152 Record of the Royal Society. 



all altitudes, but later observations were confined to tlie zenith. 

 Some of the results were discussed by General Strachey and Mr. 

 Whipple in 1891 (* Roy. Soc. Proc.,' vol. 49, p. 467). 



Recent Experimental Work. 



Of the experimental work done in recent years, or now in process 

 of execution, it would be premature to speak at length. 



Aneroid Barometers. Experiments have for some time been 

 directed to an elucidation of the elastic phenomena presented by 

 aneroid barometers under varying pressures, with a view to render- 

 ing the results obtained under one definite set of conditions at the 

 Observatory more serviceable under the varied conditions which 

 occur in nature. 



Atmospheric Electricity. At intervals during the last two years, 

 observations have been taken of atmospheric electricity at a variety 

 of points near the Observatory. One of their principal objects is to 

 investigate the extent to which the results may be influenced by 

 peculiarities in the pattern of the recording apparatus or in the 

 circumstances of its immediate environment (' Boy. Soc. Proc.,' 

 vol. 60, 1896, p. 96). 



Electrical Resistance Thermometers. Within the last year a series 

 of experiments have been commenced with electrical resistance ther- 

 mometers. The object is to test their suitability as instruments of 

 precision in scientific research, and also their convenience for the 

 ordinary observer and manufacturer. 



For meteorologists, the suitability of resistance thermometers for 

 the measurement of earth temperatures is a matter of considerable 

 importance. To investigate this, two resistance thermometers of a 

 pattern devised by Professor Callendar and Mr. E. H. Griffiths have 

 been buried near the Observatory, along with a delicate platinum 

 resistance thermometer, and an elaborate comparison is being made. 



Instruction to Observers. 



There is one other sphere of usefulness for the Observatory to 

 which reference should be made, viz., that of a school of instruction. 

 Not a few members of the staffs of other British and Colonial Obser- 

 vatories have received preliminary instruction at Kew ; and the 

 taking of magnetic observations has been studied there by a con- 

 siderable number of officers of H.M. Navy and others intending to 

 proceed on exploratory voyages. 



The plans accompanying this description of the Observatory were 

 drawn by Mr. B. S. Whipple, son of the late Superintendent, who 

 likewise gave valuable assistance in the compilation. 



