172 TrTiscellanies. 



11. Effect of certain mineral poisons on living plants, in a letter 

 to the Editor, from Dr. Hare. — In order to destroy the caterpillars 

 which feed upon them so ravenously, I was desirous of ascertaining 

 how far certain poisonous solutions could be introduced into the 

 circulation of plants without injury to them. Having cut off a few 

 twigs from a Linden tree, I introduced a twig, with its leaves attach- 

 ed, into different phials of water, severally impregnated with iron, 

 copper and arsenic ; also one into pure water. That introduced into 

 the ferruginous solution, died in about twenty four hours. The twig 

 exposed to the copper lost its proper hue and looked sickly in about 

 two or three days, and finally appeared dead in about five days. 

 Nearly five days had elapsed before the twig in the arsenious acid, 

 although saturated, became sensibly injured, and even then it was 

 only changed in color. During the first three days no difference 

 could be perceived between the leaves of the twig here mentioned 

 and that sustained by pure water. It would appear from these ex- 

 periments that metallic solutions are poisonous to a vegetable in the 

 inverse order from that in which they affect animals, and that small 

 portions of arsenic may be introduced into trees, so as to be poison- 

 ous to the insects which destroy their foliage. On macerating a leaf 

 of the twig in the arsenious solution, only about forty five hours 

 after it was introduced into it, the water to which it was subjected 

 gave with the ammoniacal nitrate of silver a yellow precipitate, and 

 after five or six days, this experiment being repeated, a copious pre- 

 cipitation ensued, indicating arsenite of silver. Caterpillars put upon 

 the leaves impregnated with the arsenic died in a day or two, except- 

 ing one which was too far advanced to eat. These observations in 

 your Journal, so hastily made and described, may need some indul- 

 gence from your readers. 



12. JVotice of a Barn Sivallow, in a letter to the Editor dated 

 Windsor, Turky Hill, June 7th, 1820, from Samuel TVoodruff. — 

 This bird is one size larger than the common barn swallow, and 

 more garrulous; tail not forked, but full and square; plumage about 

 the head and upper side of the neck of a shining black, with the 

 exception of a cross bar of white on the forehead immediately back 

 of the beak; breast and belly a light brown; a narrow longitudinal 

 stripe of a dull white on the back ; rump a light brown, tinged with 

 yellow ; wings much of the color of the barn swallow, but less pointed. 



