REV. WILLIAM THORP. 
431 
the Mueseler type, fitted witli a bonnet, was most suitable, and he 
agreed with the commission that a quick explosive was the most 
desirable, and with the explosive recommended viz., gelatine dynamite 
which is fired surrounded by water, the effect being instantaneous 
and giving off no flame. 
At a meeting held at Barnsley in 1866, Dr. H. 0. Sorby read a 
paper on some remarkable properties of the characteristic constituents 
of steel. The microscopical examination of suitably prepared speci- 
mens of iron and steel shows that there are two well marked 
constituents. One of these is comparatively soft, and is iron which 
is free from carbon ; the other is intensely hard, and probably con- 
tains combined carbon, since it occurs in white cast iron, blistered 
steel, and other varieties known to contain carbon in that state. 
Besides these there is another which gives beautiful colours like 
mother-of-pearl. With very high magnifying powers this pearly 
constituent is shown to have a structure closely like that of pearl, 
being made up of alternating thin plates. Dr. Sorby came to the 
conclusion that these plates are alternating layers of soft iron, free 
from carbon, and of the intensely hard compound with carbon. The 
only satisfactory explanation for this remarkable structure appears to 
be that at a high temperature the stable compound of iron and carbon 
exists, which is not stable at a lower temperature, but breaks up into 
extremely thin laminated alternations of the two. 
Mr. H. B. Stocks described a concretion found in sandstones, 
and consisting of a grey or brown friable sand which is called Acres- 
pire. A chemical examination of this concretion showed it to contain 
about 30 per cent, of carbonate of lime. 
Mr. Wm. Horne, of Leyburn, gave an account of the discovery 
of a tumulus and some ancient burials, about three-quarters of a mile 
to the west of Leyburn, on a plateau beneath the Shawl. He inci- 
dentally discovered a portion of a human skeleton on the edge of a 
small landslip, and further investigation proved that the place had 
been used as one of interment by some- pre-historic people. With 
the human remains he found several bones of the reindeer, quantities 
of charcoal, and several burnt stones and pot boilers. The plateau 
seenied to have been used as a camping ground for a long period, as 
