9° 
Oe 
that this process is sometime undergone in veins of asbestos, so that what mav 
have been originally true asbestos is now chrysotile. Prof. Dana states that all 
crystalized serpentines are pseudomorphs. In the report of Dr, Harrington on 
some of the mineials of Ottawa County, in the Geological Report for 1877-78, 
instances are given of asbestos being an alteration product or pseudomorph of 
pyroxene. 
The following table shows the results of analyses of the several varieties 
of Asbestos, with the localities from which the specimens came : 
# a = 23 rie 
2 = Nea | Se) o> 
5 A Aa SS 3) — > 
SE ys oases mi Maa (Peck 
as a= Gaia SI a0 
ace ae oF A oe Sic iar) 
<2 <= | #% ee ce om 
5 as cet oe Saige) ro] fe qe = 
Oo: )e Sy ago =O aie 
ce Si ‘a N ws OS: 4 
om SIN ts 25 come Bo 
z= = ofa oe oun Oo = 
—e Es gee o/2 ve | 2S 
aS as Sore aeee ae Be 
a sss) Feet =| me cS mS 
4 en <q oC re) oO 
DMMCANe se. ee asoten 58.20 55.87 58. 19 43.50 44.05 42.62 
MAINTE WG ee cise ne ao al) edhdigii® ec paatcne tens Pedant ble Ss 3c 
Magnesia ....... lee tO -20035 | 30.00e | 40LCOrW 39s 24a eae non 
Protoxide of Iron..... 3.08 A Bil (93 DEOS) |? Sar 53 SPATS 
Protoxide of Manganese! $y i Ves OA renee bh Seiaad lh Ae Fee 
Oxide of Alumina .... ; 14 Severe .18 !} 40 | Saree _& 
Hydrofluoriec Acid..... .60 a 1.86 Reo None 3 Aas 
AWiateR ce sei. Kon biti 14 Sani ats\ ove 13.80 13.49 45:25 
100.02 | 99.89 | 98.95 | 99.78 | 99.31 | 100.19 
| 
i 
The origin of the fibrous forms does not appear to be fully explained, but it 
seems probable that they were formed later than, and out of, the chemically 
similar rocks surrounding them. Dr. Hare explained, in a lecture delivered 
before the Literary and Scientific Society, that mineral veins were formed by 
water, or other chemical fluid, penetrating the rocks in which the minerals were 
disseminated, combining with them into new chemical compounds, and finally 
depositing them in fissures, where they had an opportunity of crystallizing. This 
would seem a natural way of accounting for the presence of the fibrous silicates 
now under consideration, 
Or they may have been crystallized and deposited in the fissures which con- 
tain them, in some way by the action of the same heat that crystallized the sur- 
rounding rocks. ; 
In Europe, asbestos occurs very abundantly, being found in Piedmont, 
Saxony, Switzerland, Salzburg, the Tyrol, Dauphiné, Hungary, Silesia; also in 
Corsica so abundantly as to have been used for packing other minerals; at St. 
Kevern in Cornwall, in Aberdeenshire, and in some of the islands north of 
Scotland. ; ; 
On this continent it occurs in Greenland, and in nearly all of the United 
States, particularly in North Carolina, on Staten Island, at Baltimore, and at 
Montarville, N.J., the quality differing in different localities. There is said to 
be a gradual increase in the tenacity of the fibre in proceeding from Georgia 
northwards, this improvement appearing to culminate in northern Vermont, 
3 
