Report of the Kew Committee. 351 



Thermometers, ordinary Meteorological 1518 



„ Standard 166 



Mountain 69 



Clinical 5365 



Solar radiation 143 



Total 7261 



Besides these, 27 Deep-sea Thermometers have been tested, 2 cf 

 which were subjected in the hydraulic press, without injury, to 

 pressures exceeding three and a half tons on the square inch, and 73 

 Thermometers have been compared at the freezing-point of mercury, 

 making a total of 7361 for the year. 



Duplicate copies of corrections have been supplied in 145 cases. 



Eleven Standard Thermometers have also been calibrated and 

 divided, and supplied to societies and individuals during the year. 



The following miscellaneous instruments have also been verified : — 



Hydrometers 195 



Anemometers 12 



Rain Gauges 4 



Theodolites 4 



Sextants 36 



Index Glasses for ditto, unmounted 2 



Horizon „ ,, ,, 2 



Prismatic Compasses 4 



There are at present in the Observatory undergoing verification, 

 7 Barometers, 160 Thermometers, 10 Anemometers and 7 Sextants. 



A Barograph and Thermograph have been examined, and had their 

 scale values determined for the Government Astronomer, Adelaide, 

 South Australia ; and a Standard Barometer has also been com- 

 pared for Professor Tacchini, of the Italian Meteorological Service. 



A Redier Barograph, purchased by Mr. Dowson at the suggestion 

 of the Superintendent, was put up at the Observatory, and its per- 

 formance tested for a fortnight before being forwarded to him. 



Dr. Siemens having placed one of his Electrical Thermometers at 

 the disposal of the Meteorological Society for their observations of 

 the temperature at the summit of Boston Church Tower, 270 feet 

 high, this instrument was tested for a few days at the Observatory and 

 found to work satisfactorily. 



Sextant-testing . — A report upon the errors of Sextants, based upon 

 the comparisons made at the Observatory since the introduction of the 

 present system in 1865, has been submitted to Mr. Galton, at his 

 request. 



