Scienlljic Intelligence. 
a clear whit.e, not unaptly compared by Haller to snow. Dr Ja* 
cob’s method of examining these jmrts is very ingenious. He takes 
a hollow sphere of glass, about two or three inches in diameter, 
about one-fourth of which is cut off at the part where it isopen, 
and the edges are ground down, so as to ht accurately upon a 
piece of plate-glass, the surface of which is also ground. The 
object to be examined is attached to a piece of wax, fastened 
upon the plate of glass, and immersed in a basin of water, with 
the cut sphere, which is inverted over it, of course full of water, 
and the whole withdrawn from the basim In this way, the de- 
licate membrane floats in water, and may be unfolded and dis- 
played. By this method, also, a preparation may be handed round 
a class-room. — See Phil. Trans. 1819? part ii. p. 300 — 307. 
- 43. Nearest approach to the North Pole. — In the year 1806, 
“Mr Scoreshy? when mate in his father’s ship, the Resolution of 
Whitby, succeeded, after great efforts, and by exposure to im- 
vminent hazard, in reaching the latitude 81° 30', within about 600 
.miles of the Pole. This took place in longitude 19° East. The 
nearest approximation to the South Pole has been to the 72d 
,<legree, about 1170 miles from the Pole. — See Scoresby’s Ac^ 
.count of the Arctic Regions^ vol. i. p. 312. 
44. Method of Blowing up Ice. — As it is often of great im- 
portance to clear rivers and canals, &c. of ice, the following me- 
thod, which was first suggested and successfully put in practice 
by Mr John Merricks of Esk-Hill, will be found to be simple 
and easily executed. A hqle having been dug in the ice with 
a chisel, and a piece of board placed across it, a tin-canister, 
containing -a few ounces of gunpowder, and terminating up- 
wards in a tin tube, is suspended about two feet under the ice, 
and rests by a shoulder upon the piece of wood. The gun- 
powder being exploded by a match in the ordinary way, the 
ice will be blown up in all directions. In one trial, where the 
ice was 3| inches thick, the ice was broken through a space 15 
yards long and 11 broad. Mr Merricks suggests that this me- 
thod might be of use in the Greenland Seas, when a vessel is 
frozen in ice. Mr Scoresby, to whom we communicated this 
ii^ea, remarks, that he has seen a case, in Avhich a vessel was 
