ICE 



2903 



ICEBERG 



planes; there they are packed in sawdust or 

 other material and kept in storage until 

 needed. The average cost of harvesting a ton 

 of natural ice is about eighty cents. 



Natural ice is harvested in the United States 

 and Canadian provinces on an enormous scale. 

 The industry in the former country dates from 

 the early part of the nineteenth century, the 

 two most important fields of operation being 

 in Maine and on the Hudson River. There are 

 also huge ice houses on the lakes and streams 

 of Wisconsin, Minnesota and Michigan, some 

 of which are nearly 300 feet long and five sto- 

 ries high. The total capacity of the buildings 

 used for storing natural ice throughout the 

 country is about 30,000,000 tons. 



Artificial Ice. The trouble and expense at- 

 tending the transportation of natural ice long 

 distances and the changeable weather conditions 

 have resulted in the rapid development of the 

 artificial-ice business in those sections far re- 



HOW AN ICE-MAKING MACHINE IS 



CONSTRUCTED 

 (a) Low pressure (e) Brine inlet 



gauge (/) Brine outlet 



(&) High pressure (g) Evaporator 



gauge (7i) Condenser 



(c) Compressor (i) Water outlet 



(d) Regulating valve (j) Water inlet 



moved from natural ice fields. The first im- 

 portant ice factory established in America was 

 erected at New Orleans in 1866, and at the 

 present time the people of the Southern states 

 depend almost entirely upon the manufactured 

 article for their supply of ice. The Middle 

 states also produce great quantities. Natural 

 ice enters into successful competition with arti- 

 ficial ice farther north; the states of Maine, 

 New Hampshire, Minnesota, North Dakota, 

 South Dakota, Montana and Wyoming reported 

 no ice factories to the Thirteenth Census (1910), 

 while the latest Canadian census (1911) lists 

 only four of such establishments. However, 

 manufactured ice is gradually making its way 

 into the northern territory, and its use is con- 

 tinually increasing. According to a recent esti- 

 mate, there are 3,500 ice factories in the United 

 States, with a yearly output of 18,000,000 tons, 



valued at $45,000,000. These establishments, 

 which do not include the numerous private 

 plants operated by breweries, cold storage 

 houses, etc., represent an investment of about 

 $150,000,000. 



The manufacture of ice is a practical appli- 

 cation of the principle that when a liquid 

 changes to a vapor or gas heat is drawn from 

 surrounding objects and their temperature is re- 

 duced. Ammonia, because of its cheapness and 

 the low temperature at which it is converted 

 into a gas, is the liquid most commonly used 

 as a refrigerating agent in ice factories and cold- 

 storage plants. Ammonia gas is condensed into 

 a liquid by means of a powerful force pump 

 which is driven by steam. The resulting liq- 

 uid, which contains no water and is known as 

 anhydrous ammonia, is then sent "through a 

 valve into a system of pipes from which the air 

 has been pumped, and which pass back and 

 forth in a large tank containing salt water, or 

 brine. In these pipes the ammonia expands 

 into a gas, the heat required for the process 

 being absorbed from the brine. The latter, 

 though it does not freeze, is cooled until its 

 temperature is several degrees below the freez- 

 ing point of fresh water. 



The water which is to be frozen is placed in 

 cans the shape and size of the desired blocks 

 of ice, and these are kept submerged in the cold 

 brine until their contents have frozen solid. 

 After the freezing process the cans are raised 

 from the tank by a hoist and then dipped into 

 warm water to loosen the cakes of ice within 

 them. The above operations require from 

 twenty to sixty-six hours, the time varying 

 with the size of the blocks of ice and the tem- 

 perature of the brine. 



Considering all seasons of the year, it costs 

 from $1.10 to $1.50 to produce a ton of arti- 

 ficial ice; wholesale prices range from $2.00 to 

 $2.25 per ton, and the retailer pays from fifteen 

 to forty cents per hundred pounds, according 

 to the season and locality. In large cities cou- 

 pon books good for 1,000 pounds of ice are 

 sold to consumers, the cost of such books being 

 from $2.50 to $3.00 each. B.M.W. 



Related Subjects. For material of interest in 

 connection with this subject, the reader is re- 

 ferred to the following articles : 



Iceberg 



Snow 



Thermometer 



Ammonia 

 Cold Storage 

 Expansion 

 Freezing 



ICE 'BERG. The deadliest perils that ships 

 have to face, especially in the North Atlantic 



