206 The Artificial P/odudion [-"^piil, 



again to the boiler a. The gaseous ammonia passes out of the 

 analyzer by the pipe g into a tubular rectifier, d d, where the 

 remaining steam is condensed and separated, while the ammonia 

 passes on through a condenser, f f, where it is liquefied, and then 

 flows through the pipe e to the refrigerator, h, the supply being 

 regulated by a cock, ii. 



Meanwhile a regulated cui'rent of spent liquor passes from the 

 boiler into a long tube, c, called the heater, fitted with an internal 

 set of tubes, through which the concentrated solution of ammonia is 

 forced by the pump j, into the top of the analyzer. By this means 

 the solution of ammonia is heated, and at the same time the hot 

 liquor from the boiler is sufficiently cooled to be supplied to the 

 absorber i, into which it is forced by the pressure of the boiler, 

 through the pipe x x, fitted with a cock, w, to regulate the supply. 

 In the absorber i this water becomes saturated with gaseous 

 ammonia discharged from the refrigerator h, and the resulting 

 strong solution of ammonia is then pumped out into the analyzer. 



The important feature of this arrangement consists in the 

 application of the analyzing column b, and the rectifier d d, by 

 which it is intended that the dehydration of the ammonia should 

 be carried so far that the condensed liquid passing into the refrige- 

 rator may be practically free from water, while in Carre's apjoaratus 

 the liquid supplied to the refrigerator contains 25 per cent, of 

 water, and only 75 per cent, of actual ammonia. 



The efiect of this difference upon the working of the apparatus 

 would be very great. Thus, for instance, the distiUate passing from the 

 boiler of Carre's apparatus, is separated into 95 per cent, of a hquor 

 containing 25 parts of ammonia — which after being cooled is used 

 for supplying to the absorber — and 5 per cent, of a distillate con- 

 sisting of f ammonia and ^ water; which passes through the con- 

 denser without any further separation of the water. Therefore only 

 f of the liquid supplied to the refrigerator is ammonia ; and since 

 water, at the temperature of from — 22^ to — 40^ Fahr., which 

 is produced in the refrigerator, is capable of dissolving and retain- 

 ing in solution its own weight of gaseous ammonia, only two- 

 thirds of the ammonia in the liquid supplied to the refrigerator 

 will be available for refrigeration, the remaining third being 

 retained by the water in that liquid, so that there will be a residuum 

 of solution of ammonia, which must be run oft" from time to 

 time from the refrigerator. Therefore since the effective refrigera- 

 tion in an apjmratus capable of making 5 cwt. of ice an hour from 

 water at 60' Fahr., must be equivalent to the vaporization of 106 lbs. 

 of ammonia within that time, it would be requisite to produce in 

 the condenser a distillate at the rate of 212 lbs. per hour, for of this 

 quantity 53 lbs. will be water, and that water will retain 53 lbs. of 

 ammonia in solution, leaving only 106 lbs. available for refrigera- 



