Hlftory ofJJlronomy for the Year 1800. J^ 



Form the 500 pages as above announced. It was apprehended 

 that the ufe of the old calendar and the old meafures found ia 

 this work would thwart the projefts of government, and this 

 facrifice was made for the fake of peace. But the amateurs of 

 this colle6lion of the Connoiffance des Temps will be deceived 

 if they have the volume of the year 9 without the Melanges, 



In thefe Melanges,- page 282, I announced the publication 

 of Malefpina's Voyage round the World; but it has not 

 taken place, and that officer is ftill in priibn. I am, how- 

 ever, of opinion, that in the maps about to be publilhed ia 

 Spain, advantage will be taken of his obfervations. 



The Memoirs of the French National Inftitute, vol. ii. for the 

 year 5, were publiflied on the 12th of November 1799. They 

 contain calculations of two comets and feveral eclipfes already 

 obferved ; the theory of the fecular equation of the moon by 

 Laplace, the difcovery of which we announced, and which 

 may be found alio in the Mecan'ique Celefte, that grand and 

 important work, of which we have already fpoken, and of 

 which three long extracts were publiflied by Briot in the 

 Magazine Encyclopedique. Burckhardt has given a German 

 tranllation of it, that his former country may enjoy the va- 

 luable difcoveries of Laplace. 



In the Philofophical Tranfaftions for 1799, ^here is a new 

 method for finding the latitude by two altitudes of the fun, 

 and the interval of time elapfed, by Mr. Lax, profeflbr of aftrp- 

 nomy at Cambridge. Alfo, a fourth catalogue of ftars, com- 

 pared with each other in order to eftimate their degree of 

 light, by Dr. Herfchel. 



In the Tranfa6lions for 1800, there is an interefting me- 

 moir, by Dr. Herfchel, on the power of telefcopes to pene- 

 trate into fpace; that is to fay, to render femfible very diftant 

 and very faint objefts, which, by their want of light, would 

 be imperceptible without the aid of inftrumenls ; ufefiil re- 

 marks on the difference between that force of liy;ht and that 

 of amplification or enlargement; on the different cafes to 

 which either is applicable, and the means of procuring the 

 neceffary degree of light, ilegivescaiculations alfo of the lofs 

 gf light occafioned by mirrors or glaffes. It appears to him 

 that the greatell amphfication cannot exceed that produced 



bv 



