EXAMPLES. 133 



10. If the sum of the readings on Fahrenheit's and the 

 Centigrade thermometer be zero for the same temperature, 

 find the reading of each thermometer. 



Ans. llf ; llf. 



11. If 327 cubic inches of gas at 280 be allowed to cool 

 down to 56, find the volume.* Ans. 223 cubic inches. 



12. If, by the application of heat, 120 cubic inches at 

 60 R expand into 180 cubic inches, find the temperature. 



Ans. 320. 



13. If the pressure be 14.7 Ibs. on the square inch at the 

 temperature 62, what will it become if raised to 420 ? 



Ans. 24.78 Ibs. 



14. If the pressure at 50 be 15 Ibs., and if the tempera- 

 ture be so far increased as to make the pressure 21 Ibs., find 

 the temperature. Ans. .254. 



15. The air in a spherical globe, one foot in diameter, is 

 compressed into another globe, 6 inches in diameter, and 

 the temperature is raised t. Compare (1) the pressures of 

 the air under the two conditions, and (2) the pressures on 

 the surfaces of the globes. . j (1) 1 : 8 (1 + at) ; 



M() l:2(l + *). 



16. The temperature of the air in an extensible spherical 

 envelope is gradually raised t, and the envelope is allowed 

 to expand till its radius is n times its original length. Com- 

 pare the pressure of the air in the two cases. 



Ans. \-\-at : n s . 



17. A mass of air at a temperature t is contained in a 

 cylinder which has an air-tight piston fitting into it, and it 

 is found that the air exerts a pressure P on the piston ; the 



air being suddenly compressed into : - of its former vol- 



* Fahrenheit's Thermometer is understood, unless otherwise expressed. 



