RAIN AND MAN. 293 



paratively innocuous. That organic matter 

 exists in rain-water, no one who has made the 

 experiment of keeping it for a day or two will 

 be disposed to deny. Its rapid putrefaction is 

 sufficiently indicative of the presence of such 

 impurities in it. Muriatic acid, salts, and earthy 

 matters, are very commonly found in rain- 

 water. It may be justly remarked that the 

 purifying influence of rain in this respect is of 

 a limited degree, and of local application princi- 

 pally, but it is not therefore to be considered as 

 unimportant. In fact, it may very reasonably 

 be doubted whether our large towns would be 

 able to exhibit such low rates of mortality as 

 many of them in average seasons do, were it not 

 for the frequent heavy showers, the occurrence 

 of which too often forms the subject of com- 

 plaint against our unstable climate. The dirty 

 and defiled condition of our public edifices in 

 England, especially in the metropolis, the inky 

 waters which roll down the most splendid of our 

 architectural fl^ades, obscuring the labour of 

 the sculptor, and greatly defacing the artistic 

 beauties of the structure, show, in a striking 

 manner, the mass of impurities contained in the 

 air, and the necessity for some effectual means 

 of ridding it from them. The rain which falls 

 through the smoke-filled air of our towns, con- 

 tains a large quantity of soot in a mixed state, 



