538 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



12 ozs, of nitric-acid at 1.38 specific gravity (or 8 oz. at 1.50) ; 

 and digesting at a gentle heat til] the solution is complete. 



4. Siret's Compound. — Sulphate of iron 20 ll)s. ; sulphate of 

 zinc 6\ lbs. ; wood or peat, charcoal 1 lb. ; sulphate of lime 2(5| 

 lbs. ; mix and form into balls. To be placed in cesspools, etc., 

 to deodorize them. M. Siret has subsequently modified this com- 

 pound, thus : sulphate of iron, 100 parts ; sulphate of zinc, 50 ; 

 tan, or oak-bark powder, 40 ; tar 5 ; and oil, five parts. 



5. Collins' Disinfecting Poioder. — Mix two parts of dry chlo- 

 ride of lime with one of burnt alum. To be set in shallow dishes 

 in rooms, etc., with or without the addition of Avater. 



A Valuable Secret. 

 The S cientific American says : " The unpleasant odor produced 

 by perspiration is frequently a source of vexation to persons who 

 are subject to it. Nothing is simpler than to remove this odor 

 much more eflectually than by the application of such onguents 

 and perfumes as are in use. It is only necessary to procure some 

 of the compound spirits of ammonia and place about two table- 

 spoonsful in a basin of water. Washing the face, hands and 

 arms with this, leaves the skin as clean, sweet and fresh, as one 

 could wish. The wash is perfectly harmless, and very cheap. It 

 is recommended on the authority of a physician." 



A Pleasant Mouth Disinfectant. 

 A writer in the Dentist, Lcipsic, 1866, gives the following 

 formula for a corrective of the bad odor from decayed teeth, 

 which he suggests may prove to the dentist cleansing them, and 

 the individual suffering from them, a source of cholera. Formula: 

 Hypermanganate of potassa and hyperoxydate of barium, of each 

 twenty-four grains, one-half to be rubbed up into a mass, with 

 sugar and glycerin, and divided into 144 lozenges. Every ill- 

 smelling mouth will become, by their use, perfectly odorless. — 

 Medical Record. 



New Test for Acids and Alkalies. 

 Owing to its property of being reddened by acids and turned 

 blue by alkalies, prepared litmus is perhaps the most generally 

 useful of all the chemical tests which have been hitherto known. 

 A test of a similar nature, but very much more sensitive than 

 litmus, has recently been found .by Scuhnbcin, to be furnished by 



