iCIENTIFIC NEWS, Qg 



•till left open till the 1st of October, 1810. 'Die prize is a 

 medul of the value of 6000 francs [£250]. 



The ordinary prize subject for next year is: " To exa- Another prize 

 Kline whether there be any circulation in the animals knows, question. 

 by the names of asteriae, echini, and holothuriae; and, if there 

 be, to describe its course and organs." The description 

 must be accompanied with observations made on living ani- 

 mals, and include the vessels of the respiratory organs, if 

 there be any such, as well as those of the principal circula- 

 tion. To examine the chemical effect of the respiration on 

 the air and water, would be a desirable adjtion, but this is 

 not absolutely insisted on. The examination of one species 

 of each family only is required ; but it is expected to be 

 by no means superficial, and accompanied with drawings, 

 so that the principal details may easily be verified. The 

 prize is 3000 francs [^£125], and the term as abov . 



The history of the mathematical division of the class of Mathematical 

 physical and mathematical sciences exhibits this year a sine tla¥S% 

 gular circumstance; one of the most difficult and most im- 

 portant points of the solar system treated with equal success, 

 though after different methods, by two geometricians of the 

 first rank ; to both of whom the investigation was suggested 

 by an interesting paper read to the class by a young geome- 

 trician. Astronomers had remarked a perceptible accelera* p r8 blem w he- 

 tion in the course of the moon: -consequently other planets, lher ,he P 1 *- 

 and among them the Earth, must have a similar accelera- constant ac- 

 tion. If the motion of the Earth be accelerated, it must c«leration. 

 be owing to its approaching the centre of motion : and, if it 

 do, will it not ultimately fall into the sun ? The danger of 

 this indeed must be infinitely remote, for the acceleration is 

 extemely slow; and it appears from the instance of the 

 moon, that the acceleration continues but for a time, and is 

 afterward changed into retardation. Still however the ques- 

 tion is particularly interesting to astronomers, who in all 

 their calculations suppose the unchangeableness of the 

 ellipses described by the planets. 



Mr. Laplace first examined this question, and found by L R ,,i^ ce s >, ow . 



a learned but merely approximate calculation, that the mean td they have 



motions and axes are really invariable ; at least taking into not h . v an a P* 



. • " proximate caK 



consideration only the first powers of the masses, and the culation^ 



second 



