i86 



NATURE 



\7uly 8, 1875 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself respdnsible jor opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts, 

 No notice is taken of anonymous cotnmunications.'] 



Temperature of the Body m Mountain Climbing 

 I HAVE read with great interest the able paper on the Tem- 

 perature of the Human Body during Mountain Climbing in 

 Nature, vol. xii. p. 132, and as it is there mentioned that the 

 results obtained by Drs, Marcet and Lortet require confirmation, 

 I am tempted to send some extracts from notes of observations 

 made on myself while on a walking tour last autumn, in the 

 Yorkshire moors. I made in all five ascents, of heights over 

 2,000 feet, during all of which I took notes of my temperature 

 at intervals. As, however, I had no more than a hearsay ac- 

 quaintance with Dr. Marcet's results, and was not aware of the 

 important influence of the act of ascending as distinguished from 

 the elevation attained, my earlier results were not sufiiciently 

 connected to be worth publishing. Suffice it to say that I 

 always obtained a fall of from one to two degrees. On the fifth 

 day of observation, when I was alive to this and other sources of 

 error, I made the following observations in the course of the 

 ascent of Whernside and Gragreth. 



la comparing the temperatures above it should be borne in 

 mind that I uniformly found my temperature in bed in the morn- 

 ing 97"6 or 977, and about the same at 9 or 10 at night ; while 

 the day previous, when detained in the house by bad weather, it 

 had been 98*4 and 98*6 in several observations, between 10.30 

 A. M. and 6 p.m., and this I have found the case on many other occa- 

 sions, so that the difference between the second and third obser- 

 vations really represents a greater depression than is apparent. 



It is worthy of note that the two lowest temperatures, viz. , 

 96-4, both occurred during steep ascents and before stopping, 

 arid while I was perspiring freely and feeling hot. In each case 

 I immediately sat down and noted a progressive rise in the tem- 

 perature, though at the same time I was feeling much cooler. 

 "When I began to shiver from sitting above half an hour in a 

 strong wind on the top of Whernside the temperature had actu- 

 ally risen to 99°*3. This reminds one of the cold stage of ague, 

 when a patient may have a temperature of 105° while his teeth 

 are chattering with cold, 



I entirely agree with Dr. Marcet that it is the fact of actively 

 climbmg and not the actual elevation, which influences the tem- 

 perature. When sitting quiet on the top of Whernside and 

 Gragreth the temperatures were at or above the normal. The 

 steepness also appears to have great influence ; both these moun- 



tains have flattish tops, and the temperature on reaching the top of 

 Whernside shows less depression than during the ascent, while 

 that taken walking on the flat top of Gragreth, though without 

 stopping, after the ascent showed scarcely any. 



I noticed no depression of temperature in descending, though 

 I often came down at a run, and none in several long level walks. 

 And now as to any possible fallacies. The same thermo- 

 meter was used in all the observations. It is a Philips' maxi- 

 nium, by Wood and Co., of York, is graduated in fifths of a 

 degree, and easily reads to tenths, I have compared it with a 

 thermometer certified at Kew, and find it very exact. It rises to 

 within a degree of the truth in ten seconds after putting under 

 the tongue, and I am accustomed to rely on its indications after 

 being in about two minutes. In all the above observations it 

 was left in the same position under the tongue five minutes by 

 the watch (except the reading at 2.33, when it was only four) ; 

 consequently any failure to rise to the true temperature would 

 be likely to affect all the readings nearly alike. Whatever error 

 may be due to this cause would be likely to show itself in raising 

 the readings during the ascents, as at these times the heart was 

 beating strongly and the circulation particularly active ; so that 

 the cooling of the mouth by the cold bulb would be quickly 

 neutralised. I was also particularly careful not to allow any air 

 to enter through the lips and as little as possible through the 

 fauces, and feel confident that there is no appreciable error from 

 this cause. 



As to the rationale of the process, may not the following 

 theory embrace all the facts as observed by Marcet, Forel, and 

 others ? 



Heat motion and chemical force are merely varieties of one 

 force convertible under certain conditions. The human body is 

 an engine, in which muscle and other tissues are oxidised, and 

 the resulting chemical force is transformed into an equivalent 

 amount of motion and heat. Now it is manifest that there is a 

 limit to the rate at which oxidation can go on in the body, and 

 consequently to the amount of force available for transformation 

 in an unit of time into motion and heat. Usually the human 

 machine is not worked up to its full power ; the amount of motion 

 produced is nothing approaching what is possible, and only suffi- 

 cient force is transformed into heat to keep the body at the 

 normal temperature of 98 '4 ; but in the limit the two processes 

 become complementary to each other, and if from any cause the 

 force converted in one direction exceeds a certain amount, the 

 excess can only be obtained at the expense of what would ordi- 

 narily be converted in the other. Now, in mountain climbing 

 the amount of motion as expressed in foot-pounds of work done 

 is very great, and much exceeds the amount to which most of us 

 are accustomed in walking on a level road. If this be pushed to 

 the limit it encroaches on the amount of force destined for the 

 supply of heat to the body, and the temperature falls. It is 

 clear that these processes habitually go on at different rates in 

 different individuals ; if so, may not the limit of the rate of tissue 

 change be different ? One man may be able to push his motion 

 production nearly to the limit up to which his oxidation will work, 

 thereby encroaching on what ought to sustain his temperature, 

 while another, whose muscles are less fully under the dominion 

 of his nerves, or whose power of oxidation is considerable, may 

 be unable to reach that limit. 



To this class I believe Dr. Forel to belong ; in the other, the 

 slow oxidisers, I find myself in the honourable company of Drs. 

 Marcet and Lortet, Tempest Anderson 



17, Stonegate, York 



Trevandrum Magnetic Observations 

 Though I have felt much gratified with the notice by Prof. B. 

 Stewart of the first volume of the " Trevandrum Observations " 

 which appeared in last week's Nature, p, 163, I desire, never- 

 theless, to make a few remarks on the only point on which we 

 appear to differ. 



There are two methods of investigating the laws of magnetic 

 disturbance, which have quite distinct objects ; one, which has 

 been employed with much success by that eminent veteran of 

 science Sir E. Sabine, seeks, as he has expressly stated, the laws 

 of the larger disturbances only, and for this end chooses only 

 those deviations from the mean positions that are greater than 

 some arbitrary value. The other method seeks the laws of dis- 

 turbances of all magnitudes, and employs deviations of all 

 amounts. 



As Prof. Stewart regrets that I have employed the latter 

 method, and suggests that the former may yet be used by others. 



