\«^iimteli%tfo^*,o/if«<i(^ia.^e Steam-engine. |^.j<| 



gM. Similarly, by means of the last of these equations, we may 

 eliminate the mass fx^ ; and as to the other mass /u,, although it 

 may be a little greater than /ulq, yet the terms which contain it 

 as factor are altogether so unimportant, that we may without 

 hesitation give it the same value as we have found for /Xq ; in 

 other words, for the numerical calculation we may give up the 

 assumption, made for the sake of generality, that the mass in 

 the vicious space is partially liquid and partially vaporous, and 

 suppose that the mass in question consists entirely of vapour. 



The substitutions here mentioned may be made in the general 

 equations (XIV), as well as in the simplified equations (XV). 

 As they present no difficulties, however, we will here limit our- 

 selves to the last, in order to obtain the equations in a form con- 

 venient for numerical calculation. 



After this change the equations become, ,.,f,,j,i 



<;(T,-To) 



+ Mor( joj — j»2)> HScrndffrB*^ -^o rrofinrfRfny^ odi al ^r? ^ JaJ M 



...,.,, 44. In order to refer these equations, which now express the 

 work done in a stroke or by the quantity m^ of vapour, to the 

 unit of weight of vapour, we have to proceed in the same manner 

 as when the equations (35) were changed into (XII) ; that is to 

 say, we divide each of the three equations by m^j and set 



M v' W 



Hereby the equations become 



'(XVI) 



b9l§9ff. 



W: 



r, + lc{T,^T,) 



-(V-/<r)(T3<,3-;,3+/.o)+6V 



ro-c(T3-To) 



45. These equations may be applied in the following manner 

 to the calculation of the work. From the intensity of evapora- 

 tion, supposed to be known, and from the velocity with which 

 the machine is at the same time driven, we determine the volume 

 V which corresponds to the unit of weight of vapour. By means 

 of this value we calculate the temperature Tg^ from the second 



oi^) 10 gflOiJfiwp-) ov.'j i>nii yjij m /jovi-o yn wiModi "to ^^i}iur 



(XVII) 



