44 REPORT — 1860. 



may prove of very great value. Prof. W. Thomson is anxious that obser- 

 vations should be made on the electrical condition of the atmosphere. He 

 has described in the article on the Electricity of the Atmosphere ill Nichols 

 'Cyclopaedia,' a portable electrometer, and also a mode of collecting electricity 

 by that which he styles the water-dropping system, which would, in his 

 opinion, be easily applicable. The observations might be carried on, first, 

 by ascending to very moderate heights, and then going as high as possible. 

 Dr. Lloyd desires that observations should be made for "the determination 

 of the decrease of the earth's magnetic force with the distance from the sur- 

 face." The failure of Gay-Lussac to detect any sensible change ought not 

 to deter future observers. His methods were wholly inadequate ; but Dr. 

 Lloyd is of opinion that if attention be confined to the determination of the 

 total force or its vertical component (instead of the horizontal), it would be 

 easy to arrive at satisfactory conclusions. Sir David Brewster suggests that 

 further information may be obtained as to the polarization of the atmosphere 

 and the height of the neutral point. And, lastly, Dr. Edward Smith and 

 Prof. Sharpey are desirous that experiments should be made as to "the 

 quantitative determination of the products of respiration at different high 

 elevations." Dr. Smith has, as it is well known, been for the last two or 

 three years engaged in experimental inquiries on inspiration, and he is so 

 satisfied of the value and importance of the investigation, that he is not only 

 willing, but desirous to make the requisite experiments himself. Dr. Smith 

 has furnished directions as to the points to be observed and the mode of ob- 

 servation. 



Report of Committee appointed to prepare a Self -Recording Atmo- 

 spheric Electrometer for Keiv, and Portable Apparatus for observing 

 Atmospheric Electricity. By Professor W. Thomson, F.R.S. 



Your Committee, acting according to your instructions, applied to the .Royal 

 Society for £100 out of the Government grant for scientific investigation, to 

 be applied to the above-mentioned objects. This application was acceded 

 to, and the construction of the apparatus was proceeded with. The progress 

 was necessarily slow, in consequence of the numerous experiments required 

 to find convenient plans for the different instruments and arrangements to 

 be made. An improved portable electrometer was first completed, and is 

 now in a form which it is confidently hoped will be found convenient for 

 general use by travellers, and for electrical observation from balloons. A 

 house electrometer, on a similar plan, but of greater sensibility and accuracy, 

 was also constructed. Three instruments of this kind have been made, one 

 of which (imperfect, but sufficiently convenient and exact for ordinary work) 

 is now in constant use for atmospheric observation in the laboratory of the 

 Natural Philosophy Class in the University of Glasgow. The two others are 

 considerably improved, and promise great ease, accuracy, and sensibility 

 for atmospheric observation, and for a large variety of electrometric re- 

 searches. Many trials of the water-dropping collector, described at the last 

 Meeting of the Association, were also made, and convenient practical forms 

 of the different parts of the apparatus have been planned and executed. A 

 reflecting electrometer was last completed, in a working form, and, along 

 with a water-dropping collector and one of the improved common house 

 electrometers, was deposited at Kew on the 19th of May. A piece of clock- 



