160 Intelligence and Miscellaneous Articles, 



ployed to determine the variations of the normal angles or of the tor- 

 sion of the wires. 



I expect to be able by means of this instrument to determine the 

 height of mountains more accurately than by any other plan (the 

 trigonometrical excepted). I hope to be able to publish soon the 

 results of my experiments upon this and upon the other questions 

 relating to the variations of gravity. 



I beg you, Sir, to do me the honour of communicating this letter 

 to the Academy of Sciences. 



Receive, Sir, &c, 

 M. Elie de Beaumont. John Allan Broun. 



ELECTRIC INDUCTION IN THE PYRENEES. EXTRACT OF A 

 LETTER FROM CHARLES PACKE, JUN. 



" Gavarnie, June 28, 1863. 

 "..;.;, Three nights ago I passed two days and one night on the 

 summit of the Pimene, 8200 feet. I went up and returned by myself 

 heavily laden with rifle, barometers, telescope, and other instru- 

 ments, but Laurent came up at nightfall with my sleeping-bag and 

 provisions. At daybreak Laurent returned, as he is busy con- 

 structing a grange and ecurie ; but I remained till after midday, 

 when a threatened thunder-storm sent me down. A most singular 

 circumstance befel me, which I do not expect you to believe ; indeed 

 I should not believe any one who told me the same. On leaving the 

 Pimene I had occasion to remount a second and somewhat lower 

 peak of the crete, to repeat some experiments I had made in ascend- 

 ing. The road lay over a snow slope ; and as I approached the top, 

 I heard what appeared to be an excessive creaking of the straps at 

 my back ; at least, being heavily laden and feeling the weight at my 

 back, this was my first thought. As I reached the top the noise 

 increased, and on taking the rifle off, which was slung at my back, 

 it made such a noise as if it was trying to go off. It was loaded, 

 but I knew this was impossible ; still 1 could not help keeping it 

 pointed away. The noise was as if some large bee or beetle had got 

 down the barrels and was trying to escape. I shook the rifle to 

 shake it out ; and directly the barrels were lowered to the ground 

 the noise ceased, but was renewed directly I raised them. The air 

 was much charged with thunder-cloud, and there had been two or 

 three thunder-claps ; and it then first occurred to me that the pheno- 

 menon might be connected with electricity. On raising the sympieso- 

 meter to look at it, it produced the same noise, as also did my pole, 

 though neither of them so loudly as the rifle. The noise much resem- 

 bled that given off by an electric conductor when a wire is approached, 

 but not near enough to cause a discharge. I am convinced myself that 

 this was the cause, and I wish I had macie more experiments; but 

 as soon as this occurred to me I did not care to prolong my proxi- 

 mity to the lightning, not knowing how near it might be, and I 

 hastened down. As soon as I had descended a little, the noise ceased, 

 and I could hold up my rifle with impunity. There was no wind, and 

 scarcely any rain. The storm did not reach Gavarnie, but at Bareges 

 I hear it was very violent." 





