Intelligence and Miscellaneous Articles. 



83 



I have succeeded. I first made some attempts by diffusion, but 

 hitherto without any- great success ; but I expect an apparatus which 

 I have had constructed, and with which I hope to succeed. I then 

 sought for some substance which should really absorb ozone, but 

 without decomposing it as iodide of potassium does. I have found 

 it in oil of turpentine and in oil of cinnamon, which destroy ozone 

 in a mixture of this gas and of oxygen, producing a diminution of 

 volume. It is natural therefore to suppose that these oils absorb 

 the ozone entire ; hence the possibility of determining the density, 

 not perhaps with great accuracy, but with a sufficiently close 

 approximation to decide whether it is 1|, 2, or 3 times that of 

 oxygen. It is sufficient to compare the diminution in volume of 

 the gas treated with the oil, with the volume of oxygen absorbed by 

 the iodide of potassium, or, what comes to the same thing, with the 

 increase of volume which it experiences under the influence of heat. 

 I have thus found that the diminution of volume by the oil is the 

 double of the increase of volume by heat ; and I thence conclude that 

 the density of oxygen is once and a half that of oxygen, and have thus 

 confirmed the hypothesis mentioned above. The following are the 

 results which I have obtained: — 



Absorbent. 



Diminution 

 in volume. 



Expansion by heat. 



Calculated. 



Observed. 



Difference. 



Oil of turpentine 



>y >> 



cub. centims . 

 6-8 

 57 

 5-8 

 5-6 

 67 

 6-9 

 57 



cub. centims. 

 3-4 

 285 

 2-90 

 2-80 

 335 

 3*45 

 2-85 



cub. centims. 



377 

 3-20 

 314 

 3-32 

 3-30 

 3-45 

 272 



cub. centims., 



4-0-37 

 +0-35 

 4-0-24 

 4-0-52 

 -005 



-013 



„ turpentine 



>> }> 







The agreement is as close as can be expected in this kind of mea- 

 surement, especially for the three last experiments, in which I 

 avoided a slight source of error which I had not at first perceived. 

 I worked with flasks of about 230 cubic centims. capacity, and with 

 oxygen ozonized by electrolysis. 



NOTE OF AN EXPERIMENT ON VOLTAIC CONDUCTION. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 

 In the last Number of the Philosophical Magazine I suggested a 

 crucial experiment to decide whether the electric force of the voltaic 

 pile is conveyed by the entire thickness of the conductor or by the 

 external surface only. It has since occurred to me that the point 

 might perhaps be tested without delicate apparatus, by an appeal to 

 the sense of touch. I provided two polished steel cylinders exactly 

 alike, each 3 inches long and -^ inch diameter. One I covered with 

 bright copper wire T J-jj- inch diameter, coiled round it quite tight 

 and close, thus forming a cylinder 0* 12 inch diameter, having a cop- 

 per surface. The other I covered with steel wire -^ inch diameter, 

 coiled also close together, thus forming a cylinder 0'14 inch dia- 



