TRANSACTIONS OP THE SECTIONS, 21 



jar. While, if both ends of the wire were discharged to earth simultaneously, a lift 

 of 96,000 grains was obtained, thus realizing as a return, more than five times the 

 amount which the battery gave on short circuit. Again : A feeble magneto-current 

 of only 4 grains was adequate to work a telegraphic receiving instrument, a sensitive 

 galvanometer being placed in the same circuit ; but this latter gave most uncertain 

 indications of value ; its unsteady movements ranged wider with slow and feeble 

 currents, and indicated a lesser value for stronger currents, which followed more 

 rapidly in succession, all which however were accurately pourtrayed by the new 

 instrument. Again : A pair of induction coils, excited by six small Smee cells, gave 

 27,000 grains ; the mere addition of a soft iron armature at one end augmented 

 this to 43,000, while a similar one at the other end increased the current's value 

 up to 47,500. 



Mr. Whitehouse called it a " Magneto-electrometer " from its special adaptation 

 to the measurement of magneto-electric currents, while the terms galvanometer, 

 voltameter, and electrometer sufficiently indicated for these instruments their con- 

 nexion with other forms of electricity. 



The desirability of a definite and common standard of comparison was insisted on, 

 and Mr. Whitehouse promised to set aside for this special use the most accurately 

 finished and perfect instrument he could obtain, for the free use of any fellow- 

 labourers in the same field. 



The Law of the Squares — is it applicable or not to the Transmission of Signals 

 in Suhmarine Circuits? By W^ildman Whitehouse. 



Referring to the proceedings of this Section last year at Glasgow, the author 

 quoted Prof. W.Thomson's paper on this subject, where he stated " that a part of the 

 theory communicated by himself to the Royal Society last May, and published in 

 the ' Proceedings,' shows that a wire of six times the length of the Varna and Bala- 

 klava wire, if of the same lateral dimensions, would give thirty-six times the retar- 

 dation, and thirty-six times the slowness of action. If the distinctness of utterance 

 and rapidity of action practicable with the Varna and Balaklava wire are only such 

 as not to be inconvenient, it would be necessary to have a wire of six times the 

 diameter ; or better, thirty-six wires of the same dimensions ; or a larger number of 

 small wires twisted together, under a gutta-percha covering, to give tolerably 

 convenient action by a submarine cable of six times the length." The author then 

 stated, that circumstances had enabled him to make very recently a long series of 

 experiments upon this point, the results of which he proposed to lay before the 

 Section ; adding, that an opportunity still existed for repeating these experiments 

 upon a portion of cable to which he could obtain access, and that he was ready to 

 show them before a committee of this Section in London, if the important nature of 

 the subject should seem to render such a course desirable. Although the subject of 

 submarine telegraphy had many points of the highest importance requiring investi- 

 gation, and to the consideration of which he had been devoting himself recently, 

 Mr. Whitehouse proposed to confine his remarks on this occasion to the one point 

 indicated in the title, inasmuch as the decision of that one, either favourably or 

 otherwise, would have, on the one hand, the effect of putting a very narrow limit 

 to our progress in telegraphy, or, on the other, of leaving it the most ample scope. 

 He drew a distinction between the mere transmisssion of a current across the 

 Atlantic (the possibility of which he supposed everybody must admit) and the 

 effectual working of a telegraph at a speed sufficient for " commercial success ; " 

 and we gathered from his remarks that there were those ready to embark in the 

 undertaking as soon as the possibility of " commercial success" was demonstrated. 



The author then gave a description of the apparatus employed in his researches, 

 of the manner in which the experiments were conducted, and, lastly, of the results 

 obtained. The wires upon which the experiments were made were copper, of No. 

 16 gauge, very perfectly insulated with gutta percha — spun into two cables, con- 

 taining three wires of equal length (83 miles), covered with iron wires and coiled in 

 a large tank in full contact with moist earth, but not submerged. The two cables 

 were subsequently joined together, making a length of 166 miles of cable, containing 

 three wires. In addition to this, in some of the latest experiments he had also the 



