872 



LORD RAYLEIGH ON THE COMPRESSIBILITY OF CASKS, HTC. 



interval was allowed to elapse between the reduction of pressure and the corre- 

 sponding readings, whether the big bulbs were in use or not. Any anomalies not 

 dependent upon the walls of the big bulbs themselves are thus eliminated. In 

 addition to commercial ammonia, a special sample prepared by Dr. SCOTT in accordance 

 . with STAS' directions was employed. It will be seen that there is no certain 

 difference between the results from the two kinds. 



The departure from BOYLE'S law, in this case, is almost more than can be provided 

 for in the side apparatus. It became therefore necessary to allow a small difference 

 of temperature between the high- and low-pressure observations such as would some- 

 what prejudice the accuracy of the results, were it possible to expect the attainment 

 of the same high degree of accuracy as for the less condensable gases. Under the 

 actual circumstances the variation of temperature was of no importance. 



AMMONIA. 



