Hourglass

Hourglass - lub invention uas hloov lub cwj pwm ntawm cov neeg nyob rau ntawm lub sij hawm. Keeb kwm tsis muab ib tug ntshiab lus teb hais txog lawv cov keeb kwm, txawm li cas los, nws yuav lam xav hais tias xws li ib tug ntaus ntawv tau paub nyob rau hauv ancient Asia BC.

Nws yog ib tug yooj yim tsis tau heev mobile txhais tau tias ntawm xab lub sij hawm - lawv sai kis nyob rau hauv cov Nrab Hnub nyoog thiab ua ib tug yawm sib ntxiv rau qhov nrov nyob rau ntawm lub sij hawm, lub sundial.

Hourglass tso cai los ntsuas sij hawm thaum lub sij hawm tsaus ntuj zuag thiab tau npaum li cas ntau yog clepsydra. Ib tug tshwj xeeb qhov chaw yog nyob los ntawm cov saib rau ntawm ships txij li thaum pitching tsis sib sib zog tsa xws li ib tug loj ntxim rau cov ncuav xuab zeb, tsis zoo li cov dej moos. Feem ntau ntawm lawv lub nkoj ceev txiav txim - yog dumped rau hauv dej hlua nrog cov pob caus ntawd thiab nyob ib tug 30-thib ob lub sij hawm moos yog ntsuas. Nyob rau tib lub sij hawm inverting moos sailors nws txo qis ib tug hlua mus rau hauv cov dej pib rau suav, mus rau lub kov, "ntshav" - li no muaj ceev nyob rau hauv cov pob caus ntawd. Tsis tas li ntawd, lub ships siv plaub teev hourglass, siv lawv rau pinpoint lub sij hawm derzhurstva saib ib pab neeg.

Lub ntsiab drawback ntawm xws hourglass me me kom muaj nuj nqis yog muaj los ntsuas cov sij hawm luv. Yog li ntawd, nws yog tus nrov tshaj plaws saib, ntsuas ib teev los yog ob tug, tej zaum peb lub sij hawm. Nyob rau hauv ntau lawm feem ntau kuj siv lub moos yog taub txua yim los yog kaum ob teev - qhov ntev ntawm lub hnub ua hauj lwm.

Cov neeg ntawm xws li ib tug moos nyob feem ntau nyob rau hauv qhov zoo ntawm cov xuab zeb. Feem ntau siv rau hauv tib lub xuab zeb uas yog cov siv thiab ua cov iav - annealed, nplua thiab sifted los ntawm ib tug zoo sab cib. Es tsis txhob ntawm cov xuab zeb yuav kuj yuav siv finely grated plhaub zoo li los yog marble crumbling. Tsis tas li ntawd hourglass raug nyob rau ntawm qhov chaw zoo ntawm cov iav siv, txawm li cas los nrog rau cov zaj uas lub sij hawm, los ntawm puas xuab zeb iav puab nto, cov neeg ntawm xws li ib tug moos ntog.

Nyob rau hauv lub 18th - 19th centuries, nrog rau cov tshwm sim los ntawm factories thiab factories, uas ua nyob rau hauv cheaper ntau lawm, dav siv, ib zaug kim thiab tua txhua yam ua si thiab lub tswb moos. Raws li ib tug tshwm sim - lub hourglass raug ntiab tawm ntawm niaj hnub siv, tab sis txawm hais tias txawm niaj hnub no lawv yog lug siv nyob rau hauv kev lag luam, cov tshuaj thiab ntau lwm qhov chaw.