446 



MEDICINE AND MEDICAL STATISTICS. [Sect. XIV. 



r 



affect health, there are not, it may be assumed, any great 

 difficulties to be encountered as regards instrumental 

 observation ; in these mathematical precision, at all events, 

 is not so essential as they would be^ were the results 

 aimed at depending on the truth of a series of arithme- 

 tical sums. There is, nevertheless, a proper degree of 

 accuracy required in the mere registration of this kind of 

 formulae, as one omission may invalidate a whole set of 

 observations.— 





uch for example as the geographical po- 



sition of the ship at the time the observations were made. 

 With regard to the atmosphere, the principal things to 

 be observed are its heat, degree of humidity, and weight. 

 That the two first greatly influence health there is not any 

 reason to doubt : but with regard to the tiiird, it would be 



• 3» 



hazardous to offi^^r any decided 



who have devoted much of their time and attention to the 



v> minion. Amonget men 



V 



L 



ew who consider that it has 



at least some imluence in disturbing occr ionally the equa- 

 nimity of the mental functions. Thermomctrical obbcr- 



vations with the view of noticing the influence of atmos 



pherical heat on lieaith, should be made several times a 

 day, in order that the minimum, medium, and maximum 

 in the shade may be ascertained ; or even more frequently 

 should there be a sudden rise or fall of the mercury. On 

 board a ship under wcl^li^ it is hardly possibloj in conse- 

 quence of the g-.^t variety of a^p. tb In v^mch she may 



arious 



m 



place Li th' instrument; the black bulwarks and ham- 

 mock-cloths rapidly absorb the heat of the sun's ravs. and 

 again tlirow it out by radiatT^n for a considerable time even 







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