A new Green Colour. 145 
to introduce, in the most advantageous manner, the good effect 
indicated above, or any other improvement for the rapid trans- 
mission of air to greater or smaller distances.” The prize is 300 
frances, and is to be adjudged in April 1822. 
ROYAL ACADEMY OF SCIENCES OF TOULOUSE. 
This Academy has proposed as the subject of prize essays, ‘a 
physico-mathematical theory of drawing and_ forcing pumps, 
stating the ratio between the moving power and the quantity of 
water elevated; attention being given to all the obstacles which 
the force has to overcome.” Among these obstacles are enu- 
merated, the weight and inertia of the column of water, its fric- 
tion against the tubes, its contraction at the apertures of the 
valves, the weight and friction of the pistons, the weight of the 
valves, the inequality between the upper and lower surface at the 
moment the pressure opens them, &c. The papers are to be 
written in French or Latin, and sent in before May 1823, The 
prize is a gold medal of 500 francs value. 
{ 
XXXVILI. Intelligence and Miscellaneous Articles. 
. A NEW GREEN COLOUR. 
To Dr. Tilloch. 
Sir,— Tur discovery of a new green colour by M. Bizio, which 
was announced in your last Number, has induced me to make 
some experiments with other vegetable substances; and I beg to 
state that I have succeeded in producing a green colour brighter 
than what I could procure by using coffee, and possessing che- 
mical properties somewhat different. 1 formed a strong decoc- 
tion of tobacco by boiling it for some time in pure water ; then 
added solution of sulphate of copper, and precipitated with sub- 
carbonate of pvtassa. The precipitate when dry is of a light 
green colour. Mixed with linseed oil it became darker and 
brighter, and very like a rich grass green. Dissolved in nitric 
acid it forms a green solution. It also tinges sulphuric acid of 
a green colour. I do not find that it is acted upon either by 
water, alcohol or ether, 
I am, sir, your obedient servant, 
No. 6, Dartmouth-street, Westminster, Cuarves M. WILtICH. 
Feb. 18, 1822, 
Mr. Willich with the above communication favoured me with 
specimens of his new green, both dry and mixed up with linseed 
oil. It is a most beautiful colour, and will probably prove highly 
useful in the arts.—A. I’. 
Vol. 59. No. 286. Feb, 1822. hk: CAR- 
