Licence: Public Domain Mark
Credit: The atmosphere in relation to human life and health. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![from all kinds of infcc^tive yiiiins, and tlicrofore o|»id(jinic discaHcs are unknown at sea, <'xc('i)t in so far as tlicy arise from the material, i)ro- visioiis, or watei- of the ship, or have been bronj2:ht on board by crew or ])assenj;ers. Much of tiie benefit which wonhl otherwise l)e deiix'ed from a sea voyaji'i' is often connteractcfl l)y tin- small s|);ire and difli- <;ulties of veiitilatinn of sh'epin^- bcrtiis and cabins, 'ihe fcnipcratare of the tropics has a l)ad effect upon the crew and passenj^ers of ship.s from colder climates, and loss of wei^^ht results; but, iu {general, the weight and stren<,^th of passen<>:(U's are increased by voyaging in a fair climate. Much depends, of course, upon tin- accommodation and diet, as well as upon the atmosjiheric conditions, TIIK IM1M{()VEMKNT OF CLIMATK WITH SLKiHT ELEVATION. From a cerrain number of experiments and from a review of observa- tions taken by meteorologists of differences between temperature and humidity at different heights above the ground, the ])resent writer came to the following conclusions,' shortly stated: The mean temperature at a height of about 100 feet above the ground does not differ sensibly from the mean temperature at 5 feet, but seems to be slightly in excess. The means of daily maxima at heights of (Jl) and 128 feet fall short of the mean maxima at 10 feet, and still more of the maxima at 4 feet. The means of daily minima at the greater heights exceed the mean minima at the smaller heights. There is a certain altitude, apparently' al)out 150 feet above the ground, al which, while the mean temperature is equal to that at 4 feet, the maxima are lower and the minima higher than at any lower point. On an average of nineteen mouths, the mean of maxima was about 1.5° F. lower at 128 feet 10 inches than at 10 feet, and the niean of minima about 0.55° higher. In cyclones the higher, and in anticyclones the lower, points gen- erally have the lowest mean tem])erature. The mean night temperature is always highest at the higher points, and the mean day temperature always lowest. About sunset in clear or foggy weather, when calm, temperature falls much faster near the ground than at some height above it. Equality of lower and upper temperature seems to occur about two hours V)efore suiiset and after suniise, but varies witli tlie season. In clear weather and low fogs, betwecm sunset and sunrise, temi)era- ture is always, or nearly always, higher at heights varying from 50 to 300 feet above the ground than at heights from 2 to 22 feet. In bad weather the higher points are coldest by day and night. In foggy weather, especially with ground or radiation fogs, temperature is very much the lowest near the ground, and within the fog nuich lower than above it. ' Trans. Sanit. Inst, of Great Britain.](https://iiif.wellcomecollection.org/image/b21208724_0101.jp2/full/800%2C/0/default.jpg)
