234 List of Patents for neiv Inventions. 



a pen, if the ink has a little ox-ga!l put into it. Mr. 

 Caihery sells it for the same price at which the common 

 tracing paper is sold. 



Tke Preparation. — Take one quart of the best rectified 

 spirits of turpentine, and put to it a quarter of an ounce of 

 sugar of lead finely powdered ; shake it up, and let it stand 

 a day and night ; then pour it off, and add to it one pound 

 of the best Canada balsam, set it in a gentle sand heat, and 

 licep stirring it till it is quite mixed, when it will be fit for 

 use ; then lay your paper on a smooth board, and with a 

 large brush, brush your paper over verv even with the mix- 

 ture, and then hang it upon lines to dry, and it will be fit 

 lor use in about four days. 



The Society voted five guineas to Mr. Caihery for his 

 communication. 



EFFECTS OF COLOURED RAYS IN A MIXTURE OF OXY- 

 MURTATE AND HYDROGEN GAS. 



Mr. Leebeck, a German chemist, having made a mixture 

 of these eases exposed them to the light of the sun, which 

 suddenly decomposed them with a great explosion. This 

 experiment was suggested by Gay Lussac and Thenard, 

 and M. Leebeck has repeated it with success by means of 

 gas collected over hot water. He afterwards introduced 

 this gas into a yellowish red bell glass, and another of a 

 deep blue, which he exposed to the solar rays. In the blue 

 bell glass the decomposition took place instantly without 

 any explosion, and in a minute at most it was ended, and the 

 greater part of the bell glass was filled with water. On the 

 contrary, in the red bell glass the decomposition took 

 place very slowly : after being exposed for twenty minutes 

 to very strong solar rays, a very small quantity of water 

 rose in the red bell glass. This mixture of gas in the red 

 bell glass was introduced into a white bell glass, and also 

 exposed to the solar rays : no explosion took place, but in 

 a few minutes the decomposition was complete, and the 

 glass was filled with water. The experiments were several 

 times repeated with similar results. 



LIST OF PATENTS FOR NEW INVENTIONS. 



To William Chapman, of Murton House, in the county 

 of Durham, civil engineer, and Edward Walton Chapn)an, 

 of Wellington Ropery, in the parish of Walls End, in the 

 county of Northumberland, rope-maker, for their methods 

 of facilitating the means and reducing the expense of car- 

 jiagc on rail ways and other roads. — 30lh December, 1812. 



To 



