426 Mr. J. R. Harrison's Experimental Researches 



thick ; a few threads of unspun silk wound round the head of 

 the thermometer-tube hold it in position. This I will call the 

 " enclosed " thermometer, and the other the " naked " one ; 

 both thermometers are fixed to one cork and placed in a glass 

 tube. The whole apparatus is seen in fig. 2. is the cork with 

 thermometers attached , the bulbs of which are at a distance of 

 one inch from each other; T, a glass tube 12 inches long and 

 1^ inch internal diameter containing them; V, a glass vessel 

 8 inches long and 4 inches internal diameter, fitted with a 

 cork to admit the tube T ; this vessel is filled with water at 

 the boiling-temperature ; t, a tube to convey the steam given 

 off by the water to condenser K. The mode of performing 

 the experiment is as follows: — 



The thermometers being in their places, the tube containing 

 them is placed in a freezing-mixture and allowed to remain 

 till both thermometers register 0° C. The water in the vessel 

 V is heated by the aid of a spirit-lamp which is withdrawn 

 when the water boils ;< when ebullition has ceased the tube is 

 taken from the freezing-mixture and quickly passed into the 

 vessel V, and the rise of both thermometers noted from minute 

 to minute. When the enclosed thermometer has reached its 

 maximum temperature, the tube is then withdrawn, placed in 

 the freezing-mixture, and the descent from minute to minute 

 noted. The result of the experiment is seen in the following 

 Table:— 



Registration of both thermometers at commencement of 

 experiment, 0° C. 



Naked thermometer 









Enclosed thermometer. 



After the 







gain in 





After the 









gain in 



lapse of 1 minute 



, 35°; 



temp. 



35° 



lapse of 



1 minute, 9°; 



temp. 



2 



„ 



55 



a 



20 



tt 



2 



it 



20 



a 



3 



>> 



64 





9 



it 



3 



a 



28 



a 



4 



n 



69 . 



tt 



5 



a 



4 





35 



it 



• r > 



it 



70 



» 



1 



tt 



5 



it 



40 



it 



6 



» 



70 



»> 







a 



6 



11 



45 



it 



7 



a 



71 (max 



•) „ 



1 



tt 



7 



»» 



49 



it 



8 



n 



71 



»> 







tt 



8 



it 



52 



ti 



9 



n 



71 



n 







a 



9 



it 



55 



it 



10 



n 



70 



Loss 



1 



it 



10 



it 



58 



it 



„ 11 



» 



70 



»» 







a 



11 





60 



it 



12 





69 



»» 



1 



tt 



12 



it 



61 



11 



13 



n 



69 



„ 









13 



ti 



62 



it 



14 



n 



68 



n 



1 



tt 



14 



it 



63 



11 



15 



n 



67 





1 



?> 



15 



tt 



63 



n 



16 





66 



n 



1 



ti 



16 



a 



63 





17 



11 



65 



n 



1 



a 



17 



a 



64(max.) „ 



18 



11 



65 



n 







ti 



18 



it 



63 



Loss 



19 



>> 



64 



n 



1 



it 



19 



it 



63 



ii 



20 



n 



64 



n 







tt 



20 



it 



63 





21 



it 



62 



11 



2 



tt 



21 



it 



62 



a 



9° 

 11 

 8 

 7 

 5 

 5 

 4 

 3 

 3 

 3 

 2 

 1 

 1 

 1 

 

 

 1 

 1 

 

 



1 



