1879.] Mr. C. Tomlinson on the Action of Solid Nuclei. 27 



immediately covered with a jar of nitrogen and the other with a jar of 

 air. After three days the solutions were still liquid. The spills were 

 then removed, and fresh ones, not previously heated, were introduced, 

 when one solution immediately became solid, and the other some time 

 after. 



If the filtering paper, pumice, plaster, &c, acted by absorption, 

 then the effect of heat would be to increase the absorptive power, and 

 consequently their activity as nuclei ; whereas the contrary result 

 is obtained, so that absorption does not seem to be a vera causa. 



When it is stated that the nuclei became active on being exposed to 

 certain winds in preference to others, the locality in which the experi- 

 ments were conducted must be taken into account ; for, as Professor 

 Stokes suggested at the reading of my former paper, a westerly or 

 southerly wind might be equally active in another place. I found this 

 to be the case at Eastbourne, where a westerly wind produced, in the 

 course of ten minutes, a deep orange-brown stain on ozone test-paper, 

 and made the oils singularly active after a few minutes' exposure. For 

 example, on the 10th of June oil of lemons was inactive in the house, 

 but on being exposed to a strong south-west wind from the sea, about 

 a mile away from the town, it became viscid in the course of a few 

 minutes' exposure, so that it dropped very slowly. The solutions, on 

 contact with this oil, immediately became solid. On the 11th, a 

 limpid paraffin oil, on being redistilled, was inactive within doors. It 

 was taken to the end of the pier, 1,012 feet from the shore, and 

 exposed in drops to a strong westerly wind for about three minutes, 

 when it became powerfully active. On the 13th there was scarcely 

 any wind, but what there was was west south-west. Freshly dis- 

 tilled oil of cajuput was inactive within doors, but, on being exposed 

 to the outer air for about fifteen minutes, it became active. 



In July, at Bournemouth, the weather was sultry ; ozone test-paper 

 was scarcely acted on, even after an exposure of some hours, and 

 inactive oils did not become active under the influence of the air. 



In September, at Denchworth, near Wantage, ozone was abundant, 

 judging from its action on test-paper. Some inactive turpentine oils 

 thickened on being exposed to the air (wind north and south-east), 

 and the effect on the solutions was decisive. 



Before concluding I must refer to the nuclear action of alcohol . In 

 order to test this once more, a day was selected when the wind was in 

 the east, when rain had fallen during some hours, and continued to 

 fall all the time the experiments were being conducted in the open 

 air of my garden. About ten flasks of sodic sulphate (3 to 1), and 

 about the same number of potash alum (4 to 3) were prepared. In 

 filling the belly of the flasks about half full, a small funnel with a long 

 stem was used, and was dipped into warm water after each filling, so 

 as not to soil the necks of the flasks ; and in reboiiing> each flask was 



