JOURNAL OF HORTICULTURK AND COTTAGE GAEDENEE. 



289 



ency in nimihor -was amply compeusated by the beauty of some 

 of tiiose esliibited. 



Mr. J. Liudeu, of Brussels, sent MasdevaUia Lindeni-svith eight 

 flowers, one of the most lovely of all cool-house Orchids, the 

 colour a brilliant violet mageuta. This had a cultural com- 

 mendation. Enchiliriou corallinum, purplish crimson and 

 yellow, also of great beauty, was hkewise sho^vm by the same 

 firm, as also Tillandsia Lindeni vera, with deep rose-coloured 

 bracts and beautifiil violet-blue flowers. Messrs. Veitch had a 

 first-class certificate for Oncidium Croesus, a fine form with 

 yellow and deep brown flowers. 



From Mr. Bull came Dracaena metalKca with dark-bronzed 

 foliage — this received a first-class certificate ; and a similar 

 award was made to Zalacca edrrlis, an ornamental Palm. Messrs. 

 Kollisson, of Tooting, sent Cymbidium pendulum atropurpu- 

 reum mth dark crimson, wliite, and orange flowers ; and from 

 Mr. Eichaids, gardener to Baron Rothschild, Gunnersbmy, Ac- 

 ton, a variety of Odontoglossum Alexandi'se, with narrower petals 

 and sepals, and not equal in beauty to the better-known form. 



Messrs. F. & A. Smith, Dulwich, sent a collection of Cinerarias, 

 many of them very beautiful and new in colour, and which will 

 doubtless be seen in better condition hereafter ; also Beauty of 

 Surrey Azalea, unquestionably one of the finest white Azaleas 

 ever seen, and of extraordinary form and substance. Mr. Pizzey, 

 gardener to Sir E. Perry, Fulmer, Slough, sent a good variety 

 of crimson Intermediate Stock ; Mr. W. Paul, Hybrid Perpetual 

 Eose SirW. Gull, velvety purple, not large, hut which will pro- 

 bably be better seen hereafter ; Mr. Day, florist, Acton, a double 

 Cyclamen ; Mr. Ware, Tottenham, a singular Iris named sibi- 

 rica ; Edward Leeds, Esq., Manchester, and Messrs. Barr and 

 Sugden, Covent Garden, collections of Narcissus ; and Mr. 

 Green, gardener to W. Wilson Saunders, Esq., Hillfield, Eeigate, 

 Stenomesson coccineum, a vei'y ornamental plant with pale red 

 flowers, Grevillea pulchella, and Gladiolus quadrangularis with 

 greenish white flowers, produced on tall flower-stalks. 



THE CHEMISTRY OF MANURES. 



Allow me thank " J. M." for his interesting article on the 

 chemistry of manures, in youi' issue of the 21st ult. Although 

 I am not quite orthodox, yet I agree in all he said, especially 

 when he says, " That manures are valuable only iu so far as 

 they contain a maximum of nitrogen I do not believe, but I 

 do believe that farmyard manure, as a general rule, is the best, 

 because it contains all the constituents of former crops, and 

 is, therefore, best suited for the production of futiu'e ones." 



I am afraid I must plead guilty of loose phraseology, if I 

 used the expression that nitrogen in the form of ammonia was 

 a solvent for every form of carbon. I did not think of feeding 

 plants with diamonds, nor yet with charcoal. What I meant 

 was, that in vegetable moulds, especially most kinds of i^eaty 

 soils, there is present a great quantity of vegetable matter in the 

 form of humic acid, geic acid, ulmic, crenio, apocrenio acid, &c., 

 fdl of which acids are more soluble in alkaline solutions than 

 iu piu'e water ; and that ammonia acts an important part by 

 uniting with the carbonic acid arising from the decomposition 

 of these vegetable acids, and forming carbonate of ammonia, 

 which carbonate of ammonia is far more soluble than carbonic 

 acid itself. 



One of my objects in wi'iting on the chemistry of manures 

 about three years ago was to expose the fallacy of Liebig's 

 argument that plants assimilated all their carbon through 

 their leaves. Very likely if no supply of carbon were given to 

 plants by means of theh' roots, a plant might in time assimi- 

 late its supply of carbon through the ah- only, but to suppose 

 that the roots only suppUed the mineral ingredients necessary 

 for the vitaUty of the plant and nothing more, was to deny the 

 plant a function iu its highest state of health and vigour which 

 it was known to be possessed of iu its process of development 

 from the germ, when in its embryo state from the seed it had 

 no leaves by means of which to supply itself with carbon. I 

 will not, however, go over all the arguments again ; but, as a 

 general rule, it is true that the rapid development of a plant 

 is in exact proportion to the rapidity with which, by means of 

 its leaves and roots, it can assimilate carbon, and so buUd the 

 carbon up into its system. Heat, moisture, and stimulating 

 manures are the great agents whereby the roots of the plant 

 absorb and assimilate this carbon ; the carbon in the first 

 instance being decomposed and uniting with oxygen to form 

 ■carbonic acid, the carbonic acid in its turn combining with 

 ammonia, and being readily taken up into the sap of plants in 

 the form of carbonate of ammonia. 



I quite agree with " J. M." that the carbon of vegetable 

 moulds must assume the gaseous state before it is again assi- 

 milated into the plant. 



I have not tried the experiment of collecting gases from 

 aquatic plants gi'owing iu an aquarium. I had always under- 

 stood the gas given off was oxygen, but thought it arose from 

 the Uberation of oxygen from carbon and not from hydrogen ; 

 I mean that as the jjlant assimilated carbon from carbonic 

 acid it set free oxygen. I was not aware that any experiments 

 had proved that the plant decomposed water and not carbonic 

 acid, and I should be glad to hear of any experiments on this 

 subject. — C. P. Peach. 



PEAR PLY. 



In your number for March 2ith, 1870, I pubUshed a letter 

 on the Pear fly, and you invited communications on the sub- 

 ject, as the insect was a spreading evil. Since then nothing 

 more has been said about it, though I have looked anxiously 

 tor something on such an important matter. After reading 

 your note to my letter, I purchased two cartloads of spent 

 tanner's bark, and laid it at once under every Pear tree, 

 pyramids and espaliers, young and old, biit to no purpose. 

 Young trees which had never even bloomed before were attacked 

 by the Pear fly. I afterwards removed the entire upper soil 

 from the large standard Marie Louise mentioned in my letter, 

 and threw it into the river about half a mile from the orchard, 

 and last year a few Pears set on this tree. Will you insert 

 this as a second letter on the subject, and ask for more com- 

 munications, with a special note of your own ? — Centueion. 



[We have no note to add. We said iu 1870 all we knew on 

 the subject. If any of our readers can throw any hght on the 

 matter we shall be obliged by their so doing. — Ens.] 



FORCING VEGETABLES.— No. 7. 



THE CADLIFLOWER. 



Although the Cauliflower is not, strictly speaking, a forcing 

 vegetable, it is necessary from its popularity as a deUcious 

 dish, to prolong its season of usefulness by both early and 

 late cultivation under glass. I may, therefore, be pardoned 

 for placing it under the head of forcing vegetables, and my 

 remarks upon it will be confined to the treatment of it under 

 glass, as its out-door cultivation is that more generally 

 adopted and better understood. I am in the habit of pro- 

 ducing a good sujiply of this vegetable up to Christmas, as do 

 many gardeners ; but tlie system is by no means general 

 amongst them, nor thought so much of as it should be, neither 

 is the production of the first spring crop regarded by all gar- 

 deners as of the same importance. The great point is to have 

 the latest crop connected with the incoming of winter Broccoli, 

 and for the earUest spring crop there should be no vacancy 

 allowed if possible between the late BroccoU and CauUflower. 

 The latter object is, perhaps, more easily accompUshed, be- 

 cause we have now the advantage of two of the best BroccoUs 

 grown, those are Lauder's Late White Goshen, and Cattell's 

 Eclipse. The latter may generally be cut up to June, at which 

 time CaiUiflowers from frames and haud-Ughts come into use. 



Where there is scope the best things a gardener can have in 

 connection with his kitchen garden are turf pits, cool frames, 

 and hand-glasses. I ought not to omit the French cloches, for 

 I find them most useful adjuncts. If these are provided in 

 accordance with the demand, Cauliflowers for autumn use, 

 and plants for the first out-door crop and also for the first 

 spring crop, may be stored, protected, and grown for the table. 



Now, to provide for these demands I make a good large 

 sowing of seed iu the middle of July, and again in August, 

 for autumn supply. The plants which arise from these 

 are planted amongst good soil in a spare border, and ill 

 such quantities as are required to meet the demand ; they 

 should be encoiu'aged to grow vigorously, and if they are 

 planted out at intervals will come in for use successively. 

 Should the autumn prove mild so much the better, but if 

 not, the most forward of them may be transplanted care- 

 fully into tm-f pits, and so continue to fill-up all such spare 

 places as they become vacant. Those that may be already 

 fit for use must not be exposed to a too low temperature, or 

 else the flavour deteriorates, but must be laid-in under pro- 

 tection carefully. Those that have been transplanted will, if 

 care be taken of them, gradually come in for use, and wiU be 

 found the most delicious vegetable for table at that season of 

 the year. Of course, they must have Ught and air on every 

 opportunity. 



We now come to store plants. These I sow in September, 

 about the first week, on a south border in the garden. After 



