A few weeks since—on page 181—we gave a description of murexid as employed in dyeing, and in the last number of Newton's London Journal, we find the description of an improvement, for which a patent has been obtained in England by Wm. Clark, relating to the preparation of this new coloring agent. The patentee states that it has been known heretofore that by treating alloxantine with carbonate of ammonia murexid was obtained. The improved process consists in taking alloxantine in a powdered state or in crystals, and submitting it to contact with ammonia in a gaseous state. A closed chamber or vessel is therefore necessary for conducting the operation, to bring tho gas in contact with the alloxantine. Very pure murexid is also obtained by treating the alloxantine with liquid ammonia mixed with alcohol. The ammonia dissolves the alloxantine, and after this, by driving off the alcohol and ammonia by heat, the murexid obtained is very pure, and capable of being preserved a considerable time. Alloxantine is ' the product of uric acid dissolved in nitric ( acid and exposed to heat.