940 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



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



"5 A pumj) similar to the chloride pump, but i)laced at the opposite 

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

 called pump Ko. 5. 



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

 called pump Xo. 6. 



''I will now describe the working of these diiferent 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 Ko. C, identical in its action to the pump X, takes, by 

 means of the tube f, f, /, 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 mn,j be placed in any suitable position. 



" The pump ]N'o. 2, which is an air pumj) similar to the pump O, draws 

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

 H; it therefore allows the trimethylamine 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 api^aratus. A. cock placed at v w, allows 

 of regulating this action, as will be understood. The pump No. 2 m^y 

 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 trimethylamine may be absorbed. This receiver is shown 

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

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

 cates with the puritier; and one at a? f, which communicates with the 

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



" The working of the chlorure pump 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 finally in the absorber J, to 

 be employed in the absorption. 



"The motive x>ower 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 vapours which escape from H through It are very cold, but the 

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

 thus causing them to circulate in opposite directions; 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 air produces cold, and that the effect is analogous to the change 



