HARDWICKE'S SCIENCE-GOSSIP. 



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The African-Mediterranean project.— Among 

 the grand projects of M. de Lesseps'was one for cutting 

 a canal from the Mediterranean on the coast of the 

 Gulf of Gabes, in order to flood that neighbouring 

 part of the desert, a large area of which is supposed 

 to be below the sea-level. There appears to be a 

 hitch somewhere ; either the depression proves, on 

 further survey, to be much less than was originally 

 supposed, or there are difficulties in the cutting, 

 which was at first described as very easy. The 

 project, however, is not to be abandoned. Com- 

 mandant Landas, who is there apparently as the 

 agent or representative of M. de Lesseps, has ascer- 

 tained the existence of underground waters in the 

 region in question, and is at work sinking wells, 

 one of which yields 1S00 gallons per minute, another 

 2000 gallons per minute. These wells are sunk for 

 the purpose of fertilising the district, and thus afford- 

 ing support to the labourers who are to work upon 

 the canal which is to supply the projected inland sea. 



Carbonic acid in School-rooms. — Experi- 

 ments have been recently made by W. Fossek 

 on the quantity of carbonic acid in an unven- 

 tilated school-room before and after the meeting 

 of the class. In three determinations made before 

 the pupils entered, he found the air to contain 

 respectively 0*078, o , OQ2, and o - oS8 per cent, by 

 volume. After three hours' occupation by the class 

 of fifty-eight scholars, it contained o - 620, 0*637, and 

 °'557 P er cent., or between seven and eight times as 

 much. Besides this there are the bodily exhalations, 

 which are still worse than the carbonic acid. The 

 practical lesson taught by these facts is, that wherever 

 school accommodation is at all limited, the pupils 

 should clear out for a run between each lesson. 



Basic Cinder as Manure. — Further study of 

 the manurial efficiency of the cinder obtained by 

 applying the Thomas-Gilchrist, or basic process, in 

 Bessemer steel-making from very bad pig-iron, ^brings 

 out higher estimates of its value. Many such in- 

 vestigations have been made on the Continent 

 during some years past, and quite recently Aitken 

 has published his results in the " Transactions of 

 the Highland and Agricultural Society " for 1887, 

 p. 245. He compared basic cinder containing 40 

 per cent, of phosphate of lime with Curacoa phos- 

 phate containing 87 per cent., Canadian phosphate, 

 59 per cent., and Carolina phosphate, 57 per cent. ; 

 and found that when applied to the soil under cor- 

 responding conditions, it was about as effective as 

 the above-named phosphates. He attributes this 

 superiority, in proportion to its constituent phos- 

 phorus, to its finely-ground condition as supplied in 

 the market ; but Dr. J. M. H. Munro ascribes it to 

 the great relative solubility of the phosphate of lime 

 contained in it. There is but little difference between 

 these explanations, so far as practical application is 



concerned. The important fact is that the basic 

 process brings forth a vast quantity of buried phos- 

 phates that may be laid upon the surface to increase 

 the food supplies of the world, and that it does this 

 at a smaller expense than such phosphates are other- 

 wise obtainable. 



Manure from Granite. — Intimately connected 

 with the above in its economic bearings is the use 

 of felspar as a manure. It contains potash, one 

 of the absolutely indispensable constituents of 

 fertile soil, and that particular one which is the 

 most liable to be wastefully washed away, owing 

 to the free solubility of the nitrates, chlorides, 

 sulphates, and carbonates of this alkali. But the 

 silicate that exists in the felspar is the one excep- 

 tional salt of potash that is not freely soluble. It 

 is slowly decomposed in the presence of water and 

 carbonic acid, and is thus gradually supplied to the 

 plant-roots as they require it. If, however, the fel- 

 spar were added to the soil in lumps like the natural 

 crystals, the process of solution would, on the other 

 hand, be too slow ; but by grinding it to a certain 

 degree of fineness the just medium is attainable. 



Mr. Aitken describes, in the " Transactions of the 

 Highland Agricultural Society," some experiments 

 made at Pumphuston on turnips, and at Boon on 

 peas, with felspar ground sufficiently fine to pass 

 through a sieve of 120 meshes to the linear inch. On 

 the turnips the felspar did better than an equivalent 

 quantity of sulphate of potash, on the peas not 

 so well. 



Seeing that we have mountains of granite and 

 porphyry largely composed of felspar, and these in 

 sterile regions, the fact that we can produce valuable 

 manure by simply crushing the boulders and other 

 rock fragments that cumber the ground, and adding 

 to the powder some phosphates of lime, such as the 

 waste cinder of ironworks above described, opens a 

 wide field for agricultural enterprise. We hear much 

 about the emigration of the London "unemployed." 

 They need not be transported across the Atlantic, 

 nor to the Antipodes ; there is work enough for 

 them in the reclamation of Dartmoor and the 

 granitic wastes of Cornwall, and they would do 

 the work well and cheerfully under arrangements 

 that would ultimately render them the owners of 

 the land they had rendered fertile. 



The Rabbit Plague in Australasia. — The 

 magnitude of this scourge is not yet sufficiently 

 appreciated in our hemisphere. It it remains un- 

 checked, it practically amounts to the ruin of the 

 otherwise most hopeful region of the world. But 

 there is now some hope. Pasteur has come to the 

 rescue, and science is to be applied. Most of my 

 readers will have learned how, ere this will be 

 published. Chicken-cholera broth is to be sprinkled 

 on tempting herbage, the rabbits are to eat this, and, 



