Prof. Berzelius on Meteoric Sioues. 4-29 



at riglit angles to each other and to Ox, that of the expres- 

 sions for t',^ andtj/, one shall be a maximum, the other a 

 minimum. 



If the last expression for i;^/, and the observations subse- 

 quently made, be compared with the expression in art. 119, 

 and the observations in articles 120 and 121 of Professor 

 Airy's Tract before quoted, it will be perceived that we have 

 now deduced the fundamental laws of M. Fresnel's theory of 

 refraction for biaxal crystals. But the direction of vibration 

 is, as we have previously found in the case of uniaxal crystals, 

 perpendicular to that which this ingenious philosopher sup- 

 posed. The consequences of these laws have, as it appears 

 from the British Association's Report on Physical Optics, been 

 so ably traced and verified by Sir William Rowan Plamilton 

 and others, that I deem it unnecessary to pursue this part of 

 the theory any fnrther. 



I am, Gentlemen, yours, &c., 



Evesham, June 28, 1836. JoHN ToVEY. 



P.S. In my last paper, vol. viii., p. 501, line 2 from the 

 bottom,/or 1 read^ ; p. 502, 1. 8 from the bottom, dele comma 



after (3; p. 505, 1. 11, for — read — . 



In the valuable paper from M. Cauchy in your last [June] 

 Number, I have noticed the following errors. Vol. viii. p. 461, 

 formula (2. ), for au + bv + cxv read a ti^ + b Vi+cw^; and line 

 5 from bottom, for w read u. P. 462, formula (7.), for s„ in the 

 denominator read ?/„. P. 463, 1. 13, prejx of; and line 3 

 from the bottom, /or read a. P. 464, line 14, for Ui read w, ; 

 and 1. 15, for we read We. P. 465, 1. 12, for 19 read 16; 

 and I. 28, for aw read aii. P. 466, 1. 13,^0/- C 7-ead /3. P. 467, 

 lines 1 and 3, for = v, in every place, read = ; and line 10 

 dele the first w. 



LXXX. On Meteoric Stones. By P/'o/t-ssor Berzelius.* 



THE author commences this interesting memoir by consi- 

 dering which of the conjectures respecting the formation of 

 meteoric stones is the most probable. That which refers these 

 bodies to eruptions of the volcanos of our earth cannot be 

 supported, on account of the distance of the places where they 

 have fallen from any volcano, and also from the different con- 

 stitution of volcanic products and meteorites; neither can 



• From the Joiinwl fic P/inniirirlr for February 18.36: communicated by 

 J. D. Smith, Esq., bting a tianshitinn of an extract, by M. Valict, from a 

 memoir in PoggendDrfs Annalcn dcr I'lnjaik und Chemic, vol. xxxiii. p. 1. 



