General Notices. 615 



Carbon, Hj/drogen, (incl O.vi/gen in different Kinds of Wood. — Two German 

 chemists, M. Petersen and Schodler, have made elaborate experiments in 

 order to ascertain the quantities of carbon, hydrogen, and ox)gen contained in 

 each species of wood. They have anahsed -^4 different kinds ; and, after hav- 

 ing dried them and reduced them to powder, they have taken 100 parts of each 

 in weight, and found that the quantity of carbon in each does not vary more 

 than from 48 to 50 per cent; the hydrogen, from 5^ to nearly 6 per cent; and 

 the oxygen, from 43 i to 45 \ per cent. The proportions would be ditterent in 

 relation to volume. For instance, a cubic metre of oak weighs 479 lb., while 

 the same body of poplar weighs only 221 lb. (Times, Dec. 24. 1836.) 



Effects of difercnt Kinds of Salt on Plants. — The result of an experiment 

 made by S. Florio, and given in detail in the Repertorio d'Agricoltura for 

 1836, is as follows : — " Common sea salt entii'ely prevented the germination 

 of wheat and maize. With soda, some grains of wheat germinated, but pro- 

 duced very feeble plants ; with potash, on the contrary, wheat and maize germi- 

 nated freely, and prodnced beautiful plants. Sal ammoniac entirely destroyed 

 all signs of vegetable life ; and nitrate of potash only allowed some grains 

 of wheat to germinate. All these salts were mixed with the same kind of rich 

 mould, each kind in several different proportions. The mixtures were put 

 into small pots, and they were all kept in a uniform temperature and degree 

 of moisture during the experiment." {U Hermes, Nov. 23. 1836.) 



Salt has a luonde/fiil^lnjluence in subduing Flame ; and when conflagrations are 

 to be extinguished, it would be well if salt were to be mixed with the water. 

 — James Munro. Castle Ashby, Nurtliamptonshire, Dec. 20. 1836. 



Coal, or Gas, Tar in the Formation of Gravel Paths. — To gardeners unac- 

 quainted with the efficacy of coal, or gas, tar in preserving gravel paths from 

 weeds, such as the couch grass (Triticum repens), &c., which might have esta- 

 blished themselves in the soil previously to the formation of the paths, it 

 may be well to say that a thin layer of this tar, spread equally and entirely 

 over the surtiice of the ground, previously to laying on the gravel, is certain 

 destruction to whatever roots may remain beneath it, and nuist, consequently, 

 preserve the gravel free from weeds. Having myself given it a trial, which 

 was attended with the most complete success, I can speak confidently of its 

 merits. I tried it in the formation of a path over a piece of ground which 

 had for years been lying almost neglected, and was become, by the time the 

 path was to be made, one mass of roots. After merely turning over and 

 cleaning the ground once, which is now nearly three years ago, the tar was 

 applied, and not one blade of couch, or other weed, has found its way through 

 it into the gravel above where the tar was spread. 



The price, or the smell, which may by many be considered offensive, need 

 not, in the slightest degree, prevent its general application ; as the first is so 

 low, that every one who resides within a moderate distance of a gasometer 

 may procure it at about \d. per gallon ; and the last, if carefully kept on that 

 ground only which is to be converted into a path, is lost inmiediately that 

 the. work is completed. I feel certain that every gardener who gives it 

 a trial will readily confess that, even during one-season, more than its actual 

 cost is saved in the labour that would be required to keep a path in order, 

 formed under similar circumstances, without such a precaution having been 

 taken. — JV. H. B. Baysivater, 1836. 



Cultivation of Potatoes. — It has lately been frequently stated, that, in some 

 counties, there is a great failure of the potato crop. This, I think, may be reme- 

 died, another season, by sowing the seed, instead of planting sets. Sets will 

 not last above twelve or fourteen years : after that time, they decline, and 

 hardly return treble the bulk of the potatoes planted. I tried the experiment 

 last year in a small way, and the produce was astonishing. What appears 

 remarkable to me is, that these seedlings produce potatoes of different kinds, 

 and, sometimes, new sorts are procured. I saved the red rough seed, and I 

 had five sorts fiom it. The following is the method to get them the si^ of 



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