138 ' 



heat, according to Captain Duperrey's supposition, but as a 

 source or centre of magnetic attraction, if I may dare say so 

 in the present uncertain state of science. 



" The mean results of the observations made by us on 

 magnetic intensity of forces, confirm very nearly the ratio 

 between the equator and our latitudes, as first given by our 

 distinguished countryman Captain Sabine. The dip was 

 13°. 9'. but varied a little under the sun's influence. 



"The maxima and minima of the barometer's range, 

 confirmed partly M. Boussingalt's results. 



"The mean temperature of the place, as given, 1st, by 

 the daily observation of the thermometer ; 2nd, the heat of 

 springs ; and 3rd, that of the ground at small depths, was 

 27.5 grades ; nevertheless, the bottom of an Artesian well, 

 200 feet deep, was 24.0 grades, being much colder than at 

 the surface. This was measured three times, as it seemed 

 contrary to our received theories on a geocentric focus of 

 heat. 



" M. Selligue of Paris, has succeeded in making a 

 folding iron barometer, which has been observed every day 

 after a thorough shaking. It has not altered its primitive 

 error of .001 metre. I confess that I am rather sanguine 

 about this instrument, which I shall carry with me to Egypt 

 and beyond the Red Sea." 



M. Abbadie is at present in Abyssinia, whence he will 

 proceed along the shores of the Red Sea. 



Professor Lloyd communicated to the Academy the 

 results of his observations on the diurnal march of the 

 horizontal needle, made on the 31st of August and 13th of 

 November, 1837. 



These observations having been made with the apparatus 

 of Professor Gauss, Mr. Lloyd commenced by describing 

 the construction and uses of that apparatus, the principal 

 parts of which he exhibited to the Academy. He then ex- 



