J. L. Smith on rubidium and cesium in Leucite. 835 
examined by Mr. Greg ; the preter lead was detected by him 
in small masses of varied dimens 
I have examined several sei cut from the original 
mass of iron, two of which are in my possession, and my con- 
Viction is, that the metallic lead was altogether foreign to the 
iron when it originally fell, and has been doubtless derived 
m lead with which the mass was probably treated by the 
original discoverers for the purpose of extracting some precious 
metal, they being ignorant of its true nature. My reasons for 
coming to this conclusion are, that the lead is found in cavities 
near the surface of the iron, these cavities aving channels of 
more or less size leading to the exterior of the mass ; the iron is 
honey-combed in its character in many places, which is evident 
to the eye, and is also indicated by its specific gravity 65. In 
Pieces of the i iron, detached from the interior of the mass and ex- 
amined with the utmost care by a magnifying glass to see that 
there i is no possible fissure in it, no lead has been found. These 
pieces are exceedingly difficult to obtain, and can only be had in 
ve ; 
€ crust of the i = having the most cavities furnishes 
lead, and is in some parts covered by a fused yellow sitet of 
oxyd of lead ; this 1 last fact has no significance, however, in the 
present consideration of the matter. Without venturing to in- 
mend this view of the subject to those having larger specimens 
of the iron than myse 
Arr. XXXIV.— Remarks on the alkalies contained in the min- 
eral Leucite; by J. LAWRENCE SMITH. 
In examining recently many of the silicates containing alka- 
lies, m aiseiiteon has a i Leucite, and it is on a 
