June 30, 1882.] 



♦ KNOWLEDGE 



67 



a haLit of storing food would be highly useful to the nest 

 as a whole ; and, taking nests as units in the struggle for 

 existence, which they really are, those nests which possessed 

 any such trick would survive in seasons when others might 

 perish. So the tendency, once set up, would grow and be 

 strengthened from generation to generation, those ants 

 which stored most food being most likely to tide over bad 

 times, and to hand on their own peculiarities to the other 

 swarms or nests which took origin from them. 



A set of primitive ants, living upon the honey of the 

 oak-galls, have no tendency to produce wax, like bees, 

 because their habits with regard to their larvae do not lead 

 them to make such cells at all. The eggs and grubs 

 .simply lie about loose amongst the chambers of the ant- 

 hill, instead of being confined in regular hexagonal cradles. 

 Hence the bees' mode of honey-storing is practically im- 

 possible for them : they have not the groundwork habit 

 from which it might be developed. But the ants have a 

 crop, or first stomach, in which they store their undigested 

 food, before passing it into the gizzard, exactly as in fowls. 

 When ants come back from feeding, whether on flowers, on 

 aphides, or on galls, their crops are very much distended ; 

 and they can bring back the food to their mouths from 

 these distended crops, to supply the grubs and their other 

 helpless dependents in the nest. If, therefore, some of the 

 ants were largely to over-eat themselves, they would be 

 able to feed an exceptionally large number of depen- 

 dants. 



Dr. McCook observed that some very greedy workers, 

 returning to the nest, fastened themselves upon the 

 roof in the same position as the honey -bearers, and in 

 fact seemed gradually to grow into rotunds. The other 

 ants would soon learn that such lazy, overgrown creatures 

 were the best to go to for food ; and, in time, these gorgers 

 might easily become specialised into a honey-bearing set 

 of insects. The workers would bring them honey, which 

 they would store up and disgorge as needed for the benefit 

 of the rest as a whole. If the honey passed into their 

 gizzards and was digested, they would be a positive dead 

 loss to the community, and so the tendency would soon be 

 eliminated by natural selection, because the nests possessing 

 such workers could not hold their own in bad times against 

 neighbouring communities. But as only a very small 

 quantity is ever digested — just as much as is necessary to 

 keep up the sedentary life of such immovable fi.xtures — 

 the eflect is about the same as if the honey were stored in 

 cells of wax. The ants, in fact, utilise the only good 

 vessel or utensil they have at their disposal, the flexible 

 and extensible abdomen of their own comrades. 



The greatest difliculty is to understand how the workers 

 first acquired the habit of feeding these lazy members to 

 such repletion ; but as all ants " take toll " of one another, 

 this is much less of a crux than it looks at first sight. A 

 very greedy ant, which not only ate much itself while out 

 foraging, but also took toll of all otliers in the nest, after 

 it was too full to move about readily, would be in a fair 

 •way to become a rotund. And as it would thus be per- 

 forming a useful function for the rest, at the same time tliat 

 it was gratifying its own epicurean tastes, the habit would 

 soon become fixed and specialised, till at last we should get 

 just such a regular and settled form of honey-storing as we 

 see in this Colorado species. Indeed, another totally distinct 

 type of ant in Australia has arrived at exactly the same 

 device quite separately, as so often happens in nature under 

 similar circumstances. Whatever benefits one creature 

 under any given conditions will also benefit others whoso 

 conditions are identical ; and thus we often get adaptive 

 resemblances between plants and animals very widely re- 

 niovetl from one another in genealogical order. 



HOW TO RIDE A TRICYCLE. 

 By John Brownisg 



(Trtaturerof the London Trin/cU Club). 



T^HE greatest disadvantage the tricycle has to contend 

 with is the supposition that anyone can ride it 

 without learning. I have proved the reverse, to my 

 own satisfaction, in the following simple manner: — I 

 have driven a double tricycle with my wife by my side 

 and fifty pounds of luggage beliind us for twenty miles 

 without fatigue, while I have ridden with a strong man 

 less than eight miles on the same machine without luggage 

 and been tired out. Yet my wife, on the occasion to which 

 I refer, did not drive, but had her feet on the foot-rests, 

 while the gentleman, being a very powerful man, was, 1 

 feel certain, exerting twice the strength I was using myself. 

 There seems to me but one possible explanation of this — 

 that riders without practice press down both feet together, 

 pressing one foot down a little harder only than the other, 

 instead of lifting up one foot and pressing down the other 

 at the same time. 



Again, tricycle riding brings muscles into action that 

 are not used in walking, and these mtiscles require to be 

 gradually strengthened by practice before either long rides 

 or fast riding are attempted. Many persons having hired a 

 machine, and driven it a few miles, have found it very 

 hard work, and given up all idea of purchasing one. 

 Beginners should restrict themselves for several weeks to 

 riding from five to ten miles at a pace not exceeding six 

 miles an hour. 



I know one case in which a gentleman bought a tricycle, 

 and against advice rode it home about ten mUes. The next 

 day he wrote to the agent and asked him to send for the 

 machine and sell it for an}- price he could get for it. 

 Another instance I was told of where a gentleman hired a 

 tricycle in the north of London for a week, and paid for it, 

 and started to ride to Portsmouth. In less than two hours 

 he brought the machine back, and a-ked to return it and 

 forfeit any amount of the payment he liad made the maker 

 pleased, adding that he had had enough of it. 



Hills should never be attempted until the rider can ride 

 well on the level. Considerable practice is required to ride 

 hills without great fatigue. Time and strength are saved 

 in the long run by dismounting as soon as the strain is felt 

 to be at all severe. An exceptionally strong rider may 

 soon succeed in riding up a tolerably steep hill, but he will 

 waste strength which would have carried iiim at a greater 

 pace or to a further distance if he had liusban.ied it by dis- 

 mounting. After a few months' practice the rider will run 

 up hills almost unconsciously which would ot first have 

 taxed him severely. 



Next, as to riding down hill. Choose a machine with a 

 break which is applied to both tlie driving wheels. When 

 riding on the level or down a slight incline put on tlio 

 break slowly, but firmly. If it acts efficiently it will bring 

 the machine to a standstill without causing it to swerve to 

 eitlier side. Should it swerve round the rider should not 

 attempt to desceiul a steep hill on it until the fault has 

 been corrected, under the penalty of being thrown out by 

 its turning over. The swerving is caused by one break 

 acting on one tiro more than the break on the other. 

 Machines which drive both wheels by means of what is 

 called a balance gearing from one cliain are not liable to 

 this serious fault 



In descending a hill on a tricycle w ith a trustworthy 

 break, the f.et should be taken ofl" the pedals and planted 

 firmly on the foot-rests, as the body is steadier, and the 

 macliine can be steered moiv accurately than when the 

 legs are moving rapidly, and the legs are, of course, rested. 



