ON ARTIFICIAL EEFEIGERATION. 903 



The distance by sea from America led to enteii"»risiug dealers visiting 

 Norway, and Lake Oppegaard was purchased with the privilege of renam- 

 ing it ; the i)urchasers having made all necessary arrangements for ship- 

 ments of ice thence to England, the lake has ever since gloried in the 

 name of Wenham. Drobak, Drammen, Christiania, Brockstadt, and 

 other iS"orwegian ports supply England also. 



Mr. Holdsworth,* writing in 1874, said: "It is yet a question 

 whether it will pay to apply steam to the actual trawlers, but Ave had 

 an opportunity in 1872 of observing in an experimental vessel the prac- 

 tical advantage gained by its use, both when fishing and goiug to and 

 returning from the fishing ground," This at once indicates the j)roba- 

 bility of using refrigerating machines instead of bulky, costly, and dete- 

 riorating processes, and likewise render fishermen altogether independ- 

 ent of ice-crops and ice-merchants. 



B.— IMPOETAXCE OF riSH-CULTUEE IN GREAT BEITAIN. 



The favorable conditions of an extensive sea-shore, encirling islands 

 which can be crossed by rail in a few hours, with innumerable streams, 

 to permit the ascent of spawning fish, are most tempting to the fish cul- 

 turist, and would indicate that a large fish trade could be developed 

 even without ice. The slow progress in the artificial propagation of 

 fish in England is a matter for surprise. 



Until this scientific remedy can be applied, the ice-question is a serious 

 one all round the British Isles, and, indeed, the supply of fish, to inland 

 towns, is determined more by the scarcity of ice than the scarcity of fish. 

 The Irish coast would supply large quantities of excellent fish, and 

 many a fishing-village might be made populous and i)rosi)erous by an 

 unfailing suijply of cheai:) ice. 



C— ORIGIN OF KNOWLEDGE OF ARTIFICIAL COOLING. 



The germ of all the modern improvements in making ice dates back 

 to 1755, when the great Dr. CuUen, Professor of Medicine in the Uni- 

 versity of Glasgow, attemiited to determine whether the solution of cer- 

 tain substances, in spirits of wine, was attended with elevation or lower- 

 ing of temperatiu-e. One of his pupils, entrusted with these experiments, 

 observed that, on withdrawing the thermometer from the alcoholic solu- 

 tion, the mercury fell, and, with the aptitude of an original observer, 

 Cullen tried the pure spirit. By moistening the bulb Avith a feather and 

 blowing to hasten evaporation, the temperature dropped from 41o to 

 below 32'^. He pursued his investigations further, and tried a variety 

 of volatile substances, of which he found the " quick-lime spirit of sal am- 

 moniac" the most i^owerful. This is a singularly felicitous anticipation 

 of the knowledge we now possess, that no hqiiid, boiling at low temper- 

 atures, absorbs more heat than ammonia. 



* Dcep-Sea Fishing and Fishing Boats. London, 1874. 



