go 
NATURE 
| Dec. 1, 1870 

portant of his many splendid contributions to physics, and 
one having the most direct bearing upon the future of the 
physical universe. The rest of the statement, as it stands, 
is also false. It may be made correct by writing one of 
the words, work, ower, potency, or preferably energy, in 
place of force, and also in place of momentum. What 
would be thought of a man who should say—* I paid 
six weeks for it,” meaning “pounds” by “weeks.” For 
“momentum” cannot be transformed or “ transmuted ” at 
all, it remains for ever unchanged. 
Again, when bodies impinge on one another, “ the rise 
of temperature is exactly proportioned to the visible 
momentum destroyed.” Let us put the correct word 
“energy” in the place of momentum, and we find that this 
asserts the startling physical fact that the specific heat of 
every body is the same at all temperatures. If we take 
the statement as it stands without correction, it is simply 
nonsense. 
Again, “the foot pound, meaning the force expended 
in raising one pound weight one foot, which is the same 
as a (séc) momentum of one pound moving at eight feet 
per second.” 
Raising one pound weight one foot is a feat which, by 
proper combinations of machinery, may be effected by 
any given force whatever, be it the weight of a grain or of 
a million tons. Buta “foot pound,’ and the ‘momen- 
tum of one pound moving at eight feet per second” cannot 
possibly be compared with each other, any more than a 
cubic yard can be expressed as a number of square yards, 
or the height of a mountain in acres, roods, and poles. 
You will see that the error in the examples I have just 
chosen (excepting of course the fatal one about restora- 
tion of energy) is in great part due to the misuse of words. 
Yet it is from a treatise on Logic that I have quoted ! 
The essence of the lesson taught by all this is simply 
the conviction that scientific knowledge has reached such 
an immense development that no one man can now pos- 
sibly master thoroughly more than one or two of its many 
branches. There can be no “Admirable Crichtons” in 
our days. The greatest logician the world has pro- 
duced, or is likely to produce, for many a long day, the 
lamented George Boole, more than once expressed his 
regret that a systematic logical treatment of human know- 
ledge, even in moderate compass, and going little farther 
than the elements in each branch, had become absolutely 
impossible as the work of one man—impossible, that is, 
for a man who revolted at the idea of publishing anything 
he knew to be defective. 

MOUNTAIN CLIMBING 
7% the number of NATURE for June 23, 1870, I de- 
scribed an ascent of Mount Etna which I made on 
March 4 of this year, with an excellent guide, Pietro Cra- 
vagna. 
I now propose to make some remarks on a few points 
of interest with regard to mountain climbing. One of the 
most important of these is the alleged lowering of the 
internal temperature of the body under such conditions. 
During two ascents of Mont Blanc made on the 17th 
and 26th of August, 1868, by Dr. Lortet, of Lyons, and Dr, 
Marcet, of London, and described by Dr. Lortet in the 
Lyon Médical of September 26, 1869, experiments made 
apparently with great precaution on Dr. Lortet himself 
with a registering maximum thermometer (of Walferdin), 
by which (between + 30° C.and + 4o° C.) hundredths of a 
degree could be appreciated, showed that the internal 
temperature of the body under such conditions is lowered 
to a very remarkable extent. 
I will quote Dr. Lortet’s own words: “ A jeun et exacte- 
ment dans les mémes conditions, Jendant la marche, la 
décroissance de la température intérieure du corps est 

trés-remarquable, e//e est d peu prés proportionelle d Valti- 
tude a laquelle on se trouve.” 
In effect, from the table given in the paper referred to, 
I find that during the first ascents the internal tempera- 
ture descended gradually from 36°3° C. (that during exer- 
cise at Chamounix, 1,050 metres above the sea) to 32° C. 
at the summit of Mont Blanc (4,810 metres above the sea) ; 
while during the second ascent the difference was from 
35°3. GC. toignrs: |G 
Dr. Lortet found that as soon as he stopped for a few 
minutes, the temperature of his body rose briskly to the 
normal standard, except on the summit itself, where “il 
a fallu prés d’une demi-heure pour que le thermométre 
atteignit sa hauteur habituelle.” 
During digestion, in spite of the exercise being taken, 
the temperature remains normal, or even rises ; but this 
does not last long: “ Une heure & peine aprés avoir 
mangé, le corps se refroidit de nouveau par les efforts.” 
The descent of the temperature of the body under such 
conditions, then, amounts sometimes to more than 4° C. ; 
and if we take the difference between the normal tem- 
perature of the body a¢ resf, and that observed by these 
experimenters on the top of Mont Blanc, the difference 
amounts in one case to 5°C., “abaissement énorme pour 
les mammiféres dont la température était reputé con- 
stante!” as Dr. Lortet justly exclaims. 
Now Mount Etna is particularly suitable for such ex-. 
periments ; one begins to walk either at Nicolosi, or pre- 
ferably at the Casa del Bosco, and one has nothing to do 
but to go straight up ; there is nothing in the way, it is 
simply a long “grind” of some five or six hours or more, 
according to the state of the snow. A series of misfor- 
tunes with my maximum thermometers prevented my 
repeating the above-described observations, and I have 
referred to them at such length in the hope that some one 
may be induced to take the excellent opportunity afforded 
by the expedition to Sicily of deciding so important a 
oint. 
q The state of the circulation is hardly less important 
than that of the internal temperature. 
Dr. Lortet found that the pulse increased in frequency 
from 64 per minute at Chamounix to 172 on the summit 
of Mont Blanc, and he was further enabled, by means of 
the 8phygmograph, to make some observations as to the 
state of the pulse at various altitudes. In ascending Etna 
I made some comparative observations on the frequency 
of my guide’s pulse as compared with my own, which show 
some points of interest. 
At the Casa del Bosco my pulse was 68, my guide’s 
74; we had both rzdden to that point, and the difference 
is probably an illustration of the established fact that the 
circulation of persons living in mountainous districts is 
quicker than that of those living in plains. On arriving at 
the summit of Etna after a ride of an hour and a quarter 
(from the Casa del Bosco), a rest of fifteen minutes, and 
a stiff walk of three and a quarter hours over dry, hard, 
snow (an exceptionally easy ascent),* my pulse was very 
irregular, and about 114 or I15 to the minute, while the 
guide’s was only 89—that is to say, that mine had in- 
creased 46 beats in frequency, his only 15 ; or mine was 
about $rds, his only about 4th, as fast again ; showing 
the slight effect of such ascents on those who are used to 
them, and who live habitually in mountainous countries. 
But this was still more forcibly illustrated by the state 
of our pulses after a very quick descent, a regular trot all 
the way (we had stayed two hours at the summit, and 
eaten a hearty breakfast) ; at the place where we left the 
mules, I found that while my pulse, after a minute or 
two’s rest, was at 106 or 107, the guide’s was at 99 or 100; 
mine being 8 beats Zess than it was on arriving at the top, 
his 10 beats more, his circulation was ess disturbed by 
* Later on in the month of March, when much snow had recently fallen 
the Rev. A. G. Girdlestone and I, with two other friends, made an ascent : it 
took us nearly eight hours to walk from the Casa del Bosco to the Casa degli 
Inglesi, and we saw nothing but a very heavy snow-storm. 
