2 1 8 Annals of the Philosophical Club 



lamps. These were on the Swan system and arranged under 

 the direction of Dr. Siemens. " The shaded light was 

 steady, pleasing, and ample for the exhibition of diagrams 

 and apparatus, as well as for the general illumination of 

 the hall." 



1882. Jan. 2oth, 3i2th meeting. Dr. Carpenter de- 

 scribed the results of his examination of a limestone from 

 Sutherland at the request of Professor Heddle. 1 Parts of 

 it exhibited that regular alternation of calcareous lamellae 

 and those of a magnesium silicate which characterises 

 Eozoon Canadense. The latter, however, instead of being 

 serpentine, is chondrodite, a magnesium silicate containing 

 fluorine. This, however, has been recognised by Professor 

 Sterry Hunt, to whom he had sent specimens, in certain 

 limestones of North America. These are of the Laurentian 

 era, so there can be little doubt the Sutherland limestone 

 belongs to it and not to the Silurian, as hitherto supposed. 

 The laminated specimens do not indeed exhibit the micro- 

 scopic structure characteristic of the best preserved speci- 

 mens of Eozoon, but he had found this in the parts with a 

 more acervuline habit, and he considered the resemblance 

 to an organic structure, presented by the grains of chondro- 

 dite as they lay loosely scattered in the calcareous areolae, 

 to show that this was not merely due to metamorphic action, 

 as Messrs. King and Rowney had maintained in the case 

 of Eozoon. 



Feb. 23rd, 3i3th meeting. Dr. Siemens gave the sub- 

 stance of a paper which he was to read on March 2nd to the 

 Royal Society on the " Conservation of Solar Energy." It 

 suggested how the vast amount of heat and light, supposed 

 to be radiated into space, could be to a large extent recovered 

 by the sun. The explanation rested on the postulates, 

 (i) that interstellar space is filled with attenuated matter 

 including aqueous vapour and carbon compounds, (2) that 



1 The crystalline limestone (or dolomite) of Ledbeg is described by 

 Professor Heddle, Mineralogical Magazine, vol. v. pages 274-281. The 

 structure is represented on Plate VII. Figs, i and 2, and some " simulating 

 Eozoon " are given on Plate VIII 





