236 Dr Hall 07i the Mean Temperature of Montreal, 



with only some dilute sulphuric acid ; the gas thus obtained is 

 to be set fire to as it issues from the jet ; and if no metallic film 

 is deposited on the bit of flat glass, and no white subhmate with- 

 m the open tube, the zinc may be regarded as in a fit state for 

 use. 



Mean Temperature of Montreal, Lower Canada, for the period 

 of Ten Years, viz. from 1826 to 1835 inclusive. By Ar- 

 chibald Hall, M.D. In a Letter to the Secretary of the 

 Wernerian Natural History Society. 



Montreal, Lower Canada, 

 SlE, February 8. 1836. 



I HAVE taken the liberty of transmitting to you, through the 

 hands of Alexander Shakel, Esq. A. M. of this city, the fol- 

 lowing statement, manifesting the mean temperature of the city 

 of Montreal, and which, I conceive, might prove an addition to 

 other data in your Society's possession of a similar nature. 



The mean temperature, as given below, may be relied on as 

 substantially correct, being deduced from the meteorological 

 tables of the afore-mentioned gentleman, who has been in the 

 habit of making daily observations for the last fifteen or twenty 

 years; and moreover, his thermometer, having never during 

 that time been removed from the station it at present occupies, 

 indicates a (emperature upon which the same modifying powers 

 have always exerted a corresponding degree of influence. 



The means of the months are deduced from the series of two 

 daily observations, the one at 7 o*'clock a. m., when it may be 

 assumed that the temperature is at miniinum, the other at 

 8 o'clock p. M., when it may be stated to be at maximum. 



I have also appended the mean temperature of the seasons, 

 and the hottest and coldest days in each year, with the tempe- 

 rature of each, as recorded in the journal. With respect to the 

 correctness of the former, it may be urged in opposition, that 

 they have not the same tri-monthly duration here as in other 

 latitudes; our spring and autumn, e.g. seldom exceeding six 

 weeks or two months. My sole object in allotting to each their 



