PRIZES FOR THE INVENTOR 



141 



in the form of cloud or rain. No great 

 amount of heat is required to produce 

 ■evaporation and no great amount of cold 

 is necessary to effect condensation. 



Such considerations as these may lead 

 to some cheap industrial process for the 

 manufacture of fresh water from the sea. 

 All that is necessary is a current of air 

 over your salt water to remove the water 

 vapor collected there, and then the carry- 

 ing of this confined current into a cool 

 reservoir where the water may condense. 



THE THERMOS-BOTTLE IDEA APPLIED TO A 

 WATER TANK 



As little or no artificial heating is re- 

 ■quired, a great saving can be effected in 

 the matter of fuel. It is extraordinary 

 how wasteful we are in our means of 

 producing heat and in retaining it after 

 it has been produced. It is safe to say 

 that a great deal more heat goes up the 

 -chimney than we utilize from a fire. 

 Then when we cook our dinner or boil 

 water, we allow the heat to escape by 

 radiation and the things soon cool. 



A cosy for our teapot, a fireless cooker 

 for our dinner, and a thermos bottle for 

 • our heated liquids show how much heat 

 may be conserved by simply taking pre- 

 cautions to prevent radiation. Our hot- 

 water boilers are not protected by cover- 

 ings of asbestos paper or other insulating 

 material, so that the water gets too cool 

 for a warm bath very soon after the fire 

 is put out. 



I have made experiments to ascertain 

 whether some of the heat wasted by radi- 

 -ation could not be conserved by insulat- 

 ing materials, with rather astonishing re- 

 sults. A large tank of zinc was made 

 which would hold a great deal of water. 

 This was inclosed in a box very much 

 larger than itself, leaving a space of about 

 three or four inches all around, which 

 was filled with wool. I then found that 

 hot water put into that tank cooled al- 

 most as slowly as if it had been a thermos 

 bottle. 



I then attempted to save and utilize 

 some of the heat given off by a student's 

 lamp. A couple of pipes were led out of 

 this insulated tank and placed in a hood 

 ■over the lamp. Thus a circulation of 

 water was effected. The water heated by 



the lamp found its way up into the tank 

 and produced a sensible rise of tempera- 

 ture there. Next day when the lamp was 

 again lighted it was found that the water 

 in the tank still felt slightly warm. It 

 had not lost all of the heat it had received 

 at the former heating. When the lamp 

 was again put out, the temperature of the 

 tank was considerably higher than on the 

 former occasion. 



This process of heating was continued 

 for a number of days, and it became ob- 

 vious that a cumulative effect was pro- 

 duced, until at last the water in the tank 

 became too hot to hold the hand in, and 

 it was determined to see how long it 

 would hold its heat. The temperature 

 was observed from time to time, and 

 more than a week after the lamp had 

 been put out the water was still so warm 

 that I used it for a bath. 



CUTTING DOWN THE CHIMNEY TAX 



Since then this insulated tank has been 

 taken up to the attic of my house in Nova 

 Scotia and has been installed there as a 

 permanent feature. I have the habit of 

 working at night and like to take a warm 

 bath somewhere about 2 o'clock in the 

 morning. Unfortunately the heating ar- 

 rangements in the house have given out 

 long before that hour and only cold water 

 comes from the kitchen boilers. I con- 

 nected the insulated tank with an iron 

 pipe let down my study chimney in the 

 hope of saving and utilizing some por- 

 tion of the heat that escaped up the chim- 

 ney every time the fire was lighted. 



I have had this apparatus in use for 

 over a year, and find that at any time of 

 the day or night I am always sure of a 

 warm bath from the heat that used to be 

 wasted in going up the chimney. In this 

 case there was only one straight pipe, so 

 that the amount of heat recovered bears 

 only a small proportion to that still 

 wasted. A coil of pipe in the chimney or 

 special apparatus there would, of course, 

 be much more efficient. 



I think that all the hot water required 

 for the use of a household, and even for 

 warming a house, could be obtained with- 

 out special expenditure for fuel by utili- 

 zation of the waste heat produced from 



