COLORADO AS A WINTER SANITARIUM. 671 



highly esteemed by the advocates of elevated and cool resorts, we find 

 in Colorado that, so far as elevation is concerned, the range in the 

 towns is from that of Denver, at 5,280 feet, to that of Leadville, which 

 is somewhat over 10,000 feet above sea-level. Intermediate are Colo- 

 rado Springs, 6,000 feet ; Manitou Springs, between 6,000 and 7,000 

 feet.; Caiion City, about the same ; Salida, 7,000 feet ; Poncha Springs, 

 Idaho Springs, Boulder, and Longmont, about 7,500 feet ; Gunnison, 

 Georgetown, and Alamosa, in the neighborhood of 8,000 feet, and so 

 on. So that all the arguments derived from elevation above sea-level 

 are applicable to Colorado as well as to Davos. 



If at Davos it is found that there is diminished atmospheric press- 

 ure ; that, as a consequence, there is a slower abstraction of beat 

 from the body, so that low temperatures do not feel so cold as they 

 would in a lower and denser region ; that there is greater heating 

 power in the direct rays of the sun, and that there is a freedom from 

 germ-life (a supposition based on the experiments of Pasteur and 

 Tyndall), all due to simple elevation, the same has been found to be 

 true in Colorado. 



As regards the humidity of the air, on which condition writers on 

 climate lay so much stress, and among them the author to whom we 

 have already referred, the data are full and satisfactory. 



Colorado is situated in the zone of greatest atmospheric dryness, 

 both relative and absolute, of any inhabited portion of the United States. 



A compilation of the statistics of the Signal-Service Bureau, 

 United States Army, shows that the mean relative humidity of Denver 

 for four years was only 45*8. That is, taking the saturation-point, or 

 the point at which the atmosi^here is holding all the moisture that it 

 can, as 100, then the air at Denver is only 45*8 per cent of saturation, 

 and it is capable of holding 54*2 per cent more moisture than it does. 

 The same table shows that the air of New York is 70*2 per cent of 

 saturation ; that of Jacksonville, Florida, 69 per cent, and that of 

 Los Angeles 65*8 per cent. 



It must be understood, in this connection, that the saturation-point 

 is not at all a fixed one, nor is it a constant quantity at any given 

 place, as it varies both with the barometric pressure and with the tem- 

 perature ; so that, as a consequence of this, many writers prefer to 

 speak of the absolute rather than of the relative humidity, in making 

 comparisons of the atmospheric dryness of places. 



Several years ago we had occasion to point out, in this connection, 

 that, while a mean for four years showed that the Denver air con- 

 tained only 1-81 grain of vapor (by weight) to the cubic foot, the air 

 of Jacksonville contains 5 '38 grains, and that of Los Angeles 3*77 

 grains, to the foot ; or, as we then remarked, an " amount which, as 

 between Denver and Jacksonville, is as 1 to 3, and, as between Denver 

 and Los Angeles, is as 1 to 2." * 



* " Climate in the Cure of Consumption " ("Science," September 28 and October 5, 1883). 



