TRANSACTIONS OF THE SECTIONS. 23 



author then examined the evidence of the law of the squares, as shown hy the value 

 of a current taken in submarine or subterranean wires at different distances from the 

 generator thereof, which he showed were strongly corroborative of the previous 

 results. He next examined the question of the size of the conducting wire ; and he 

 had the opportunity of testing the application of the law, as enunciated by Prof. 

 Thomson last year. The results, far from confirming the law, are strikingly opposed 

 to it. The fact of trebling the size of the conductor augmented the amount af 

 retardation to nearly double that observed in the single wire. The author, however, 

 looked for the experimentum crucis in the limit to the rapidity and distinctness of 

 utterance attainable in the relative distances of 500 and 1020 miles. 350 and 270 

 were the actual number of distinct signals recorded in equal times through th^e two 

 lengths respectively. These figures have no relation to the squares of the distance. 

 " Now, if the law of the squares be held to be good in its application to submarine 

 circuits, and if the deductions as to the necessary size of the wire, based upon that 

 law, can be proved to be valid also, we are driven to the inevitable conclusion that 

 submarine cables of certain length to be successful must be constructed in accord- 

 ance with these principles. And what does this involve ? In the case of the 

 Transatlantic line, whose estimated length will be no less than 2500 miles, it would 

 necessitate the use, for a single conductor only, of a cable so large and ponderous, 

 as that probably no ship except Mr. Scott Russell's leviathian could carry it, — so 

 unwieldy in the manufacture, that its perfect insulation would be a matter almost of 

 practical impossibility, — and so expensive, from the amount of materials employed, 

 and the very laborious and critical nature of the processes required in making and 

 laying it out, that the thing would be abandoned as being practically and commer- 

 cially impossible. If, on the- other hand, the law of the squares be proved to be 

 inapplicable to the transmission of signals by submarine wires, whether with refe- 

 rence to the amount of retardation observable in them, the rapidity of utterance to 

 be obtained, or the size of conductor required for the purpose, then we may shortly 

 expect to see a cable not much exceeding one ton per mile, containing three, four or 

 five conductors, stretched from shore to shore, and uniting us to our Transatlantic 

 brethren, at an expense of less than one-fourth that of the large one above men- 

 tioned, able to carry four or five times the number of messages, and therefore yielding 

 about twenty times as much return in proportion to the outlay. And what, I may 

 be asked, is the general conclusion to be drawn as the result of this investigation of 

 the law of the squares applied to submarine circuits ? In all honesty, I am bound 

 to answer, that I believe nature knows no such application of that law ; and I can 

 only regard it as a fiction of the schools, a forced and violent adaptation of a prin- 

 ciple in Physics, good and true under other circumstances, but misapplied here. " 



Astronomy, Meteors, Waves, 



On the Tides of Nova Scotia. 

 By the Rev. Professor Chevallier, B.D., F.R.A.8. 



The observations to which reference is made were taken by a tide-gauge fixed 

 upon a wharf at the north end of the naval yard at Halifax. The tides there are 

 small in amount, the spring tides rising from 65 to 9 feet at Hahfax, and 8 feet at 

 Sambro Isle, twelve miles south of that place. The tides themselves appear to be quite 

 regular ; but in addition to the ordinary tide-wave there occurs a series of undula- 

 tions succeeding each other at intervals of twenty minutes or half an hour, the 

 difference of elevation and depression rarely exceeding 6 inches, and being usually 

 much less. They are more perceptible near low water ; but occur at all times of 

 tide, and are very distinctly marked upon the curve traced by the self-acting tide- 

 gauge. The question to be considered is, what is the cause of these small waves ? 

 1. They do not arise from any influence which the casual swell of the sea might 

 exercise upon the tide-guage : for the rise and fall of one of these waves very 

 seldom takes less time than a quarter of an hour, and often requires half an hour. 



