Section III., 1885. [ 95 ] Trans. Roy. Soc. Canada. 



VII. — Tidal Observations In Canadian Waters. 



By Alexander Johnson, M.A., LL.D., Dublin ; Professor ol' Mathematics and Natural 



Philosophy, McŒll University, Montreal. 



(Read May 28, 1885.) 



The subject of the following paper has both a practical and a scientific side, but as 

 I desire to bring the practical value of tidal observations especially before you, an explana- 

 tion of the origin of the paper may be useful. My attention was first drawn to the subject 

 in its practical aspect, apart from the mere theory of the tides, by the loss of the S.S. " North 

 Briton " near the Miugan Islands, in the Gulf of St. Lawrence. This was many years 

 ago, before the tim<i of Confederation, I think ; but the exact date I do not recollect. 

 The vessel was lost in calm weather, and the first reports of the occurrence stated that the 

 wreck must have been due to an error of the compass ; but, eventually, it was generally 

 agreed that the true cause was an unknown current carrying the vessel out of the course 

 in which she was supposed to be sailing. No attempt was made, so far as I know, to seek 

 out the cause of this current, whether it was permanent or shifting, or whether any direc- 

 tions could be given by which other vessels might avoid a like fivte. 



The interest then aroused was kept up by reports from time to time of other wrecks 

 on other parts of the Canadian coasts, said to be due to the same cause, viz., unknown cur- 

 rents. These, I strongly suspected, were due mainly to the tides ; but no satisfactory 

 means of bringing the matter directly to piiblic notice presented themselves until this 

 Society was formed. Last year I had hoped to bring a paper on the subject before this 

 Section, but pressure of other work prevented it. Then came the meeting of the British 

 Association in Montreal, and it occurred to me that such an opportunity should not be lost ; 

 the British Association had been for many years making strenuous efforts to extend tidal 

 observations, and it would only be necessary, I felt, to call their attention to Canada's 

 wants in this respect, in order to secure their advocacy. Probably even this may not have 

 been necessary. At any rate, I had no sooner brought forward the subject than it was 

 taken up warmly. A committee was at once appointed, consisting chiefly of members of 

 this Section, to promote these observations in Canada, while the Council of the Association 

 was requested to communicate directly with the Canadian Government. The Council of 

 our own Society was not wanting to the occasion. It addressed a petition to Parliament 

 in favor of a money-grant for the observations. 



The direct object of this paper being to call the attention of the Society, and through 

 the Society to arouse the public to the practical value of and urgent need for observations, 

 it is unnecessary to dwell on the theory of the tides. Yet I cannot forbear noting that 

 work done now is a continuation of the w^ork begun by Newton two «-enturies ago, when 

 he laid the foundations of tidal theory. For, as Dr. Whewell says in liis well-known paper 

 on cotidal lines, published in the Philosophical Transactions of the Royal Society of Lon- 



