434 PHILOSOPHICAL TRANSACTIONS. [aNNO I67O. 



second relates to the discovery of oyster-shells and other marine productions 

 in some mountains between Beziers and Narbonne, two leagues from the sea, 

 and about 15 or l6 fathoms above the level thereof. In the mountains near 

 Nice cockle-shells are found imbedded in the same manner. In the last ob- 

 servation there is an account of the liquor of the pericardium being found 

 congealed into a consistence fit to be cut with a knife, and two square fingers 

 thick about the heart. 



Magnetical Variations at Rome. By M. Auzout. N" 58, p. 1184. 



The declination of the loadstone has for many years been observed not to 

 continue always the same in the same places ; and the variation to be such, 

 that it can be no longer imputed to any defect in the observations, as it was 

 believed at first, when it was not very great : it has been noted some years 

 since, that the magnetic needle, which almost every where had declined east- 

 ward to 8, 10, and 12 degrees, after its diminishing little by little as far as to 

 the meridian, began to decline westward. 



M. Adrian Auzout has made here in Rome the following observation about 

 the declination of the loadstone, on many meridian lines drawn as exactly as 

 possibly he could with a needle, three quarters of a palm long ;* and on all the 

 lines it was seen to decline somewhat more than two degrees westward, and on 

 some near two degrees and a half. 



But by the observations here made formerly, it appears that the needle has 

 declined eastward to eight degrees, and has afterwards been diminishing, till it is 

 come to the other side, where we find it at present. 



It seems not that this difi'erence of ten degrees and more can be attributed to 

 the change of the pole of the earth, as some esteemed, perhaps before they 

 knew it was so great ; nor, as others would have it, to the magnet, or to the 

 iron, that are found in certain places, because there is but little loadstone ; and 

 Mr. Auzout affirms, that the mines, which he has seen, make no impression 

 at all on the needle. So that it is difficult to hit the true cause of such a varia- 

 tion; yet, however, if the direction of the magnet, and of the needle touched 

 by it, depends on the flux of a certain matter, passing through the whole earth, 

 or the exterior parts of it, straight along the axis; it may be said that it proceeds 

 from changes made in the said flux, which, supposing the inequalities of the 

 earth, and the alterations continually made therein, as well artificial, by excava- 

 tions and such-like other works, as natural, by corrosions caused by fire and 

 water, or by the generation of metals and stones, cannot but in progress of 



* This is about six inches. 



