CASELLA-MILLER DEEP-SEA THERMOMETER. 895 



Test No. 22— Continued. 



This test shows the necessity of care that the mercury is neither ris- 

 ing nor falling when the instrument is sent down for temperature. 



Test No. 24. 



In a mixture of fine ice, salt, and a little sea-water. 



Test ISTo. 24 is not accurate, as it was impossible to keep the temper- 

 ature at all regular, the standard going up and down four or five de- 

 grees at a jump as we stirred the mixture in the slightest degree. 



From the experiments recorded I drew the following results : First, 

 and most important, that there are but few cases where "five minutes 

 are sufficient for the thermometer to take up the temperature of its 

 position," as described in the manual accompanying the instruments, 

 and that the length of time necessary to procure a correct record de- 

 pends upon the difference between the temperature as recorded by the 

 instruments when being lowered, and that of the temperature which is 

 to be measured. 



