ANALYSIS OF 
SIGNAL SERVICE STATISTICS 
WITH REFERENCE TO 
COLORADO CLIMATE, 
BY 
SAMUEL A. FISK, M.D., 
DENVER, COX.ORADO. 
(•Reprint from the “ Transactions ” of the State Medical Society for iSSj.) ANALYSIS OF 
SIGNAL SERVICE STATISTICS, 
WITH REFERENCE TO 
COLORADO CLIMATE. 
By Samuel A. Fisk, M.D., Denver, Colo. 
Three years ago the writer suffered from an attack of 
acute, lobular, catarrhal pneumonia. This was the second 
pneumonia that he had had in two years, and the third in 
twenty years. By the advice of specialists in Boston and 
New York, he came to Colorado, and, although he was re- 
garded as an “unfavorable case,” he is now in the posses- 
sion of health, and it is with thankfulness that he presents 
the following remarks as a “ first-fruits offering:” 
It has seemed desirable that, if possible, some reliable 
and authentic statistics should be presented to the profes- 
sion and to the large class of consumptive invalids, in regard 
to the salutariness of the climate of the eastern slope of the 
Rocky Mountains for persons suffering with pulmonary 
troubles. 
Drs. Denison and Solly, of our Society, have made some 
valuable investigations in this department, and the writer 
offers his remarks, which by the request of the Society he 
has put into their present shape, as in some measure sup- 
plementary to their efforts. He wishes at the same time to 
acknowledge his indebtedness to the Signal Service Bureau 
at Washington and in other places, and especially to Ser- 
geant Neal, of the Denver station, for the kindly manner in 
which they have furnished him with the data for the fol- 
lowing accurate and reliable tables. 
In selecting places for comparison he has chosen the well 
known resorts for phthisical patients, and has put them in 
justaposition with each other and with the localities where 
phthisis abounds. Augsuta, Ga., has been selected as being 
the nearest Signal station to Aiken, S. C., from which place 
it is only a few miles distant. He wishes to emphasize, as 2 
a leading thought of what he has to write, the value and 
importance of this analysis by comparison. It seems to 
him as important as a statement of absolute facts in regard 
to the climate of our mountain slopes. 
TABLE I. 
SIGNAL STATIONS. 
I 
• 11 
III 
IV 
V 
VI 
VII 
Elevation. 
Barometer. 
Relative Humidity. 
Grains moisture in 
cubic foot air. 
Mean Precipitation. 
Mean Temperature. 
Prevailing Wind. 
Augusta, Ga 
183 
30 140 
69 2 
4 56 
48 98 
64 2 
N K 
Jacksonville, Fa 
43 
30 O3O 
69 0 
5 38 
55 94 
6a 2 
N K 
Boston, Mass 
142 
29 840 
18 5 
2 66 
49 47 
48 5 
W 
Newport, R. I 
34 
29 950 
74 3 
3 °7 
50 20 
5° 3 
s w 
New York City 
164 
29 857 
70 2 
3 02 
42 7° 
5* 3 
N W 
Philadelphia, Pa 
52 
3° 584 
68 8 
3 >7 
4i 89 
53 » 
S W 
Chicago, Ilk 
661 
29 30 
69 2 
2 77 
35 47 
49 3 
s w 
St. Paul, Minn 
811 
29 t33 
67 i 
a 23 
29 59 
43 9 
S E 
Denver, Colo 
5294 
24 778 
45 8 
1 81 
14 77 
49 1 
S 
Santa Fe, N. M 
7046 
22 262 
41 4 
I 6l 
14 17 
48 5 
E 
Salt Lake, Utah 
4348 
25 644 
4° 3 
I 76 
17 52 
5> 8 
S E 
Los Angeles, Cal 
35° 
29 647 
65 8 
3 77 
18 97 
59 8 
W 
In the study of climatology, as applied to the cure of 
phthisis, there are certain conditions, certain qualities of 
the air, certain meteorological phenomena, certain soil for- 
mations which are well recognized as being favorable to the 
cure of pulmonary troubles. While our knowledge of them 
is largely empirical, dependent, like much else in medicine, 
upon clinical experience; and while, further, we have often 
been governed in our conclusions by the law of per contra, 
yet in many cases the operations of these causes, in pro- 
ducing favorable results, have been explained and applied. 
A study of climatology involves, therefore, an 
tion and testing of climates by these recognized principles. 
It involves, further, an analytical comparison, for even if a 
given climate does not fill the bills in every particular, it 
may, at least, possess such a predominance of desirable 
qualities as to make it, by comparison, the climate par ex- 
cellence. It is in accordance with this view that the follow- 
ing data have been collected and compiled, and it is in con- 
formity with these ideas, and using, so far as we are able, 
an unbiassed judgment, that we shall proceed to analyze 
the facts. 
What effect does elevation have upon the human system, 
and how is phthisis affected by it ? The atmospheric pres- 
ELEVATION. 3 
sure is diminished, and in consequence of it the amount, 
by weight, of oxygen in a given space is likewise diminish- 
ed. As the vital functions are governed, to some extent, 
by physical laws, the effects upon the system of diminished 
atmospheric pressure and oxygen can be formulated. 
Our space will not allow of our doing so, and we must con- 
tent ourselves with stating results. 
I. Effect on circulation.—It is known that an increase of 
elevation accelerates the pulse rate. This increase has been 
stated as two beats for every 1000 feet. This means an in- 
crease in the rapidity of circulation or the bringing of the 
blood to the lungs to be aerated, a greater number of times 
per diem. 
It also means an increase of the flow of blood to the dis- 
eased portions of the lung. This may aid in the throwing 
off of the product of disease, as is evidenced by the in- 
crease of expectoration; or in its absorption, as is shown 
by clinical experience ; or in encapsulating it. 
On the other hand we must recognize the fact, that when 
these results do not follow upon an increase of elevation, 
that bad ones do, and that the destruction of tissue and 
the extension of the disease is rapid, and haemorrhage en- 
sues. 
Experience, however, has shown that where the extent 
of the disease is not great, and where the affection is incip- 
ient, and recovery may reasonably be expected, that a resi- 
dence at a considerable elevation is beneficial, even where 
an hereditary taint exists. If heart lesions are present, an 
increased elevation is, of course, to be avoided. 
II. Effect on Respiration.—Experience shows that the 
respirations are quickened and that the inspirations become 
deeper and the chest expansion greater. This seems to be 
due to the following facts, but the extent of their individual 
action is difficult to estimate: I. An increased demand 
for oxygen, due to the increased rapidity of circulation. 2. 
To the diminished osmose, due to the diminished atmos- 
pheric pressure. 3. To the obstruction to the transpiration 
of the air through the brochi, due to diminution of press- 
ure. 4. To the effect of diminished atmospheric 
pressure upon the large extent of chest walls and lung 
area. 5. And possibly to the diminished amount of oxy- 
gen in the air, though this cause is questionable, as even 
under a great diminution of atmospheric pressure, the 
amount of oxygen present is greatly in excess of the 
amount absorbed by the lungs. 4 
The great advantage, as it seems to us, is derived from 
the increased depth of the inspirations, and the greater ex- 
pansion of the lung, If Ruehle’s assertion be correct that 
*“ The diminished respiration in the upper part of the lungs 
and the exaggerated respirations in the lower part, result- 
ing from this cause, serve to explain the very general fact 
that pulmonary consumption almost always begins at the 
apices of the lungs. But there is probably still another 
cause in the peculiar position of these parts. They project 
from three to four cm. above the clavicles, and this projecting 
portion, being situated outside of the chest, is subjected to 
the pressure of the external air. The supraclavicular re- 
gion sinks in during inspiration, and consequently the in- 
spiratory expansion of the apices is less than of other parts of 
the lung.” If, then, this assertion be correct, we can easily 
understand the benefit derived fioma lessened atmospheric 
pressure upon the apices, and from the greater depth of in- 
spiration, which would expand the collapsed cells and start 
a healthy activity in these parts. 
III. Immunity from Consumption of Elevated Regions.— 
While the mortality from consumption at sea-level is about 
thirty per cent, of all deaths, the deaths from consumption 
originating in Colorado was only a total of fourteen deaths 
for four years and a half. This accords with other statistics 
which show that an elevation of from 4,000 to 6,000 feet, 
affords an almost absolute immunity from this disease. This 
factor indicates then, the benefit of elevation as a prophy- 
lactic measure, and also its bearing upon cure, by the law of 
per contra. 
IV. Ozone.—Although positive experiments are wanting 
to show that the amount of ozone in the atmosphere is in- 
creased by elevation, yet such is considered to be the fact. 
We know the oxydizing power of ozone and its action in 
purifying the air of the products of decomposition ; whether 
it has any direct action in burning up such products in the 
lungs must still be regarded as problematical, but certainly 
it must be acknowledged that simply as an agent in purify- 
ing air it plays a part in the cure of consumption. 
V. Effects of an aseptic atmosphere.—In these days of 
Koch’s experiments and of the recognition of the bacillus 
tnberculosis, we must acknowledge the remedial influence 
of an aseptic atmosphere in the cure of phthisis. Tyndall 
has demonstrated the prevalence of germs floating in the 
*Note—Ziems-.cn—Vol. V., pages, 486 and 487. 5 
air at lower levels and the absence of germs at the “ Belle 
Alp Hctel,” at an elevation of 7,000 feet. Is not this known 
absence of germs at high altitudes a strong reason for re- 
commending such altitudes to consumptives ? 
Resume.—of the benefits derived from elevation: 
From the foregoing it is evident that the benefit that con- 
sumptives may look for from an increase in elevation are 
dependent upon the absorption and elimination of the 
products of inflammation ; the expansion and use of col- 
lapsed and unused portions of the lungs; the immunity 
from consumption ; the ozone in the air and the aseptic at- 
mosphere, combined with the conditions of humidity, tem- 
perature, etc., that we shall have occasion to speak of pres- 
ently. 
The extent of elevation desirable is shown to be that of 
immunity and of freedom from germs, or anywhere from 
5,000 to 7,000 feet. 
Now turning to Table I, column 1, gives the elevation of 
the barometer above sea-level, and column 2 gives the mean 
barometric register for a series of years. From this wesee that 
Santa Fe and Denver, or, in other words, the eastern slopes 
of the Rocky Mountains furnish the elevation and atmos- 
pheric pressure that we have found to be advantageous in 
the cure of phthisis. 
HUMIDITY. 
The amount of moisture that a cubic foot of air is capa- 
ble of holding depends on the atmospheric pressure and its 
temperature. The greater the pressure and higher the tem- 
perature, the greater the capacity of the air for moisture. 
When the air is saturated, a diminution of temperature 
causes a precipitation. It is on this principle, by means of 
observations of the wet and dry bulb thermometer, that the 
amount of moisture in the air, or the relative humidity of 
the air is ascertained. Taking one hundred as the satura- 
tion point, the relative amounts of moisture to a cubic foot 
of air will be indicated by figures rangingfromo—ioo. We 
have seen, however, that these observations are subject to 
variations, according to the variations of temperature, and 
they are further subject to error, according to the various 
exposures of the thermometers. Consequently, while tables 
founded upon the relative humidity will give an approxima- 
tive estimate of the moisture of the air sufficiently accurate 
as a basis of comparison, we have also added tables giving 
the absolute amount of moisture, or the number of grains 
of moisture contained in a cubic foot of air. 6 
I. Effect of Humidity on Consumption—The Seventh An- 
nual Report of the Register-General for Scotland, showed 
that the death rate from phthisis diminished in proportion to 
the dryness of the site. 
*Dr. H. I. Bowditch, of Boston, has shown that phthisis 
is prevalent in damp soils in the Uuited States. It is 
also common in Holland and other countries liable to damp 
fogs and an atmosphere saturated with moisture. tRuehle 
says, “ It appears that moist air favors consumption,” and 
the Dittsonian lecturer, |Dr. C. T. Williams, writes, “ As to 
to the desirability of moist climates for consumptivepatients 
the evidence is decidedly against their use in the treatment 
of ordinary chronic phthisis.” 
II. Evaporation Dependent on Humidity.—VVe further 
know that the amount of heat that a man can endure de- 
pends on the rapidity of the evaporation from his skin, 
and lungs, which is more rapid in a non-saturated air. Cold 
too, is more readily borne in a dry air and feels less sharp. 
III. Diathermaey.—Moreover, the diathermacy of the 
air, or its power of transmitting heat, is greater in a dry air, 
as the solar and terrestial radiations are more rapid. 
Resume.—From all of the loregoing it is apparent that a 
moist atmosphere is a breeder of phthisis, and that a dry 
one is an important factor in its cure. Turning now, to our 
tables, (Table I, columns iii and iv.) we see that the Rocky 
Mountain slope furnishes, in addition to a desirable elevation, 
a comparative degree of absolute and relative humidity of 
the air, a comparison, which, as between Denver and Jack- 
sonville, is almost 1:3. . 
PRECIPITATION, 
Closely connected with atmospheric moisture, in a consider- 
ation of climate, is an investigation of the mean annual 
amount of precipitation in rain and snow. It has a bearing 
upon our subject in several ways. 
i. Of the amount of precipitation, a part is lost by evapo- 
ration and thus tends to increase the humidity of the air; a 
part sinks into the soil and disappears, though if the soil be 
a humus or clayey soil, it increases the injurious sub-soil 
moisture ; and the remainder is drained off in the rivers. It 
is evident that the less the precipitation the less will be the 
effects from these causes. 
♦Reynolds, vol. iii, p. 548. 
fZiemssen, op. cit., p. 491. 
Rocky Mountains, p. 67. 7 
II. It is well known that pneumonia and other pulmonary 
troubles are prevalent in those places where the “ spring 
thaw ” throws a large amount of moisture on the air, and we 
know that in our Rocky Mountain homes, in places outside 
the mountains themselves, there is no such a thing as a 
“ spring thaw,” for the amount of snow-fall is so slight that 
snow never remains on the ground; we scarcely ever have 
enough for a respectable sleigh-ride, and when it comes it 
melts so rapidly, and is drunk up so eagerly by our thirsty 
porus, sandy soil, that the air is not chilled or damp, and the 
ground is seldom muddy. 
III. Further than this, the amount of precipitation has a 
bearing upon our subject as showing, approximately, the 
ability of the invalid to lead an out-of-door life; but we shall 
have occasion to speak of this further on, and in conclusion 
we would simply emphasize the fact that our sandy soil 
carries off the precipitation rapidly, and that at the best we 
have (vide table i, column v.) only an average of fourteen 
inches of rain and snow-fall on our Rocky Mountain in- 
habitable slopes, or one-sixth of what they have in Florida, 
or a half of that of Minnesota. 
TEMPERATURE. 
Dr. J. H. Bennett, in Reynold’s (loc. cit.) says : “ It was 
formerly supposed that warm climates were beneficial for 
consumptive patients. But it will invariably be observed 
that unaccustomed warmth is most injurious. What is really 
required is a cool, temperate climate, free from great altera- 
tions of temperature. On the other hand, Ruehle, (op cit.), 
says that the temperature of a country has “ nothing to do 
with the prevalence of consumption.” “ A uniform climate 
whether, cold or warm, so long as it is dry, rarely excites 
consumption.” Dr. Austin Flint calls attention to the fact 
that “ the disease is oftener developed during the spring 
months and the hot months of summer,” when either the 
moisture of the air or the debilitating effects of heat are 
present as factors. 
We know that the effect of high temperature is to raise 
the body heat; lessen the number of respirations; quicken 
the pulse; lessen the digestive powers and the appetite; 
diminish the amount of urea, because of the diminished 
amount of food taken, and to depress the nervous system, 
especially if the heat be accompanied by moisture of the 
air. 
We can fairly conclude, therefore, it seems to us, that a 
temperate, dry climate is the one to be sought by consump- 
tives. Our tables have shown that the Rocky Mountain furnish a dry air. The mean temperature (vide table I, col- 
umn vi.) is neither an extreme of heat or cold. But more 
important, we think, are the daily variations, which we shall 
have occasion to discuss further on. 
The element that we wish to analyze in regard to the 
winds, are the direction and velocity : 
I. Velocity.—A cold wind abstracts heat, and that in pro- 
portion to its velocity. So faras this element is concerned, it 
is evident from our tables that the velocity of the winds is 
much less in the Rocky Mountain region than in our east- 
ern states, and, hence, that while the mean temperature is 
nearly the same, the chilling effect of the wind is much less. 
On the other hand, having a considerable greater velocity 
than that of Augusta, by which we mean Aiken, and Los 
Angeles, it lias a proportionately greater purifying power, 
in bringing fresh air and fresh ozone, and in blowing away 
the products of decomposition. 
II. Direction.—But of equal, if not greater importance, is 
the direction of the wind. The favorable and unfavorable 
directions vary for different places, according to their sites, 
and geographical locations. The east and north winds 
along our Atlantic coasts are known to be the trying winds, 
and our table shows that this is the prevailing direction for 
the winds at Augusta and Jacksonville. 
The west wind, the cold, fog-bearing wind, is the trying 
one on the California shores, and our table shows that to 
be the prevailing one at Los Angeles. 
The south wind is the salubrious one for the eastern slope 
of the Rocky Mountains, in Colorado, and our table shows 
that to be the balmy wind that blows. 
Table I, column vii, gives the mean prevailing wind for five 
years. Table II, gives the mean for three years, showing 
how many times the wind was observed blowing in the 
several quarters of the heavens and also the mean velocity 
in miles, for each day. 
WINDS. 9 
TABLE II. WINDS. 
DIRECTION AND VELOCITY OF THE WIND. 
STATIONS. 
MEAN OF THREE YEARS. 
Velo- 
city. 
N 
N E 
E 
S E 
S 
s w 
w 
N\V 
Calm 
Daily 
Augusta 
57 
154 
68 
Il8 
86 
109 
94 
120 
3°4 
79mS 
Jacksonville .... 
77 
282 
120 
Il6 
102 
180 
83 
76 
60 
1 59 
Boston 
70 
59 
88 
72 
85 
155 
286 
186 
60 
238 
Newport 
”3 
80 
5i 
73 
112 
299 
183 
164 
28 
236 
New York 
76 
136 
54 
98 
83 
175 
188 
290 
14 
207 
Philadelphia 
123 
157 
92 
40 
102 
162 
179 
208 
9 
256 
l.hicago 
H7 
122 
85 
99 
142 
239 
151 
114 
3° 
203 
St. Paul 
95 
37 
91 
223 
72 
122 
129 
223 
70 
211 
Denver 
150 
! 95 
78 
150 
3°7 
67 
76 
155 
12 
145 
Santa Fe . . .... . 
*39 
IO9 
157 
IOO 
78 
142 
59 
n9 
201 
J52 
Salt Lake 
81 
64 
56 
252 
39 
33 
49 
269 
249 
135 
Los Angeles .... 
IO4 
i55 
80 
58 
55 
208 
274 
53 
142 
103 
CLEAR, FAIR AND CLOUDY DAYS 
We come now to our last general consideration and the 
one that seems to us, perhaps, the most important of all, for 
it in some measure embraces the most of the others, viz : 
a comparison of the number of clear, fair and cloudy days, 
in a year, at the different stations. In examining the tables 
it must be borne in mind that the results given are the means 
for five years and represent the means of four observations 
per diem, for that time. By the term cloudy is meant a day 
in which the sky is clouded from seven-tenths to its whole ex- 
tent; fair is when the sky is from four-tenths to seven-tenths 
cloudy; clear is from absolutely clear to four-tenths cloudy. 
For our purposes, clear and fair days maybe classed as one, 
and we shall arrive at our results by a comparison of the 
number of cloudy days. 
Effect of Sunshine.—But little is known of the effect of 
sunshine on the human economy. We can theorize upon the 
influence of solar radiation, its heat and actinic rays, but we 
know nothing absolutely. However, it is certain that a life in 
the open air is a prime factor in the remedial agents of phth- 
isis. Nothing can take its place. All authorities agree in this. 
Our tables show that on the Rocky Mountain slope there 
are, on an average, only forty odd cloudy days. Only one 
ninth of the year when a consumptive is compelled to stay 
cooped up in doors, because of stormy weather. For 320 
days in every year he can be out and about, enjoying the 
life-giving, the dry, the bracing air. Does not this one ele- 
ment make Colorado, the consumptives El Dorado? TABLE III. CLEAR, FAIR AND CLOUDY DAYS. 
SIGNAL STATIONS 
Mean for Five Years. 
Clear. 
Fair 
Cloudy. 
Augusta 
123 
>So 
Q2 
Jacksonville 
126 
152 
87 
Boston 
105 
>45 
• >5 
Newport 
108 
140 
III 
New York 
IOI 
>55 
109 
Philadelphia 
114 
>39 
112 
Chicago 
104 
•54 
107 
St. Paul 
103 
158 
104 
Denver 
177 
142 
46 
Santa Fe 
>74 
148 
4> 
Salt Lake 
>4> 
•3> 
93 
Los Angeles 
164 
148 
5> 
We have tried to be candid and unprejudiced in analyz- 
ing these data. They are correct even if the conclusions 
arrived at be false. From them we have proven, we think, 
the efficiency, both absolutely and by comparison, of the 
climate of the eastern slope of the Rocky Mountains, in 
the cure of consumption. We have shown, we think, that 
it furnishes a desirable elevation; a small amount of relative 
and absolute moisture in the air; a small annual fall of rain 
and snow; a desirable mean temperature ; a mean velocity of 
wind, neither excessive nor too small; a prevailing balmy 
and salubrious south wind; and lastly a large, an exceed- 
ingly large number of clear days in which the invalid can 
be in the open air. Surely these simple, but accurate statis- 
tics speak volumes. 
SEASONS. 
It seems to the writer that quite as valuable as the fore- 
going tables, would be accurate tables on these several 
points under consideration, but tables giving the data for 
the seasons of the year rather than the mean for several 
years. The space allotted to our article will not allow of 
our going into detail as much as we would like, and in ad- 
dition, we are informed by the Chief Signal Officer that the 
data that we desire, cannot be copied for our use, because 
of “ the reduction in the force ” in his office. We shall 
content ourselves, therefore, with annexing, without much 
comment, the few facts that we have been able to collect. 
The writer would state that in selecting the year 1880 as 
the basis of comparison, it has been done at random and 
without reference to whether it was favorable or unfavorable 
to the facts that he wishes to elicit. 
The following table will give us the relative and absolute 11 
moisture in the air, for the places under consideration, for 
the four seasons. In this table R. H., stands for relative hu- 
midity ; G. V. for grains of vapor to the cubic foot of air. 
The second part of the table has reference to the precipita- 
tion in inches of rain and melted snow for the same time. 
TABLE IV. 
i88o. 
1880. 
Relative and Absolute Humidity. 
Precipitations. 
SlfiNAT. 
Spring. 
Summer. 
Autumn. 
Winter. 
bo 
.£ 
V 
G 
c 
6 
V 
RH GV 
RH 
G V RH 
GV 
RH 
G V 
cu 
'SI 
G 
3 
si 
3 
< 
£ 
Augusta 68 i 4.7 
64 
7.2 
74 
4.9 
72 
32 
5.0 
4.2 
2.8 
3-9 
Jacksonville 66 5.5 
69 
8.0 
75 
5-6 
70 
3° 
3-5 
5 9 
9.5 
3-5 
Boston <>r 2.5 
70 
5-4 
67 
3° 
69 
i-5 
2.6 
3-5 
2.6 
3.8 
Newport 71 2.7 
76 
5-9 
75 
3-5 
76 
1.9 
3.9 
5-° 
3-4 
3.6 
New York 65 2.9 
79 
5-5 
70 
3-8 
65 
2.0 
2-5 
4.2 
2.5 
2.8 
Philadelphia 61 2.7 
66 
6.1 
68 
3° 
72 
2.1 
2.1 
4-8 
i-5 
2.6 
Chicago 63 2.9 
70 
5.9 
66 
2.3 
69 
1.8 
41 
3-7 
2.1 
2.4 
St. Paul 62 2.9 
69 
5-i 
66 
2.9 
71 
2.1 
4tO 
2.3 
1-5 
Denver 37 1.1 
43 
8-5 
55 
2.3 
51 
•9 
o-5 
i-3 
1.0 
0.2 
Santa Fe 35 1.2 
36 
2.6 
5° 
2.S 
50 
0.25 
i-7 
0.7 
0.6 
Salt Lake 41 1.5 
25 
1.5 
33 
1.6 
5° 
i-3 
1.6 
0.3 
0.7 
I.I 
Los Angeles 74 3.6 
73 
4.8 
63 
3-8 
68 
29 
2.2 
o-3 
3.8 
The table gives the mean for each month, in the three 
constituting the season. The spaces left blank have not been 
calculated. From this table it is seen that both the relative 
and absolute humidity, and the precipitation of rain and 
snow is very small on the Rocky Mountain slope in com- 
parison with other places on the table; especially does this 
hold true for the winter and spring months, the trying 
months for consumptives in the east. This table confirms 
the results arrived at from our other tables and shows, in 
addition, that the Colorado air is the dryest, and the amount 
of precipitation is the smallest during those months of the 
year that breed and kill consumptives in our eastern cities. 
The next table that we shall offer is one of temperatures. 
We are not able to present this subject in just the form that 
we should like to, on account of our lack of data. The first 
series gives the maximum and the minimum thermometer, ob- 
served during the three months constituting the season ; the 
second series gives the mean monthly range, and mean of 
temperature for the same seasons. While these tables show, 
as our previous tables did, a desirable mean temperature for 
the Rocky Mountains, they show a wide range ; in fact, the 
widest range of any place in our tables. This requires an explanation. We have seen that the 
Colorado air is a dry air; that the absolute amount of va- 
por to the cubic foot is very small; that the diathermancy 
of the air is great; conditions which favor rapid solar 
and terrestial radiation, so that, on the one hand, the 
heating effects of the sun’s rays are soon felt, and on the 
other, the heat from the earth is soon radiated. Again, the 
air itself retains less heat and gives up its heat more rapid- 
ly, because of its dryness, so that this would be another cause 
for great variations in temperature. The great exposure of 
a sandy soil is another reason for the amplitude of the varia- 
tions of temperature existing in Colorado. It must be ac- 
knowledged that these changes are not as severe nor as 
trying as in a damp climate. It mustfurther be granted us 
that, however great the variations may be, the midday tem- 
perature, as a rule, is equable and adapted, to an invalid’s 
leading an out-of-door life. Unfortunately we cannot give 
tables as we had hoped to do, to prove this point. We in- 
sist, however, that even if the evenings and early mornings 
may be cold, the midday is balmy and soft. Moreover, the 
cool nights prevalent throughout Colorado, render it a de- 
lightful summer resort. 
TABLE V.—THERMOMETRIC VARIATIONS, l880. 
Sig Stations 
Spring. Summer. Autumn 
Wi 
nter 
6 
3 
a 
;§ 
3 
Spring 
Summer 
Autumn 
Winter 
Maximum 
Minimum 
j Maximum 
Minimum 
| Maximum 
Minimum 
| Maximum 
V 
bA 
C 
a 
04 
K 
V 
b* 
c 
rt 
04 
V 
2 
| Range 
c 
V 
3 
| Range 
s 
rt 
V 
3 
Augusta . . 
90 
35 99 
6o 
91 
28 
81 
7 
47 
66 
32 
81 
45 
63 
54 
5‘ 
Jacksonv’le. 
95 
42 IOO 
69 
9' 
39 
78 
*9 
43 
71 
29 
82 
37 
69 
45 
59 
Boston .. . . 
92 
12 IOI 
47 
93 
3 
59 
-5 
58 
47 
48 
69 
52 
5* 
52 
3.3 
Newport .. . 
84 
14 88 
49 
87 
15 
6l 
I 
44 
47 
33 
69 
42 
53 
48 
38 
New York . 
94 
16 92 
48 
9* 
14 
65 
-6 
54 
51 
38 
72 
45 
53 
52 
38 
Phila 
96 
20 95 
51 
91 
IO 
97 
.-5 
56 
54 
37 
75 
49 
55 
53 
37 
Chicago . . 
85 
19 95 
52 
83 
I 
6.3 
-I5 
47 
51 
42 
72 
5.3 
48 
57 
3i 
St. Paul . . 
Qi 
-7 98 
47 
90 
-18 
59 
-27 
59 
46 
43 
69 
62 
42 
87 
21 
Denver.. . . 
89 
-10 96 
39 
89 
-13 
59 
-II 
66 
48 
48 
89 
6d 
44 
72 
29 
Santa Fe.. . 
8->- 
0 88 
33 
80 
-II 
58 
-3 
87 
47 
45 
66 
59 
48 
6l 
27 
Salt Lake.. . 
78 
5 95 
40 
88 
3 
49 
2 
5* 
45 
51 
68 
51 
49 
44 
3* 
Los Angeles 
97 
36 87 
50 
91 
35 
80 
30 
45 
58 
38 
64 
47 
61 
46 
54 
In conclusion we would say that we think that our inves- 
tigation of these facts bears out our common experience in 
regard to the efficacy of a residence in Colorado as a cure 
for consumption. We must admit, however, that as a rule, 
patients with marked advance of the disease do not make a 
recovery here; but in those cases where the disease is taken in hand early in its course, in such cases we may hope for 
good results from a change to the slopes of the Rocky 
Mountains. 
There is much that could be written in regard to places 
on this eastern slope, for we know that there is a difference 
between them, and that they are not all equally good. We 
know from experience, too, that there is a surprising ignor- 
ance amongst physicians and people in the east in regard to 
Colorado, and that much of value could be written for them 
in regard to things that are every-day facts to us. Our 
space will not admit of our undertaking such a task at 
present, and we will let what we have written, which we have 
intended should be a conscientious analysis of reliable data, 
suffice. We feel that in simply putting these data on re- 
cord, we are aiding somewhat the investigations that are 
constantly going on in regard to the climate of Colorado. 
Note—Column iv of table I. is computed from column iii of the same 
table by means of Glaisher’s tables, and is not taken from Signal Service Re- 
ports. 
ADDENDA. 
TABLE VI.—MEAN MONTHLY TEMPERATURE, i:C>7 P.M. 
(Local Time) at Denver, Colorado. 
00 
00 
“ 
00 
00 
I 
o 
p 
OJ 
NO 
January 
(O 
ON 
On 
February 
to 
4^ 
ON 
n 
to 
On 
4^ 
March 
u> 
H 
w 
tjl 
ON 
U1 
to 
April 
to 
''J 
NO 
S 
ON 
May 
00 
OJ 
June 
Ui 
M 
4*- 
NO 
July 
On 
ON 
NO 
00 
H 
August 
* 
U) 
ON 
NO 
OJ 
Sept 
!o 
NO 
On 
October 
4»» 
00 
OJ 
On 
0 
Nov 
tn 
00 
w 
4- 
u‘ 
Dec 
“ 
<* 
oo