THE ATMOSPHERE. 11 



in possession of this metal, it readily transfers it to the 

 surfaces of numerous substances, and extends it over a 

 greater space than can be done by beating or any other 

 process. By the aid of this agent, then, numerous uten- 

 sils, and even cloth, cords, and thread, are gilded at a 

 most trifling expense. 



Not only paints, but dyes are prepared, and attached 

 to the surfaces or fabrics to which they are to be applied 

 by this general agent. Without its aid in giving perma- 

 nency to colors, most dyes are mere stains, and entirely 

 removed at the first washing. Some colors it heightens 

 or deepens after they are applied. Ink of a good quality, 

 is sometimes pale, when first applied to paper, but after a 

 few days, it becomes of a deep and permanent black. 

 Indigo, when first formed from the plant, is green, as it 

 is when first applied to cloth ; but by a short exposure to 

 the air, or to oxigen, it becomes the beautiful and perma- 

 nent blue so extensively witnessed in woollen, silk, and 

 cotton goods. Oxigen is not only the most active and 

 general agent in preparing colors and fixing them to their 

 fabrics, but it is more generally and successfully employ- 

 ed than any other, for destroying them. The important 

 process of bleaching is conducted by it, whether by the 

 old method of exposing cloth alternately to moisture and 

 the sun, or by the modern and improved method of im- 

 mersing it in chlorine. 



It seems, then, that this remarkable character not only 

 fills numerous and important offices, but those of almost 

 an opposite nature, and that it possesses properties, which 

 are not only distinct, but opposite. 



Though oxigen is by far the most active and general 

 agent in conducting the innumerable chemical operations 

 of the atmosphere, another ingredient is the most abun- 

 dant. It has already been observed, that only one fifth, 

 or, more exactly, twenty one per cent., of the atmosphere 

 is oxigen. The other essential ingredient is nitrogen, 

 which constitutes seventynine parts in a hundred. This 

 ingredient, though abundant, is almost wholly inactive. 

 Its properties appear to be entirely of a negative character. 

 It neither sustains nor destroys life nor combustion. It 

 neither carries on, nor retards, fermentation in any of 



