SCIENTIFIC NEWS. 



S67 



ciently to establish the motion of the sun, and immobility and the stars 

 of the stars : it rather appears, that they are all in motion r th ^ t ji s nation 



and it is on this supposition, that Mr. du Scj our declares the cannot be de- 



,,.,,, termined. 



problem insolvable. 



Notwithstanding this decision, Mr. Buckhardt has sub- Burckhardt has 

 a j -j. j. i tt- e i examined the 



jected it to analysis anew. His formulae are more comnio- quest i on anew , 



dious, and more easy of application, than that of Mr. da 

 Sejour; and are less laborious than the trigonometrical cal- 

 culation of Mr. Herschel. He has very adroitly eliminated 

 the distances of the stars, which appear to be, and rea'iy 

 are, one of the elements of the calculation, and which will 

 probably remain for ever unknown to us. If the sun alone / 

 be in motion, this motion may be known to a certain degree 

 of accuracy, in time, by means of good observations : but 

 if the stars too move, the separation of the unknown quan- 

 tities will be impossible, and some embarrassment will en- 

 sue to future astronomers, should there be an interruption 

 to observations for a few centuries; and should they at- 

 tempt to calculate the celestial movements anew by compar- 

 ing their observations with ours, after a period of ignorance 

 of some duration. But even on this supposition, which is 

 fortunately very improbable, it would only follow, that the 

 observations of the 18th century would appear a little less 

 accurate; which would not prevent them from furnishing 

 much better helps, than we found in the small number of 

 rude observations transmitted to us by the Greeks. 



The problem of finding the train of wheels necessary to Problem of 

 represent the motions of the planets was resolved by Huy- findir >g Retrain 

 ghens in a very complete manner by continual fractions, planetarium, 

 which have the advantage of furnishing approximate values, 

 expressed by the smallest numbers possible, in every degree 

 of approximation with which the artist may think proper 

 to content himself. But to this every artist who attempts 

 to construct a planetarium is not equal. Mr. Burckhardt 

 therefore has pointed out to them calculations more easy, 

 and sufficiently exact. 



To these labours of the class may be added the reports Pyreolophorus, 

 made by its committees on the most curious and important 

 inventions submitted to its judgment. On both these ac- 

 counts we shall particularly mention the report of Carnot 



