Scientific

Spnnís'i hrown is obtained froni an cari ti dujf out of the ground. Dr. Wem i Siemens and the Gcrman ; : general have founded ftn Electro-Teclmical Society in liei'lin. The foriuor stated at rt meeting last weck üiit liis new electro-dynamkj machine had been so hnproved by Herr Von Heiiier thai its act ion U actually. cheapcr than the locomotiva tbr short distanecs. He proposes, therefore, to construct light ovei-heaá r:ú, along which carriages would Ikj propclled by the ncw ongine, wliicli, aa we liave above iudicated, has beea Mrfected siuce it 'uas slmwii at tho Berlin industrial exhüBition. ïhodyhamic engine is also applicablc to locomotives, in order to increase their tractive power. London piuple is a substnnee doBcribed by Prof. Riley as rcry valuable fov the deti"uction of insect pests. tt is obtained in the ïiiaiiutacturo of anilinc dves. it is comijosed of liin ima ,;; i ■:■:. pi ui) atum i wbhij - live per cent. of carbouaceoua matter, r h i i ! i auiTounds every atom. Experiments siiow tliüt it is more valoablo than paria arecn aa an insecticide, and b perfect antidote to canker-woro ; it kills the worm quickiy. and does not jujure thü plant. Ii is cheaper thau paris gree::, beiuga mure refuse, which, iroin Hs poisonous nature, was a drug to the manufacturera, and had to bo got rid of by dumping long distauces out at sea. Prof. Rilcy Btates that the phylloxcra has o ti!)lis'ie;l itself in California, in the Sonoma valley. afv.l destroyeu hundreds ot' acres of viucs in the most importnnt winc district in the State.The insect nppeirs to havo undergone a considerable change in habit, which modi uiuch limita its dostrud n . [i is steadily spreading frou. centres, but very slowly indeed, compared to its Burend in Frunce. Prof. E. W. Hilgnra believea this to be due to the non-appear:ince of the winged female, as he has not been able to obtain it. pNo ono seenis ab!e in this va Ik' y 'to giro any sugestión as to how the pest may bc successfully fought. E very variety of vino plantod n ihe valley has boen nttackod and partly or wholly destroyed. One of the first questiona askcd by a pei-son v.iio looks at a micróseope is, "What is its power?" and othors nsk, "What is the iiiuhest power ever reached?" Of Simple microscopes, or liaiid-g'lasses, as they may bo ternicd, one sent to the royal society of' Enl, b}' Dl Tarro, of Naples, was said to magnify 2,500 diametera. It was leut to' Baker lor trial, but lío could makc nol i of it, an..l stntca his sight was seriovisly ittjurod by trying to uso it. S'itli compound microscopes the highest power ver reachud" is 100,000 diameters. This was ob- about ten vears ago by Dr, DickinsDii. of New York City. tin. et such a power a single human biood corpuscie wonld be over tliirty-six inches in dianieter, or the si.e of a email cart-wheel. Á human huir thus marnilied (rouïd rival the gituittreoa of California, tbr it would bc: over forA. By would appear : quarters of1 ii mile long, and a claw of a houey-boo would stretch across tlie widest i-trcot n.iiil elasp the hou os on both sidos. irse, hi such a case the wholo ííy could not be seen under the micro'-scopc, as a small part of one of tho of its compound eye would iill i hole field, so that the ilMy;' would i" appear at all. This power waskmI by artificial means, and all sharp definition was lost; thus lor real work of any practical use such a power when óbtnincd is Worthless. The highest recordé;! magnifybig power of scientiflc value was that oluained by Dr, Lionel Beale, who obtainett 10,000 diameters with a one-eightiotu objective. He uses a long tube ín preference to high eye-pieoes, and no ainplifler.