Wesi London Garde7iers* Association. 177 



pots, a system which by unfah' means was puffed into public notice. Many of 

 the magazine-reading gentry expected their gardeners ought to grow them as 

 well as they were reported to be grown at Welbeck ; and, as they had not the 

 opportunity of sending scores to the rot-heap, their failures were charitably 

 attributed to their ignorance, 



Nov. 25. 1839. — Mr. John Fish read his essay " On the Utility of Draining 

 in connexion with the Growth of Fruit Trees, and Planting generally P He 

 began by observing that it was not his intention to enter into a detail of the 

 various systems of draining adopted by different gardeners, but merely to 

 mention the plan which he always practised with success. It was, to procure 

 earthenware tiles about 1 ft. long by 3 in. diameter, and to lay them down 

 with a flat tile at the bottom : they are sometimes made with perforated holes 

 ■to admit the water to pass off more freely ; but, unless the soil is very retentive, 

 he does not consider it necessary. The nearer these drams are placed to the 

 surface, the better they act : they should lead into a main drain of stone or 

 brick, with power of inspecting it at pleasure. He also saw a great deal done 

 by brushwood-draining, which acts well for a time, but cannot say how long 

 they will last. Draining is the first step towai'ds the improvement of soils, 

 and has great influence upon the purification of the atmosphere. In planting 

 fruit trees in a retentive soil, after clearing out to a proper depth, and placing 

 under each tree a quantity of stones, brickbats, &c,, great advantage was 

 found by having a tile-drain for each tree, leading into a main drain. This 

 incurs a little more labour and expense, but will amply repay by having cleari 

 healthy trees with good crops of fruit. Vegetable life, he believed, is chiefly 

 composed of carbonic acid gas, water, and oxygen. Carbon is essential to the 

 existence of trees, and it appears probable that their vigour depends upon the 

 quantity of carbonic acid they are enabled to absorb. Many causes are as- 

 signed for the circulation of the sap. Some have supposed the sap to rise 

 from changes of temperature ; others that the sap-vessels are furnished with 

 valves ; and a third party attributes it to the action of the leaf-buds. The 

 last he considers the most probable : the leaves, when expanding, attract the 

 sap nearest to them ; a vacuum is created, which is constantly supplied from the 

 fresh sap ascending from below ; and this, he thinks, accounts for the motion of 

 the sap being generally most apparent at the extremity of the branches, when 

 they first begin to expand themselves into leaves. Sap, when first absorbed 

 by the roots, is generally beheved to be water impregnated with various sub- 

 stances derived from the soil or some accidental cause. These substances, 

 some of which are useful and some injurious to vegetation, are alike absorbed 

 by the plant, but with different results. As soon as the sap, or true blood 

 of the tree, reaches the leaves, it is then exposed to the action of the at- 

 mospheric air, much in the same way as the blood in the lungs ; with this dif- 

 ference, that, while animal blood principally absorbs oxygen and gives out 

 carbonic acid gas, sap has the greatest affinity for cai'bonic acid, and gives 

 out a portion of its oxygen before it is in a fit state to afford nourishment to 

 trees or plants ; and he also thinks that every part of a tree contains a fluid 

 which is a reservoir of nourishment even in winter. Some maintain that 

 there is first an ascending sap from the roots ; and others uphold the theory 

 that there is first a descending sap from the top, because the fluid from the 

 top of the tree is first put in motion : but, in his humble opinion, both are very 

 probably wrong; because, although there is an ascending sap'before there is a 

 descending sap, the motion of it does not commence at the root, but is in 

 active movement some time in the branches before it begins to stir at the roots. 

 As the top of a tree is more acted upon by variation of temperature than any 

 other part, no sooner does the warmth of spring return than the upper- 

 most buds begin to swell, and, for the purpose of developing themselves, act as 

 so many suckers of a pump in drawing up the formerly inert but now active 

 fluid for their support. The process goes on, commencing with the uppermost 

 buds, the fluid in the main stem is drawn up, and that in the roots immediately 

 follows ; if there is not too much variation between the temperature of the 



