tion." Of the dry winds of Colorado he says: "During the prevalence of such, the humidity is invariably excessively low, and in the dry air there seems to be set up, by the movement of the wind particles and the leaves and grasses set in motion by them, an electrical state which in some undetermined way makes havoc with the emotions." 22

In similar fashion, Huntington writes: "In eastern Turkey the hot desert wind causes the whole community to become cross and irritable. I have there seen a missionary, a man of unusual strength of character, shut himself up in his study all day, because he knew that he was in danger of saying something disagreeable.” 23 Similar reports come from Italy.

Hann claims: "Damp air and increased pressure have the following physiological effects:-nervous depression; quiet sleep; increased elimination of carbon dioxid; slower circulation of the blood. Dry air and decreased pressure, on the other hand, have these effects: - nervous excitement; sleeplessness; quickened pulse; a dim skin and a decreased temperature." 24 Dry cold and dry heat are relatively easy to endure.

"24

There seems to be reason to believe that the connection between climate and behavior may be more clearly understood in the future. Many students have attempted to establish the relationship but their evidence has been too vague and fragmentary to justify very definite conclusions. The contrast shown by the charts on page 37 may well lead us to expect different reactions in the residents of New York and Denver.

Hellpach has collected considerable evidence showing

22 DEXTER, E. G. Weather Influences, pp. 81-82.
23 HUNTINGTON, E. Civilization and Climate, p. 47.
24 HANN, J. o. c., p. 57.

the influence of the advent of spring and summer on conduct which indicates that some real causes are at work: 25 DEXTER, E. G. o. c., p. 88.

It seems impossible to explain the marked rise in all the tables in April as a mere coincidence.

Very recently Huntington has published the accounts of a very valuable study made by him of the actual work throughout the year of some five hundred factory operatives in Connecticut, some three or four thousand in cities from Virginia to Florida and some 1,700 students at West Point and Annapolis (the students' records being limited to the school year). His results were compared in great detail with the weather conditions. He found that barometric changes showed little influence, that humidity was of considerable importance, but that temperature was more decisive. It was found that all these groups were physically most active when the average temperature was from 60° to 65°, that is, when the temperature at noon was 70° or over. Mental activity reached its maximum when the outside temperature averaged about 38°, that is, with frosts at night. He found that steady temperature was not favorable and that the best work was done when there was some daily change but sudden violent changes were not beneficial. Moderate changes with frequent cooling of the air gave the best results. There was a marked reduction of the work in very dry weather. Very cold weather was unfavorable and more work was accomplished on cloudy than on bright days.27

On the basis of his studies Huntington believes that the most important climatic factors are: (1) the mean temperature month by month; (2) the amount of change from day to day and (3) the relative humidity.28

He then proceeds to map the world to see in what places the best conditions are found, that is where the 27 HUNTINGTON, E. o. c., p. 8 ff.

28 Ibid., p. 137.

areas: (1) western and central Europe to the borders of greatest energy will be developed. He finds five such