ON STANDARDS FOR USE IN ELECTRICAL MEASUREMENTS, 45 
differ much from a real ohm. At present, without these standards—the 
coils actually used in the recent experiments at the Cavendish Laboratory 
have a resistance of about ‘1, 24, and 163 ohms—the operation is trouble- 
some. The simplest accurate method seems to be to combine in multiple 
arc the real ohm, and one of the 100 B. A. unit standards, and to compare 
the combination with a single unit. 
Dr. Muirhead also reports the completion of three air condensers as 
standards of capacity. 
The Committee are glad to learn that Lord Rayleigh is continuing 
his valuable researches at the Cavendish Laboratory with the view of 
obtaining an absolute unit of current. 
They would ask in conclusion that they may be reappointed with the 
addition of the names of Mr. H. Tomlinson and Professor W. Garnett ; 
and that a further grant of 100/. may be made to meet the expense of 
procuring standards of resistance in terms of the ohm. 
Siateenth Report of the Committee, consisting of Professor EVERETT, 
Professor Sir WILLIAM THomson, Mr. G. J. Symons, Sir A. C. 
Ramsay, Professor GrIkiE, Mr. J. GuaisHer, Mr. PENGELLY, 
Professor EpwarD HuLL, Professor Prestwicu, Dr. ©. Le Nrve 
Foster, Professor A. 8. HERSCHEL, Professor G. A. Legour, Mr. 
A. B. Wynne, Mr. GaLLoway, Mr. Josern Dickinson, Mr. G. F. 
Deacon, Mr. E. WeTuERED, and Mr. A. STRAHAN, appointed for 
the purpose of investigating the Rate of Increase of Under- 
ground Temperature downwards in various Localities of Dry 
Land and wnder Water. Drawn wp by Professor Everett 
(Secretary ). 
Opsmrvattons have been made in the artesian well at Southampton 
Common by Mr. T. W. Shore, of the Hartley Institution, assisted by Mr. 
J. Biount Thomas. 
The well was sunk to a depth of 1,317 feet many years ago, and has 
remained closed for thirty-two years. It has now been re-opened, with 
the view of being carried deep enough to obtain a supply of water which 
will rise to the surface. The brick portion of the well is 563 feet deep, 
with a diameter of 13 feet at the top and 7 feet at the bottom. A boring 
with a 73-inch auger was made 754 feet deeper, giving a total depth of 
1,517 feet. The water stands at 40 feet below the surface of the ground, 
and a tube about 74 inches in diameter extends from the bottom of the 
brick well to a few inches above the surface of the water. The thermo- 
meter (an inverted Negretti maximum) was lowered through this tube 
into the boring, and, to aid in carrying it past obstructions, it was 
enclosed in a perforated cylindrical case of zinc, to which was attached 
an elongated cylindrical weight, pointed at the lower end to enable it 
to penetrate mud. The result sbowed that these precautions were 
necessary, the zine case and the lower part of the weight being deepl 
scratched. The obstructions were chiefly met with at a depth of from 
600 to 800 feet, in passing through the Upper Chalk. 
The thermometer was lowered very gradually, its descent. occupying 
