BOTH SIDES OF THE BLUE GLASS QUESTION. 79 



certain proportions with ordinary daylight.' Mr. Crooke has thus found and 

 appreciated the discovery. In Europe, they followed their own ideas, and 

 failed. I followed, at an infinite distance, the plan of the Creator, who as- 

 sociates the blue light of the firmament with the sunlight in the season of 

 growth to develop life on this planet. Voita la difference. 



"Mr. Crooke proceeds: 'Bat if Gen. Pleasonton is in the right, the won- 

 derful and salutary effects of blue light upon organic life are by no means 

 the most extraordinary of its properties. Heat is also, in some unaccount- 

 able way, developed in the passage of sunlight through blue glass. * * 

 It need scarcely be said that experimentalists have not found the blue and 

 violet rays of the spectrum to be the hottest portions.' 



"In quoting from my book, Mr. Crooke says: 'During the winter of 

 1871-2, which in this city (Philadelphia) was a very cold and rigorous win- 

 ter, two ladies of my family, residing on the northern side of Spruce street, 

 east of Broad street, in this city, who, at my suggestion, had caused blue 

 glass to be placed in one of the windows of their dwelling, associated with 

 plain glass, informed me that they had observed that when the sun shone 

 through these associated glasses in the windows, the temperature of the 

 room, though in midwinter, was so much increased that on many. occasions, 

 they had been obliged, during sunlight, to dispense entirely with the fire 

 which ordinarily they kept in their room, or if the fire was suffered to re- 

 main, they found it necessary to lower the upper sashes of their windows, 

 which were without the blue glass, in order to moderate the oppressive 

 heat.' 



"Mr. Crooke concludes: 'We should feel much greater confidence in Gen. 

 Pleasonton's observations if he had been content to place them before the 

 world us novel, and if verified, important facts; but he goes much farther 

 and deduces from them an entire new philosophy. Into these, his doctrines, 

 it will be early enough to examine when the action of blue light shall have 

 been satisfactorily ascertained.' 



"The moral of which is that it will never do to find out too many of na- 

 ture's secrets at once, or to divulge them suddenly! Scientific nature can't 

 stand it! Gently, General, or you overwhelm us! 



"A writer has published in a Boston newspaper a notice of my book on 

 'Blue and Sunlights.' He is described as a scientist of great learning, prac- 

 tical experience and general intelligence. After slashing right and left, 

 and condemning it in extenso, he explodes in denouncing it 'as a burlesque 

 of science.' Though this expression is used in a sense intended to be de- 

 risive, I accept it, as Buffon, the naturalist, did, when Des Cartes ridiculed 

 the famous story of the destruction of the Eoman fleet in the harbor of 

 Syracuse, by the burning mirrors of Archimedes, declaring it to be absurd 

 and inconsistent with the science of Dioptrics, and yet Buffon repeated the 

 experiment of Archimedes, so far as to set on fire combustibles at the dis- 

 tance of nine hundred feet with plane reflecting mirrors; or, as Cervantes, 

 the celebrated author of the 'History of the renowned Don Quixote de la 



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