932 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



progress, iu certain forms at least, of industrial art. Indeed, when the 

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

 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 admirable illustrations of the combination of scientific 

 knowledge with practical skiU which the Exposition presented." 



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

 a furnace to about half its altitude. A tube extending upwards conveys 

 the liberated ammoniacal gas to a vessel called the Uqiiejier. The upiDer 

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

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

 allowing the escape of the gas. The gas passes to the aforesaid Hquefier, 

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

 water, and thence iuto a kind of bin where, under a pressure of 150 iiounds 

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

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

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

 ing partitions in a tank, and between which the substances to l^ 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 water 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 i)er 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 62°.6 Fahr., but in work the supplies return to the boiler at or 

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

 have to be raised Irom 110^ to 266^ Fahr., or through 126 degrees, and 

 also to convert 80 pounds of pure ammonia from 140° Fahr. into vai)or 

 at 266^". The consumption of fuel has been couiputed in practice at 50 

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

 the fuel for the steam-engine has to be supijUed, 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 imjjrove 

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

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

 is showered whilst air bloNv^s 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 of the ammonia is always so far from perfect that it in- 



