120 W. A. Oahorne: 



through the courtesy of Mr. Hunt, and find most interesting 

 material contained in them, though to make adequate use of such 

 data would demand more time than I am able to bestow. 



The estimation of one's state of discomfort in hot weather is ob- 

 viously impossible to carry out with any approach to exactness. I 

 have tried various expedients but without result. The amount of 

 sweat absorbed by the clothes is no guide at all, for, in this climate 

 in summer, we have days when the human body may lose over 400 

 grammes! water per hour by evaporation and yet the skin and 

 clothes remain dry and comfort is not greatly disturbed. A rough 

 and ready indication which I have come to regard as the most useful 

 is simply the clothing that is chosen as the most comfortable when 

 the body lies in an open-meshed hammock in a good shade and at 

 perfect rest. If such a hammock is not at hand, the upright position 

 is, I think, best, and much preferable to resting in, say, a deck 

 chair.- Judged roughly in this way, and by general feeling, I have 

 placed wet-bulb 73° F. as an empiric standard above which truly 

 tropical conditions arise. This wet-bulb temperature is seldom at- 

 tained in the Victorian climate. A typical instance of the effect of 

 dryness in keeping the wet-bulb down is shown in the following : — 



The last-mentioned high temperatuie I experienced personally 

 and can truthfully say that it exceeded in unpleasantness any- 

 thing that I have felt in Melbourne or its environs. 

 . The wet-bulb isotherms drawn by Mr. Hunt show very clearly that 

 of all portions of Australia the worst from the climatic standpoint 

 is the pearling coast in the north-west. In December, January and 

 February this district is included within the SQo W.B. isotherm. I 

 find that on December 24th, 1909, the shade wet-bulb temperature 

 at Wyndham on this coast was 85° F. at 9 a.m. ! 



1 W. A. Osborne. Contributions to Physiological Cliniatoloyy, Part II. J. Ph\siol., vol. 49, 

 p. 133. 



2 I have made some measurements of tlie water loss of the body in two almost successive hours 

 in practically the same meteorological conditions, the first hour in a hammock, the second in a 

 deck chair, and found that in the latter case the water loss was considerably increased in each 

 instance owing to the impeded evaporation— the water given off by the skin was of course to be 

 found in the fabric of the deck chair and in the clothing with which it was in contact. 



