NATURAL PHILOSOPHY. 143 



Instrument for determining the Value of Intermittent, or Alternating, Electric 

 Currents, for Telegraphic Purposes. At the British Association Meeting 

 for 1856, Mr. E. 0. "Whitehouse demonstrated that the effect of a weak 

 electric current, say after it had traversed 100 miles of wire on an ordinary 

 magnetic needle, was altogether inappreciable ; and even the effect of strong 

 currents at short intermitted periods, caused the needle so to vibrate as to 

 render the observing of the arcs quite impossible ; but by transmitting a very 

 feeble current in such a way as to excite a powerful coil, and produce an 

 electro-magnet by soft pieces of iron hi the axes of the coils, he showed that, 

 by a strongly framed and accurately constructed steelyard, he was able actu- 

 ally to weigh the feeblest currents, and to compare them with even the most 

 powerful current transmitted through short distances. The exhibition of the 

 apparatus, which worked admirably, and, as it were, weighed the force of 

 each current as transmitted during the ordinary rapid working of the tele- 

 graph, seemed to afford much satisfaction to the section. 



Substitute for the CopperWire in the Construction of Helices. The cost of heli- 

 ces of fine wire, and the limit of thickness to which the fine wire can be covered 

 with silk for insulation, are two impediments which M. Bonelli has sought to 

 set aside by very simple means. He takes a band of paper of the height of 

 the helix of an electro-magnet, or of the corresponding part of the galvano- 

 meter ; tlois band carries parallel to its edge, metallic lines a a', & &', etc., pass- 

 ing from one extremity to the other ; these lines, placed in the circuit, will 

 give passage to the current, while they are also insulated from one another by 

 the paper that separates them ; so that the current will pass uninterruptedly 

 provided the lines of metal are unbroken. The number of these lines which 

 may be put on a band of paper is almost indefinite. Leaving their extremities 

 free, the current may be made to pass, either along the lines united, or in all 

 of them at the same time and in the same direction. 



Globotype Telegraph. The London Artizan has recently published an 

 illustrated description of a new and peculiar telegraph bearing the above name, 

 invented by David McCallum, of Stonehouse, England. The leading cha- 

 racteristic of this invention consists in releasing small glass balls of three 

 different colors white, black, and blue in such a manner as to faU over a 

 series of inclined planes, and drop into their proper places, where, by their 

 color and the way that they are made to arrange themselves, they form a 

 message. These balls are thrown out one by one at the will of the operator, 

 and as multiplied and intermixed they form the alphabet, like Professor 

 Morse's dots, spaces, and dashes. 



THE LAW OF THE SQUARES IS IT APPLICABLE OR NOT TO 



THE TRANSMISSION OF SIGNALS IN SUBMARINE CIRCUITS ? 



The following is an abstract of a paper read before the British Association, 

 by Mr. E. 0. Whitehouse, the well known electrician and physicist. Mr. 

 TV., in commencing, stated that it was for the purpose of determining the 

 force of either intermitting or alternating currents, whose duration was not 

 sufficient to admit of the needle assuming a position of rest, that he proposed 

 the use of the magneto-electrometer an instrument rendering available the 



