WHAT WE OWE TO THE SUN. 41 



" Star-Land," in which these lectures have been pub- 

 lished. There are, however, one or two points which 

 seemed more advanced than would have been suitable for 

 the readers of " Star-Land," and which I did not accord- 

 ingly there enter upon. These are of such importance 

 that I am glad to take this opportunity of alluding to 

 them. 



It will be remembered that in Gulliver's renowned 

 Travels he visited the Grand Academy of Lagado. The first 

 professor into whose laboratory Gulliver was conducted 

 had been engaged for eight years upon " a project for 

 extracting sunbeams out of cucumbers, which were to be 

 put in phials, hermetically sealed, and let out to warm 

 the air in raw inclement summers. He did not doubt 

 that in eight years more he should be able to supply the 

 governor's gardens with sunshine at a reasonable rate." 

 This is not the only occasion on which Dean Swift has, 

 consciously or unconsciously, given us profound scientific 

 truth under a guise of absurdity. Within a page or two 

 of the passage we have quoted is the announcement of the 

 discovery xrf the two satellites of Mars by astronomers on 

 the flying island of Laputa. To this we shall return in a 

 later part of this book. The myth of the Lagado pro- 

 fessor about sunbeams and cucumbers is allied to a truth 

 still more remarkable. 



It is perfectly certain that in the growth of the cu- 

 cumber plant the leaves do lay hold of the sunbeams, 

 extract the heat from them, and lay up that heat or its 

 equivalent in the fruit which is produced. It is equally 

 certain that the heat of the sunbeams could be extracted 

 again, could even be stored in phials hermetically sealed, 



