40 



EEPOET — 1889. 



The well was sunk to a depth of 4,625 feet, but no observations were 

 made except at the depths specified. The thermometer remained only 

 from five to ten minutes during each test ; and as there were only 40 feet 

 of Avater in the well, the observations must have been taken in air. The 

 diameter of the well was 6 inches. The rock was chiefly slate, and was 

 bored by 'jumping.' The mean air temperature at Pittsburgh is 52° F., 

 and the height above sea-level about 900 feet. Comparison of the mean 

 surface-temperature (taken as 52°) with the temperature, 114°, recorded 

 at 4,295 feet shows an increase of 62°, which is at the rate of 1° F. for 

 69'3 feet ; but comparison of the observations inter se would give a rate 

 about twice as rapid as this ; hence no safe conclusion can be drawn. 

 After the hurry and worry of the gas business is over, Mr. Cummins 

 hopes to get the temperature of some deep wells in a way that will be 

 satisfactory. 



We may mention, as a contribution to the literature of Underground 

 Temperature, the recent publication of results obtained at the Old 

 Observatory, Allahabad, with thermometers whose bulbs were at the 

 depths 3 feet, 1 foot, and half an inch respectively. Harmonic reduction 

 has been applied to deduce both the annual and the diurnal variation, and 

 from the former a fairly consistent determination of the ' diffusivity,' or 

 quotient of conductivity by capacity, has been obtained. Its value, "0054 

 C.G.S., is smaller than any values that have been found elsewhere. The 

 soil is a sandy loam, which in dry weather becomes almost as hard 

 as brick. The observations extend over six years, and similar observa- 

 tions are now being carried on at the New Observatory. The gentleman 

 who is reponsible for the reductions and the description of the observa- 

 tions is Mr. S. A, Hill, B.Sc, Meteorological Reporter to Government 

 for the North-Western Provinces. 



Fifth Report of the Committee, consisting of Sir Gr. Gr. Stokes 

 (Chai')'man),'Mr. G. J. Stmons (Secretary), Professor Schuster, 

 Dr. G. Johnstone Stoney, Sir H. E. Eoscoe, Captain Abney, 

 and Mr. Whipple, appointed for the jpurpose of considering the 

 best methods of recording the direct Intensity of Solar Radia- 

 tion. 



The actinometer devised by the late Professor Balfour Stewart for the con, 

 tinuous measurement of solar radiation, which was described in the Report 

 of the Association for 1887 (p. 32), is now ready for the preliminary 

 trials, the internal thermometer, with a flat bulb of green glass, having been 

 made since the date of that report. The construction of this thermometer 



