The Kev. S. Haughton's Notes on Mineralogy. 47 



layers have a different arrangement to those nearer the axis. If 

 this is the case, it is probably also the case in different directions 

 according to the thickness of the rod, and accordingly the latter 

 relation will be different in thick from what it is in thin rods. 



In conclusion I mention some experiments made with a hard- 

 drawn brass rod of almost the same dimensions as those of the 

 three steel rods. The experiments are of exactly the same kind 

 as those made with each of the steel rods, excepting that weights 

 of 50 gr. and 100 gr. were used instead of weights of 100 gr. 

 and 200 gr. The following values of B and T were found for 

 P = 50gr.:— 



B. T. 



35-55 37-141 . ... O40l n 



35*57 37-16 f m one P 0Sltl0n ' ^4 °-l C. 



35-94 3707\ . ., ... OKO n n 



ok.qk 37*12 f m an other position ; 25 -0 C. 



Mean.... B = 35'75 T=37'12 



64-33 millims., =67*13 millims. 

 Here 5=144*65 millims. Hence using equation (14), we have 



TT^= ' 387 - 



This number has certainly not the same importance as that 

 which I have thought myself justified in assigning to the corre- 

 sponding numbers in the case of steel rods, for the elasticity of 

 a drawn brass rod is certainly different in the direction of the 

 axis to what it is in others. 



Heidelberg, June 1859. 



VI. Notes on Mineralogy. By the Rev. Samuel Haughton, 

 M.A., F.R.S., Fellow of Trinity College, and Professor of Geo- 

 logy in the University of Dublin*. 



No. IX. On the Shower of Aeroliths that fell at Killeter, Co. 

 Tyrone, on the 29 th of April, 1844. 



ON the 29th of April, 1844, a shower of meteoric stones fell, 

 in the sight of several people, at Killeter, near Castlederg, 

 co. Tyrone : they broke into small fragments by the fall, one 

 piece only being found entire; it was (according to the testimony 

 of a resident) "about as large as a joint of a little finger."" The 

 stones were hot when found. The account given by three gen- 

 tlemen, who, however, did not actually see the shower fall, was 

 that they were at a distance of three or four miles, up the hills 

 in the neighbourhood ; it was a fine sunny afternoon (three or four 

 * Communicated by the Author. 



