394 CURIOUS OR USEFUL PLANTS. 



tack the copal, which swells and dissolves, except a very smaii 

 quantity. It is of much consequence that the vessel should not be 

 opened till some time after the liquid has become perfectly cool ; 

 as it frequently happens that the whole of the contents are blown 

 with violence against the ceiling, The spirit of turpentine should 

 be of the best quality. 



JVlr. Sheldrake has lately favoured the public with another and 

 easier method of dissolving copal. This method is as follows : 

 Provide a strong vessel made of tin or other metal ; it should be 

 shaped like a wine bottle, and capable of holding two quarts ; it 

 will be convenient to have a handle strongly rivetted to the neck 

 the neck should be long, and have a cork fitted to the mouth, but 

 a notch or small hole made in the cork ; that, when the spirit is 

 expanded by heat, a small portion may force its way through the 

 hole, and thus prevent the vessel from bursting. Dissolve half an 

 ounce of camphor in a quart of spirit of turpentine, and put it into 

 the vessel ; ta.ke a piece of copal the size of a large walnut, reduce 

 it to a coarse powder or very small pieces 3 put them into the tin 

 bottle, fasten the cork down with a wire, and set it, as quick as 

 possible, upon a fire so brisk as to make the spirit boil almost im- 

 mediately ; then keep it boiling very gently for about an hour, 

 when so much of the copal will be dissolved as will make a very 

 good varnish ; or, if the operation has been properly begun, but 

 enough of copal has not been dissolved, it may be again put on the 

 fire, ar.d by boiling it slowly for a longer time, it may be at last 

 brought to the consistence desired. 



[Phil. Trans. Trans. Arts. Commerce, $c. PantoL 



SECTION VIII, 



Gum Arabic. 



Mimosa Nilotica*. Mims. 



The nilotica, or true Egyptian acacia, from which this vegetable 

 article is chiefly obtained, rises to fourteen or sixteen feet in 

 height. The fruit is a long pod, resembling that of the lupin, and 

 contains many flattish brown seeds. It is a native of Arabia and 

 Egypt, and flowers in July. Although the mimosa nilotica grows 



* Acacia vera, Wilden. 



