calculated, with the result that on clear days the diurnal range of temperature is only very slightly in excess of that of foggy days. But in summer the difference between the mean coldest and warmest hour is 1°.1; but on clear days the difference is 2°.9, or nearly three times greater.

The further prosecution of this inquiry and examination of the cyclones and anti-cyclones of North-Western Europe will engage the attention of your Committee next year, when a large portion of the time of Dr. Buchan and Mr. Omond will be given to this work.

TABLE III.-Showing at the Ben Nevis Observatory the Mean Hourly Variation of Pressure, in thousandths of an inch, during clear days. The minus sign means under the average.

TABLE IV. Showing at the Ben Nevis Observatory the Mean Hourly Variation of Pressure, in thousandths of an inch, during days of fog or mist. The minus sign shows the means under the average.

TABLE V.-Showing at Fort William Observatory the Mean Hourly Variation of Pressure, in thousandths of an inch, during clear days. The minus sign shows means under the average.

Hour

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year

TABLE VI.-Showing at Fort William Observatory the Mean Hourly Variation of Pressure, in thousandths of an inch, during days of fog or The minus sign shows means under the average.

mist.

Hour

Jan. Feb. Mar. April May June July Aug. Sept. Oct

+13 +6 +9 -2 - 2 -7 -7

1 A.M.

+9

2

4

5

-10 -10
-12

+11

+ 5

++

Nov. Dec. Year

+14 +15 +16 +12 +10

+9

+4

+1 + 5 +4

6

2

TABLE VII.-Showing at Trieste the Mean Hourly Variation of Pressure, in thousandths of an inch, during clear days. The minus sign shows means under the average.

TABLE VIII.-Showing at Trieste the Mean Hourly Variation of Pressure, in thousandths of an inch, during completely clouded days. The minus sign indicates means above the average.

Experiments for Improving the Construction of Practical Standards for Electrical Measurements.-Report of the Committee, consisting of Professor CAREY FOSTER (Chairman), Lord KELVIN, Professors AYRTON, J. PERRY, W. G. ADAMS, and Lord RAYLEIGH, Drs. O. J. LODGE, JOHN HOPKINSON, and A. MUIRHEAD, Messrs. W. H. PREECE and HERBERT TAYLOR, Professor J. D. EVERETT, Professor A. SCHUSTER, Dr. J. A. FLEMING, Professors G. F. FITZGERALD, G. CHRYSTAL, and J. J. THOMSON, Messrs. R. T. GLAZEBROOK (Secretary), and W. N. SHAW, Rev. T. C. FITZPATRICK, Dr. J. T. BOTTOMLEY, Professor J. VIRIAMU JONES, Dr. G. JOHNSTONE STONEY, Professor S. P. THOMPSON, and Mr. G. FORBES.

APPENDIX

I. Report of the American Delegates at the Chicago Conference to the
Secretary of State at Washington

II. Experiments on the Value of the Ohm. By J. VIRIAMU JONES
III. Comparison of the Standards employed by Professor Jones with the
Standards of the Association. By R. T. GLAZEBROOK

IV. Comparison of Some of the Standards of the Board of Trade with
those of the Association. By J. RENNIE

VI.

Values of Certain Coils belonging to the Indian Government. By

E. O. WALKER

FITZPATRICK

On the Specific Resistance of Copper and of Silver. By Rev. T. c. VII. Final Report of the Electrical Standards Committee of the Board of Trade, and Order in Council regarding Standards for Electrical Measurements

PAGE

119

123

128

130

131

131

.

136

THE work of testing resistance coils at the Cavendish Laboratory has been continued. A table of the coils tested is given.