^20 ALLISON ON THE PROGRESS OF WEATHER KNOWLEDGE. 



rative pressures, temperatures, &c. may be obtained, and a two-fold 

 benefit is derived from these, viz : first, the determination of gene- 

 ral comparisons betvreen all stations — neighbouring and remote — 

 and second, in telegraphing opinions and warnings, the progressive 

 rate of changes going on at any particular time may be accurately 

 marked and their arrival at the various points predicted within very 

 narrow limits. The second need is very important — longer series 

 of observations — the use of those in general is at once evident ; if 

 seven years readings are good in calculating normals, eleven years 

 are better. But a specific use of prolonged series is to fix more 

 accurately the occurrence and effect of abnormal phenomena, and 

 thus, in studying the probable appearance of any change at a given 

 station, to be able not only to form an opinion from established 

 laws affecting a whole Province, or even a larger portion of the 

 Continent; but to eliminate from those wider deductions, errors 

 which may arise from individual position, and to give their full 

 value to local circumstances whose influence may not be felt for 

 more than a few miles, but within that small area may be quite 

 sufficient to induce purely local phenomena, or even to divert from 

 its course the whirling storm at one time, while at another they 

 cease to exist and leave the district entirely controlled by the rela- 

 tive conditions normal within itself and adjacent areas. 



The last obstacle I mention is one readily susceptible of great 

 improvement, being a purely mechanical defect ; and I believe that 

 when once the whole importance of these labours is publicly appre- 

 ciated, and Government is seriously extending a thorough scheme, 

 the owners of Electric Telegraph Lines will also give to these 

 bulletins and warnings the necessary facilities of transmission, 

 causing the telegrams between Toronto and Halifax to occupy much 

 less than the four or five hours, which I regret to say is at present 

 consumed over that distance. 



Without elaborating the very fruitful subject of prospective 

 meteorology, I close this hurried paper by summarizing the progress 

 of weather knowledge in Nova Scotia as an advance from the efforts 

 of a couple of observers in 1869, to the establishment of 24 stations 

 in 1873, placed now in connection with the Canadian Government 

 System, included in the department of one of the most intelligent 



