273 



he said, for all distances that he had tried ! So it might answer for 

 the distances most usually occui-ring on the Survey; for 4 inches 

 would be proper for 40 miles, and 2 inches not much too bright 

 at 20, and it is not often that these limits would be passed. Yet it 

 is hardly possible to conceive that he should not have noticed the 

 different intensity of the lights ; had not his opportunities been per- 

 haps rather unfavourable, as his work lay chiefly in plains, where, 

 as mentioned above, the light of a grazing ray is very much re- 

 duced, and the atmospheric effect would therefore be mixed up with 

 disturbing local causes. 



I myself was much astonished at first discovering that the air had 

 so great absorbent powers, and many ideas are suggested by the 

 fact. We see at once how easily many of the planets may be ren- 

 dered habitable to beings like ourselves. Mars, e.g., may enjoy a 

 temperature little inferior to our own, by having a less absorbent 

 envelope ; and Venus may be kept as cool as we are, by having 

 one more so. 



The following Gentlemen were duly elected Ordinary 

 Fellows : — 



Mr Alex. K. Johnston. 



Dr JouN Scott, F.R.C.P. 



Dr Sheridan Muspratt, Liverpool. 



The following Donations to the Library were announced : 



Annuaire Magnetique et Meteorologique du Corps des lugenieurs 

 des Mines ; ou Recueil d'Observations Meteorologiques et Mag- 

 netiques faites dans I'entendue de I'empire du Russie, par A. 

 T. Kupffer. Nos. 1 & 2, 1849. 4to.— 5y the Russian 

 Government. 



Verhandelingen der Eerste Klasse van het K. Nederlandsche In- 

 stituut van Wetenschappen, Letterkunde, en Schoone Kunsten 

 te Amsterdam. S'^o Reeks, Deel 1, Stuk 3 en 4. 4to. 



Tijdschrift voor de Wis-en Natuurkundige Wetenschappen uitge- 

 geven door de Eerste Klasse van het K. Nederlandsche In- 

 stituut van Wetenschappen te Amsterdam. 3*^^ Dee), 1 & 2 

 Afleverings. 8vo. — By the Academy. 



