NATURAL PHILOSOPHY. 149 



firing. For yellow color they used a preparation of silver and cop- 

 per, and minerals were used more or less in the preparation of all the 

 colors for burning in. If the colors were applied by the brush, as in 

 the coloring of daguerreotypes, the process amounted, in fact, to that 

 of glass painting, properly speaking, instead of its being a mechanical 

 process, as this professed to be. His (M. Joubert's) object had been 

 to bring this invention to a purely mechanical result, so as to obviate 

 the necessity of employing artists for glass painting. The object of 

 the invention was to reproduce photographs or designs in a perfect 

 form by mechanical manipulation. 



In regard to the size and colored variety of the pictures executed, 

 M. Joubert said that the specimens he had exhibited, as being un- 

 burnt, twenty-four by seventeen and one-half inches, were the largest 

 he had yet produced, but he apprehended the size was only limited by 

 the dimensions of the kiln. There would, of course, be a little more 

 care required in manipulating upon a large picture, but there would 

 be no difficulty in producing a picture of three or four feet square. 



In regard to the combination of colors capable of being burned at 

 the same time, he could not, at present, give a definite opinion. The 

 specimens exhibited were almost all of one color. He thought 

 it better to produce them perfectly in monochrome in the first in- 

 stance, and having mastered the difficulties of manipulation in one 

 color, then to go to three or four colors. He would call attention to 

 one specimen, having a colored border with an edging which had the 

 appearance of ground glass. It was, however, produced by a coating 

 of flux. The colored border was also added, and was burnt in at the 

 same time with the white' enamel, all in one firing, showing that a 

 color and white enamel could be accomplished at the same time. He 

 had been able to produce four colors in one burning. He had no 

 doubt, with improved manipulation, a variety of colors could be pro- 

 duced at one firing ; but all glass painters were aware that to attempt 

 to produce perfect copies of pictures, with all shades of colors, would 

 be to branch into another line of art. Instead of being mere printing, 

 it would become regular glass painting. It had been his object to 

 avoid that from the first. As regards price, he believed the pictures 

 could be afforded for eight shillings (two dollars) per square foot. 



Mr. Hawes said that the members of the society must have arrived 

 at the conclusion, from what they had heard, that there was a new 

 application of one of the newest and most recent discoveries connected 

 with the art and industry of the present day. Photography, a young- 

 art, was applied in a new form, and with great facility, to produce 

 most beautiful effects. They sometimes saw decorations of windows 

 which, though beautiful within, had a very unsightly appearance from 

 the outside ; but here they had both sides equally beautiful. It was 

 an invention of a peculiar kind. It was pure photography applied to 

 glass, with this addition, that it was burnt into the substance of the 

 glass, and became as durable and indestructible as the glass itself; and 

 this he apprehended constituted one of the chief merits of the inven- 

 tion. It would enable them, he trusted, before long, to obtain copies 

 of beautiful pictures for decorative purposes, at comparatively small 

 cost. 



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