OlIobee 2*, 1888.] 



THE GARDENERS' C MX ONI CLE. 



431 



summarv of the books, and local lists published 

 during the year, with Dew species which had for the 

 first time been found in this country, including Lac- 

 tarius aurantiacus in Epping Forest. Agaricus 

 (Omphalia) chrysophyllus in Scotland, Russula 

 puellaris and K. roseipes near Morpeth ; Rus- 

 sula Barlce and R granulosa at Kew ; Kussula 

 maculata and K. armeniaca at Epping ; with 

 Hygrophorus spadiceus from Crum Forest, and 

 Agaricus (Hypholoma) catarius from Kew and the 

 Forest of Dean ; and lastly, the singular appearance 

 of Mutinus bambusinus at Sunningdale. A com- 

 parison was also instituted between the meagre 

 results of the present year's Woolhope excursions 

 and the unusually successful excursion recently made 

 in Epping Forest, but no clue could be given to the 

 causes of such divergence, which, like some other 



until he touched them did not discover his mistake. 

 The social aspect of the week was a pleasant remi- 

 niscence, but the scientific phase undoubtedly a 

 deplorable failure. M. C. C. 



Trees and Shrubs. 



P T E R O C A K Y A F R A X I N I F L I A . 



At p. 380 of your issue of the 6th inst. I notice 

 your remarks in reference to Pterocarya fraxini- 

 tolia. Just now the trees here present a very 

 beautiful appearance, and where the climate will 

 admit of it I consider it a worthy subject to 

 plant in groups with other choice trees and shrubs. 

 Our trees range from -'0 to 33 feet high ; one grow- 



FlG. 09.— STASHOPEA TIOBIKA. (SEE P. 180. ) 



phenomena associated with fungi, " no fellow can 

 understand." The usual soirl-e at the residence of 

 Mr. Cam was largely attended in the evening, the 

 papers read being " On Dr. Bull's Bmls of Her. ford- 

 shire,'' by H. T. Wharton, M.A., F.Z.S. ; " Xotes 

 aud Queries on Kussula," by M. C. Cooke ; and " On 

 Spiders," by the Rev. J. E. Vi/.e, M.A. The final 

 excursion on Friday, October 5, was made by train 

 to Pontrilas, thence by carriages to Kentchurch 

 Park, returning to luncheon at 3 p.m with Mr. aud 

 Mrs. Matthews at Pontrilas. This latter experiment 

 gave immense satisfaction at the close of a barren 

 week; the genial hospitality extended to the excur- 

 sionists compelling them to forget the immediate 

 past in the enjoyment of the present. The lawn was 

 decorated by clever models of various fungi, painted 

 by the hostess in such excellent style that one of the 

 excursionists rushed upon them with his basket, and 



ing near the margin of a lake has taken the form of 

 a bush, and covers an area of 400 square feet. The 

 bold yellow Walnut-like foliage, and the long pale 

 green catkins make the tree a very pleasing object in 

 garden landscape. Two plants glowing on higher 

 and drier ground have run up with clean stems of 

 8 feet in height, and then brancli oft' into a head ; the 

 diameter of the thickest stem at 1 foot from the ground 

 is 12 inches ; the bark has much resemblance to that 

 of the Walnut, to which it is closely allied. I send 

 you specimens for your inspection. D. Crombie, 

 Gardener, Powerseowt, Ireland. 



This beautiful tree, illustrated recently at p. 381, is 

 referred to in the accompanying paragraph as seldom 

 producing the female catkins, and therefore some in- 

 formation of the trees at Cambridge may be of interest. 

 Besides an immense mass, measuring 45 feet across 

 and 20 feet high in the centre, grown up frcm the 



roots of a tree that was blown down in 1883, we have 

 two trees, both of which fruit freely. One of these 

 is 50 feet high, but is not so fine as the one that 

 was blown down. The two finest have grown beside 

 a small stream, and to this, I suppose, must be attri- 

 buted their fine development, though the third, 

 quite away from any water, has made good growth. 

 The mass of growth above referred to bears leaves 

 very nearly 2 feet long and over a foot across. 

 7?. Irwin Lynch. 



Rhts cotincs. 

 Among shrubs in the autumn season this is one of 

 the most ornamental, as its highly coloured inflor- 

 escence is very attractive ; but to have it and see it 

 at its best, plants must stand where they can have 

 full light and sun, as it is those agents that give the 

 rich deep tinge to the bloom. When it has this it is 

 of great value for table decoration, as the lovely 

 feathery sprays show up in fine contrast with the 

 cloth, and form an excellent basis for any white or 

 pale flowers to be mixed in with the Rhus. As a 

 plant for prominent positions on lawns, or the fore- 

 ground of shrubbery borders, the Rhus cotinus is 

 quite unrivalled, and those who have not specimens 

 of it should make a point of planting a few bushes, 

 the best time for doing this being in November, or 

 as soon as the leaves fall, when all deciduous subjects 

 move without much check, as they have all the 

 winter months to be forming fresh roots. The way 

 to propagate Rhus cotinus is by cuttings of the 

 young ripened shoots, which strike readily if taken 

 oft' with a heel and dibbled in sandy soil in any shel- 

 tered spot, and there covered with a hand-light to 

 keep them close till they callus. •/. S. 



THE CHEMISTKY OF VEGETA- 

 TION, IN REFERENCE TO THE 

 GROWTH OF THE POTATO. 



(Continued from p. 32B.J 



A new line of research, which led to very im- 

 portant results, was brought about in a curious way. 

 One evening Charles X.'s guests, at a soiree at the 

 Tuileries, were effected with uncontrollable tits of 

 coughing. An inquiry as to the condition of the air 

 that caused this was ordered, and it was entrusted 

 to Brongnart, director of the Royal porcelain manu- 

 factory, at Sevres, who handed it over to his son-in- 

 law, Dumas, a chemist who was rising to wide repu- 

 tation. Most people probably know that chlorine is 

 used for bleaching, and that it has a very suffocating 

 odour. Dumas found that chlorine had been em- 

 ployed for bleaching the candles that were used in 

 such large numbers to illuminate the brilliant salons. 

 liis investigation as to why the chlorine was re- 

 tained in the candles led him to the discovery, that 

 the chlorine had " substituted the place," chemically, 

 of some of the hydrogen' of the wax hydro-carbon, 

 and that the amount of chlorine " fixed " was 

 exactly equivalent to the amount of hydrogen 

 eliminated. 



From this hint he extended his inquiries to changes 

 that may occur in other compounds, and arrived at 

 what was known as the law of substitutions,* and 

 this he later developed into a theory of chemical 

 types. The theory was that certain compounds were 

 constructed on a certain plan or type, and with it 

 was expressed the belief that one " element " may 

 entirely replace another without the type of the con- 

 struction being altered. This was in 1839. 



Gerhardt, of Strasburg, who lived only forty years 

 (1816 — 1856;, and at Leipsig, attended rather to 

 chemistry than learning the business for which his 

 father intended him, enlisted in a cavalry regi- 

 ment, and was bought off to study under Liebip, 

 at Giessen, eventually threw much of his energies 

 into the subject of conflicting chemical theories, 

 lie gave much thought to the question of types, and 

 it was chiefly through him and his fellow worker, 

 Laurent, that there came the explanations which 



"• Annate de divine et Physique, ■• bct., hi.. 1 IP. 



