164 Observation on the Planet Venus. 



paste a portion nearly equal to the augmentation of the volume 

 produced by the leaven, and it would thence result, that, in spite 

 of the part daily removed, the parts would nearly preserve 

 the same level. Now, this is precisely what happens in the 

 glaciers. The leaven is the water which percolates daily into 

 the ice, and which, dilating by congelation, makes the mass to 

 swell, and thus repairs the loss of substance which the glacier 

 undergoes at the surface. Only, the action of the leaven is 

 in this case different at different seasons ; and every thing 

 leads to the conclusion that it is much more energetic in spring- 

 time than in the midst of summer. In winter, when there is no 

 water on the surface of the ice, nor in the crevasses, and when 

 the falls of snow begin to replace the rains of autumn, the 

 swelling must cease, as must also the movement.* 



Observation on the Planet Venus at the time of its Superior 

 Conjunction. By Thomas Dick, Esq. A/.M.f 



On Monday the 2d October 1843, the planet Venus passed 

 the point of its superior conjunction with the sun at 4 h. 15 m. 

 P.M. It is only at this period that Venus can present to an 

 inhabitant of the earth a full enlightened hemisphere. At all 

 other times this planet presents the appearance either of a 

 crescent, a half moon, or a gibbous phase, when viewed with 

 a good telescope. Most astronomical writers have asserted 

 that it is impossible to see this planet at the time of its supe- 

 rior conjunction. Mr Benjamin Martin, an eminent mathe- 

 matician, asserts, both in his " Gentleman and Lady's Philo- 

 sophy," and in his " Philosophia Britannica,'' that " at and 

 about her upper conjunction, Venus cannot be seen, by reason 

 of her nearness to the sun;," and, again, "at her superior 

 conjunction, Venus would appear a full enlightened hemi- 

 sphere, were it not that she is then lost in the sun^s blaze, or hid 

 behind his body." In the Edinburgh Encyclopaedia, article 



* From the Bibliotheque UniverseUe d'e Geneve, Nos. 88 and 89. 1843. 



t To Professor Jameson. 



[Sir, — The above observation is sent for insertion in the "Edinburgh New 

 Philosophical Journal," should you deem it worthy of being recorded. It is an 

 observation, so far as my knowledge extends, that has never been previously 

 made.] 



