THE CURRENTS OF THE ATLANTIC. 413 



that the air taken in the great sewer of Montmartre, and that 

 collected in the Place de la Concorde (one of the most open spaces 

 in Paris), have been carefully compared, and found to be undistin- 

 guishable by the most delicate chemical tests. But, whatever be the 

 source of the virus, its action is, at all events, powerfully stimulated 

 by the co-operation of decaying organic matter in its ordinary 

 forms ; and as this ally of disease is within our power, we shall be 

 without excuse if we neglect the known precautions for defence.* 



I regret to have to close this brief sketch of our atmospheric 

 relations with a disagreeable topic. I have endeavoured to bring 

 before you the more salient features of our climate, so far as they 

 can be exhibited in a popular form ; and, on a review of all, we 

 have, I think, no reason to repine. If the humidity of the air by 

 which we are enveloped is at times depressing to our energies of 

 body, or of mind, we must remember that we are indebted to it 

 for the luxuriant crops, which furnish food to our cattle, and 

 through them to ourselves. Our summer temperature may be too 

 low to bring some of our seeds and fruits to perfection ; but, on 

 the other hand, it is to its moderated heat that we owe our exemp- 

 tion from some of the maladies which afflict the inhabitants of 

 more southerly climes ; while our mild winters press gently on the 

 springs of life, and suffer man to reach an advanced age. 



Let us be thankful to-ihe Giver of all good gifts for these His 

 blessings ! and if as all earthly blessings are they are at times 

 checquered by afflictions, let us remember that these too come from 

 a Father's hand. Let them serve to remind us how far we may 

 have strayed from Him, and bring us back, as sorrowing and re- 

 pentant children, to His outstretched arms ! 



* This seems to be conclusively shown by the effect of elevation on the number of 

 deaths by cholera in London, in the year 1849. The Table contained in the Reports 

 of the Registrar-general gives the heights above the Thames, and the corresponding 

 number of deaths by cholera, out of a population of 10,000. The numbers decrease at 

 first rapidly, and afterwards slowly, until, at heights above 100 feet, the variation in 

 the number of deaths is very small. The facts are justly ascribed to the imperfect 

 drainage of places situated at low levels. 



