252 THE CHEMISTRY OF CEEATIOX. 



a minute bubble, not larger than a pin's head, 

 to pass up his nostril, he immediately lost the 

 sense of smell for five or six hours, and suffered 

 for fifteen days afterwards from a most severe 

 catarrh, in all respects the same as that of in- 

 fluenza. The same effects, on another occasion, 

 followed the escape of only a bubble or two into 

 his laboratory, and he again suffered from cough 

 and catarrh. 



M. Kcemtz's explanation can scarcely be con- 

 sidered correct. Dry fog is doubtless some- 

 thing more than smoke. When its remarkable 

 accompaniments, volcanic disturbance and severe 

 epidemic attacks, are remembered, it will be 

 evident that some other cause than that specified 

 must be called in to account for this pheno- 

 menon. It has been considered of electrical 

 origin. 



It is difficult to assign to any of the causes 

 alluded to, the existence of a remarkable phe- 

 nomenon which took place in November, 1819, 

 at Montreal. On a Sunday morning the whole 

 atmosphere in this city appeared as if covered 

 with a thick haze of a dingy orange colour, 

 during which rain fell of a thick and dark inky 

 appearance, and apparently impregnated with 

 some black substance like soot. The weather 

 then cleared up, but on the following Tuesday, 

 at twelve o'clock, a heavy damp vapour enve- 



