174 PHILOSOPHICAL TRANSACTIONS. [ANNO 1797. 



to the pressure of 2 atmospheres; at the temperature of 242° -f 30° = 272° it will 

 equal 4 atmospheres; 



at 272 



at 302 



at 332 

 at 362 

 at 392 

 at 422 

 at 452 

 at 482 

 at 512 

 at 542 



+ 30° = 302° 

 + 30 = 332 

 + 30 = 362 

 -j- 30 = 392 

 -f 30 = 422 

 + 30 =. 452 

 -f 30 

 + 30 

 + 30 

 + 30 



it will equal 8 atmospheres; 



16 



32 



64 



128 



256 



= 482 512 



= 512 1024 



= 542 2048 



= 572 4096 



at 572 -|- 30 = 602, (or 2 degrees above the heat of boiling lin- 

 seed oil), its elasticity will be equal to the pressure of 8 1 92 atmospheres, or above 

 8 times greater than the utmost force of the fluid generated in the combustion of 

 gunpowder, according to Mr. Robins's computation. But the heat generated in 

 the combustion of gunpowder is much greater than that of 602° of Fahrenheit's 

 thermometer, consequently the elasticity of the steam generated from the water 

 contained in the powder must of necessity be much greater than the pressure of 

 8 192 atmospheres. Following up our computations on the principles assumed, 

 (and they are founded on the most incontrovertible experiments) we shall find that, 

 at the temperature the elasticity will be equal to the pressure of 



of 602° + 30° = 632° 1 6384 atmospheres; 



at 632 + 30 = 662 32768 



at 662 + 30 = 692 65536 



and at 692 -f- 30 = 722, the elasticity will be equal to the pressure of 131072 

 atmospheres, which is 130 times greater than the elastic force assigned by Mr. 

 Robins to the fluid generated in the combustion of gunpowder; and about » part 

 greater than my experiments indicated it to be. 



degrees of heat, in this table, are according to Reaumur's thermometer, 

 is contained in the annexed tablet j where the 1st column shows several 

 degrees of strength of the steam, being in fact the number of French 

 inches of the mercurial barometer that are balanced or sustained by the 

 steam ; in the 2d column are the corresponding degrees of heat of the 

 steam, expressed by the degrees of Reaumur's thermometer j and in the 

 3d column are the differences of these degrees, which are not the same 

 number or difference, but always increasing. Hence it appears, that 

 while the numbers in the 1st column, denoting the strength of the steam, 

 are always doubled, or nearly so, those in the 2d column, denoting the 

 corresponding heat, are always increased by differences that are unequal. 

 Were the calculation carried on, always doubling the elasticity for the 

 constant addition of 30° of Fahrenheit's thermometer, till arriving at 

 1000° of heat, we should obtain the monstrous quantity of about 100 

 millions of atmospheres for the pressure of the elastic fluid ! 



A specimen of those numbers 



Dif. 



2 

 3 

 5 

 7 

 8 



10 



11 



12 



13 



14 



15 



