CHEMICAL SCIEXCE. 197 



polariscope, no depolarizing action ; and the same remark applies to 

 the bichloride of platinum, in consequence probably of its imperfect 

 crystallization ; on the other hand, the chloride of sodium and platinum 

 in thin crystalline plates, is remarkable for its depolarizing power ; 

 and a trace of this salt, which is invisible to the naked eye, may be at 

 once detected by the brilliant display of prismatic colors which it 

 exhibits under the action of polarized light. This property may be 

 applied to the detection of soda in the following way : The other 

 bases having been removed by the ordinary methods, and the alkalies 

 converted into chlorides, a drop of the solution is placed on a glass 

 slide, and a very small quantity of a dilute solution of the bichloride of 

 platinum added, avoiding, as far as possible, an excess of that re-agent. 

 The drop is then evaporated by a gentle heat till it begins to crystal- 

 lize, and afterwards placed in the field of a microscope furnished with 

 a good polarizing apparatus. On turning the analyser till the field 

 becomes perfectly dark, and excluding carefully the entrance of light 

 laterally, the crystals remain invisible if either potash, or no alkali 

 whatever, be present, while the presence of the slightest trace of soda 

 is at once indicated by the depolarizing action of its platinum com- 

 pound. With a drop of solution of chloride of sodium weighing 

 0.0015 grm. and containing l-10,000th of its weight of chloride of 

 sodium, a very distinct effect was obtained. The quantity of soda 

 thus detected was only 1-13, 000,000th of a gramme, or about 1-1,000,- 

 000th of a grain. 



ELECTRO-CHEMICAL RESEARCHES OX THE PROPERTIES OF 



ELECTRIFIED BODIES. 



FREMY and Becquerel contributed the following paper to the 

 Comptes Rendus, March, 1852. 



For several years the attention of chemists and physicists had been 

 directed to the very remarkable modifications which certain bodies 

 present when submitted to the action of a very moderate temperature. 

 We know that, under this influence, sulphur and phosphorus acquire 

 new properties. We propose to investigage whether electricity, like 

 heat, can change the physical and chemical properties of different 

 bodies. We must examine, in the first place, into the singular effects 

 presented by oxygen in various circumstances, and referred to the 

 formation of w^hat has been called ozone ; this body appears to be pro- 

 duced in all cases in which oxygen is submitted to the influence of 

 electricity. Without wishing to cast doubt upon the sagacity of those 

 who have examined into the properties of ozone, it cannot be denied 

 that there still exists great uncertainty in the minds of chemists and 

 philosophers as to the interpretation of the phenomena observed ; we 

 have therefore thought it was important to submit these phenomena to 

 new experiments. 



After going over all the experiments made on ozone, mentioning in 

 particular the important researches of Schoubein, Marignac, and De 



