DEW. 121 



are designed, and who have not the brains to understand th.-ir 

 tendency. 



The tnir theory, we are told, was at length discovered by Dr. 

 Wells, of London, who made a series of observations with a 

 number of little wool packs, and the result was : "the rate of 

 the deposition of dew, depends upon the rate at which bodies 

 part with their heat by radiation. If the process of radiation 

 is checked, dew is less copiously deposited, and vice versa." 

 For instance, we are told that the earth is continually throwing 

 off its internal heat. If there are any clouds, the radiation is 

 checked at night and there is no dew, but when it is clear, 

 plenty of dew is the result. This, however, is incorrect, for we 

 have often observed that on a clear night no dew is formed, 

 because there was wind. A calm night is just as essential as a 

 clear one. 



Dr. Wells also asserts moon-blindness to be caused by the 

 want of clouds to check the radiation of heat from the eye, 

 which consequently becomes chilled. Moon-blindness, therefore, 

 according to his theory, ought to be as frequent on clear starry 

 nights, as on clear moonlight nights, yet we never hear of 

 persons being afflicted by it. This assertion, consequently, is 

 just as inuch to be relied on as the others. 



Let us now endeavour to find out the origin of dew from 

 atomagnetic law. 



Some objects have more dew formed on them than others. 

 I and bushes in the morning are found covered with dew, 

 while rocks and gravel roads are perfectly dry. Metal we are 

 told radiates very little heat, and no dew forms on it, yet if wo 

 place a piece of metal among grass, it will be covered with dew; 

 while a piece placed on the road bed, will have none. What is 



