412 Intelligence and Miscellaneous Articles, 



the lunar surface involved in an assumption as to the absolute 

 non-existence of a lunar atmosphere, it would appear of far greater 

 probability that some such atmosphere, however limited, exists. 

 Not only, as Dr. De La Eue has remarked, is it difficult to conceive 

 any chemical formation of matter without an atmosphere, but it is 

 also difficult to even find matter exhibiting the features and proper- 

 ties of that constituting the lunar surface, which under the known 

 conditions would not either yield an atmosphere, or require for 

 formation the presence of substances that would. 



The absolute absence of any atmosphere has never yet been de- 

 monstrated, but only the fact that it does not exceed certain limits, 

 generally supposed much more restricted than is actually the case. 

 In consequence it is usually granted that some atmosphere might 

 exist ; it is also assumed that it must be of most extreme tenuity ; 

 and the subject is dismissed as a matter of indifference, without 

 inquiring whither the admission might carry us, so far as relates 

 to this atmosphere's power of fulfilling the same purposes as our 

 own terrestrial one. 



But it would be of interest to ascertain how far this possible 

 lunar atmosphere might not effect for the lunar surface those 

 changes &c. that our own does for the terrestrial surface, and 

 whether in fact it might not amply suffice for maintenance of at 

 least some form of vegetable life. For the present, however, this 

 must be deferred. 



The only point restricting the extent of a lunar atmosphere of 

 the nature supposed appears to be its refractive power, more 

 especially as shown by the occultation of stars by the moon. Irre- 

 spective of the circumstance that these do not invariably answer 

 conclusively in the negative, it does not appear to be generally 

 recognized that we may have an atmosphere whose maximum power 

 of refraction would not be equal to one second of arc, and yet be of 

 very considerable amount. Eor, of however great tenuity in com- 

 parison with our dense terrestrial atmosphere, it would be in reality 

 present in large quantity — to be estimated in fact, with regard to 

 each square mile of surface, by very many thousands of tons. 



There can be but little doubt but such an atmosphere would 

 exert a very considerable influence on the lunar surface, render 

 possible the existence of many substances that appear to constitute 

 a great portion of that surface, and explain many selenographical 

 observations of great interest that at present appear to point to 

 some such solution, and thus support the hypothesis of the exist- 

 ence of a definite lunar atmosphere. — Monthly Notices of the Royal 

 Astronomical Society, June 1873. 



A CONTRIBUTION TO THE HISTORY OF THE HORIZONTAL PEN- 

 DULUM. BY PROF. SAFARIK. 



As it is for the most part only some time after date that 1 get a 

 sight of scientific journals that do not treat of my special depart- 

 ment (chemistry), I first became acquainted recently, through the 



