428 KANSAS CITY REVIEW OF SCIENCE. 
to seek new abodes at the resorts. The elements of elevation and barometric 
pressure will remain nearly constant the year round. But how is it in regard to 
the humidity of the air in Colorado during the winter and spring ? The writer has 
selected at random, and without reference to whether the showings would be 
favorable or unfavorable for a given place, the year 1880 as his basis for compar- 
ison. Both the relative and absolute humidity for Denver during the winter and 
spring is absolutely, and by comparison, very small; that, as compared with 
Augusta and Jacksonville, it makes a wonderful showing in these respects; and 
that the ratio of the absolute humidity as between Denver and Los Angeles is as 
I to 3 for these seasons. 
When we turn to our tables we learn that the amount oi precipitation at Den- 
ver for these seasons was almost nil; that the mean monthly precipitation at Den- 
ver for the given time was only a small fraction of an inch in rain and melted 
snow. Carry out, now, the comparison between Denver and Augusta, Jackson- 
ville and Los Angeles, and see the tremendous difference in this particular between 
these places, — showing immensely in favor of Denver. It will be seen that our 
general conclusions are very much strengthened by this particular application, 
and that we have brought strong additional evidence in favor of Colorado as a 
resort for persons affected with phthisis pulmonalis. 
When we turn to our tables to learn in regard to the winds at these places 
for the given seasons, we see that the conclusions previously reached in regard 
to Denver, in this particular, still hold true. 
Tejnperature. — We come now to our last observation, and to a brief discus- 
sion of what some may consider the weak point in regard to Colorado as a resort 
for invalids. It has been seen that most authorities favor a cold climate; but they 
add the proviso that it should be free from change. The mean monthly range of 
temperature is larger for Denver than for almost any other point in our scale. It 
will be seen, further, that the minima of temperature are very nearly the lowest 
in the scale, — not so low, to be sure, as the minima at St. Paul, but decidedly 
lower than at Augusta, Jacksonville, and Los Angeles. This state of affairs de- 
mands an explanation. 
We have seen that the air of Colorado is both dry and rare, — two conditions 
that favor rapid radiation. We have seen, further, that the soil is of a porous, 
sandy nature, — a kind that will easily absorb heat, and as easily give it off. Further- 
more, there is but little verdure or shade, — another condition, too, which will 
favor both absorption and radiation of heat. In consequence of these conditions, 
the soil and air are, on the one hand, rapidly heated in the morning, and they 
are equally rapidly cooled at night. The nights are always cool in Colorado, — a 
condition that renders the summer months enjoyable and invigorating. But the 
question, after all, is, whether this diurnal change of temperature is injurious to 
Colorado as a resort for invalids. We claim that it is not, and for this reason : it 
makes but little difference to the invalid how cold the nights are, for at that time 
he should be in-doors, where he can regulate the temperature; but it is of impor- 
tance that it should be warm at mid-day, so that he can take his exercise regularly 
