CHEMICAL SCIENCE. 245 



able to freeze mercury contained in little glass ampulas. Finally, the 

 liquid protoxyd became solidilic'd under the recipient of an air-pump, 

 the temperature being reduced to 120 below zero, Centigrade, the 

 most intense cold yet obtained. 



New I\1<><1(' <>/' Analysis, The capillarity of paper as a means of 

 analysis, as suggested by M. Schb'nbein, has been employed by M. 

 Goppelsrb'der in the separation of coloring matters. When a band of 

 paper is dipped into curcuma (Indian saffron) and picric acid, three 

 distinct layers are perceive'd; the first formed by pure water, the 

 second colored by picric acid, and the third by the yellow of the 

 curcuma. If the paper be dipped into an alkaline liquid the picric 

 laver disappears, while the curcuma remains with the brownish hue 

 which it acquires under the circumstances. Similar experiments are 

 produced with fuchsine, &c. 



Mari'iTs Process for recovering Writing on Paper or Parchment 

 which has become nearly effaced. The paper or parchment written 

 on is first left for some time in contact with distilled water. It is then 

 placed for five seconds in a solution of oxalic acid (1 of acid to 100 of 

 water) ; next after washing it, it is put in a vessel containing a solu- 

 tion of gallic acid (10 grains of acid to 300 of distilled water) ; and 

 finally washed again and dried. The process should be carried for- 

 ward with care and promptness, that any accidental discoloration of 

 the paper may be avoided. Cosmos. 



Pure Water from Lead Pipes. Dr. Schwartz of Breslau, proposes 

 to render lead pipes, used for water-conveyance innocuous, by 

 filling the pipes for a short time, with a strong solution of an alkaline 

 sulphide. A coating of insoluble sulphide of lead is thus formed, 

 which is said to act as a perfect protecting varnish, preventing further 

 action between the water and lead. C/iem. News. 



New Green Color. A prize has been awarded by the Paris Acad- 

 emy to M. Bouffe for a new green, which is produced by a mixture, it 

 is said, of picric acid and the hydrous oxyd of chrome (chrome 

 green) . The new color, called by the inventor vert naturel, is of great 

 beauty and brilliancy, and is suited to replace the arsenical greens 

 often used to color wall paper from which a poisonous dust arises. 



Lea's Cleaning Solution. Photographers are under great obliga- 

 tions to Mr. Carey Lea, of Philadelphia, for the knowledge of the 

 following glass-cleaning preparation : Water one pint ; sulphuric 

 acid, k ounce ; bi-chromate potash, A ounce. The glass plates, var- 

 nished or otherwise, are left, say 10 or I"2 hours, or as much longer as 

 desired, in this solution, and then rinsed in clean water, and wiped or 

 rubbed dry with soft white paper. It quickly removes silver stains 

 from the skin without any of the attendant dangers of the cyanide of 

 potassium. 



The Physical Analysis of the Human Breath. Mr. W. F. Barrett, 

 assistant ia the Physical Laboratory of the Royal Institution, has pub- 

 lished in the Philosophical Magazine, a record of some remarkable ex- 

 periments on this interesting subject, made chielly by means of the 

 apparatus employed by Dr. Tyndall, in his researches on the absorp- 

 tion and radiation of heat by gaseous matter. Carefully prepared 

 vulcanized India-rubber bags were filled with air from the lungs. 1. 

 About half an hour after rising: 2. About ten minutes after break- 

 21* 



