Feb. 13, 1885.] 



♦ KNOWLEDGE ♦ 



123 



and for steering. This I should take to be the safest 

 tricycle made, as, vrheu the break is applied, the riilcr may 

 leave go of both handles when running down a hill without 

 fear of the machine running too fast or changing its 

 course. The engraving shows this machine with Burdess's 

 spring seat, but it is made also with Harringtou'.s Arab 

 spring and suspension-saddle. 



The Invicta Tricycle, with ten-speed arrangement, is 

 so novel that I propose riding it for a time and reporting 

 on its performance, as it is the only multiple-speed arrange- 

 ment in which the speed can be changed while the machine 

 is being driven up hill. 



Of course, Starley it Sutton's Coventry Chair and 

 Despatch Carrier tricycles were shown, but these I have 

 described in previous articlts. 



Weston's Convertible Tandem is an ingenious and well- 

 made machine. 



The leading feature in the Stanley Show this year was 

 safety bicycles. I do not believe these will take with the 

 public to the extent that makers anticipate, but they will 

 have an important eflfect in bringing about the further reduc- 

 tion in the size of tricycle-wheels which must come. Only 

 this week Mr. Warner Jonc3, the inventor of the Devon 

 Tricycle and Swing-frame, has, after a most elaborate inves- 

 tigation, published an article in the Tricyclist, in which he 

 gives, as his matured opinion, that a man G ft. liigh should 

 ride a machine with 48-in. wheels if he rides directly over 

 the axle, but that the wheels may be 2 in. smaller in cir- 

 cumference for every inch he sits in front of the axle. Mr. 

 Warner Jones says : — " Choose a wheel two-thirds your 

 height " ; and elsewhere : — " For every inch forward the 

 wheel can be reduced 2 in. in circumference." 



As I am 5 ft. 3 in. high and sit six inches in front of 

 my axle, this would give for my use wheels 38 in. diameter, 

 and this is exactly the size I have had made for my favourite 

 machines, though I have some made with 3Gin. wheels, 

 which I like nearly as well. 



Mr. Percy Letchford, who is above middle height and 

 medium weight, and is well known as a fast and daring 

 rider, is having a Humber made for him with 30 in. wheels. 

 Hi s opinion of the machine will be awaited with interest. 



THE BEGIXNING OF LIFE.* 

 By Eichard A. Proctor. 



{Continued from p. 89.) 



I MAY, in passing, correct an error which is repeated in 

 nearly all our text books of astronomy. Indeed I 

 have never seen the correct statement in any work specially 

 devoted to that science. It is constantly stated that while 

 the place of the vernal equinox moves steadily in one direc- 

 tion, meeting the earth (the precession of the equinoxes), 

 the point of nearest approach moves steadily in the opposite 

 direction. But this is not the case. The motion of the 

 perihelion is sometimes in one direction, sometimes in the 

 other. All that can be said about it is that it is oftener 

 progressive than retrograde, and that just now it is in the 

 midst of a steady progressive motion which has lasted for 

 many thousands of years in the past and will last for many 

 thousands of years to come. I quote from my article on 

 astronomy in the " Encyclopredia Britannica" the following 

 table, showing the position of the perihelion, and the 

 amount of the eccentricity of the earth's orbit, at intervals 

 of 10,000 years from about a million years before Christ to 

 the present time. Excerpt from 100,000 B.C. to 2.50,000 



* From the Nero York Tribune, bnt corrected, extended, and 

 illustrated for Knowledge. 



