TY  - JOUR
T1  - El­-Cezerî’ninBatar TürdenBir Süreölçeri (Tarcahâr)
TT  - A sinking­type time­keeping vessel (tarjahar) of al­Jazarî
AU  - Bir, Atilla
AU  - Kaçar, Mustafa
AU  - Kayral, Mahmut
PY  - 2005
DA  - June
JF  - Osmanli Bilimi Arastirmalari (Studies in Ottoman Science)
PB  - İstanbul Üniversitesi
WT  - DergiPark
SN  - 1303-3123
SP  - 23
EP  - 33
VL  - 6
IS  - 2
LA  - tr
AB  - In ancientEgyptthepriestsneededto tell the time during the night, so thatthe ritesand sacrificescould be duly performed. On clear nights theycould use the starsto designate thehours, butthey neededa clock when itwascloudy. The Egyptianshad a water­clock for thispurpose in their templeswhich made use of theflow of water through a fine orifice for time regulation. Since the Egyptiansused a linear scale on the inside of their clocksto mark the hours, the bottom of the vessel had to have a smaller cross­sectional area then the top.The submersive float is another type of time measuring device. It was used in Antiquityto determinea given time duration. A vessel with a fineori­ fice on the bottom isputon a water surface. When the vessel sinksone knows thata predetermined time haspassed. If desired, one can pour outthe water and putthe vessel for a second time on thewater surface. If the vesselcross­section isequal along the heightof the vessel the sinking rate isconstant, and time scale generallymarked on the in­or outsidewall of thevessel islinear. Thiskind of time deviceswere inuse from Antiquitytill thebeginningof twentieth century to determine the lecturing time of a speaker or the irrigation time in agriculture.The most importantwork on engineering written before theRenaissance was the book on mechanics Kitab al­hiyal of Ibn al­Razzâz al­Jazari. It was composed in Diyarbakır (present dayTurkey) in1206. There are 50 different devices, such aswater clocks, trick vessels, liquid dispensers, and phlebotomy measuring instruments, fountains, musical automata, and water­raising ma­ chines, aswell as a submersive float(tarjahar) like the one described above. Thisisa 1½ span­long (app.35cm) sinking vessel in the form of an elegantboat in which a boatman standsand playsa flute. The boatputon water surface sinks after one hour and the boatman informsthe end of the hour by blowing a tone.Inthispaper first, a detailedmathematical modelof the outpouring and sinking processisgiven. Secondly, a calculation method isdeveloped and applied for the orifice diameter in the determination of the al­Jazari type time­ keeping vessel.
KW  - el­-Cezeri
KW  - Kitab el­-Hiyel
KW  - otomatlar
KW  - tarcahar
KW  - zaman  ölçme
N2  - In ancientEgyptthepriestsneededto tell the time during the night, sothatthe ritesand sacrificescould be duly performed. On clear nights theycoulduse the starsto designate thehours, butthey neededa clock when itwascloudy. The Egyptianshad a water­clock for thispurpose in their templeswhich madeuse of theflow of water through a fine orifice for time regulation. Since theEgyptiansused a linear scale on the inside of their clocksto mark the hours, thebottom of the vessel had to have a smaller cross­sectional area then the top.The submersive float is another type of time measuring device. It wasused in Antiquityto determinea given time duration. A vessel with a fineori­fice on the bottom isputon a water surface. When the vessel sinksone knowsthata predetermined time haspassed. If desired, one can pour outthe water andputthe vessel for a second time on thewater surface. If the vesselcross­sectionisequal along the heightof the vessel the sinking rate isconstant, and time scalegenerallymarked on the in­or outsidewall of thevessel islinear. Thiskind oftime deviceswere inuse from Antiquitytill thebeginningof twentieth centuryto determine the lecturing time of a speaker or the irrigation time in agriculture.The most importantwork on engineering written before theRenaissancewas the book on mechanics Kitab al­hiyal of Ibn al­Razzâz al­Jazari. It wascomposed in Diyarbakır (present dayTurkey) in1206. There are 50 differentdevices, such aswater clocks, trick vessels, liquid dispensers, and phlebotomymeasuring instruments, fountains, musical automata, and water­raising ma­ chines, aswell as a submersive float(tarjahar) like the one described above. Thisisa 1½ span­long (app.35cm) sinking vessel in the form of an elegantboatin which a boatman standsand playsa flute. The boatputon water surface sinksafter one hour and the boatman informsthe end of the hour by blowing a tone.Inthispaper first, a detailedmathematical modelof the outpouring andsinking processisgiven. Secondly, a calculation method isdeveloped and applied for the orifice diameter in the determination of the al­Jazari type time­ keeping vessel.
UR  - https://dergipark.org.tr/tr/pub/iuoba/issue//14235
L1  - https://dergipark.org.tr/tr/download/article-file/13285
ER  -