426 



The National Physical Laboratory. 



The number of instruments rejected in 1899 and 1900 on account of 

 excessive error, or for other reasons, was as follows : — 



1899. 1900. 



Thermometers, clinical 149 116 



„ ordinary meteorological .. . 78 79 



Sextants 151 122 



Telescopes 49 116 



Binoculars 21 31 



Various 14 28 



Four Standard Thermometers have been constructed during the 

 year. 



There were at the end of the year in the Observatory, undergoing 

 verification, 16 Barometers, 285 Thermometers, 15 Sextants, 250 Tele- 

 scopes, 30 Binoculars, 2 Hydrometers, 4 Eain Measures, 2 Bain Gauges, 

 and 4 Unifilar Magnetometers. 



VI. Bating oe Watches and Chronometers. 



The number of watches sent for trial this year is slightly less than 

 in 1899, the total entries being 403, as compared with 469 in the pre- 

 ceding year. 



The " especially good " class A certificate was obtained by 98 ; 

 movements. 



This is a marked increase on the number obtained in 1899, and the 

 general performance has been decidedly better. 



The following figures show the percentage number of watches 

 obtaining the distinction " especially good," as compared to the total 

 number obtaining class A certificates : — 



'Year 1895. 1896. 1897. 1898. 1899. 1900. 



Percentage " especially good " 16*6 30'5 28-0 22*1 26-6 35*4 



The percentage is thus higher than in any previous year. 

 The 403 watches received were entered for trial as below : — 

 For class A, 320 ; class B, 60 ; and 23 for the subsidiary trial. Of 

 these 21 passed the subsidiary test, 55 failed from various causes to 

 gain any certificate, 50 were awarded class B, and 277 class A certifi- 

 cates. 



In Appendix II will be found a table giving the results of trial of 

 the 51 watches which gained the highest number of marks during 

 the year. The highest place was taken by Mr. A. E. Fridlander, of 

 Coventry, with the keyless going-barrel Karrusel lever watch, No.. 

 25,582, which obtained 90T marks out of a maximum of 100. 



This is the first English lever watch to reach the 90 marks limit, and 

 its performance is the best since 1892. 



Marine Chronometers. — During the year, 53 chronometers have been. 



