JOURNAL OP HORTICULTURE AND COTTAGE GARDENER. 



323 



Oat flowers were in great abundance. A Gloxinia in full flower was 

 especially remarkable from the fact that it bad not been grown in soil 

 in tbe usual way, but in a bunch of damp moss in a suspended position. 

 A small collection of Zonal Pelargoniums, seedlings, I think, attracted 

 much notice. Tbe display of four collections of cut blooms of Gladioli, 

 choice sorts, would not have disgraced the Crystal Palace Show. They 

 added very much to the attractiveness of the Exhibition. There was 

 also a good collection of Fancy Dahlias well grown. The Queen's 

 Lily likewise adde4 to tbe display very much. There were two col- 

 lections of handsome cut Roses — very handsome, I say, considering the 

 difficulty in blooming them here at midsummer, when tbe sun is so hot 

 as to scorch the petals ; tbe varieties were chiefly Noisettes and Hybrid 

 Perpetuals. 



This is all I can recollect about the subjects exhibited. The officers 

 of the Society were most energetic throughout the day. 



We gardeners, of course, had to take a little refreshment, being from 

 home on this occasion ; and I have to inform the author of " Greater 

 Britain " that wo usually say to each other very politely in company 

 in a tavern, when we are obliged to meet there occasionally, " What 

 are you going to have?" and not " What'll you shout?" Gardeners 

 here do not tolerate such language as " shout " and 4i stand." I submit 

 this to show you that there are exceptions amongst us, and probably 

 the young baronet may become aware of the fact now. 



A very severe hailstorm, which was preceded and followed by thun- 

 der and lightning, broke over Christchurch at about one o'clock in the 

 afternoon of January 20th. The storm lasted for five minutes. The 

 hailstones were unusually large, many of them being larger than rifle 

 ballets. The barometer fell the day before nearly 1^- inch, the 

 fall continuing up to nine o'clock in the evening, when the mercury 

 began to rise slowly but steadily. In some places a drift of hail 

 20 inches deep could be seen. The storm was succeeded by heavy 

 rain. I will relate the damage done by it in my own garden and just 

 round where I live. Verbenas and other bedding-out plants all spoiled 

 of their beauty and destroyed ; petals of Pelargoniums and flowers 

 of Ligustrum japonicum all pelted off; the same with the Tritoma 

 flowers and Phlox paniculata ; and the petals of Dahlias all destroyed. 

 The hailstones made holes through Cabbage leaves and the leaves of 

 Scarlet Runners, threshed ripe Peas as cleanly as if with a flail, and 

 braised my Apples. My garden looked quite desolate, everything 

 being so knocked about. This was the most destructive hailstorm ever 

 known here, and all the damage was done in five minutes. — William 

 Swale, Avonside Botanic Garden, Christchurch, Cantetbury, New 

 Zealand. 



THE CHEMISTRY OF MANURES. 



I am much obliged to Mr. Pearson for the way in which he has 

 again called the attention of your readers to the subject of the chemical 

 value of nitrogen in manures. He has stated my view of the subject 

 very concisely, and I am glad he thoroughly understands that it is not 

 my wish to prove myself right and other persons wrong, but that I 

 t hink the whole subject requires fresh ventilation, and that I do not 

 think sufficient evidence has been yet adduced to prove, that though 

 nitrogen in the atmosphere is the most inert and passive of all ele- 

 ments, yet when in combination with other substances it should be- 

 come the most active and important ingredient, so that the value of 

 manures should be made to depend upon it. 



I will briefly reply to the various objections raised by Mr. Pearson. 



First, I quite agree with him that the value of an ingredient as a 

 manure is not always in direct proportion to the quantity of that ingre- 

 dient found in the growing plant. There are certain elements and 

 substances necessary to a plant which are found in so small quantities 

 in some soils, and then very often in so insoluble a form, that the 

 plant has great difficulty to obtaiu what it requires ; and a knowledge 

 of the chemical nature of a soil is very valuable to enable a gardener 

 or agriculturist to supply to the soil as a manure any element that is 

 deficient. Mr. Pearson quotes a case in point. Phosphoric acid is 

 generally a very important ingredient in manures, because it is found 

 in very small quantities in most soils, and yet is necessary to the 

 growth of all the more highly organised plants, though only in Bmall 

 quantities. For instance, it bears a very small relative proportion to 

 the carbon or oxygen in growing crops. Where, then, as in Mr. 

 Pearson's case, the land is rich in phosphates, there is no necessity to 

 add more phosphorus to the soil, and phosphatic manures would be of 

 little advantage. Clearly in the same way, as nitrogen is found in 

 only very small quantities in plants, and yet is very abundant in the 

 air they breathe, it would be of no use to add more nitrogen if they 

 can assimilate what they require from the atmosphere. 



The whole question at issue, therefore, hinges upon this point, and 

 it is upon this point we require more sufficient evidence. At present 

 the line of argument is this : Nitrogenous manures are found of great 

 value and efficacy, and therefore it must necessarily arise from plants 

 not being able to obtain their nitrogen from the air. This is arguing 

 in a circle. Liebig begins by asserting, "We have not the slightest 

 reason for supposing that plants are capable of assimilating nitrogen 

 from the air," and then upon this broad assertion lays down a further 

 general rule — that the value of a manure is in proportion to, and on 

 account of, the nitrogen it contains. 



The point I wish to have cleared up is this : Granting that a manure 

 is valuable in proportion to tbe nitrogen it contains, does it necessarily 

 follow that it is valuable only, or chiefly, on account of this nitrogen ? 



Mr. Pearson, in summing up for me what I endeavoured to bring 

 forward in my former paper on the subject, did not include the state- 

 ment that out of five substances present in the air — oxygen, nitrogen, 

 carbonic acid, aqueous vapour, and ammonia — it is universally ad- 

 mitted that plants are capable of assimilating four; and the only 

 argument as yet adduced against their being able to assimilate the 

 fifth — nitrogen, is, that as it is present in such large proportions (four- 

 fifths of the whole atmosphere), it would be found in larger quantities 

 in plants if they were capable of absorbing it, and also because it is so 

 inert and has such weak affinities for other elements ; consequently, 

 it cannot be taken up by plants except it has firBt entered into com- 

 bination with other elements. 



No doubt nitrogen when combined with hydrogen to form ammonia 

 is more soluble than it was before, and when it is still found in the 

 form of ammonia in plants it will be more eaBy for those plants to 

 assimilate it in a combined than an uncombiued form ; but then we 

 must bear in mind one law of chemistry — that an element will not 

 leave one for which it has affinity for another element for which it has 

 less affinity. If, therefore nitrogen cannot be assimilated by a plant 

 because it has only weak or no affinity for the elements contained in 

 the growing plant, it will not any more leave the hydrogen in ammonia, 

 or oxygen in nitric acid (elements for which it has affinities), and 

 enter into combination with the growing plant, than it would in its 

 previous uneombined state. This is one great reason why I think that 

 nitrogenous manures are valuable on account of their solubility, and 

 because they act as solvents for other elements necessary to the welfare 

 of the plant and are easily decomposed, rather than on account of 

 their supplying nitrogen. It is not as if nitrogen were in a solid or 

 insoluble form in the air, but as it is in a gaseous form it is capable 

 of entering into the pores of the leaves of plants, and, like other gases, 

 iscipable of expansion, contraction, and absorption. Neither have 

 we as yet any proof, as I stated in my last, that nitrogen is capable, 

 like oxygen, of assuming two forms, or that it is in any way different 

 when leaving its combination with another element from what it was on 

 its entering into combination with it. 



As to Mr. Pearson's second objection — that nitrogen is necessary to 

 the formation of muscle, I daresay he will not be surprised that I 

 equally doubt the value of nitrogen in animal food. Lewes, in his 

 tk Physiology of Common Life," adduces, I think, a great deal of evi- 

 dence which helps to prove that the value of animal food does not 

 depend upon the quantity of nitrogen it contains. I have not his book 

 by me, and it is a long time since I read it ; I cannot, consequently, 

 quote the arguments he uses. In reading, however, Wallace's " Malay 

 Archipelago," I was struck with the fact that although the inhabitants 

 of the islands of Java, Sumatra, Borneo, &c, lived almost entirely on 

 rice, or else on sago, both of which are very deficient in nitrogen, that 

 still as a race, though indolent, they were not deficient in muscular 

 power. But with regard to animal food as food for man, the truth is, 

 that the value of a food is in almost exact proportion to its digesti- 

 bility. Meat, and all food that is rich in nitrogen, is more easily 

 digested than fat or carbonaceous food. Moreover, the saline ingre- 

 dients of animal food are necessary to the support of human life in 

 health ; and though those saline ingredients can be obtained from 

 other sources, yet they are more easily obtained from animal food. 

 It would seem that in the economy of nature the office of ruminant 

 animals is to prepare food for man, the higher order of the creation. 

 Sheep and oxen, for instance, have to prepare food for man from the 

 vegetable world. The flesh and blood of these animals are closely 

 allied to those of man, and tbe more nearly the food we eat approaches 

 in its chemical composition the flesh, muscle, &c, of which our body 

 is built up. the more easily is that food digested and assimilated. The 

 muscles of a man in constant exercise require to be con=tantly renewed. 

 There is no muscular exertion or force used without the waste of 

 muscular tissue. Just as there can be no motion without heat, and no 

 heat without motion, so there can be no muscular force used without 

 waste. This waste has to be supplied from food ; and nitrogenouB 

 food, which is most easily digestible, as it is most easily decomposed, 

 is the readiest means by which this waste of tissue can be made up. 

 It is only the more highly organised forms of animal and vegetable 

 life that contain this nitrogen ; and as it is the peculiar property of all 

 highly organised food that contains nitrogen to be easily decomposed, 

 it is only fair to argue that it is this property which makes thiB kind 

 of food so valuable, and not merely the nitrogen. I purposely avoided, 

 however, in my former paper on this subject touching on the question 

 of the value of nitrogen as food for man, because it opened up so wide 

 a question. 



All manures that help to stimulate the growth of a plant will darken 

 the green of their foliage, but those manures which are rich in am- 

 monia and carbon will do so more than nitrate of soda or nitrate of 

 potash. Sulphate of soda will, I believe, produce the same effect as 

 nitrate of Boda, but is not so soluble, and consequently does not pro- 

 duce its effects so rapidly. All manures containing soda are valuable, 

 not only as supplying soda to the plant, but because they act as solvents 

 to the silicon which forms so important an ingredient in the ash fo 

 all grain- producing crops, but which is the least soluble of all the ele- 

 ments contained in the growing crops. Mr. Pearson thinks that all 

 well-cultivated soils contain sufficient carbon, but as carbon con- 

 stitutes half the weight of a plant, and many forms of carbon are 

 very insoluble, charcoal and peat for instance, any manure that 

 helps a plant to assimilate the carbon more rapidly, will hasten the 



