riiii FAKMEK'b MAGAZINE. 



31 



Tlie f'uUuwing table gives the specific gravity of 



each : — 



No. 1 . . 1.025 



2 . . 1.030 



3 . . 1.035 



4 . , 1.040 



5 . , 1.045 

 G . . 1.050 



The root, whose specific gravity was to be 

 determined, having been washed, was plunged 

 into each successive solution until it floated fairly. 

 We shall suppose a root sinks in solution No. 5, 

 but floats in No. 7; its specific gravity may be 

 considered as the mean, or 1.050; it ought con- 

 sequently remain for a moment in any part of 

 No. 6 solution, slowly rising towards the surface, 

 if its specific gravity lies between 1.045 and 1,050^ 

 or sinking if it be between 1.050 and 1.055. For 

 all practical purposes intervals of 0.005 are quite 

 enough. 



The roots, whoso specific gravities were thus 

 determined, were planted and allowed to pi'oduce 

 seed, which was sown, and the roots produced 

 from them examined. The folio Vv-ing table gives 

 the weight of roots grown from jmrent seed, and 

 percentage of solid matter : — 

 Sp. gr. of parent root, 1.070 1.050 1.030 



WEIGHT 



OF ROOTS. PEECENTAGE OF SOLID MATTER. 



14 to 20 OZ. 

 32 to 40 OZ. 

 48 to GO OZ. 



/Max. 

 t Min. 

 /Max. 



t Min. 

 / Max. 

 I Min. 



The experiments which I have made upon this 

 deeply interesting subject are not sufficiently nu- 

 merous or varied to establish so important a law as 

 that supposed to exist. The results so far are, 

 however, very remarkable ; and, whether they be 

 the expression of a general lav/ or an accident, 

 they suggest a line of investigation, which, if pro- 

 perly followed up, would assuredly yield some 

 valuable and interesting theoretical and practical 

 results.* Such experiments occupy a great deal 



* Since writing the above, I have found that M. 

 Louis Vilmorin has proposed to improve the quality 

 of the sugar-beet by selecting the densest roots, 

 and growing seeds from them, and continuing this 

 system of selection for several generations. I am 

 glad that the results of my experiments are so 

 fully in harmony with the experience of so eminent 

 an agriculturist. He determines the density of 

 the juice by cutting out, by means of a peculiar 

 instrument, a piece of the root, which he rasps and 

 presses. Small boxes, containing all the apparatus 

 required for the purpose, are sold in Paris, and 

 described by M. Vilmorin in a paper published in 

 No. 5, for March 5, 1858, of that admirable peri- 

 odical, the Journal d' Agriculture Pratique, edited 

 by M. Barral. 



of time, and demand great care and attention, and 

 could only be successfully carried out by persons 

 favourably circumstanced. To such I commend 

 the subject; and, as an additional argument, I 

 would suggest its immense practical importance; 

 for if such a law as I have supposed exists, we 

 might raise the quality of most, if not of all, 

 cultivated crops far beyond their present condition. 

 In this respect there appears to be much room for 

 improvement, as will be seen by a glance at the 

 table containing the results of the determination of 

 water and solid matter in bulbous roots. To 

 increase the solid matter in all root crops (not 

 including potatoes) by only one per cent., would 

 be equivalent, in Ireland alone, to adding 50,000 

 acres to the area under cultivation ! 



In connection with this subject, it may be worth 

 while to direct attention to the tendency which 

 some nangel wurtzcl roots have of starting, as it is 

 called ; that is, of prematurely producing their 

 flower-stalk. This, of course, exhausts the bulb 

 of its azotic and saccharine principles, at the same 

 time that it becomes woody. I have determined, 

 in several cases, the relative amount of water and 

 sohd matter in roots just about to produce their 

 flov/er-stalk, and never found the amount of the 

 latter to exceed ten per cent. Dense roots appear 

 never to exhibit that tendency; but in a crop of 

 mangel-wurtael in which the percentage of water 

 is high, a considerable number of roots prema- 

 turely produce their flower-stalk as soon as the 

 amount of water passes 90 per cent., which it does 

 when the root reaches about three pounds in weight. 



If, by a judicious selection of seed, we could ul- 

 timately succeed in growing crops of roots having 

 15 or 16 per cent, of sohd matter, it seems reason- 

 able to suppose that we ought also to be able to 

 develop some particular constituent which may be 

 of more importance than the others. Thus some 

 plants are grown for sugar, others for oil, others 

 for fibre, &c. : it would certainly be a great advance 

 in practical agriculture, if we could increase the 

 relative proportion of each of these constituents in 

 the respective plants which produce them. That 

 such an initial diiYerence of this kind may exist in 

 plants, is, I think, proved by the ditlcrent qualities 

 of flax seed. Although the quantity and quahty 

 of fibre in the flax plant are very much influenced 

 by the character of the soil, it is well known that 

 all flax seeds will not produce the same quahty of 

 fibre when grown on the same land. Some will 

 give a coarser fibre, others an extremely fine one. 

 These differences in seed are of course the result 

 of the influence of soil and climate upon the plants 

 which bore them. There can be no doubt that, if 

 experiments were made in this direction, most im- 

 portant results would be arrived at. 



