392 Scientific Intelligence. — Arts. 
sary. This is afforded by gum arabic or isinglass, of which the 
proportions vary according to the use to which the crayon is 
destined, less of it being required for soft crayons, which conse- 
quently leave their colouring matter more readily, and more for 
the hard ones, which preserve their point longer. The follow- 
ing are the proportions, deduced from experiment, to be em- 
ployed in the five kinds of crayons, which we shall enumerate. 
1. For the red crayons, with large marks, 18 grains of dry gum 
arabic to one ounce of prepared hematite powder. 2. For the 
hard-grained crayons, 21 grains of gum to one ounce of hematite 
powder. 3» For the crayons, with small and fine marks, 27 
grains of gum to one ounce of hematite. 4. For the crayons, 
with less fine marks than the preceding, 22 grains of gum. 5. 
For the crayons, with shining marks, 36 grains of ichthyocolla 
to one of prepared hematite powder. — The gum or isinglass is 
dissolved in a sufficient quantity of water ; the solution is passed 
through a linen cloth ; the powder is then added ; the liquid is 
brought near a gentle fire, until the mass is somewhat thicken- 
ed; it is then removed from the fire. The mixture is very care- 
fully bruised upon the porphyry, to render it as intimate as pos- 
sible ; and it is then formed into crayons. The mass, when it 
has acquired the proper consistence, is made to pass through a 
cylinder; the sticks thus formed are dried, and divided into 
crayons of two inches long ; they are sharpened, and the skin 
which has formed upon them, while drying, is removed .— Newe 
Kunst et Gewerllat , Jug. 1824. 
44. Steam-Carriage . — At page 349, we have given Messrs 
Burstall and Hill’s description of their patent steam-carriage. 
The description, along with the plate, will enable our readers to 
understand the ingenious arrangements which the patentees con- 
sider as sufficient, for the purposes of effective and economical 
locomotion. We regret, that, owing to the unfinished state of 
the apparatus, we are deprived of an opportunity of communi- 
cating to our readers, until next Number, the result of experi- 
ments on the powers of this locomotive machine. 
45. New mode of securing Anatomical Preparations in 
Spirits . — Dr Macartney, of the University of Dublin, has em- 
ployed a thin plate of Indian rubber, as a covering for prepa- 
