en about 1,600 meters (5,100
feet) below the Alpine summit, whose mean temperature is 3 degrees
below zero (27 degrees F.) Thus there was a difference of 32.5
degrees: that is, one "geothermic" degree corresponded to about 50
meters.

This elevation of temperature was not at first regarded with anxiety.
Soon a draught would be produced and would ameliorate the situation.
It was time, for the disease known as "miner's anaemia" had begun to
claim its victims.

The situation at St. Gothard was much more serious. As at Mont Cenis,
a temperature of 29 degrees C. (85 degrees F.) was found about 5,000
meters from the portals of the tunnel. But there remained yet 5,000
meters of rock to pierce. In the center of the tunnel there was
observed for several days a temperature of 35 degrees (95 degrees F.)
Generally it did not vary much from 32.5 degrees (90.5 degrees F.), a
sufficiently high degree, if we remember that the men's perspiration
was transformed into water vapor, and that the air was nearly
saturated with humidity. In these conditions work was very difficult,
and the horses employed to remove the debris almost all succumbed.

Man can bear more than animals. In an absolutely dry air he can endure
a temperature of 50 degrees (122 degrees F.) But in an atmosphere
saturated with water, underground, where the breath of the workmen
fills the narrow space with poisonous vapors, a temperature of even 30
degrees (86 degrees F.) entails serious consequences. In a large
number of workmen the bodily heat rose to 40 degrees (104 degrees F.)
and the pulse to 140 and even 150 a minute. The most robust were
obliged to lay off one day out of three, and even the working day was
itself reduced to five hours, instead of seven or eight.

According to Dr. Giaconni, who for ten years attended the workmen at
Mont Cenis and St. Gothard, the proportion of invalids was as large as
60 to the 100.

More strange yet, the report of the physicians who dwelt at the works
notes the presence among the workmen of the intestinal parasites
called "ankylostomes," which have been observed in Egypt and other
tropical countries, and which are the cause of what scientists call
"Egyptian chlorosis" or "intertropical hyperaemia." This pathologic
state is observed only in the hottest regions of the earth. The victim
becomes thin, pale and dark. He is bathed in continual sweat, devoured
by inextinguishable thirst, and the prey of continual fever. And thus,
add