411 a glass chimney, which does for common artificial light what Dollond effected for the telescope. He has patented a glass chimney, colored, in its melted state, with a natural or slightly blue tint, which, when in use, obstructs the passage of the red and yellow rays, and leaves tho flame of a mellow wax-like white, so imitative of daylight, that the various colors of the most delicate hues, such as ribands, silks, shawls, &e., can be most perfectly distinguished; and we understand, that

more »

... than one of our most eminent artists, who had entirely discontinued painting by gas or lamp-light, have, on obtaining the achromatic chimneys and globes, again taken to it ; as they are as able to distinguish the most delicate contrast of color as by daylight. Achromatized light is, from its extreme purity, perfectly nnirritating to the eye--a sensation of coolness and relief being produced, in place of the pain and fatigue caused by the hot glare of uncorreeted light. Tim quality which it possesses, of enabling the eye to indicate with distincmess the smallest characters of type, or manuscript, renders it unrivalled for the purposes of study, reading, long-continued exercise of the pen, as in publie and private offices, banks, counting-houses, clubs, literary institutions, &c. in short, under all circumstances, and in all situations, a universal means of improved illumination.