238 Intelligence and Miscellaneous Articles, 



plants upon iodized paper in their vicinity. By passing moist air 

 through a tubulated bell-glass covering the plants to be experi- 

 mented on, and exposing the iodized paper to the air at its exit from 

 the bell, it will be seen that whenever the plant is capable of pro- 

 ducing odorous volatile substances, coloration takes place ; in the 

 opposite case the paper remains white. 



From some experiments recently published, it would appear that 

 the oxygen disengaged by the green parts of plants under the influ- 

 ence of light is in the same state as the gas produced by the electro- 

 lytic decomposition of water, or the nascent oxygen prepared in the 

 cold by the action of sulphuric acid upon binoxide of barium. The 

 author has found that this oxygen has no effect upon iodized paper. 

 He placed some aquatic plants in a bottle filled with rain-water 

 containing about half its volume of carbonic acid, exposed the appa- 

 ratus to the sun, and collected the gas under a test tube filled with 

 water ; the gas produced no coloration of iodized paper by contact 

 for six hours. As it might be objected that the gas had lost its oxi- 

 dizing power during the short space of time occupied in collecting it, 

 he adapted to the neck of the bottle containing the plants, a glass 

 tube of 3 decimetres in length, covering its lower half with black paper, 

 and introducing a strip of test paper both into this and into the por- 

 tion left exposed to the light. The apparatus was exposed for two 

 days to the sun ; 2*25 litres of moist gas were evolved, the whole of 

 which passed over the iodized paper, of which the strip protected, 

 from the light was unchanged, whilst the other was strongly coloured. 

 This is the constant effect of the action of light upon iodized paper 

 in the presence of moist oxygen. 



It cannot be admitted that, as advanced by Schonbein, and lately 

 repeated by Scoutetten, light ozonizes the air, for although the active 

 modification of oxygen is not permanent, it may be kept for several 

 hours ; and if light possessed the property attributed to it, moist air 

 exposed to the sun, and removed for a short time from the action of 

 the solar rays, ought to act upon iodized paper in the manner of 

 ozone ; but this is never the case. However long the air may be 

 exposed to the sun, it is never ozonized. — Comptes Rendus, July 7, 

 1856, p. 38. 



ON THE PRESENCE OF MERCURY IN THE NATIVE ARGENTIFEROUS 

 COPPER OF LAKE SUPERIOR. BY M. HAUTEFEUILLE. 



The author received 200 kilogrammes of this mineral to ascertain 

 its value. Its gangue consisted principally of calcareous spar, 

 which was got rid of by dilute muriatic acid ; its weight was 50*476 

 kilogrms. The copper was covered with larger and smaller tufts of 

 metallic silver, which were removed by the graver. Fragments of 

 copper were selected which did not appear to have had any silver on 

 the surface, and cut into the centre; the author found in them 0*002 

 of silver ; the whole gave 0008 of silver when melted. The total 

 weight of copper was 138-560 kilogrms. 



The silver removed by the graver was assayed by the humid way 

 and estimated at 0*993, but the assay presented the following phae- 

 nomenas— 1, the liquid was scarcely limpid ; 2, the chloride of silver 



