March 6, 1885.] 



KNOWLEDGE 



191 



spheric air is taken in, brought into eontjict with lluid 

 matter, oxygen is absorbed, and the carbon of some used- 

 up matter is given off in the gaseous form of carbonic 

 dioxyde (carbonic acid). The gi-een matter of living 

 plants, stimulated by light, treats carbonic dioxide as food, 

 retaining the carbon and dismissing the oxygen. It is to 

 facilitate these processes that the stomal a are required, and 

 they vary in size and number in different kinds of plants. 

 Carnations exhibit tliem on the upper and under surfaces 

 of their leaves. The needle leaves of the tir tribe show 

 them all round ; the flat leaves of ordinary trees on the 

 lower surface only. The following figures from the 

 " Micrographic Dictiouary " show the numbers per square 

 inch in several cases, and the great range, from 200 to 

 160,000 is very remarkable. 



Upper Surface. Under Surface. 



Carnation 38,500 ... 38,500 



Garden Flag 11,572 ... 11,572 



House Leek 10,710 ... 6,000 



Tradescontia 2,000 ... 2,000 



Mistletoe 200 ... 200 



Holly ... 63,600 



Lilac ... 160,000 



Vine ... 13,600 



Lanreetinus ... 90,000 



When the epidermis and stomata guard-cells are infiltrated 

 with silex, as in equisetace;e, grasses, ic, the rest of the 

 matter can be removed by boiling in a little nitric acid and 

 dropping in a few crystals of chlorate of potash.* The 

 needle leaves of fir-trees, as shown in a former article, are 

 beautiful polariscope objects prepared in this way. 



The stomata are generally largest on succulent leaves 

 and smallest upon hard, leathery kinds. The thick leaves 

 of the Wax Plant {Iloya carnosa) show a moderate quan- 

 tity, with interspaces much larger than in the Begonias. 

 The cuticle may be separated with a sharp pen-knife, and is 

 a pretty object 



The leaves of the hyacinth are good for watching at 

 diflferent stages the growth of the stomata. Sacbs says of 

 these organs : " Since the stomata do not arise till rather 

 late, that is, during the expansion of the internodes and 

 leaves, their arrangement is partly dependent on the 

 already elongated form of the epidermis cells : if these are 

 greatly elongated in one direction, and arranged in rows 

 {as in Equisetum, and the stem and leaves of many mono- 

 cotyledons and piuus), the stomata also appear arranged in 

 longitudinal rows (the cleft lying in the axis of growth, the 

 guard cells right and left) ; if the epidermis cells are 

 irregular on a superficial view, curved, ic, the portion of 

 the stomata is more undefined and apparently irregular." 

 The same authority gives further details of the develop- 

 ment of the stomata, to which the more curious student 

 may be referred. 



The figures are magnified 100 linear, except the larger 

 one of a ground cell and its opening, which is magnified 

 510. 



TRICYCLES IN 1885. 



By John Browning. 



{Chairman of the London Tricycle Cluh.) 

 THE STANLEY SHOW. 



IN my previous article on the Stanley Show, considerations 

 of time and space prevented me from noticing all the 

 exhibits which I thought worthy of commendation. 



During the last two years, no firm has done more than 

 the Surrey Machinist Company to improve the make of 



• The mode of using the acid and chlorate is explained in Vol. IV., 

 p. 130. 



tricycles. This firm had previously obtained a great repu- 

 tation for making very light and fast bicycles. In 1883, I 

 saw a fuU-si/.ed bicycle of their make which did not weigh 

 more than IS lb. All the experience they had gained in 

 making such bicycles they utilised in constructing tricycles, 

 making all machines with very light tubular frauu--', small 

 ball bearings, hollow rims, and laced spokes, and putting 

 the best of work into them. The result has been a great 

 success. Both their single and sociable machines are excel- 

 lent, while their Invincible Tandem is certainly one of the 

 fastest, and possibly the fastest, tricycle we have. Their 

 exhibit was the best they have yet made, and one of the 

 best in the show. 



The St. George's Engineering Company has again im- 

 proved the make of several of their machines, and reduced 

 their weight. They exhibited a St. George Tandem, a 

 machine with several good points, one being that it can 

 easily be converted by a very simple process into a central- 

 geared front-steerer for a single rider. Their Europa Con- 

 vertible Sociable is an excellent machine, and their two- 

 speed gearing is one of the simplest and most efficient made. 

 The prices of the St. George's machines are very reasonable. 



In my first article ou the Stanley Show I referred 

 briefly to Burdess's excellent new front-steering tricycle, 

 with his patent new steering and break, actuated by screw 

 motions, instead of rack motion and lever. Since writing 

 this I have made a further trial of the admirable little 

 two-speed Sterling he made for me last year. The only 

 fault I could find with this machine was that it was not 

 geared high enough for me, being arranged to run at 38 

 and 52. I have recently had a new crank put into it, 

 with only four inches throw, which answers the same pur- 

 pose as gearing it up considerably. This has greatly 

 improved the machine in point of speed. I can now 

 ride it as fast as my Humber, and it is freer from 

 vibration than any machine I have. Burdess's machines 

 should now take well, as they are sound in workmanship, 

 and the prices are low. 



Xagel's Laced Suspension Saddle, which was mounted 

 on a .stand, was tried by many riders, and it seemed to find 

 great favour with them. This saddle has no central 

 portion : the back and front are of leather, and the space 

 between them, about four inches in length, is supplied by a 

 stout leather lace, which can be tightened to suit the taste 

 of the rider. 



For the purpose of avoiding any injurious pressure when 

 riding, I should think that Brooke's suspension saddle 

 would be even better than Kagel's, as it is made of two 

 substances of leather, about half an inch apart, and the 

 centre of the upper is removed just where pressure would 

 be prejudicial. 



Leni, of Hammersmith, showed a wooden saddle, specially 

 made for the same purpose, and this purpo.5e it seemed 

 to serve ; but I understand that he only meant tliis as a 

 model, and that he is having a saddle of exactly the 

 same form made of thin sheet-steel. When this is covered 

 with leather it will, I shoulJ think, prove the safest, most 

 efficient, and most comfortable saddle yet introduced. ^ 



Harrington's pivot mounting for a saddle is very simple 

 and ingenious. It is designed to prevent all chafing in 

 riding. The saddle swivels on a centre, and moves not up 

 and down, but sideways to and fro, with the motion of the 

 legs of the rider. I shall be glad to test this contrivance, 

 which will at least effect a saving in clothing. 



Fisher's Transparent Enamel, which was exhibited, I 

 have tried. It is intended to protect bright nickelised 

 work, steel, or gun-metal. It is easily applied cold with 

 a brush, and it appears to answer admirably. 



The Cunard tricycles, made by Frank Gibbons, of 



