124 



Mr. C. Tomlinson on 



[Feb. 21, 



active on certain days and inactive on others ; that when these were 

 active their fresh distillates were not, or at least that they required 

 time in order to become nuclear. When first added to the solution, 

 the flask could be shaken, and a good deal of the modified salt would 

 be thrown down, and then perhaps after a half-an-hour or an hour's 

 repose the solutions would become solid, although the flasks were 

 covered again after the drops had been added to the solutions. I also 

 found that different specimens of the same oil, &c, in separate bottles, 

 sometimes behaved differently on the same day, and even that an 

 active essential oil might be made inactive simply by filtering. 



But no sooner was I led to the conclusion that ozone, or an oxidised 

 condition, has a powerful influence on the nuclear action of oils, &c, 

 than the reason for the various contradictory results became plain to 

 me. Supposing that other observers worked with what would appear 

 to be the best, that is, with pure materials (Lowel, for example, 

 recrystallised his sodic sulphate, and used distilled water for his solu- 

 tions), the fixed oils used by them would probably be recently refined 

 and the essential oils redistilled. Hence it is now apparent to me how 

 it was that they obtained negative results, while the very precautions 

 against the entrance of nuclei, as taken by M. Viollette and Mr. Liver- 

 sidge, were such as to deprive the oil of nuclear action, by cutting off 

 the influence of the external air.* 



In order to illustrate this influence more fully, I will describe a few 

 out of a large number of experiments that I have recently made. 



An oil of turpentine, that had stood on my shelf during many years, 

 was found to be powerfully active. A portion of it was redistilled, and 

 the distillate had no action in solidifying the solution of sodic sulphate 

 (2 to 1), although the flask was repeatedly shaken during the day.f 



A portion of the distillate, contained in a dropping-tube, was taken 

 into the open air and allowed to fall drop by drop into a small clean 

 beaker. The oil immediately became active, several of the last-named 

 solutions becoming solid as soon as the oil reached the surface, or on 

 gently shaking the flask. 



But in such a case, as it has been affirmed over and over again, the 



* Mr. Liversidge (" Proo. Roy. Soc," xx, 427) took up oil in a dropping-tube, 

 and then closed its upper opening, and passing the tube through a plug fitted it 

 tightly into the neck of the flask containing the supersaturated solution. After 

 waiting an hour or two, lest any nuclear particles should hare entered the flask, he 

 allowed a drop of oil to fall upon the solution. Under such conditions he found 

 the oil to be inactive. Using the same method, I found that the phosphorised oil of 

 cajuput, an oxidised oil of turpentine, ether, and absolute alcohol were active : 

 so also was glacial acetic acid, but not so promptly as the others. 



f 8th February. I have since noticed that during a north or a north-east wind, 

 the distillate of oil of turpentine may become nuclear while being transferred from 

 the condenser to the dropping-tube. In some cases hydric peroxide may be the 

 force that confers the nuclear action. 



