ON ATMOSPHERIC ELECTRICITY. 103 



Report of the Committee, consisting of Professor G. Forbes, Pro- 

 fessor Sir William Thomson, and Professor Everett, appointed 

 for the purpose of making arrangements for the taking of cer- 

 tain Observations in India, and Observations on Atmospheric 

 Electricity at Madeira. 



The Committee lias purchased three electrometers. These hare been 

 given, one to Surgeon-Major Johnson, in India ; the second to Mr. Michie 

 Smith, in India ; and the third to Dr. Grabham, in Madeira. Surgeon- 

 Major Johnson was engaged in the frontier war in India ; and Dr. Grab- 

 ham has hitherto been too much occupied to make observations, while 

 Mr. Michie Smith has not yet had time to furnish any. So that up to the 

 present time no observations have been received. Tour Committee feel 

 confident of obtaining results from Mr. Smith, and hope also from the 

 other observers, but in the event cf their being unable to furnish regular 

 observations, your Committee would get the electrometers back and make 

 them available for other persons. They propose that the Committee 

 should be reajipomted. 



Report of the Committee, consisting of Professor Sir William 

 Thomson, Professor Clerk Maxwell, Professor Tait, Dr. C. W. 

 Siemens, Mr. F. J. Bramwell, Mr. W. Froude, and Mr. J. T. 

 Bottomlet, for commencing Secular Experiments upon the 

 Elasticity of Wires. Drawn up by J. T. Bottomlet. 



The Committee have to report that the arrangements for suspending the 

 wires for secular experiments on elasticity are now complete ; and that 

 within the last few days two wires, one of palladium, and the other of 

 platinum, have been suspended in their places. 



An iron tube has been erected in one of the rooms in the tower of 

 the University buildings in Glasgow. It is 60 feet long, 9 inches wide, 

 and 4^ inches deep from face to back. It is of rectangular section, in 

 lengths of 6 feet ; and it is supported by being firmly attached to the 

 heavy outer stone wall of the tower. 



At the top of the tube there is a heavy gun-metal plate, which is sup- 

 ported independently of the iron tube ; and from this plate the wires 

 under examination are to be suspended, as well as additional wires to be 

 used for carrying additional comparison marks. With this arrangement 

 no yielding of the supporting plate that may take place will introduce 

 errors into the results of measurement of the lengths of the wires ; for 

 the point of support of the wire carrying comparison marks will expe- 

 rience the same amount of lowering, due to the yielding, as is experienced 

 by the wire to be measured against these marks. The gun-metal plate 

 has been pierced with three rows of holes through which the wires are 

 to pass. The holes are trumpeted at each end so as to avoid sharp con- 

 tact with the wires, and the rows are arranged so that the wires shall 

 hang down in planes parallel to the face of the tube. It has not yet 

 been decided what is the best way of fixing the upper ends of the 



