BOTH SIDES OF THE BLUE GLASS QUESTION. 91 



tory, are frequently compelled to travel hundreds of miles in the dead of 

 winter. The capital of the new territory will be the young but rapidly 

 growing town of Bismarck. Fortunately, at the suggestion of Senator 

 Bogy, the name was changed from Pembina to the more euphonious one of 

 Huron. The latter is an Indian name, while the former is a corruption of 

 two French words. — Washington Star. 



CHEMISTRY. 



BOTH SIDES OF THE BLUE GLASS QUESTION. 



In the issues of February 24th and March 3d, 1877, the Scientifi^c Ameri- 

 can attacks the blue glass theories of Gen. Pleasonton in detail, and wind& 

 up by saying, "It is hardly necessary to add that in our opinion the use of 

 blue glass, as advocated by Gen. Pleasonton, is devoid of benefit." In order 

 to place the subject before our readers in its entirety, as elaborated and put 

 forth by its assailant and defender in their best and most able manner re- 

 spectively, we will give the objections proposed by the first and the answer- 

 thereto, as nearly in full as our space will allow, beginning with the Scien- 

 tific American: 



"On September 26, 1871, Gen. A. J. Pleasonton, of Philadelphia, Pa., 

 obtained a patent for ' utilizing the natural light of the sun transmitted' 

 through clear glass, and the blue or electric f!) solar rays transmitted 

 through blue, purple, or violet colored glass, or its equivalent, in the propa- 

 gation and growth of plants and animals.' In his specification, of which 

 the above constitutes one claim, he states that he has discovered 'special 

 and specific efficacy in the use of this combination of the caloric raj^s of 

 the sun and the electric blue light in stimulating the glands of the body, the 

 nervous system generally, and the secretive organs of man and animals.' 

 He also states that he finds that vegetation is vastly improved by the trans- 

 mitted blue light. 



"These alleged re-discoveries — for the General only claims to have de- 

 vised the method of utilizing them — were extensively promulgated through 

 the press early in 1871. Subsequently, in 1876, Gen. Pleasonton published 

 a book -on the subject, the volume being appropriately^ bound in blue and 

 printed in blue ink. Eecently public attention has again been called to the 

 subject by a New York daily journal. The peculiar kind of glass in ques- 

 tion is known as 'pot-metal blue,' that is, it is stained a bluish violet 

 throughout, and is not clear glass covered with flashings of blue glass. It 

 is used in greenhouses, etc., in connection with clear glass; and in Gen. 



