148 Scientific Intelligence. — Chemistry. 



These observations may explain the formation of a great number 

 of hepatic mineral waters. M. Dumenil had already observed the 

 presence of acetic acid in some mineral waters, and the observations 

 have been confirmed by M. Vogel. — Idem. 



9. Instantaneous light apparatus. — Amongst the different methods 

 invented in latter times for obtaining a light instantly, ought certainly 

 to be recorded that of Mr. Walker, chemist, Stockton, upon Tees. 

 He supplies the purchaser with prepared matches, which are put up 

 in tin boxes, but are not liable to change in the atmosphere, and also 

 with a piece of fine glass-paper folded in two. Even a strong blow 

 will not inflame the matches, because of the softness of the wood 

 underneath, nor does rubbing upon wood or any common substance, 

 produce any effect except that of spoiling the match } but when one 

 is pinched between the folds of the glass paper, and suddenly drawn 

 out, it is instantly inflamed. Mr. Walker does not make them for ex- 

 tensive sale, but only to supply the small demand that can be made 

 personally to him. — Idem. 



10. Sympathetic Ink. — A weak solution of nitrate of mercury 

 forms a good sympathetic ink on paper. The characters become 

 black by heat. — Idem. 



11. On a peculiar principle in blood, distinctive of its source, 

 (Ann. D'Hygienne publique.) — This principle has been remarked 

 and described, and its utility in medical jurisprudence stated by M. 

 Barruel. Whilst preparing the coloring matter of blood according to 

 M. Vauquelin's process, the clot of ox blood was boiled, with a large 

 excess of sulphuric acid of moderate strength ; on which occasion a 

 strong odor of beef was observed. Some time after, having occa- 

 sion to operate upon the blood of a man who had taken opium, 

 the fluid was first coagulated by heat, and divided; after which, it 

 was boiled with weak sulphuric acid : immediately so strong an odor 

 of the sweat of man was evolved, as to infect the whole laboratory, 

 and render it necessary for the persons to leave the place. This and 

 the former fact combined, induced M. Barruel to extend experi- 

 ments on these subjects, and the following are the results. 



I. The blood of each species of animal contains a principle pe- 

 culiar to each. II. This principle, which is very volatile, has an 

 odor resembling that of the sweat, or the cutaneous or pulmonary 



