The following extract is taken (1) from ‘A Tramp Abroad’, Chatto & Windus 1880, by Mark Twain.
Our distresses being at an end, I now determined to rest the men in camp and give the scientific department of the Expedition a chance. First I made a barometric observation, to get our altitude, but I could not perceive that there was any result.
I knew, by my scientific reading, that either thermometers or barometers ought to be boiled, to make them accurate; I did not know which it was, so I boiled both. There was still no result, so I examined these instruments and discovered that they possessed radical blemishes: the barometer had no hand but the brass pointer, and the ball of the thermometer was stuffed with tin foil. I might have boiled those things to rags and never found out anything.
I hunted up another barometer: it was new and perfect. I boiled it half an hour in a pot of bean soup which the cooks were making. The result was unexpected: the instrument was not affected at all, but there was such a strong barometer taste to the soup that the head cook, who was a most conscientious person, changed its name in the bill of fare. The dish was so greatly liked by all, that I ordered the cook to have barometer soup every day. It was believed that the barometer might eventually be injured, but I did not care for that. I had demonstrated to my satisfaction that it could not tell how high a mountain was: therefore I had no real use for it. Changes of the weather I could take care of without it. I did not wish to know when the weather was going to he good: what I wanted to know was when it was going to be bad, and this I could find out from Harris's corns. Harris had had his corns tested and regulated at the government observatory in Heidelberg, and one could depend upon them with confidence. So I transferred the new barometer to the cooking department to be used for the official mess. It was found that even a pretty fair article of 'soup could be made with the defective barometer: so I allowed that one to be transferred to the subordinate messes.
I next boiled the thermometer, and got a most excellent result: the mercury went up to about 200° F. In the opinion of the other scientists of the Expedition, this seemed to indicate that we had attained the extraordinary altitude of' 200,000 feet above sea level. Science places the line of eternal snow at about 10,000 feet above sea level. There was no snow where we were. Consequently it was proven that the eternal snow line ceases somewhere above the 10,000 feet level and does not begin any more. This was an interesting fact, and one which had not been observed by any observer before.
The success of my last experiment induced me to try an experiment with my photographic apparatus. I got it out, and boiled one of my cameras, but the thing was a failure: it made the wood swell up and burst, and I could not see that the lenses were any better than they were before….
We continued on up the mountain.
The difficulties of the next morning were severe. but our courage was high, for our goal was near. At noon we conquered the last impediment - we stood at last upon the summit - and without the loss of a single man, except the mule that ate the glycerine. Our great achievement was achieved - the possibility of the impossible was demonstrated.
I boiled a thermometer and took an altitude, with a most curious result: the height was not as high as the point on the mountain side where I had taken the first altitude. I had made an important discovery.
Yes. I had made the grand ascent: but it was a mistake to do it in evening dress. The plug hats were battered, the swallow-tails were fluttering rags, mud added no grace, the general effect was unpleasant and even disreputable.
But nevertheless Harris and I walked proudly into the great dining-room of the Riffelberg Hotel and stood our alpenstocks up in the corner.
There were about seventy-five tourists at the hotel - mainly ladies and little children and they gave us an admiring welcome which paid us for all our privations and sufferings. The ascent had been made, and the names and dates now stand recorded on a stone monument there to prove it to all future tourists.
ButI prepared to verify the important discovery about the heights. There happened to be a still higher summit (called the Gorner Grat) above the hotel, and notwithstanding the fact that it overlooks a glacier from a dizzy height, and that the ascent is difficult and dangerous, I resolved to venture up there and boil a thermometer. So I sent a strong party, with some borrowed hoes, in charge of two chiefs of service, to dig a stairway in the soil all the way, and this I ascended, roped to the guides. This breezy height was a summit proper - so I accomplished even more than I had originally purposed to do. This foolhardy exploit is recorded on another stone monument.
I boiled my thermometer, and sure enough this spot, which purported to be 2000 feet higher than the locality of the hotel, turned out to be 9000 feet lower. Thus the fact was clearly demonstrated that, above a certain point, the higher a point seems to be, the lower it actually is. Our ascent itself was a great achievement, but this contribution to science was an inconceivably greater matter.
Cavillers object that water boils at a lower and lower temperature the higher and higher you go, and hence the apparent anomaly. I answer that I do not base my theory upon what the boiling water does, but upon what a boiled thermometer says. You can't go behind the thermometer.
(1) Blackall, R. M. B. 1986. Weather, 41, 199-200.