104 Mr. Crosse's Electrical Experiments. 



fluid within, the insects were similarly produced. The ap- 

 paratus was covered with them ; they hid themselves where- 

 ver they could find shelter ; many were plainly perceptible 

 to the naked eye, as they nimbly crawled from one spot to 

 another. On examining the table with a lens, no such ex- 

 crescence as that which marks their incipient state, could be 

 perceived. Other experiments were also in progress at this 

 time, with different-sized batteries. On a clay slate, suspend- 

 ed in a glass cylinder by two platina wires, in a similar solu- 

 tion to the foregoing, similar excrescences, and growth to 

 perfect insects, were observed. Between the poles of the bat- 

 tery were interposed a series of seven glass cylinders, filled 

 with the following concentrated solutions: — 1, Nitrate of cop- 

 per ; 2, sub-carbonate of potassa ; 3, sulphate of copper ; 4, 

 green sulphate of iron ; 5, sulphate of zinc ; 6, water, acidi- 

 fied with a minute portion of hydrochloric acid ; 7, water, 

 poured on powdered metallic arsenic, resting on a copper cup 

 connected with the positive pole of the battery. All these 

 cylinders were electrically united together by arcs of sheet 

 copper, so that the same electric current passed through the 

 whole of them. After many months' action, and consequent 

 formation of certain crystalline matters, similar excrescences 

 appeared at the edge of the fluid, in every one of the cylin- 

 ders, excepting the two which contained the carbonate of 

 potassa, and the metallic arsenic, and in due time a host of 

 insects made their appearance. In another experiment, a 

 bent iron wire, one-fifth of an inch in diameter, in the form 

 of an inverted syphon, was plunged some inches into a con- 

 centrated solution of silicate of potassa, and connected with 

 the positive pole, whilst a small coil of fine silver wire joined 

 it with the negative. Similar insects were formed on the ge- 

 latinous silica on both wires, also on that part of the wires 

 free from the siliceous deposits, about half an inch below the 

 surface of the fluid. Some of them were formed on the in- 

 verted part of the syphon-shaped wire, yet did they repeatedly 

 contrive to arrive at the surface, and to extricate themselves 

 from the fluid. The room in which the three last batteries 

 were acting was kept almost constantly darkened. — Morning 

 Post, Jan. 22nd, 1838. 



At the Linnean Society. Nov. 1th, a paper was read from 

 Dr. John Hancock, on the Angostura bark tree, {Orayuri), 

 and its botanical characters, compared with those of Cusparia, 

 or Bonplandia trifoliata, Willd. The essay consisted chiefly 

 of answers to some objections which have been urged against 

 the former being considered a distinct species, and a vindica- 

 tion of the accuracy of the description, published by the 



