KEW OBSERVATORY AND METEOROLOGY 227 



perfectly, to a considerable improvement in the make 

 of the cheaper sextants. 



Another thing that I did was to contrive an 

 apparatus by which thermometers could be rapidly 

 and yet very accurately verified, and by which from 

 ten to twenty thousand clinical thermometers are still 

 annually tested. Mr. De la Rue gave me help in 

 devising this. The few pence gained on each of these 

 many thermometers amounted to a respectable sum, 

 and confirmed the solvency of the institution, whose 

 margin of profit over loss, was always small and had 

 been precarious. We were thus in a better position 

 to extend our work and to add to our instruments, 

 and we did so. 



Another operation which I was among the first, 

 if not the first, to suggest, was the rating of watches. 

 This has been a real success. The performances of 

 watches, when we first took the matter in hand, was 

 by no means proportionate to their cost, more than 

 one highly ornamented and expensive time-keeper 

 failing to obtain a class-place equal to that of others 

 of much inferior pretensions. Now a Kew certificated 

 watch has a special and recognised value, and the 

 makers of valuable watches are far more on their 

 mettle than they used to be. 



The influence of the Kew verifications as time 

 went on extended in many other directions, as by 

 testing the performance of telescopes and opera-glasses 

 supplied to the army and navy, in order to ascertain 

 whether their capabilities were up to the specified 

 standard. Mariners' compasses of complicated and 

 delicate construction were also dealt with. A beauti- 

 ful apparatus devised by Sir Wm. Abney and Major 



