284 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[August, 



sufficient surface of metal was present to convey the current into and ou 

 of the water. Before proceeding to apply this fact, however, the first expe- 

 riment was repeated, but with a smaller battery. 



" A copper wire was next laid down on the gravel walk along the north 

 bank of the Serpentine River, from the bridge which separates Hyde Park 

 from Kensington Gardens, to the east end of the river. About three square 

 feet of metallic surface was attached to each end of the wire and put into 

 the river; a galvanometer was put into the circuit at the bridge, and a 

 small Grove's battery at the other extremity of the wire. The electric cur- 

 rent passed by the water, and returned by the wire, and with as much power 

 as would have been the case with an ordinary metallic circuit. Iu this 

 arrangement the magnetic influence ceased the moment the circuit was 

 broken, as it would have done in an entirely dry circuit. 



" Reflecting on the foregoing experiment, it occurred to Mr. Bain that the 

 satural moisture of the earth might be a sufficient conductor for the electric 

 ?urrent, and with a view to ascertain the correctness of this assumption, a 

 ■wire was led along a wood-paling extending from the river to a well about a 

 hundred and fifty yards distant ; one of the metallic surfaces attached to the 

 ■wire was put into the river, and the other into the well; the galvanometer 

 was put into the circuit near the river, and the small battery near the well. 

 On completing the circuit, the current passed freely, as in the former experi- 

 ruents, showing that ichtn sufficient moisture is present, the earth is a good 

 conductor of voltaic electricity ; and that one-half of a voltaic circuit is all 

 that is necessary to be insulated from surrounding conducting matter. 



" While reflecting upon these experiments, some few months after they 

 had been performed, Mr. Bain was led to infer, that if a surface of positive 

 metal was attached to one end of a conducting wire, and an equal surface of 

 negative metal to the other end, and the two metallic surfaces put into 

 water, or into the moist earth (the wire being properly insulated from sur- 

 rounding matter), an electric current of considerable energy would be esta- 

 alished in the wire. This proposition was soon tested by an experiment per- 

 formed in the grounds of Mr. Finlaison (the government calculator), at 

 Algher's House, Loughton, Epping Forest." In a moat distant 150 yards 

 from a pond of water, was placed a plate of about 1 2 inches surface of posi- 

 tive metal, and in the pond a similar size plate of negative metal, and a 

 galvanometer with a conducting wire connecting the two plates were laid 

 along*a gravel walk. " The moment this arrangement was completed, the 

 galvanometer showed that an electric current was passing from the metal 

 in the pond, through the earth to the metal in the moat, returning back 

 again by the wire. The current was of considerable energy, and this experi- 

 ment was repeated a number of times with unvarying success." 



Similar experiments upon a larger scale were tried upon the Serpentine 

 River, in Hyde Park, with equal success. 



"These points being satisfactorily established, Mr. Bain next proceeded 

 to make the experiment as shown in the annexed diagram. 



A surface of zinc (Z), was buried iu the moist earth in Hyde Park, and, at 

 rather more than a mile distance, a copper surface, C, was similarly deposited ; 

 the two metals were connected by a wire, suspended on the railing, and on 

 placing a galvanometer, G, in the circuit, an electric current was produced, 

 which passed through the intervening mass of plate from the eartb, return- 

 ng by the wire. In the first experiment, the metallic surfaces being small, 

 the electric current produced was feeble, but on using a larger surface of 

 metal a corresponding increase in the energy of the current was obtained, 

 with which an electrotype process was conducted, and various electro- 

 magnetic experiments performed with uniform success.* | 

 ,. " Subsequent experiments have shown that if two metal plates (a negative 

 and positive) of sufficient surface are sunk in the earth as a batten-, and 

 wires led therefrom, electrotype deposition may be effected, and every 

 description of electro-magnetic apparatus worked for any length of time. 

 The most successful results have, however, been obtained by depositing 

 several surfaces of positive metal in the earth connected into a group by 

 wires, from which a conducting wire was led to a series of negative surfaces 



irailarly disposed at a more remote spot. When considerable power is 

 required, this is the arrangement that should be adopted. It is essential to 



snecess, that the earth wherein the plates of metal are deposited should be 

 of a moist nature. A current has, indeed, been obtained in dry soils, but of 

 such small energy as to be of no practical utility. This, however, may have 

 been occasioned by the very small proportion of metallic surface with which 

 the experiment was made. 



" Such a source of electricity as the foregoing promises to be most exten- 

 sively useful in the arts. Among other advantages, its simplicity and cheap- 

 ness are no small recommendations, while the uniform character of its power 

 is of the utmost importance. A battery of this description, under very dis- 

 advantageous circumstances, has produced a power which for upwards of six 

 months has been found unvarying." * 



" If a copper wire, one-sixth of an inch in thickness be imbedded in a bar 

 of boiling asphaltum and sent along the railway (for its better protection) 

 from London to Liverpool — if two tons weight of zinc plates be immersed 

 in the Mersey at Liverpool, and attached to that end of the wire — and if one 

 ton weight of copper be sunk in the river Thames, and attached to this end 

 of the wire, no rational man can doubt that an electric current would be 

 established often times the power necessary to work a telegraph." 



" Now, in the voltaic circuit in question, it may be a bard matter to say 

 whether the current flies round the coast by the sea, or whether it penetrates 

 the earth superficially. One thing is, however, certain — the experiment is 

 not likely to be tried at the sole cost of the inventor, and it is humbly con- 

 ceived that the country, which is to be benefitted by the discovery, should 

 incur the trifling charge of bringing it into use. Supposing, however, the 

 very improbable event, that the current, from some unforeseen cause, could 

 not be passed to the distance of 200 miles, it may still be sent, as far as it 

 will go, in relays, connecting these very easily by means which are well 

 known to every practical electrician." 



" The following diagram exhibits Mr. Bain's latest improved pendulum, 

 which is moved by a metallic surface, in the moist earth, of no more than 

 four or five feet. It is, indeed, very necessary in these times to publish it 

 without delay, lest the merit of this invention also should be snatched from 

 hiiu by some one or other of the fakeurs of the day. Can any man new 

 foresee the important ends to which this little instrument may hereafter be 

 applied ? In the ordinary use of it for the measurement of time, diminished 

 friction, and hence far greater accuracy, is obviously secured. Its perma- 

 nence of action is probably the nearest approach yet made to the impossible 



