which occurred in the month of January 
in many parts of the country, have attracted 
an unusual amount of attention to questions of 
thermometry. 
observed that the areas of excessive cold were 
smaller than might have been anticipated, great 
differences often existing where there were no 
In some instances it has been — 
[Vou. III., No. 58 - 
