138 Experiments on the Composition of 
VII. An ounce and a half of pulp, mixed with two 
ounces of glue, two ounces of white bole, and as much 
chalk, yielded a smooth plate as hard as hone. 
VIII. An ounce of pulp, one ounce of glue, three ounces 
of white hole, and an ounce of linseed oil, produced a 
plate sufficiently perfect and elastic. 
IX. A plate which I formed of an ounce of pulp, with 
half an ounce of glue, three ounces of white bole, an ounce 
of chalk, and an ounce and a half of linseed oil, Was su- 
perior to that mentioned in the preceding experiment. 
This substance retains figures impressed upon it, and, 
tinged with half a dram of Prussian blue, assumed a 
blueish- green colour. 
X. An ounce and a half of pulp, with an ounce of 
glue and four ounces of chalk, afforded a plate exceed 
ingly spongy. 
XI. An ounce and a half of the same pulp, one ounce 
of sulphat of iron, and four ounces of white bole, without 
glue, produced a plate yellowish and spongy. 
XII. An ounce and a half of pulp, four ounces of 
white bole, with an ounce of sulphat of iron, and the 
same quantity of glue, produced a yellowish plate a little 
more solid. 
I tried several other mixtures ; but as the plates they 
produced were of an inferior quality, I shall not give any 
account of them. The plates which had been prepared 
in the above manner I cut into several pieces, and daub- 
ed over a specimen of each with boiled linseed oil. The 
parts covered with the oil assumed a darker colour, and 
the superficies acquired more solidity, nor were they less 
capable of resisting fire. 
Being desirous of comparing the productions of my ex- 
periments with specimens of the Swedish stone paper, I 
macerated about an inch square of each in cold water. 
After they had been macerated four months, the sped- 
