.scientific news. 369 



tensity and impetuosity of this new moving principle ; and 

 valuable results may be expected from it, when by repeated 

 trials all the energy of which it is susceptible is imparted to 

 it. Such is the opinion of the committee, and the class de- 

 termined, that the whole of their report should be inserted 

 in the historical part of its memoirs, to preserve the remem- 

 brance and date of the first trial of an invention that may- 

 prove highly important. 



Mr. Pictet presented ten models of scapements from New scape- 

 Messrs. Malley of Geneva, three of which belonged in part 

 to Mr. Tavan, the artist who made them all. They dis- 

 played an inventive genius, and great merit in the execution. 



Mr. Dcsmarcts read an interesting report on a new ma- Frame for 

 chine for weaving ribbed stockings, invented by Mr. Bel- JJ^jj* ribbed 

 lemerc. This is not above half as expensive as the English 

 stocking-frame, and its movements are much lighter. Its 

 advantages are confirmed by two years experience. 



From the learned researches of Mr. Coulomb, and the Variation and 

 formula? of de Borda and Laplace, we are now able to de- ^ °a n dma«^ 

 termine with sufficient precision, and without too many dif- netic power. 

 Acuities, the variation and dip of the needle, and the inten- 

 sity of the magnetic forces. But these nice observations 

 require perfect instruments, time, and an exact knowledge 

 of the meridian of the place- The observations which na- 

 vigators, to whom most of these arc often wanting, have 

 been able to make, arc not to be depended upon sufficiently 

 for us to infer from them with certainty the situation of the 

 magnetic poles and equator,. and the points where the mag- 

 netic equator intersects that of the earth. Mr. Biot how- Mr Biot has at- 

 ever has attempted to determine, from the observations *f certain the el' - 

 la Peyrouse and von Humboldt, all these elements of the ments of the 

 magnetic theory of the globe; and he has given the neces- "^^lobe" 1 ° 

 sary formulae for calculating what the variation and dip of 

 the needle should be in any given place. 



The journey which Messrs. von Humboldt and Gay- Humboldt and 

 Lussac have since made in Italy, France, and Germany, ha a ^ c " S j ac 

 has afforded them repeated opportunities of comparing their many observa- 

 obscrvatiuns with the hypothesis of Mr. Biot. The diffi- JJ™ etSdlt* 

 cult v of ascertaining the meridian prevented them from ob- and the mag- 

 Be?;ving the variation of the needle at their different stations ; "^'^5^ ° f 



but 



