932 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



j)rogress, in certain forms at least, of industrial art. Indeed, ^^'llen the 

 apparatus is examined in its details, and the ingenious felicity with wliicli 

 the difficulties involved in the problem have been met is understood and 

 appreciated, this invention cannot fail to be recognized as presenting 

 one of the most admii-able illustrations of the combination of scientific 

 knowledge with practical skill which the Exposition presented." 



A solution of ammonia is introduced into a boiler which is heated by 

 a fiu'uace to about half its altitude. A tube extending u^) wards conveys 

 the liberated ammoniacal gas to a vessel called the liqucfier. The upiier 

 part of the boiler is occupied by broad shallow vessels pierced with holes, 

 constituting the rectifier, so as to return the water to the boiler whilst 

 allo^\dng the escape of the gas. The gas passes to the aforesaid liquefier, 

 which is a combination o± zigzag and spiral tubes in a tank of cold 

 water, and thence into a kind of bin where, under a pressure of 150 pounds 

 at 70° to 80° Fahr., the gas is liquefied. From here the ammonia flows 

 into a small receiver adjoining the refiigerator, and which is called the 

 (listrihutor. Thence the liquid passes into zigzag or spiral tubes form- 

 ing i)artitions in a tank, and between which the substances to be cooled 

 are placed. These tubes of the refrigerator converge into the collector^ 

 which is a horizontal tube, from which an ascending pipe returns the 

 ammonia rendered gaseous by heat to a vessel, the absorber, partially filled 

 with water, and which greedily absorbs the gas ; a current of cold water 

 passes through a coil in this vessel. This w^ater has also to cool the 

 spent liquor from the boiler and which is to reabsorb the gas. When the 

 gas has been reabsorbed, the strong solution is forced by a pump into the 

 boiler. 



Taking a machine with a production of 400 pounds of ice per hour, 

 it must distil, liquefy, evaporate in the refrigerator, and redissolve 80 

 pounds of pure ammonia. The 80 pounds of ammonia with 1,600 pounds 

 of water give 1,680 pounds of liquid to be acted on. This liquid is at 

 first at 02O.6 Fahr., but in work the sui)plies return to the boiler at or 

 above 140° Fahr., so that for continuous work 1,600 pounds of water 

 have to be raised from 140° to 266° Fahr., or throngh 120 degrees, and 

 also to convert 80 pounds of pure ammonia from 140° Fahr. into vapor 

 at 266°. The consumption of fuel has been couqiuted in practice at 50 

 pounds per hour, each pound making eight poimds of ice; besides this, 

 the fuel for the steam-engine has to be supplied, and in most cities the 

 water has to be paid for. That water Professor Barnard calculated at 

 3,200 gallons per hour, or nearly one gallon per second, making less than 

 five tons of ice per day. Many attempts have been made to imi)rove 

 these machines since by Oscar Kropf, liees Eeece, Martin, Beath, Mshi- 

 gawa, and others. With condensing and absorbing coils in which water 

 is showered whilst air blows across to favor evaporation, a great economy 

 in water is effected ; but the pressures and leaks in these machines are 

 very objectionable, the construction is complicated, parts numerous, and 

 the dehydration qf the ammonia is always so far from x^erfect that it in- 



