June 22, 1883.] 



♦ KNOWLEDGE ♦ 



3G9 



recently made me, a much easier machine to push up hill 

 than any I have tried previously. 



During the next season I trust we shall see " Sociable " 

 tricycles in the market which will be nearer 1 Oil lb. in 

 weight than 200 lb., and, eventually, I have little doubt 

 that their weight when required for light riders may be re- 

 duced below 1001b. Single tricycles are now made of 

 various patterns — ■ for instance, the " Humber," the 

 " Monarch," and the " Coventry " — which do not e.xceed 

 65 lb. in weight, and yet are strong enough for all 

 ordinary work ; and a double tricycle need not certainly 

 weigh so much as two single tricycles. The elder Starley, 

 the creator of the tricycle, who, being a very heavy man 

 himself, always erred on the side of weight, only began by 

 making his " Sociable " weight 180 when the single 

 weighed 1101b. 



To reduce the weight of the " Sociable " the machine 

 must have smaller wheels. 



To make the machines as light as they well can be, the 

 wheels should not be more than tO inches in diameter. For 

 average riders these might be geared level, but for strong 

 riders they would be better geared to 45 in. One great 

 advantage of a machine with 40 in. wheels is that it can 

 be put into a guard's van and carried anywhere in a train. 

 A machine with larger wheels requires a truck, and is 

 charged at carriage rates. 



The performance of " Sociable " tricycles will, however, 

 not be satisfactory until they are provided with two-speed 

 gearing. It is common on such machines to ride with 

 some friend, eitlier a lady or gentleman, who, from want of 

 practice, can do but little towards propelling the machine. 

 Under such circumstances, a head wind, rising ground, or 

 a rough road will soon nearly stop the riders. Two-speed 

 gearing would then be invaluable. A machine with 40- 

 inch wheels should, for average riders, bo geared down to 

 30 inches for power for all hard work, and up to 50 inches 

 for speed. For strong riders, who wish to travel as fast as 

 possible, the power gear should be 35 inches and the speed 

 gear 55 inches. 



The following makers are already prepared to supply 

 machines with two-speed gearing. The St. George's 

 Foundry Company, Bricknell i Co., the makers of the 

 " Merlin," and Burdess, who is known as the ingenious 

 contriver of the " Sterling " and " Rucker," and Singer, 

 are preparing to supply such gearing. 



Lloyd Bros., the maker of the novel and excellent rear- 

 steerer, the " Quadrant," are making for me a two-speed 

 machine on an entirely new plan. The readers of Know- 

 ledge shall be informed as to the details and the perform- 

 ance of this machine directly I have tried it 



A subscriber of Knowledge has asked me to repeat my 

 warning to tyros not to deviate from a straight course to 

 avoid either stones or ruts when running quickly down a 

 steep hilL Such a deviation is most dangerous. Should it 

 incautiously be made, the error cannot safely be corrected 

 by using the steering handle only. The brake should be 

 carefully, not suddenlij, applied at the same tiynt;, and it 

 will be found more beneficial in steadying the course of 

 the machine than it is in checking it. This use of the break 

 is not known as it should be. 



Before I found out the advantage to be gained by using 

 the break in this manner, I had two very ugly accidents ; 

 but of late I have experimented on all kinds of uncertain 

 rear-steering machines with safety. Had it not been for 

 the use I have constantly made of the break in the manner 

 described, I doubt if I should be tricycling now. 



One shilling will he paid for a copy of the Index to Voinme I. 

 Knowledge. Apply or address to the Publishers, 75, Great Qneen- 

 Btreet, London, W.C. 



TPIE ORIGIX OF WHALES.* 



By liiciiAED A. Proctor. 



THE capture of a bottle-nosed dolphin, which is now 

 disporting itself in a tank at the Brighton Aquarium, 

 synchronises rather happily with Professor Flowers's sug- 

 gestive lecture on whales at the Royal Institution — a 

 lecture bringing out very etiectively some of the most 

 remarkable evidence in favour of the modern theory of 

 biological evolution. The idea prevails that this theory 

 depends in large degree on the resemblances existing 

 between different forms of animal life. It is supposed, for 

 instance, that because men and monkeys, and horses and 

 sheep are all backboned animals, therefore science recog- 

 nises relationship among these various classes of animals. 

 In reality, the modern theory of development does not 

 depend at all — whatever may have been the case with 

 older theories — on mere features of resemblance in structures 

 and in organs manifestly useful. It might be reasonably 

 said in answer to any argument of the sort that the speciiil 

 arrangements which are good for one class of animals, are 

 not, therefore, necessarily bad for another class, but may 

 be the best for that class also. The antecedent proba- 

 bility would seem to be that certain types would be found 

 to prevail among animals even if the structure of each 

 order had been made a matter of special teleological 

 arrangement. The resemblance between the handles of a 

 screw-driver, a chisel, and a gouge, does not show that 

 these instruments have either been developed one from 

 another, or that they have all been developed from a com- 

 mon form ; bnt arises from the simple circumstance that 

 that form of handle is convenient for the work which all 

 these instruments are intended to do. But as a matter of 

 fact, the modern theory of biological evolution depends 

 rather on the differences than on the resemblances between 

 races presumed to be more or less akin, is based rather on 

 the partial disappearance of structures or organs in par- 

 ticular races — or rather on the way in which such partial 

 disappearance is found to have been brought about — than 

 on the existence of the same sets of structures or organs 

 in different animals. For the absence, or almost total 

 absence of a structure or organ in any animal is proof 

 that the animal can do very well without it, and does 

 not need it ; so that an organ found to be practically 

 wanting is one for which nature manifestly had no 

 occasion to make provision ; and if it is found that, 

 nevertheless, nature /ins made provision for some such 

 organ, which yet has not come to its full develop- 

 ment, or remains practically non-existent, then there is 

 strong evidence in favour of natural development or 

 evolution, as distinguished from special creative acts. For 

 instance, the presence of the bones of the fore-arm in man 

 affords scarcely any reason for regarding him as akin to 

 the monkey, the horse, the sheep, all of which also have 

 the same bones ; for the fore-arm is obviovisly as useful to 

 man, though not in the same way, as it is to those other 

 animals ; but the presence of tail-bones in the human 

 skeleton indicates kinship, because man needs no tail 

 either for prehensile purposes, as with certain classes of 

 monkeys, or to sweep away annoying insects, as with the 

 horse. If such kinship were not rendered probable by the 

 actual structure of the tail bones, with the rudiments of 

 parts, such as in lower animals have useful purposes, it 

 would be rendered so hj the embryological evidence, which 

 shows how the rudimentary tail in each human being began 

 with relatively important proportions, and with acces- 

 sories suggestive of future usefulness in more ways than 



From the Neuxastle Weekly Chronicle. 



