124 



Report of the Kew Committee. 



testing of Anemometers and Air-meters ; but in the opinion of 

 Dr. Robinson it will be better to postpone its erection for a time. 

 Meanwhile these instruments, temporarily erected on the roof, are 

 compared directly with the Standard Anemograph, and tables ot 

 corrections supplied to reduce their readings to the same scale of 

 velocities as that indicated by the latter instrument. 



The experiments made in 1874, and described in the Report for 

 that year, to determine by means of a " steam- circus " at the Crystal 

 Palace, the true value of Robinson's factors for Anemometers at 

 different velocities, are under discussion by Professor G. G. Stokes, 

 F.R.S., and have been found to afford valuable results. A paper, 

 which he intends to communicate on the subject to the Royal Society, 

 is nearly ready. 



Experiments have been made with one of M, Hagemann's Anemo- 

 meters (" Quart. Jour. Met. Soc," vol. v, p. 203), designed for use at 

 sea, the results being submitted to the Meteorological Council. 



A Bridled Anemometer, designed by Mr. F. Galton, has also been 

 tried. 



The Galton Thermometer -tester has had a new water-heater fitted to 

 it, and has besides undergone thorough repair and renovation. 



The Winchester Observatory of the Yale College, U.S.A., having 

 recently established a department on the Kew system, for the 

 verification of thermometers, Professor Newton, Secretary of the 

 Institution, visited our Observatory, studied the methods employed for 

 comparing thermometers, and procured copies of the various forms 

 and certificates used in the work. 



The Sextant-testing apparatus has been improved during the year 

 by the substitution of reticules, photographed on glass, for the glass 

 threads in the focus of the collimators. The latter, by their breakage, 

 rendered frequent re-adjustment of the instrument necessary. 



Standard Barometers. — Numerous comparisons have been made 

 during the year between the two Welsh Standard Barometers, the old 

 Royal Society Standard (which it is found cannot without risk of 

 derangement be returned to Burlington House), and Newman, No. 34, 

 the working Standard of the Observatory. 



Arrangements have been made by means of which the latter may, 

 when desired, be read by the cathetometer, as well as by its own scale, 

 the correct value of which has also been re- determined. 



VI. Aid to Obseevatoeies. 



Waxed Papers, 8fc., supplied. — Waxed paper has been supplied to the 

 following Observatories : — 



Batavia, Colaba, Glasgow, Lisbon, Montsouris (Paris), Mauritius, 

 Oxford (Radcliffe), and Utrecht. 



