Report of the Keio Committee. 



219 



Aneroid Altitude Scales. — The Committee have also had their atten- 

 tion called to the fact that several scales are in use for graduating the 

 scales of heights upon the dials of aneroids. Upon consideration the 

 Committee recommend as desirable the employment of Sir G. B. Airy's 

 scale, published in 1867, and the equivalent metric scale, in all cases 

 where possible. 



Two highly sensitive aneroids with Bourdon tubes substituted for 

 the ordinary corrugated vacuum boxes, constructed by MM. Richard, 

 Freres, of Paris, have been examined for constancy at the request of 

 the Meteorological Council. It was found, however, that the metal 

 of the tubes underwent changes similar to those experienced by the 

 usual aneroid boxes, and the instruments were therefore liable to the 

 same errors as the common aneroid. 



A Beckley Ram Gauge was obtained, fitted with a Stonyhurst dis- 

 charger, and, after due trial, sent to the Mauritius Observatory, where 

 an opportunity will be afforded of noting the behaviour of the im- 

 proved instrument during tropical rains. 



Hygrometers. — Dr. Doberck, the Director of the Hong Kong Obser- 

 vatory, having obtained a Royal Society grant for the purpose of 

 re-calculating Hygrometric tables, Mr. Whipple procured and for- 

 warded to him examples of Alluard's, Crova's, and Dines' instruments, 

 after making preliminary observations at Kew. 



Hot Springs. — Mr. G. J. Symons, F.R.S., having received a grant 

 from the Government Grant Fund of the Royal Society, for the pur- 

 post, of investigating the temperatures of certain hot springs in the 

 South of France and the Pyrenees, had a number of specially pre- 

 pared thermometers carefully verified at the Observatory, both before 

 and after he had made use of them abroad. 



Anemometer Constants. — At the request of Colonel Knight, F.R. 

 Met. Soc, a number of comparisons with the standard Anemometer 

 were made of a small Robinson's Anemometer he had constructed, 

 having cups fitted to arms of variable length, and the moving parts 

 provided with friction rollers. 



Anemographs. — Mr. Whipple has, at the request of the Imperial 

 Chinese Customs, superintended the construction of a new Beckley 

 Anemograph for use at Formosa, as well as a similar instrument for 

 Dr. A. S. Viegas, of the Coimbra Observatory, and two smaller 

 instruments for the Meteorological Council. 



Navy Telescopes. — By the kindness of the Astronomer Royal the 

 Kew Observatory has been favoured with descriptions of the tests 

 applied to Navy telescopes supplied by contractors to H.M. Service, 

 and also with descriptions of the apparatus employed at the Royal 

 Observatory, Greenwich, for applying the tests. 



A standard Admiralty telescope has been purchased, and the neces- 

 sary appliances are now being constructed, with the view of enabling 



