~ The following is a list of seven of the most abundant of the 
meteoric species, (which are enumerated in the supposed order 
of their prevalence, ) in the aggregate of meteor-masses at present 
“1. Nickeliferous iron. 5. Anorthite. 
a Re Peridotesd — 35 « 6, Native iron. 
- + 3. Pyroxene. . 7, Chiadnite. 
_ +» 4) Magnetic iron pyrites. 
And of these, it is probable, that No. 1 constitutes ,%;ths the 
_ Weight of all known meteor-masses; while the seven species ta- 
_ ken together, form 12ths of such masses. 
The four species out of these seven which are common to the 
earth, (peridot, pyroxene, magnetic iron pyrites, and anorthite,) 
3 form too insignificant a part of the crust of our globe to enable 
+ to give, even a conjectural expression, in numbers, of their 
amount. Kea 
- The contrast is therefore very 
Position of the meteor-masses and of our earth. A species whose 
Specific gravity is above 7, and which is metallic in its character, 
ib eG oe fe ee +1 ¢ fi a 
forms ,°,ths of the former, while all the analogous species (i. e., 
those belonging to the order metal,) taken together, do not prob- 
ably constitute rasleaath part of our globe! This remarkable 
iscrepancy however will be much diminished, when allowance 
is made for the loss of all those meteoric stones which have fal- 
len in early times, prior to the period in which mankind have - 
begun to collect and preserve them. From the peculiar chemical 
Composition of meteoric stones, it is plain, that unless collected 
Soon after their fall, they would cease to be cognizable : whereas 
the iron-massés are capable of withstanding almost indefinitely, 
the action of the atmosphere and other destructive agencies to 
which they may be exposed after contact with our earth. 
It is probable then that Yasths, at least, of the meteor-masses 
wn, fell in early times; some of it perhaps, anterior to the . 
existence of man on the earth: and if we would form an idea of 
the correspondence between the metallic and the stony meteors 
Of those times, we can only do so by comparing the ratio between 
the two during’a fixed modern period, within which the masses 
ofboth kinds have been observed. ‘Taking the last one — 
Years With such a view, we find in the weight of the two iron- 
falls (Croatia, 1752, and Tennessee, 1835) as set off against that 
__ Bkcoxp Senizs, Vol. If, No. 6—Nov., 1846. 50 
