294 Notices respeciing New Books. 
ployed with advantage during the summer months in preserving 
meat,” it is added that ‘ from the salmon fisheries in Scotland 
and the north of England, the fish are sent to the metropolis, 
during the greater part of the season, packed with ice, in boxes 
about four feet long and eighteen inches deep. When packed, 
the ice, which is previously broken as small as bay-salt, is put 
over them and beaten down as hard as can be without bruising 
the salmon. In this manner they are kept perfectly fresh for two 
or three weeks.” ’ 
In treating of the advantages which may be derived from arti- 
ficial cold, Mr. Parkes recommends the use of frigorific mixtures 
to freeze occasionally the brain and the eyes of those animals 
which are to undergo dissection by anatomical pupils, those parts 
not being easily dissected in any other way, and informs us that 
this method was first practised by the great Mr. Boyle. In the 
directions which are given for the use of saline mixtures to pro- 
duce artificial cold, Mr. Parkes has very properly remarked that 
<< it is of consequence to have the salts fresh crystallized, thorough-- 
ly dried, and then finely pulverized ; that the mixtures be made 
rapidly, and in vessels as thin as can be procured.” 
An expedient related by Mr. Parkes, and which is adopted by 
people in northern regions for procuring water in winter, 1s 
curious. ‘* During the winter at Hudson’s Bay, the surface of 
the lakes and rivers is covered with ice of such great thickness, 
that no water can be procured without cutting through the ice 
with axes and wedges, which is a very laborious and_ tedious 
operation. As soon, therefore, as the surface of the water which 
has been laid open has acquired a thin plate of ice, the labourer 
heaps over it a quantity of snow, which, by being a bad conduc- 
tor of heat, prevents the caloric of the water from passing upwards 
according to its natural tendency. Then, during the remainder 
of the winter, the inhabitants have only to remove a little of the 
snow, when occasion may require it, and they have water im- 
mediately.” 
A hint which Mr. Parkes gives in vol. i. p. 284, respecting the 
fuel proper for steam engine and other large iron boilers, deserves 
to be noted. In such cases “ sulphurous coals should be avoided, 
as the sulphur which rises during combustion is apt to occasion 
a rapid decay of that part of the beiler which is exposed to the 
action of the fire. It produces a sulphuret of iron, which wastes 
away as fast as it is formed.” 
The last 100 pages of this essay are chiefly occupied in giving 
directions for building stills, furnaces, chimneys, &c. aud in advice 
respecting the choice and management of fuel, all arising from 
the author’s experience in his own manufactory ; but we must con~ 
fine our notice to a short extract relating to the management of 
reverberatory 
