194 



below zero. The snow had just fallen, and the air was very 

 clear. 



The reason the world is colder in the winter than in the 

 summer is not because the sun is not so hot; the sun is in 

 reality hotter, but owing to the angle at which his rays strike 

 the earth we get less benefit from them. For instance, in 

 England the sun's rays strike the earth in winter at an angle 

 as low as 35, so that the rays are spread over a much 

 larger surface, consequently we have much colder weather. 

 But when you turn a surface directly towards the sun, as we 

 do our heaters, then you get more heat in the winter than in 

 the summer. Therein lies the difference between our heaters 

 and the earth's surface in general; in the former case the effect 

 is one of concentration, in the latter of diffusion. 



Mr. P. J. BURGESS : If you are going to adapt your sun- 

 power plant to places outside the tropics, it will be necessary 

 for you to tilt your sun-catching machine, will it not ? 



Mr. SHUMAN : If we were to put up a sun heater here we 

 would not turn the apparatus from north to south, but from 

 east to west. 



Mr. BURGESS : You would have to have a movement in both 

 directions. 



Mr. SHUMAN : We would prefer very much to have a move- 

 ment in both directions, because we would get a better result 

 in that case. But as the practicability of this system depends 

 upon the yield of power per pound sterling invested, we have 

 to throw that extra advantage away because, if we attempted 

 to do that, our sun heater would cost so much more. If we 

 had to turn it in both directions, it would mean such compli- 

 cated mechanism that it would not be practicable. 



Mr. BURGESS : Is not that a consideration which practically 

 precludes the possibility? 



Mr. SHUMAN : No, I would not propose a sun heater at the 

 North Pole, or in unreasonable places, but I was speaking just 

 now of Indian conditions in winter. That was the question 

 which brought up this discussion. The sun in winter in the 

 tropics is by no means so low as in India. I do not know 

 exactly the latitude of that portion of India which was referred 

 to just now, but I imagine the sun would still be at a fairly 

 steep angle in winter, and that would make the use of a sun 

 heater quite practicable. 



Mr. BURGESS: One more question. As I understand, this 

 sun-power plant catches the heat of the sun, turns it on to the 

 water, turns the water into steam, and the steam is made use 

 of in the usual way. Is there no way of turning this sun heat 

 directly into electricity ? Steam is JDecoming rather an anti- 

 quated form of power now. Could we not turn the heat 

 directly into electricity? 



