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Comparative Strength of Wood and Iron.--Heln~ finds that, in most eases, a unifl)vm stren~'th of'struet:ure(~an 1)e more ee()non~ieally ~eeured t)y the use of w.o(I than by the use of iron. The sti-e,gth of w(iod is twol)ortio,w(I t(, ils d(~,~sity, a~,I (';m be in(:rcased by its immersion t'~)r two or thJ'('e days, ,,v iznti] (:o]~)l)Iete saturati()n, in ]in~eed .il, kept at a leml)eval.i~(~ ~,f' t'r()m 1 50 ยฐ t. 212 ยฐ ]?ahr.--l~'o~'/.~c/, '. dcr Z(.it. C.
Artificial Imitation of Native Iron.--S. Mean ier h,s (.on flrmed his tho()Py ill l'(!gttl'(| to the t(~rP(!stvial origh) o$" the snl)posed meteoric native iron .f (~reenland, by the action of ])r.to('hlori(le of" iron :and chlol'hle of ni(',k(d upon fl'agments of' iron in a porcelain tube. lie thus obtained a fhe-simile, upon a mieroseopi(, se;de, of the huge blocks which were I~v.ught from ])iseo liy M. Nordenslqjohl.--
๐ SIMILAR VOLUMES
Trouvg has invented a cylindrical microphone, which resembles a small dark-lantern, with a carbon crayon substituted for the candle. When placed in the middle of a room, it reveals all secrets. It transmits the voice admirably to a receiving telephone, even when the speaker stands 25 metres (82 ft.)