Prof. Maskelyne and Dr. Lang's Mineralogical Notes. 437 



Fig. 5.— o(l 11), 0(01 1), b (2 11), r(10 0), e(011), 



if (201). 

 Fig. 6.— o (1 1 1), fl(Oll), 6(211), r(lOO), *(211) J 



s(lll), e(011), A (12 2), w(2l0). 



eo = 50 38 calc, 



50 18 obs. 



^o =26 „ 



25 45 „ 



re" = 53 5 „ 



52 55 „ 



n'e=24 3 „ 



23 42 ,. 



On a crystal of eudialyte with the planes o (1 1 1), a (0 1 1), 

 t (2 1 1), e (0 1 1), re (2 1 0) belonging to Dr. Percy, the follow- 

 ing angles were observed : 



re" = 53 5 calc, 53 15 obs. 

 en' = 24 3 „ 24 3 „ 



Notices of Aerolites. By Nevil Story Maskelyne. 

 10. Perth. 



A small stone fell on the field known as the North Inch at 

 Perth on May 17, 1830. The only record of its fall that I have 

 as yet been able to trace is that which accompanied two small 

 specimens of the aerolite, and is in the handwriting of the late 

 Dr. Thomson of Glasgow, in whose collection it was preserved. 

 Mr. Nevill became the owner of the specimens, and presented 

 one of them to the Museum. He very liberally also let me have 

 a microscopic section cut from his own specimen. 



The note in Dr. Thomson's writing is as follows : — " Part of a 

 meteorolite that fell on the North Inch of Perth during a thunder- 

 storm on the 17th of May, 1830, at half-past 12 o'clock noon. 

 The mass of which this is a portion was about 7 inches in dia- 

 meter." 



The section of this little stone exhibits a beautiful structure, 

 placing it high in the series of chondritic aerolites. The sphe- 

 rules in it are rather numerous and pretty distinct, and exhibit 

 great variety. The fanned kind of spherule, and some very sharp 

 crystals of a mineral with a diagonal cleavage, are set in a small 

 amount of a granular ground-mass. The general aspect of the 

 stone presents a bluish-grey hue. 



The iron in it is present in small particles very sparingly 

 scattered, and also in some amount as fine microscopic (intro- 

 crystalline) dust. The particles of meteoric pyrites are in con- 

 siderable excess over the ir.on particles, and there are seen here 

 and there on a section small isolated spots of rust. 



Its specific gravity is =3*494. 



