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[[Image:2699.jpeg|right|thumb|200px]]

[[Image:2699.jpeg|right|thumb|200px]]

An '''hour glass''' is an obsolete [[time]]-keeping device. It is made up of two bulbs connected by a narrow passage, through which sand flows at a given rate. Hourglasses were probably invented in [[Alexandria]], [[Egypt]] between 200 and 300 A.D. <ref>

An '''hour glass''' is an obsolete [[time]]-keeping device. It is made up of two bulbs connected by a narrow passage, through which sand flows at a given rate. Hourglasses were probably invented in [[Alexandria]], [[Egypt]] between 200 and 300 A.D.<ref>

{{Cite book

{{Cite book

| publisher = W. & R. Chambers, Ltd.

| publisher = W. & R. Chambers, Ltd.

| date =

| date =

| year =

| year =

}}</ref>. Though they are no longer used for the purpose of keeping time, they are sometimes used in lieu of electronic timers, for example, as egg timers.

}}</ref> Though they are no longer used for the purpose of keeping time, they are sometimes used in lieu of electronic timers, for example, as egg timers.

==Sources==

==Sources==

{{reflist}}

{{reflist}}

[[category:technology]]

[[Category:Technology]]