546 Intelligence and Miscellaneous Articles. 



strip of moist iodide of potassium paper into the vessel, and if this is 

 coloured, add more solution of indigo until the decolorization is 

 complete, when the quantity of solution employed gives the amount 

 of ozone in the gas. 



When, for example, 250 grms. of the test-solution are decolorized, 

 the weight of ozone causing this effect would be 250-7-10=25 mil- 

 ligrms., in which amount there is no allowance for the quantity of 

 air displaced by the 250 grms. of solution. If the volume of the 

 tested gas reduced to 32° and 76 centim. bar. amounts to 30 litres, 

 and the weight of ozone in it to 30 milligrms., this air contains yy^s 

 ozone, since under these conditions a litre of air weighs 1298 mil- 

 ligrms, and in this quantity of air there is 1 milligrm. ozone. 



My recent experiments have proved that atmospheric air may be 

 ozonized to the extent of j-gVo ^7 nieans of phosphorus ; and did not 

 ozone act so energetically upon phosphorus, a much higher degree 

 of ozonization might be attained. At this point, however, the pro- 

 duction and consumption of this substance appear to be equal, and 

 ignition of the phosphorus takes place in consequence of the rapid 

 oxidation. 



I have already often pointed out the great similarity between the 

 effects produced by chlorine and ozone. One instance of this is the 

 fact that like chlorine it combines with phosphorus at ordinary tem- 

 peratures. There can therefore be no doubt that this body would 

 immediately take fire in pure ozone gas,"as in chlorine, even in the 

 cold. 



As the above-mentioned test-solution of indigo is very dark blue, 

 it may be very greatly diluted, and still appear deeply coloured. 

 I therefore employ two more dilute solutions of such a strength, 

 that 10 grms. of one is decolorized by I'lO milligrm., and 10 grms. 

 of the other by 1*100 milligrm. of oxygen. By this means it is evi- 

 dent that even very small fractions of a milligrm. of ozone may be 

 detected and estimated. 



With this very delicate reagent I have found that ozone diluted with 

 500,000 times its volume of atmospheric air may still be recognised 

 by its smell, sufficiently proving that the pure ozone must have a 

 most intense odour. — Ibid. 



ox THE MOTION OF FLUIDS FROM THE POSITIVE TO THE NEGA- 

 TIVE POLE OF THE CLOSED GALVANIC CIRCUIT. BY M. WIE- 

 DEMANN. 



The author has communicated to the Prussian Academy of Sciences 

 a memoir on the mechanical action of the voltaic circuit, which is of 

 essential interest and importance. The apparatus employed con- 

 sisted of a porous earthenware cell, closed at the bottom and termi- 

 nated above by a glass bell firmly cemented to the upper edge of 

 the cylinder. Into the tubulure of the bell a vertical glass tube was 

 fitted, from which a horizontal tube proceeded so as to permit the 

 fluid raised to flow over into an appropriately placed vessel. A wire 

 serving as the negative pole of a battery passed down through the 



