Manchester Memoirs, Vol. xlii. (1898), No. 6. 49 



was the same in all. This series, when compared with 

 others that follow, was of use, in so far as it showed to 

 seme extent the limit of error involved in the method of 

 eliminating the loss of heat by radiation. 



The results obtained from the first series were so satis- 

 factory that the lagging of the brake was at once pro- 

 ceeded with. This consisted of a layer of about i ^ inches 

 of loose cotton covered with thick flannel. 



Series 11. to VI I. 



Contained trials Nos. 12 to 42. In trial No. 12 the 

 lagging was evidently damp, and the results obtained 

 were consequently rejected. Trials Nos. 24, 25, and 26 

 have not been reduced at all, because the load carried by 

 the brake was 1244-12 ft.-lbs., and therefore the results 

 were not readily comparable with the other heavy trials, 

 which carried a load of 1200 ft.-lbs. In addition to this 

 the tightness of the bottom regulating cock on the brake 

 was so great, as to impede its motion by a moment of 

 30 ft.-lbs. about the engine shaft. 



Series V., containing trials 27 to 32, also suffered under 

 the latter defect, and have, therefore, been allowed no 

 weight in the final result. The individual results do not 

 differ materially from others which have been obtained, 

 but the want of freedom of the brake was thought 

 sufficient to condemn them. 



The annexed table gives the maximum, minimum, 

 and mean values of K given by these series. 



1 



Number of 



Values of K obtained. 





Determi- 

 nations. 





1 





Maximum. 



Minimum. 



Mean. 



Series IL 



2 



7783 



777-02 



77766 



Series III. 



3 



77946 



776-63 



777 94 



Series V. 



3 



778-46 



77775 



778-1 



; Series VI. 



2 



778-59 



777 16 



77789 



' Series VII. 



^ 



778-55 



777-02 



777-86 



