112 Lieut.- Col. Sabine's Report on the Meteorology of Toronto. 



I have now only to apologize to the Section for the length of time that I 

 have occupied them, and to thank them for their patient attention. 

 York, September 27th, 1844, 



Postscript, Woolwich, Nov. 30. 



After the preceding pages were printed, I received from Mr. Airy the 

 volume of the Greenwich magnetical and meteorological observations for 

 184-2, in which the meteorological reductions have been made in almost 

 exactly the same form as those of Toronto. The volume was accompanied 

 by a suggestion from the Astronomer Royal, that it might increase the interest 

 of this communication, if I were to add a few words by way of appendix, 

 showing the points of similarity or dissimilarity in the results at the two 

 stations. I have much pleasure in adopting this suggestion, and in availing 

 myself of Mr. Airy's permission to do so ; for I have had great satisfaction 

 in noticing the very remarkable similarity which prevails in the results at 

 Greenwich and Toronto, with reference to several points which have been 

 the objects of especial notice in the preceding discussion. In the diurnal 

 variations of the elastic force of the vapour, — of the gaseous pressure, — and 

 of the force of the wind, — the evidence of a direct dependence on the diurnal 

 march of the temperature is fully as striking at Greenwich as at Toronto, as 

 will be seen by the following synopsis : 



Synopsis of the Diurnal Variations at Greenwich. 



At Greenwich the force of the wind is estimated at each observation hour 

 in numbers varying within the limits of to 6. At Toronto the estimation 

 is in lbs. pressure on a square foot of surface kept perpendicular to the 

 current. In single instances the scales are comparable, because the square of 

 the number expressing the force at Greenwich corresponds approximately to 

 the pressure in lbs. avoirdupois. But the comparability of the scales does 

 not hold good when the sums of the forces and the sums of the pressures are 

 taken. The sums of each are however comparable inter se, and show the 

 hours of maximum and minimum force, and the regularity of the progression. 

 The registry of the anemometer at Greenwich shows that the pressure of the 

 wind is more than doubled in its mean diurnal range. 



The following table exhibits the differences at the several observation hours 

 of Greenwich and Toronto, of the temperature, of the vapour pressure, and 

 of the gaseous pressure, from their respective mean yearly values. The sign 

 4- signifies above the mean value of the year, and — below it. 



