
-_ = ~~ 
Dee. 1, 1870] 
NATURE 91 

walking fast up the mountain, carrying a load of provisions, 
than by running down it with nothing to carry ; mine, on 
the contrary, as one would expect, much more so by walk- 
ing up than by running down. (Of course I could get no- 
thing in the shape of sphygmograph at Catania.) 
Dr. Lortet has recorded some interesting observations, 
made with the aid of the anapnograph of MM. Bergeon and 
Kastus, on the state of the respiration. It is much quick- 
ened, as is well known ; the expiration is much prolonged, 
its amplitude much lessened, the inspiration shortened 
and quickened ; much less air being inspired and expired 
_than is normally the case. 
These effects are partly due to the rarefaction of the 
air, less oxygen by weight being taken in at each inspira- 
tion, and partly to the excessive muscular exertion, which 
demands a corresponding increase in the animal heat, 
and so a corresponding increase in the amount of oxida- 
tion taking place in the blood; this not being always 
obtainable and the exercise being continued all the same, 
the normal temperature of the body cannot be maintained, 

and so it falls, and one becomes miserably cold while 
walking, and has to stop to get warm again. 
Now as to the amount of work done; that is very 
much greater than is commonly supposed : leaving out of 
consideration the difficulties encountered in walking 
either over soft snow or over slippery places, especially 
when very steep, I find that in climbing Etna, starting as 
I did, on the occasion that I have already described, from 
some distance above the Casa del Bosco, I lifted about 
150lb. to the vertical height of at least 5,700 ft., or about 
350 tons one foot ; adding ro foot-tons (little enough) for 
the horizontal distance traversed, we have 390 foot-tons 
as representing work done in 3} hours : now 390 foot-tons 
is about the work done by a person of the weight above 
mentioned in walking 22 miles on level ground ; that is to 
say that, without making any allowance for the increased 
difficulty of breathing due to the rarefaction of the air or 
for any of the consequences of this (increased action of 
heart, &c.), one has walked 22 miles in the time ordinarily 
taken to walk 13. 












































































































































































































































































































































































































































































































































































































































A VIEW OF ETNA 
To put it in another way : 390 foot-tons is a hard day’s 
work, as it is found that something over 300 foot-tons is 
the average day’s work of strong labourers. One there- 
fore does a hard day’s work in 3} hours, and this after an 
ordinary day’s work, Z/us a fatiguing ride of some four 
hours on a mule, over lava currents and cinders, in the 
middle of the night and without any chance of sleep. 
Taking everything into consideration, it is difficult to 
believe that the fatigue is, as it is often stated, out of all 
proportion to the work done; we must not only consider 
the amount of work, but che time in which it ts done, and 
this is what I have especially wished to point out, as one 
can easily understand that the fatigue must increase very 
fast as the time in which the work is done decreases. 
At the summit of Etna (the accompanying woodcut, 
from a rough sketch taken when a good deal of the snow 
had melted, can give but a feeble idea of the exquisite 
effect produced by the dazzling whiteness of the snow 
against the perfectly clear blue Sicilian sky) the range of 
temperature within a few feet of vertical distance is very 

remarkable. Just after sunrise I found that the tempera- 
ture of the air at the height of four feet or so above the 
ground was — 2° C.; on the ashes where the snow had 
melted it was + 9°C. ; just under the surface it was 20° C., 
and a few inches under it was higher than 36° C. (my 
minimum thermometer, the only one I had left, not allow- 
ing me to register a higher temperature than this). 
This high temperature of the ashes only occurs where 
they are mixed with sulphur, which is continually under- 
going oxidation ; the other parts of the cone and crater 
are in the winter covered with snow, and it is very strange 
to see snow a foot deep or more, quite close to ashes that 
really feel uncomfortably hot. 
Those who wish to “ get up” the history of Mount Etna 
and its structure, should refer to Sir Charles Lyell’s “ Prin- 
ciples of Geology,” tenth edition, vol. ii.; or for a much 
more detailed account of the eruptions, its present and 
past conditions, &c., to “ La Vulcanologia dell’ Etna,” by 
Carlo Gemmellaro, published at Catania in 1858. 
W. H. CORFIELD 
