time. — Mr. Wh 



Chemistry and Physics. 279 



e sermon in three different churches at the same 



telegraph ; which consisted of a tube perforated with a series of small 

 tubes, for the conveyance of telegraphic wire, and which, for the pur- 

 pose of preventing its being acted upon by sea water or marine insects 

 was banded or braided round by a small rope, and its being perfectly 

 air-tight, would render it quite impervious to the atmosphere. 



10. Report on the Air and Water of Towns; by Dr. Smith, 

 (Proc. Brit. Assoc, Athen., No. 1087.) — In commencing his report 

 the author says, it has long been believed that air and water have the 

 most important influence on health, — and superstitions have there- 

 fore constantly attached themselves to receptacles of the one and ema- 

 nations from the other. The town has always been found to differ from 

 the country : this general feeling is a more decisive experiment than 

 any that can be made in a laboratory. The author proceeds to exam- 

 ine all the sources from which the air or water can be contarnina- 

 ^ ted. The various manufactories of large towns, the necessary condi- 



tions to which the inhabitants are subjected, and the deteriorating influ- 

 ences of man himself are explained. If air be passed through water 

 a certain amount of the organic matter poured off from the lungs is to 

 be detected in it. By continuing this experiment fov three months. Dr. 

 Smith detected sulphuric acid, chlorine, and a substance resembling 

 impure albumen. These substances are constantly being condensed 

 upon cold bodies, and in a warm atmosphere the albuminous matter 

 very soon putrifies and emits disagreeable odors. The changes which 

 this substance undergoes by oxydalion, &c., were next examined, — and 

 shown to give rise to carbonic acid, ammonia, sulphuretted hydrogen, 



and probably other gases. The ammonia generated fortunately from 

 the same sources as the sulphuretted hydrogen, materially modifies its 

 influences. The consequences of the varying pressure of the atmos- 

 phere have been observed; and it is shown that the exhalations of 

 sewers, &c, are poured out in abundance from every outlet when the 

 barometric pressure is lowered. By collecting the moisture of a crowd- 

 ed room by means of cold glasses and also dew in the open air, it was 

 found that one was thick, oily, and smelling of perspiration, capable of 

 decomposition and production of animalcules and conferva, — but the 

 dew beautifully clear and limpid. Large quantities of rain-water have 

 frequently been collected and examined by Dr. Smith; and he says, 

 — I am now satisfied that dust really comes down with the purest rain, 

 and that it is simply coal ashes. No doubt this accounts for the quan- 

 tity of sulphites and chlorids in the rain, and for the soot, which are 

 Ihe chief ingredients. The rain is also often alkaline,— arising prob- 

 ably from the ammonia of burnt coal, which is no doubt a valuable 

 agent for neutralizing the sulphuric acid so often found. The rain- 

 water of Manchester^ about 2J° of hardness,— harder, in fact, than 

 the water from the neighboring hills which the town intends to use. 

 This can arise only from the ingredients obtained in the town atmos- 

 phere. But the most curious point is the fact that organic matter is 

 never absent, although the rain be continued for whole days. The 

 state of the air is closely connected with that of the water; what the 

 air contains the water may absorb, what the water has dissolved or ab- 







