In spinnintr cotton, liantes inl'orms us that one man can produce as mucli yarn as two hundreci and iifiy could have dono undcr the old systoms. Thia machino spun yorn, says Ure, possessos a more uniform twist, and s in evory respect superior :o hand spui) ynrn. As in spinning so in wenvlng. One water wlieel wiil set one thousand luoms to work. One of these looms will make ns mucli cloth as fuur looms worked by hand. - Onc fertialo superintends a loom merely tosupply full bobbins, and mend ihrcnd that happens to break in tlio process of weaving. Nails,auys Dr. Ure, are rnanufactured with littlc or no uiil Trom the human iinnd. The making of nails Ã3 no Jonger a haiulicraft operation, but bolones lo a diciionary of Arts. Not long as;o bread stufl's wero ground in a hnnd mijl. Two men might In ablo wlih groat labur, to grind a bushei of gram in a tiuy. Now uno water inill tui ns out oue ihousai.d buÃ¡hels in twonty-four hours. In book-binding, Ure informa us tbat n machine ha been recently inventcd by an Englishman named Hancock, which entirely dispenses with the operaiion of stitching. scwing, snwing. nnd hainmering the buck, or the use of paste or gluo. CalicÃ³ piinting was formerly a long and tcdious handicraft operation. Il is nov performed by cylindrical machines rcvolving with tho rapidity of light. In manufacturing steam -boiler, mucli of the labor is now performed by machinery. Thus we soe the iron monster has lacility of reproducing itself. Tho employment whinh our lakes nnd rivere promiaed to aflord a numerous population will be almost wholly suspended by the sleam engines aflaat. In tho eraf: of boot and shoe making, machinery is beginning to show itself, and we may not estÃmate the progress itwill make in thia department even in our l y. Certainly .--k I! in this handicraft will uÃ±brd a vory insecuro dependonco for our childrcn. Alachincry, saya Dr. Ure, is ready fo nccomplisli every thing in the manufacture of hats ; but he adds that it is kopt down for the present by what he calis lawlcsscombinationsof journeymen. Thia ie in Britain, and the Doctor predicts that this combinntion will soon be broken down by the genius of machinery. In rope making the machine has taken almost entire possession. The recent improvenients ennblo four or five hands to do the work of ten times that number oÃ regular hands. Such is the distress and desperation that this changc hns ereated among the working men, that sevcral machine honsfs have receiilly been destroyed in the neighborhood of London, by incendiary firea. - They wero, howexer, immcdiately rcbuilt, ancnow in full opcration. Lvcn tho bakers nre not safe - a powerful ikneading machine is coming tnto uso in EngIÃiikI. Two thirds of our carpenter's work Ãs pcrfornied by raochinery. To tliis also it is coming with our ship builders. Tho letter prcas primor bolongs almost to a past order of thinps ; mncmnery is even trying its hand at lyoe-seiting. In cnrrying leaiher thcy uso a machine which makes one into twu. Heavy cluth garments' oÃ on elegant etyle are now made in England by the hatting process, thereby diepensing wiih the thimble and she.irs. Steam coaches now navigato the streets of Londoii, to the great dismay of the cabinen; our very scovengers ore jnstled out of the way by the snme power ; and while the Yankee Pndily moves the hills with all .he ease of a Titan, the same power is hard at work in anothcr quarter, cutting out tho precise niachinery of Yankee docks. Indeed, we Ãind that tcience ha already enterad the field of agriculture. Already are 0team-ploughB io profitable employment even inlbo British alands where manual labor can be liad for almo8t noihing. Alrcady is a machine at work on our southern plontations, that can n cultivatin-g sugnr, perfonn tlie work oÃ forty ncgroes. Alrcady do we obeerve that scveral paicnts have been taken out at Washington for machines to be used in the cutting down and gathering in of field crops.