928 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



consumed in trials witli this macliine, and the most discouraging prac- 

 tical difficulties were brought to light. It was not till long afterward 

 that the inventor could discover the proper modes of obviating these difB- 

 culties. Nevertheless, this first small machme served as a complete 

 verification of the facts, principles, and numerous small experiments which 

 had been relied upon; and it thus became an encouragement in the end 

 to attemi)t a vastly larger construction." 



On the 15th of February, 1855, an engine calculated to produce 2,000 

 pounds of ice per day in ten freeziug-cisterns of cast iron, each divided 

 into seven water-chambers, w;is in readiness for trial. With only two 

 cisterns of the ten, 371 jjomids of ice were made in eight hours. The 

 water einjjloyed for condensation was thirty times in quantity the water 

 frozen. In the vacuum- vessel the tension of vaj^or began with 5.7 inches 

 of mercury and ended with 2.7 inches. In the condenser, the tension 

 rarely exceeded 2 pounds above the atmosphere. The i)ump was Sc- 

 inches bore and 18 inches stroke, working 90 double strokes per minute. 

 On the 2d of March, 1855, G61 pounds of ice were made in eleven hours 

 and ten minutes with only four cisterns. In difi'erent trials during the 

 summer, eight cisterns of the ten were put on. The machine would at 

 any time freeze up in these cisterns 56 cakes of ice, each 1 foot square and 

 C inches thick, and weighing together 1,680 x)Ounds. With ten cisterns, 

 a ton could be frozen. 



The great merit of Professor Twining's invention was extending the 

 surface over which ice could be formed, by extending the "freezing-cis- 

 tern" containing the ice-moulds, and using an uncongealable liquid which 

 was stagnant around the moulds. This was the great advance on Mr. 

 Jacob Perkins. In a patent issued April 22, 1862, he claims a pump to 

 agitate or circulate the uncongealable liquid. Twining described in 1852, 

 but a patent was only issued on the 15th of April, 1862, the method of 

 using a refrigerator, as in the Harrison machine, with vertical tubes closed 

 beneath or entering a cul de sac, allomug the ether to run down and its 

 vapor to escape upward. The vaporized li<iuid thus abstracts heat from a 

 contiguous uncongealable liquid that surrounds the pipes, and in its cold 

 state is drawn out by a circulating-pump in place of running the cold 

 volatile liquid through the freezing-cistern. This pumj) circulates the 

 brine in open troughs which contain the water-vessels. Professor Twin- 

 ing aimed at extending surfaces, and for this he had described 2i percolator. 

 He had perforations, or perforated branches or channels, girdling every 

 exposed side of each water-chamber, and made to inject the ether in jets, 

 or drops or films, ui)on or between its exposed surfaces or coatings. The 

 volatile liquid thus si)read uj)on or running down the water-chambers 

 freezes through the uncongealable liquid and the icater-vessels in those 

 chambers. 



Mr. James Harrison, of Geelong, Australia, did excellent work in his 

 jjivestigations of this subject, and so instructive are his specifications 

 that they may be said to constitute the most substantial contributions to 



