168 REPORT — 1856. 



following da}'. The Thames water was then replaced by clear well-water. The 

 apparatus was again adjusted. The quantity of water weighed in the box 437 lbs. 

 The temperature of the air was 65° Fahrenheit when the experiment commenced, 

 and of the water 64° Fahrenheit. 



The apparatus made 270 revolutions per minute, and in 55 minutes raised the 

 temperature of the water from 64° to 73^°, or an increase of 9}° Fahrenheit. 



The experiments were continued on the third day with well-water at 59°, and the 

 temperature of the air 60i°. The apparatus was worked from 10i> 5°" a.m. to l"- 5™ 

 P.M., when the temperature of the water was raised from 59° to 75i°, or 161' in- 

 crease in three hours. 



On the third day the apparatus was defective from the slipping of the strap, and 

 only made 140 revolutions instead of 270 revolutions per minute. 



The apparatus having been repaired was again set to work on the 24th of June, 

 being the fourth and last day of experimenting. 



The following were the results : — 



Number of revolutions of apparatus 240 per minute. 



Temperature of well-water in the box 59^° Fahrenheit. 



Began at 10 a.m. Temperature of Water. 



10-0 591 deg. Fahr. 



10-5 691 



11-0 74 



11 SO 74 „ 



11-34 75 



12-0 79 



12-8 80 



1 P.M. 89 



Stopped at 1 p.m. for one hour, and on starting again at 2 p.m., found that the 

 temperature of the water had fallen to 76", being a loss of 13o Fahrenheit. 



This, however, was owing to the tube which contained the thermometer being 

 exposed to the influence of the east wind : started the engine and apparatus at 



2 P.M. 



At P.M. Temperature. 



2-0 76 degrees. 



2-5 (increase 10°) 86 



2-15 88 „ 



30 92 „ 



3-30 95 „ 



4-0 974 „ 



4-15 99' „ 



4-45 100 „ 



5-0 101 1 „ 



515 102 



5-30 stopped 103 „ 



The total increase of temperature having been 44i° in 6J hours. 



On examining the foregoing Tables, it will be seen that the increase of tempera- 

 ture seems to follow no regular laws ; thus : — 



From 10 a.m. to 11 a.m. the increase is 141° Fahrenheit. 



„ 11 A.M. to 12 a.m. „ 50 



„ 12 A.M. to 1 P.M. „ 16° 



„ 2 P.M. to 3 P.M. the temperature of the water 



rose from 76° to 92°, being an increase of 16° in 1 hour. 



„ 3 P.M. to 4 P.M. „ 92° to 971° „ 51° 1 only 



„ 4 p.m. to 5 P.M. „ 97° to 101 1° „ 4° ^ per 



„ 5 P.M. to 51 P.M. „ 1011 to 103^° „ 2° J hour. 



So that, had the experiments continued longer, the rate of increase per hour might 

 have been reduced to an equilibrium. 



As a proof that the box radiated very little heat, on one occasion the apparatus 

 (after the temperature of the water had been raised from 60° to 103° Fahrenheit) 

 was left all night for 14 hours exposed to the external air. The temperature of the 



