After the conclusion of his last lecture, Prof. Dewar distributed among
the younger listeners small pieces of a portion of the Dhurmsala
meteorite, which had been broken up for presentation to them by Mr. J.R.
Gregory, whose collection of rare minerals was recently to some extent
described in these pages. The lecturer stated that Sir F. Abel had given
him a large piece of a large meteorite, because he thought that the
speaker's piece ought to be bigger than theirs.
Professor Dewar also presented the listeners with a printed detailed
account of the fall of the Dhurmsala meteorite, including the report of
the occurrence sent to the Punjaub Government, and dated July 28, 1860.
The following are the main facts:
"On the afternoon of Saturday, the 14th of July, 1860, between the hours
of 2 and 2:30 P.M., the station of Dhurmsala was startled by a terrific
bursting noise, which was supposed at first to proceed from a succession
of loud blastings or from the explosion of a mine in the upper part of
the station; others, imagining it to be an earthquake or very large
landslip, rushed from their houses in the firm belief that they must fall
upon them. It soon became apparent that this was not the case. The first
report, which was far louder in its discharge than any volley of
artillery, was quickly followed by another and another, to the number of
fourteen or sixteen. Most of the latter reports grew gradually less and
less loud. These were probably but the reverberations of the former, not
among the hills, but among the clouds, just as is the case with thunder.
It was difficult to say which were the reports and which the echoes.
There could certainly not have been fewer than four or five actual
reports. During the time that the sound lasted the ground trembled and
shook convulsively. From the different accounts of three eyewitnesses
there appears to have been observed a flame of fire, described as about 2
ft. in depth and 9 ft. in length, darting in an oblique direction above
the station after the first explosion had taken place. The stones as they
fell buried themselves from 1 ft. to 1½ ft. in the ground, sending up a
cloud of dust in all directions. Most providentially, no loss of life or
property has occurred. Some coolies, passing by where one fell, ran to
the spot to pick up the pieces; before they had held them in their hands
half a minute they had to drop them, owing to the intensity of the cold,
which benumbed their fingers. This, considering the fact that they were
apparently but a moment before in a state of ignition, is very
remarkable. Each stone that fell bore unmistakable marks of partial
fusion."
Several meteors were seen at Dhurmsala on the evening of the same day.
Dr. C.T. Jackson analyzed a portion of one meteorite weighing 4½ oz.; the
piece was 2½ in. long, 1¼ in. wide, and 1 in. in average thickness. In
the course of his report he stated: "Its specific gravity is 3.456 at 68
deg. Fahr., barom. 29.9. Its structure is imperfectly granular, but not
crystallized, and there are small black specks of the size of a pin's
head, and smaller, of malleable meteoric iron, which are readily removed
from the crushed stone by the magnet. The color of the mass is ash gray.
A portion of the surface is black and is scarified by fusion. Its
hardness is not superior to that of olivine or massive chrysolite.
Chemical analysis shows that its composition is that of a ferruginous
olivine. One gramme of the stone, crushed in an agate mortar, and acted
on by a magnet, yielded 0.43 gramme of meteoric iron, which was
malleable. After the removal of this a qualitative analysis was made of
the residual powder. Another gramme was also taken, without picking out
the metallic iron, and was tested for chlorine and for phosphoric acid.
The results of the qualitative analysis were that the stone contains
silica, magnesia, a little alumina, oxide of iron and nickel, a little
tin, an alloy of iron and nickel, phosphoric acid, and a trace of
chlorine. These ingredients being determined, the plan for a quantitative
analysis was laid out, and was duly executed by the usual and approved
methods The following are the results of this analysis, per centum:
Silica, with traces of tin 40.000
Magnesia 26.600
Peroxide of iron 27.700
Metallic iron 3.500
Metallic nickel 0.800
Alumina 0.400
Chlorine 0.049
Phosphoric acid not weighed --
______
99.049"
Messrs. Dewar and Ansdell analyzed the gases in the meteorite, of which
it contained three times its volume; the gases were in the following
proportions to each other:
Carbonic acid 61.29
Carbonic oxide 7.52
Hydrogen 30.96
Nitrogen 0.23
______
100.00
* * * * *