Lunar Volcanoes 1 1 3 



constructed with such an extremely accurate movement as 

 is now frequently required. He described practical diffi- 

 culties which had arisen on making drawings of nebulae, 

 and thought photography might be applied to them, if 

 sufficiently sensitive plates could be made. To an enquiry 

 about the measurement of y-Virginis, Lord Rosse replied 

 that he had not worked at double stars with his telescope, 

 for the nebulae occupied the observer's whole time. 



When Sir R. Murchison raised the question of lunar 

 volcanoes, Lord Rosse replied that he had observed several 

 features, corroborating the idea that the moon's surface 

 wholly consisted of them. These were such as, holes in the 

 apices of the conical mounds in the centres of the basins, 

 material on the plains resembling ejected debris, streams like 

 consolidated lava, in some of which light could be seen 

 through an arch over a fissure, and the white lines consisting 

 of precipitated snow-like matter. As the conditions on the 

 moon diminution of gravity, absence of wind, etc. differed 

 from those on the earth, the character of the surface could 

 not be identical. He regarded, however, with some scepticism 

 the statement that an actual eruption had been observed, 

 though the number of craters appeared to multiply with 

 the improvement of telescopes, for nearly twice as many 

 could be seen on any part of the moon's surface with the 

 six-feet reflector as with the three-feet one. To a remark 

 that the volcanoes of the moon appeared to have been 

 active where its surface was in a viscous condition, Colonel 

 Sykes replied that he had received by the last mail an 

 account of the discovery of mud volcanoes at Materam 

 in India. 



At the 3oth meeting (May 23rd) Mr. Galloway made some 

 remarks about daguerrotyping astronomical objects, and 

 Mr. Grove spoke of the differences in the aspects of some 

 of the mountains on the moon, according as they were more 

 or less illuminated. After this Dr. Royle gave the results 

 of investigating the action of physical agents on plants. 

 In cotton the length and fineness of the fibre are more de- 

 pendent on the continuous presence of a moderate degree 

 p.c. H 



