THE HAEDY FRUIT aARDEK, 



175 



These experiments teaoh us that, as a rule, fertile 

 eoils, cultivated in the ordinary manner, contain a 

 sufficient store of mineral substances for the produc- 

 tion of healthy and vigorous plants ; but that the 

 ■quantity of nitrogenous matters which the plants 

 are capable of extracting either from the air, the 

 soil, or from the natural rain-water supply, is insuffi- 

 cient, and must be supplemented by manures con- 

 taining them. Ammonium salts or sodium nitrate 

 increase plant-growth by promoting the absorption 

 of other substances already present in the soil. 



Water-culture. — The absorption of water by 

 plants takes place in great abundance, and is con- 

 nected with many of the most important phenomena 

 of vegetation. It has been shown from experiments 

 by Lawes and Gilbert that about 2.000 lbs. of water 

 pass through a plant for every poimd of incombus- 

 tible matter fixed in it. 



Experiments in water-culture have contributed 

 very much to our knowledge of the conditions of 

 vegetable growth. The operation consists in raising 

 plants without any soil at all, but with their roots 

 immersed in water, in which have previously been 

 dissolved, in the desired proportions, the chemical 

 ingredients of plant-food. 



The solutions are put into glass jars, and the young 

 plants, from seeds germinated or spfouted in sand, or 

 moist cotton wool, are then suspended from the top 

 of the jars, with their fibrous roots dipping into, the 

 solutions, proper support being given as the growth 

 proceeds. In this way plants can be raised as large, 

 as healthy, and in every way as perfect as those 

 cultivated in soil, and they may become not only a 

 source of pleasure and amusement, but of great 

 practical value, as may be gathered from the 

 engraving in Fig. 12 of a series of experiments with 

 Buckwheat conducted by Dr. Nobbe at Tharandt. 



The engraving with the explanations show that 

 in the normal solution, containing all the essential 

 elements of plant-food, the Buckwheat was robust- 

 and healthy, and the best plant (I.a) grew to be' 

 nearly 3 J feet high. Another plant (II.) grown 

 under precisely the same conditions, except that no 

 potash was suppHed, led a starving and sickly life, 

 and attained a height of scarcely three inches. 

 When potash was added at a later period of growth 

 (in II.3) the plant so treated revived, pushed out 

 with some vigour, but was unable to overtake its 

 better-fed neighbours ; proving that the water solu- 

 tions, unlike the sand previously referred to, were 

 entirely unable to supply any constituent beyond 

 what was artificially added to them, but when the 

 proper ingredient in an available form was applied, 

 the solutions immediately became capable of support- 

 ing and carrying on the plant to perfect maturation. 



Nor did the plants grow well in lack of either 

 lime (IX.) or chlorine (X.) or nitrogen (XI.). 



Dr. Nobbe remarks that these are the results not 

 of single, but of many repeated trials, and they all 

 agree in this one general conclusion : that the in- 

 organic constituents of plants are entirely absorbed 

 by the roots ; and it is as a solvent for them that the 

 large quantity of water continually passing through 

 the plants is so important. These ingredients exist in 

 the soil in particular states of combination, in which 

 they are scarcely soluble in water. But their solubility 

 is increased by the presence of carbonic acid contained 

 in the water, and which causes it to dissolve sub- 

 stances otherwise insoluble. It is in this way that 

 lime, which occurs in the soil principally as an in- 

 soluble carbonate, is dissolved and absorbed. 



Phosphate of lime is also taken up by water con- 

 taining carbonic acid, or even common salt (sodium 

 chloride) in solution. The amount of solubility 

 produced by these substances is extremely small; 

 but it is sufficient for the purpose of supplying to 

 the plant as much of its mineral constituents as are 

 required for healthy and vigorous growth. 



THE HAEDY FEUIT GAEDEN. 



By D. T. Fish, assisted by "William Caemichael. 



THE PEACE ANB NECTARINE. 



PEACH culture under glass has already been 

 so fully and exhaustively treated, that com- 

 paratively little space need be devoted to its culture 

 in the open air. The two methods, while differing 

 in several respects, have .much in common. But, 

 first of all, it may be desirable to vindicate the 

 wisdom and expediency of attempting to grow such 

 fruits in our climate without the protection of glass. 

 So much has been written of late years anent the 

 deterioration of our climate, and the hopelessness of 

 perfecting Peaches or Nectarines in the open air, 

 that not a few have relinquished aU hope of success. 

 Hence Pears have been substituted for Peaches on 

 walls. Doubtless in many localities Pears are a far 

 more certain and profitable crop than Peaches, and 

 the more Peach-walls are converted into Peach- 

 houses, or glass-cases, the greater the certainty of 

 regular crops of well-ripened fruits. StOl, it is needful 

 to affirm once for all that the deterioration of climate 

 rests on no reliable data. The fact that as fine, or 

 finer, Peaches and Nectarines were grown in the 

 open air last year as were ever grown before, disposes 

 of any number of plausible hypotheses advanced to 

 prove that our climate has so seriously deteriorated 

 during the last fifty years as to be incapable of 

 bringing such fruits to maturity. And as to quality, 



