940 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



"4. A feed pump IS", moved by an excentric n rt, keyed on the sliaft Q. 



'^o. A jjump similar to the chloride pump, but placed at the opposite 

 end of the shaft Q ; this x)ump is not seen in the drawing, but it shall be 

 called pump No. 5. 



"Another feed pump similar to the i)umx) N, not seen in the drawing, 

 called pump No. G. 



"I will now describe the working of these different pumps. 



" The pump O is used for withdrawing, by means of the tube o, o, o, o, 

 the air brought by the water steam into the tubes of the condenser B, ' 

 and therefore insures the proper working of the same. 



"The pump No. 6, identical in its action to the pump N, takes, by 

 means of the tube t, t, t, the condensed water in the condenser B, and 

 conducts it into the boiler, which furnishes the steam to the cylinder of 

 the engine A, and which mny be placed in any suitable position. 



"The pump No. 2, which is an air pump similar to the x>nnip O, draws 

 in through the tube v all the air which may be in the apparatus J and 

 H ; it therefore allows the trimethylamiue which arrives there to evap- 

 orate at low pressure and carries off at the same time the air which by 

 chance might enter into the apparatus. A cock placed at v iv, allows 

 of regulating this action, as will be understood. The pump No. 2 may 

 be so fixed that it may be disconnected when required. As the air 

 which it draws in is charged with methylamine, it does not send it 

 directly into the atmosphere, but into a receiver containing water, and 

 in which the tiimethj'lamine may be absorbed. This receiver is shown 

 at X. As will be easily seen, it is provided with three tubes, one at x, 

 which communicates with the pump No. 2 ; one at x a, which communi- 

 cates with the purifier 5 and one at a; f, which commuDicates with the 

 interior. Finally, a cock x m allows of drawing off the saturated liquid. 



" The working of the chlorure pumj) P has been hereinbefore described. 



"With regard to the pump No. 5, it draws up water from any suitable 

 source, and raises it into the upper reservoir to distribute it either around 

 the condenser E, or round the cooler L, and finallj^ in the absorber J, to 

 be employed in the absorption. 



"The motive power furnished by the cylinder engine A needs no 

 description ; it is used in the ordinary way. 



"The current of cooled chlorure of calcium which escapes through </, d 

 may he utilized for producing ice or cold. 



"The operation of the changer K will be readily understood. 



" The vapoiu"s which escape from H through h are very cold, but the 

 trimethylamiue which runs through the worm h o, h o, is slightly warm, 

 thus causing them to circulate in opposite directions j the greatest 

 amount of cold is extracted to carry it back to H." 



P.— AIR-MACHINES. 



The opinion has widely prevailed that the simple expansion of com- 

 pressed ail" produces cold, and that the effect is analogous to the change 



