100 SCIENCE 12s r SHOUT CHAPTERS. 



Nineteenth Century. All wlio have read my essay on " The 

 Fuel of the Sun" are surprised at the statement with which 

 the magazine article opens viz. that this " may be termed a 

 first attempt to open for the sun a debtor and creditor account, 

 inasmuch as he has hitherto been regarded only as a great 

 almoner pouring forth incessantly his boundless wealth of heat, 

 without receiving any of it back." 



Some of my friends suppose that Dr. Siemens has willfuly 

 ignored the most important element of my theory, and have 

 suggested indignation and protest on my part. I am quite 

 satisfied, however, that they are mistaken. I see plainly 

 enough that although Dr. Siemens quotes my book, he had not 

 read it when he did so ; that in stating that " Grove, Hum* 

 boldt. Zollner, and Mattieu Williams have boldly asserted 

 the existence of a space filled with matter," he derived this 

 information from the paper of Dr. Sterry Hunt which he after- 

 ward quotes. This inference has been continued by subse- 

 quent correspondence with Dr. Siemens, who tells me that he 

 saw the book some years since, but had not read it. My con- 

 tributions to the philosophy of solar physics would have been 

 far more widely known and better appreciated had I followed 

 the usual course of announcing firstly " a working hypothesis," 

 to warn others off the ground, then reading a preliminary 

 paper, then another and another, arid so on during ten or a 

 .dozen years, instead of publishing all at once an octavo volume 

 of 240 pages, which, has proved too formidable even to many of 

 those who are specially interested in the subject. 



I am compelled to infer that this is the reason why so many 

 of the speculations, which were physical heresies when 

 expounded therein, have since become so generally adopted, 

 without corresponding acknowledgment. This is not the place 

 for specifying the particulars of such adoptions, but I may 

 mention that in due time " An Appendix to the Fuel of the 

 Sun," including the whole history of the subject, will be pub- 

 lished. The materials are all in hand, and only await arrange- 

 ment. In the mean time I will briefly state some of the 

 points of agreement and difference between Dr. Siemens and 

 myself. 



In the first place, we both take as our fundamental basis of 

 speculation the idea of a universal extension of atmospheric 

 matter, and we botk regard this as the recipient of the diffused 

 solar radiations, which are afterward recovered and recon- 

 densed, or concentrated. Thus our " fuel of the sun" is 



