634 



The Earl of Bosse 



[May 31, 



seem to me to indicate a low temperature of the lunar soil, they have 

 made me a convert to the opinion that your measures on the transmissi- 

 bility of glass indicate a great relative emission from the soil, and I 

 feel that the effect can only in part be accounted for by selective 

 reflection." It is much to be regretted that at the death of Mr. Thaw, 

 a citizen of Pittsburg, the funds which he had furnished to Professor 

 Langley for these special researches ceased. Professor Langley was 

 soon after appointed secretary of the Smithsonian Institution, and 

 most unfortunately his further undivided attention to these investiga- 

 tions was lost to science. 



Fig. 14. 



I should here mention the ' Prize Essay ' of Mr. Very, of Alle- 

 ghany, with whom Langley left his radiation apparatus. In response 

 to the request for a lunar-heat phase-curve, sent out by the Utrecht 

 Society of Arts and Sciences,* Mr. Very constructed such a curve 

 from only eight values, obtained on eight nights. The curve agrees 

 nearly with ours, but he had our curve, based on some thirty or 

 more nights' work to guide him. Slide 14 is a reproduction of his 

 diagram. He, however, did also what was new, but outside the 

 request of the Society, and it is for this reason that I allude to his 

 work. He made determinations of the relative radiation from various 

 parts of the visible lunar surface on each of those eight nights, and 

 Slide 15 is a reproduction of his diagrams of the distribution of heat. 

 From summation of these values he obtained his total heat-values 

 for each night. 



Mr. C. V. Boys, F.R.S., has made a new departure in apparatus, 

 taking as his model the galvanometer of DArsonval. In this, instead 



Martinus "Vishoff, The Hague, 1895. 



