46'2 Scientific Intelligence. [Juuf. 



The paper was illustrated by a large coloured drawing. 

 Mr. Plumptre stated, that a deposition of manna had been ob- 

 served by Mr. Gray, in the same part of Arabia, at a distance from 

 any trees, apparently condensed, or precipitated from the atmosphere, 

 and appearing deposited on objects like hoar frost. 



March. I3lk. — An anonymous paper was read, entitled " Physical 

 elucidation of a passage in Horace." 



It appears to the author of this paper, that notwithstanding all 

 the difficulties which have been felt, and the learned ingenuity which 

 has been exercised upon the passage, (Ode 10. bk. iii.) 



" Puru numine Jupiter," 

 the epithet " Turo" may be allowed to stand as the true reading, 

 being entirely conformable to the known belief of the ancients; 

 according to which the coldness of the night was inseparably asso- 

 ciated with the clearness of the sky. This impression, though 

 sometimes mixed up with fanciful conceits as to the effect of the 

 moon's rays, &c. was very probably grounded on extensive observa- 

 tion, though they might be little aware of the cause to which the 

 effect was to be referred. This is now well understood to be the 

 radiation of heat from the earth's surface ; which goes on more freely, 

 or in other words, the earth cools more rapidly, at night (caeteris 

 paribus) under a clear sky, than under a screen of clouds, which 

 intercepts the radiant heat. 



An anonymous paper was read " on a difficulty in the history of 

 the publication of Newton's Principia." - 



In Birch's History of the Royal Society, (vol. iv. p. 486.) the 

 following passage is given, as extracted from the journal books of 

 the Society : 



u Minute of the Council. 1686, June 2. 



" Ordered, that Mr. Newton's book be printed, and that Mr. 

 Halley shall undertake the business of looking after it, and printing 

 it at his own charge, which he engaged to do." 



But it also appears, that at a meeting of the Council on the 19th 

 of May (1686) it was resolved "that the MSS. should be printed 

 at the Society's expense, and that Dr. Halley should superintend 

 it while going through the press." 



Yet this seems to be contradicted by the language of the first 

 extract ; and the difficulty has been remarked by the learned author 

 of the " History of Hadley's Quadrant," which has appeared in 

 several recent numbers of the Nautical Magazine. He expressly 

 observes in a note, u It is hardly possible to conceive, that the R. 

 Society, after undertaking to publish the work, could, either from 

 deficiency of funds, or from any other cause, have thrown the burden 

 of it upon Halley. But the minute is unintelligible, if it does not 

 imply, that he either engaged for some positive expense, or gave 

 up some serious remuneration, to which he would have been justly 

 entitled in the prosecution of the publication." 



The author, however, wishes to submit, whether the whole diffi- 

 culty may not be cleared up at once, by the simple consideration of 

 the punctuation of the first extract ; viz. if we read it thus : 



" That Mr. Halley shall undertake the business of looking after 



