Electrical Conductors for Ships. 231 



If, in the process just described, sulphuric acid be added, 

 the tartaric acid will change wholly into carbonic acid, water, 

 and formic acid, and consecjuently a greater quantity of the 

 latter will be obtained : the best proportions are — 1 part of 

 crystallized tartaric acid ; 2^ of peroxide of manganese ; 2\ of 

 concentrated sulphuric acid, in two or three times its weight of 

 water. 



I presume that in several other processes, — for example, in 

 treating sugar, alcohol, and other vegetable substances, with the 

 nitric acid, — and perhaps even in many plants, formic acid is 

 produced, which chemists will be able to observe in future ; it 

 is vei'y possible in many cases, where it was su])posed that the 

 acetic acid had been observed, that it was the foi-mic acid ; for 

 it is known that Fourcroy, and M. Vauquelin himself took the 

 acid drawn from ants for the acetic acid. By means of the 

 relations which I have discovered between the formic acid and 

 concentrated sulphuric acid, and the soluble salts of silver or 

 of mercury, whether dissolved in water or combined with a 

 base, it may be sufficiently and almost instantly distinguished 

 from the acetic acid ; so that in future it will not be easy to con- 

 found the one with the other. — [Annalen derPhysik, ixxi. 107.) 



On this the editors of the Annales de CJiimie observe, " We 

 liave hastened to repeat the very interesting experiment of 

 M. Doebereiner, and have obtained exactly the result which 

 he describes." ■ 



ELECTRICAL CONDUCTORS FOR SHIPS. 



The following account has been jmblished of an invention 

 by Mr. W. S. Harris, of Plymouth, for conveying the electric 

 fluid, by means of a copper conductor fixed in the masts, through 

 the bottom of ships. The experiment has taken place in Ph- 

 mouth harbour, and completely succeeded, as will be seen from 

 the following details : — 



Althougli the advantages of conductors on land arc admitted, 

 yet on shipboard, wliere the eflects of lightning arc most to be 

 dreaded, from the inflammairility of the materials of the shij), 

 the introduction of electrical conductors has been neglected or 

 injudiciously eu)pIoyi;(l, Tliis, indeed, may in some measure 

 be traced to the difficulty of placing any fixed or contiguous 

 conducttu- in a situation so liable to change and motion as the 

 mast and rigging of a siiij); and consecjuently the only species 

 of conductor that has been adopted is a chain, or long linkS of 

 wire, one end of which is designed to be hoisted to the mast 

 head, whilst the other passes over the side of the ship, and 

 conniumicates with the water; but, indej)endently of its defective 

 construction, from its small dimensions, the inconvenience of 

 being ccjustanlly hoislcti, anil its conscMjuent liability to be in- 

 jured. 



