62 



KNOVSALEDGE 



build castles in that region for lialf-an-hour or so, then 

 j)ack up shirt A, and do the last stage of j'our day's walk 

 at a swinging pace in the cool evening. Shirt A does 

 duty as a night-shirt, B is resumed on the next morning, 

 when A "goes to the wash," as B did the day before. 



The success or failure of a pedestrian excursion of any 

 length depends primarily on the reduction of luggage. 

 Everybody takes too much. I did so on this occasion, 

 having included a comb and hair-brush, besides the 

 above-named collars. On reaching Christiania I had my 

 hair cut. The operator used very long shears, and pre- 

 sently I discovered that there remained on my head 

 nothing to brush, and less to comb. The Norwegians 

 clip their horses annually, themselves likewise, and in 

 the same degree. The only occasion on which I did not 

 take an excess of luggage was on a suddenly extemporised 

 trip through Belgium, the Rhine, Bavaria, the Tyrol, 

 Venice, the Italian lakes, Alsace vid the Spliigen and 

 Zurich, thence by the Moselle to Nancy, and from Nancy 

 to Paris by rail. My luggage on starting from London 

 by the Dunkirk packet was a penny sheet of brown 

 paper and a bit of string. Every other requirement was 

 purchased on the way as the demand arose. The natural 

 course of evolution in this case finally converted the 

 sheet of paper into a German satchel filled with hand- 

 books and photographs. If you eat a raw turnip or a 

 hard apple every morning, the supposed necessity for a 

 tooth-brush is refuted by a rediictio ad ahsurdum. 



So far I have only considered clothing material in 

 relation to its resistance to the passage of heat and the 

 transpiration of aqueous vapour. The saline constituents 

 of the perspiration are very variable in composition ; 

 varying with different individuals, and in the same indi- 

 vidual at different times, according to the conditions of 

 health, exercise, climate, and food. To the.se variations 

 I attribute the contradictory results obtained by able 

 chemists and physiologists who have collected and 

 analysed these secretions. I will not enter upon the 

 details of such analyses, especially as I have recently 

 discussed them in connection with the physiology of 

 nutrition in my papers on " The Chemistry of Cookery." 



At present it is sufficient to note that there are given 

 out either urea itself or nitrogenous salts of similar com- 

 position and physiological significance ; salts which are 

 products of the degradation of tissue, and therefore con- 

 stituting excrementitious matter, which is more or less 

 poisonous, and should be removed. The foulness of the 

 arm-pit portion of a dirty shirt, or the feet of over-worn 

 socks, indicate this, and jjrove the necessity of frequent 

 changing of underclothing. 



In reference to these, I am inclined to conclude that 

 my towel shirts, described in the last paper (I learn that 

 the technical name of the material is " huckaback "), are 

 better than flannel. Flannel assists gaseous transpiration 

 better than the towelling ; but this is decidedly superior 

 to flannel in removing the liquid perspiration, and all 

 that it holds in solution. This may be tested by simply 

 washing one's face, and then wiping it with flannel, as 

 against good soft huckaback. Therefore, I conclude that 

 persons who are troubled with excessive liquid or 

 sensible perspiration may find the towel shirts even better 

 than flannel. Should any of my readers repeat my 

 experiment, they will do good service by recording the 

 results. 



The experience of furnace-men is in favour of such 

 material. I have seen much of them, and find that the 

 "mop," which is thrown loosely round the neck or over 

 the shoulders, and used for wiping or mopping the face 

 and breast, is usually of towelling material. I do not 



remember ever to have seen a flannel on 

 above ground or in a coal-pit. The ( 

 huckaback shirt is unquestionable. 



ILLUSIONS OF THE SENSES. 



Bt Richard A. Peoctor. 



(Continued from page 40.) 



THE sense of heat is in like manner usually a 

 with the sense of sight, so that illusions affecting it 

 are either corrected or modifit-d Ly vimuiI inii>rfs>i..n.s. 

 Yet there are cases where this m n-c i^ il.rru ,..1 vAwn 

 acting alone. For instance tin r.- i^ tlir wi !1 kiK.wu 

 experiment in which after one Imml li:i^ luin plmnl for 

 a time in water as hot as can be borne, and the other in 

 ice-cold water, both hands are plunged simultaneously 

 into tepid water. Immediately the hand which had 

 been in very hot water recognises a comfortable sense of 

 coolness, and as it were pronounces the water cold ; the 

 other hand as quickly recognises a comfortable sense of 

 warmth and pronounces the selfsame water hot. Here 

 even sight will not correct the illusion. We see as 

 plainly as possible that both hands are in the same basin, 

 yet one hand seems to be in warm water the other in 

 cold. I find a singular effect produced if while the 

 attention is strongly directed to the circumstance that 

 both hands are in the same water, the hands are freely 

 moved about in the water. For it seems then as though 

 there were currents of hot and cold water in the same 

 basin, moving so as to follow or rather to accompany the 

 hands. 



Without making definite experiment in this way, we 

 can easily in the ordinary experiences of life, recognise 

 the readiness of the heat sense to be deceived. Thus we 

 come out of a warm room into the hall outside and find 

 the air there pleasantly cool. We then, perhaps, see a 

 friend home through the cold night air and jiresently 

 return to the same hall. But now, coming into it from 

 the cold outer air, we find it pleasantly warm. 



Professor Lo Conte remarks that " during the Arctic 

 voyages made by Parry, Franklin, Ross, Kane, Nares, and 

 others, it was found that a zero temperature seemed quite 

 mild after the thermometer had been twenty or thirty 

 degrees below that point." But, althoiigh in California 

 temperatures of twenty or thirty degrees below zero may 

 not be common, an American has no occasion to leave the 

 United States, or even the middle states, to experience 

 the illusion in question. I have repeatedly walked along 

 the streets of New York with the temperature a degree 

 or two below zero, without wearing an overcoat or feeling 

 the want of one, when such a temperature has followed a 

 few days of much colder weather. And conversely, even 

 as I write I am feeling unpleasantly cold at Columbia, 

 South Carolina, with the temperature only just below 

 zero (and the air still), simply because I have been enjoy- 

 ing during the last few days in Charleston, S.C, a soft 

 and balmy warmth resembling that of a June day ia 

 England. 



Again in caverns like the Mammoth Cave, Kentucky, 

 or Kent's Hole in Devonshire, there is in summer always 

 a sense of coldness and in winter always a sense of heat, 

 yet in reality the thermometer shows that, as might be 

 expected, the air is somewhat warmer within such caves 

 in summer than it is in winter. Here, then, the illusion 

 is not only incorrect but the verj- contrary of the truth, 

 the air seems colder when it is really warmer and warmer 

 when it is really colder. Because the range of tempera- 



