Report of the Kew Committee. 



321 



up to the present 367 watches have been tried, of which 39 were 

 submitted by the owners, and 328 by the manufacturers or dealers. 



The 302 watches received during the year were entered for testing 

 in the following classes : — 



For class A, 254 ; class B, 38 ; and class C, 10. Of these 72 failed 

 to gain any certificate ; 6 passed in C, 60 in B, 110 in A, and 6 

 others obtained the highest possible form of certificate, the class A 

 especially good. 



Owing to numerous requests from manufacturers and others, a 

 system of awarding marks to class A watches, indicating the degree 

 of relative efficiency exhibited during trial, was adopted, being based 

 upon plans already in use in the Geneva and Yale Observatories. 

 In it the number of marks awarded to a watch that only just succeeds 

 in obtaining an A certificate is 0, but to an absolutely perfect watch 

 would be 100, made up as follows : — 40 for a complete absence of 

 variation of daily rate, 40 for absolute freedom from change of rate 

 with change of position, and 20 for perfect compensation for effects 

 of alteration of temperature. 



As, however, the trials already in use do not comprise a test for the 

 going of travellers' or explorers' watches, experiments are in progress 

 with a view of constructing apparatus to test the behaviour of watches 

 when kept in motion, as in the case of daily wear and travelling, in 

 order to make a special examination on this point for watches sub- 

 mitted for trial by the Royal Geographical Society. 



A series of tests for pocket chronographs has also been introduced 

 by special request of the Cyclists' Union. 



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

 the watches which have gained the highest certificates in each class. 



The following table will indicate the nature of the trials to which 

 ordinary certificates refer : — 



Position of watch during test. 



For certificate of Class 











A. 



B. 



C. 





10 days 



14 days 



8 days 



right 



5 „ 







5 » 







5 „ 



14 days 



8 days 





5 „ 









5 „ 



1 day 







5 „ 



1 „ 







5 „ 



1 „ 







45 days 



31 days 



16 days 



T 2 



