ON THE INTENSITY OF SOLAR BADIATION. 



41 



occasioned a good deal more trouble than had been anticipated. No 

 attempt has at present been made to render the instrument self-register- 

 in"-, as it would obviously be unwise to incur the outlay wliich any 

 construction for this purpose would involve, unless the result of preliminary 

 trials were such as to encourage a hope that the instrument might be really 

 useful if rendered self-recording. 



Report of the Committee, consisting of Professor G. Carey Foster, 

 Sir William Thomson, Professor Ayrton, Professor J. Perry, 

 Professor W. G. Adams, Lord Rayleigh, Dr. 0. J. Lodge, Dr. 

 John Hopkinson, Dr. A. Muirhead, Mr. W. H. Preece, Mr. 

 Herbert Taylor, Professor Everett, Professor Schuster, Dr. 

 J. A. Fleming, Professor Gr. F. Fitzgerald, Mr. R. T. Glaze- 

 brook (Secretary), Professor Chrystal, Mr. H. Tomlinson, Pro- 

 fessor W. Garnett, Professor J. J. Thomson, jNIr. W. N. Shaw, 

 Mr. J. T. Bottomley, and Mr. T. Gray, appointed for the 

 purpose of constructing and issuing Practical Standards for 

 use in Electrical Measurements. 



The Committee report that the work of testing resistance coils has been 

 continued at the Cavendish laboratory. A table of the values found for 

 the various coils is appended. 



In March 1889 a coil of platinum silver, marked 'Elliott, No. 95,' 

 which had been tested for Professor Roiti, of Florence, in November 1883, 

 was again compared. It was found to have the value of •90903 B.A. 

 units at 128° Centigrade. The value given to Professor Roiti in 1883 

 was: — 



R = -99977 (1 + -00031 (t - 15-2)} 



This leads, at 12-8°, to exactly the same value, -99903, as found in 1889. 



