1905.] New Low Temperature Phenomena. 177 



WEEKLY EVENINa MEETING, 

 Friday, January 20, 1905. 



LUDWIG MOND, Esq., Ph.D. D.Sc. F.R.S., Vice-President, 

 in the Chair. 



Professor Sir James Dewar, M.A. LL.D. D.Sc. F.R.S. M.R.I. 



New Low Temperature Phenomena. 



The porosity of matter, and the possibility of the occlusion of gases 

 in it, has been the subject of scientific thought for ages. As early as 

 1674, Boyle,* under the title " Suspicions about the hidden Qualities 

 of Air," writes : " It may not seem altogether improbable, that some 

 bodies we are conversant with, may have a peculiar disposition and 

 fitness to be wrought on by, or to be associated with, some of those 

 exotic effluvia that are emitted by unknown bodies lodged under- 

 ground, or that proceed from this or that planet. . . . We may be 

 allowed to consider whether among the bodies we are acquainted with 

 here below, there may not be found some that may be receptacles, if 

 not also attractives, of the sidereal and other exotic effluviums that 

 rove up and down in our air." While other matters took up his im- 

 mediate attention, this one was not lost sight of, for ten years later, 

 in 1684, he returns to the subject in a special discourse. " Experi- 

 ments and considerations about the porosity of Bodies,"t in which he 

 says : " When I consider how much most of the qualities of bodies, 

 and consequently their operations, depend upon the structure of their 

 minute and singly invisible particles, and that to this latent con- 

 texture, the bigness, the figure, and the collocation of the intervals 

 and pores do necessarily concur with the size, shape and disposition, 

 or contrivance, of the substantial parts, I cannot but think the 

 doctrine of the small pores of bodies of no small importance to 

 Natural Philosophy." Felix Fontana, the famous physicist to Duke 

 Ferdinand II. of Tuscany, seems to have been the first to have dis- 

 covered the absorptive power of hot charcoal for gases, a property 

 which he communicated to Priestley, about 1770, and which Priestley 

 confirmed. Lowitz, in 1791, noticed that charcoal decolorised organic 

 solutions. Later experiments were made by Morozzo, and another 

 series of observations were made by two Dutch physicists, Pouppe 

 and Norden. Shortly after this, early in last century, the subject of 

 the action of gases on charcoal was elaborately examined by Theodore 



* Boyle, Works, vol. iii., p. 470, col. 1. 

 t Boyle, Works, vol. iv., p. 206, col. 1. 



Vol. XVIII. (No. 99.) n 



