March 17, 1881] 



KNOWLEDGE 



429 



which arc made of good steel, are now to be utilised as a liorseshoe 



magnet in the following manner: — Left wide open, the pole of a' 



big horse-shoe magnet (tlie use of which I am sure would be allowed 



for a few minutes by any enterprising and generous optician in 



London) marked " N," is to be carefully and squarely drawn down 



I either side (say, that shown in the Bgnre) from the part marked e 



■'■ tlic tip of tlie leg beyond d : this is to be repeated, say, twelve 



s. Then the plies arc to be turned over, so that the other side 



uppermost, and it is to be, in like manner, gently but firmly 



■ iii'd by the magnet, always in the one direction, from « to <(, by 



cither .S. pole of the big horse-shoe. The Pyrologist will now 



-iss quite a strong little magnet for testing iron, &c., in minerals, 



. i by closing the legs with the brass collar, as at a, no armature 



- ruquii'cd. The ('ud c acts as a charcoal borer or small scrcw- 



Iriver. 



I :im requested to mention that Messrs. Herring & Co. decline to 



' r. acid retail. I get mine from Mr. Woostcr, chemist, Broad- 



., Turnham Green. 



THE USE OF THE TRICYCLE.* 

 By Dk. B. W. Rkh.\rdsox, F.R.S. 



WOL'LU specially recommend persons who are excessively 

 nervous and of uncertain mind not to use the tricycle. In snch 

 iple the anxiety attendant on the exercise is injurious, — out of 

 portion to the service that is pained by it. They are ever on the 

 rain to avoid accident and danger, and ever on the look-out for 

 :cident and danger. From these causes they fail to obtain a good 

 mmand over the instrument. They are not certain what to do 

 then other vehicles meet or pass them ; they are not sure how to 

 ke a turning ; they are in doubt as to the mode of going down- 

 1), and of resting in going uphill ; altogether they are perturbed 

 the attempts they make beyond the value of the attempt. If, 

 erefore, persons of this nature do not, after a few weeks of fair 

 I, get over these anxieties, they had better not continue to court 

 pm. I would strongly i-ecommend all who have a sense of 

 iddiness or of sinking and sickness, after they have made a little 

 y on the tricycle, to give up the exercise, unless after a short 

 fining they find these sensations pass away. Or, if while climbing 

 ^liill there is felt a sensation of fulness in the head, with a want 

 i power and precision in managing the machine, I would tender 

 le same recommendation. Again, I would as a general rule recom- 

 lend those who suffer from tlie affection called hernia not to 

 |come tricyclists ; and if they break this rule, I would earnestly 

 ^commend them to be moderate in their exercise, and not endea- 

 vor to compete with their more favoured comrades. 

 jPaterfamilias is often joked by his young friends that he cannot 

 |rfonu their feats, cannot stand on his head, or give a back, or, as 

 te late John Leech forcibly and famously pnt it, leap over a 

 ^Iking-stick. For these stiff-jointed inactives the tricycle comes 

 iwith great force, if they use it with judgment, and do not tres- 

 ]^s too much on reacquired skill. During the late autumn, I 

 qTomp.anied a fellow-rider who. though maay years older than my- 

 4f, could beat me in getting along, and who told me that before he 

 iBg&n be was so rigid in niuscle and joint, he could scarcely get into 

 tfe machine. A few weeks' ]>nictice had set him at liberty from 

 Bad to foot with such effect that in walking and riding — for he 

 ivariably walked up steep hills, pushing the machine before him — 

 h coald average his five to six miles an hour for five or six hours 

 ^d«y, and think nothing of tlie task. 



[It would seem, at first sight, that men who are fat and cumbrous 

 IBnot quite the persons to mount the tricycle ; but, if such men are 

 i fair health, they are, after a little careful and judicious training, 

 1 oefited by it more than any others. It constantly happens 

 lat men of this build, while they leel the need for exercise more 

 I an the sligliter-built sort, are unable to take a proper amount of 

 " ercise, because of the great weariness which they experience soon 

 ! ter they have walked even a short distance. The natural result 

 ' this easy sense of fatigue is that exercise is given up almost 

 ■ together in a great number of cases, while in other cases it is a 

 lere pretence ; so that practically a habit is developed which pro- 

 lotcs an objection to exercise, and a steady increase of all the 

 uigers which follow upon prolongetl muscular inactivity. In this 

 »te, they who are ijfected are apt to follow one of two courses, 

 oth of which are bad. They either settle completely down to 

 ipose, and attain a form of clironic feebleness, which requires to 

 a provided against by avoicbng every, kind of lively effort ; or, 

 iking sudden alarm it some sensation they have experienced, or 

 )me observation they have listened to, they rush into forms of 

 iolent exercise, such as climbing mountains, or volunteering, or 

 >aldng forced walks, or such-like efforts. I believe I have seen 



more mischief induced in the class of persons whom I am now de- 

 scribing, by their attempts to get into condition through the means 

 of excessive exercise and physical strain, than in any other class. 



They who court this mode of recovery from their helplessness are 

 of all less fitted to bear sudden strain. In them the muscles are 

 feeble and out of play; in them the muscles, including that most 

 important of all the muscles, the heart, are overloaded with fat; in 

 them the blood-vessels aie often weakened, and have lost their 

 natural resilience, if they have not undergone actual change of 

 structure; and in them the breathing organs are in such bad form 

 for extra work, f hat breathlessness is produced by very little extra 

 exertion. They are, in short, unfit for walking, and they are equally 

 nntit for those extremer measures which arc commonly designated 

 as training, or as athletic exercises. To this class of persons, then, 

 if they are not subject to actual disease, organic affection of the 

 heart, the lungs, or the brain, the exercise that may bo got from 

 the tricycle is exceedingly useful. 



The exercise sought in this manner should not be violent; it 

 should not include attempts to go against ttmo ; it should not 

 include attempts to climb steep hills or to run down .steep hills at a 

 rattling pace ; but it should be taken for some time on level ground, 

 it should be carried on to a point just short of fatigue, and it should 

 be increased little by little each day, until the labour of working 

 accommodates itself to easy habit. 



•From "Tricycling in Relation to Health," bv Dr. Richardson, 

 I Good Words for M*rch. 



CHANGE OF HABIT IN ANIMALS. 



A S an instance of change of habit in animals, as noticed in your 

 j\. issue of the 3rd inst., with regard to the carnivorous parrot, 

 I may mention that within the last five or six years the baboons of 

 a certain region in the colony of the Cape of Good Hope have 

 developed a flesh-eating taste. 



I do not bear that this has become general among the baboons of 

 the colony, but 1 know that some farmers in the mountaiuous parts 

 skirting "the Karroo plains towards GraafT-Reinet have suffered 

 severely through their depredations among their flocks. Formerlj- 

 these animals were satisfied with prickly pears and other kinds of 

 fruit, birds'-eggs, locusts, and, as a rare treat, scorpions, which I 

 have seen them busily turning over huge stones to obtain. I have 

 never been near enough to see the process of killing the scorpion, 

 but my husband told me that they most cleverly divested the little 

 reptileof its sting before trusting it between their teeth ; but never 

 till of late were they kno^vn to kill a sheep or a lamb for food. I 

 have also been told by one farmer that the baboons on his place 

 had killed many quite young lambs, and torn them open, merely to 

 obtain the milk contained in the stomach. Is this preliminary to,. 

 or a farther development of, the carnivorous propensity ? 



As a more pleasing change of habit and adaptation to circum- 

 stances in the same part of the world is the fact that a small bird, 

 called by the natives " Tink-tinky," on account of its notes, and by 

 the Dutch colonists, " Kapock (frost) vogel," from its .snow-white 

 nest, which, before the introduction of sheep, made use of the silky 

 fibre of the wild cotton as material, now uses the wool which it 

 gathers in sufficient quantities from the Nimosa and Euphorbia 

 thorns, finding probably that it is more easily woven into the thick 

 felt of which the beautiful little bottle-shaped nest is composed, 

 merely placing a little of the silky fibre in the bottom of the nest as 

 a linin". M. Cauev-Hobson. 



THE "SOUND" OF FISHES. 



I OBSERVED some few weeks back (Knowlkoge, p. 295) that 

 Mr. Mattieu Williams objected to my naming the "air- 

 bladder " of a fish the " sound," Mr. Williams's contention being 

 that this latter name should more properly be applied to the aorta 

 or chief artery of the fish. With all deference to Mr. Williams 

 (who is not a biologist, as " Old Fossil," in your last issue, remarks), 

 I maintain that he is confusing, not two names merely, but two 

 distinct systems of terminologj'. It is perfectly immaterial to me, 

 as a naturalist, what fishmongers or fishermen call the " sound." 

 As a zoologist, I have no concern with the terminology of 

 lisher-folk or of fish-dealers. What does concern my readers and 

 myself, is that I should use names which are in common use 

 in natural history science. Tlie name "sound," as a popular 

 name for the " air bladder," has been in use in natural history 

 class-rooms for many years back, and whatever be the justification 

 for its use, I maintain I was entitled to employ it, for the reason 

 just mentioned. The question raised by Mr. Williams amounts to 

 this : — Whether a scientific or a fisherman's use of a i.articular 

 name is to be held as correct. Personally, I prefer to call the sac 

 in question the "air-bladder"; but I cannot, at the .same time, 

 permit Mr. Williams to suggest that my nsage of the name is an 

 eiToneous practice. " Sound," in fact, is a scientific as well as a 

 popular term. It is not my fault if the meanings attached to it are 

 of varied nature. " A.vdrew Wilson., 



