previous next

Par′al-lel Rul′er.

A draftsman's instrument, consisting of two wooden or metallic blades, so joined together by jointed cross-pieces as to open to different intervals and yet retain their parallelism.

A still simpler form is a rolling cylinder a.

b is the ordinary form of two--leafed ruler with two links.

c is a two-leafed ruler with cross links.

d is a three-leafed ruler, the middle section being united by links to the main sections.

e is a flat ruler with a pair of grooved wheels, fixed on an axis, rotating in bearing-posts fastened to the ruler.

Fig. 3552 is a form of ruler having a graduated ruling-blade moving in contact with a graduated blade which represents the vertical. In the two parallel arms of the ruler are slots parallel to the edge of the ruler. Through these slots pass pins from the ends of cross-arms, the other extremities of which [1632] are pivoted to the two parts of the ruler; distances apart of the bars are measured on the vertical bar.

Parallel rulers.

Parallel ruler.

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 United States License.

An XML version of this text is available for download, with the additional restriction that you offer Perseus any modifications you make. Perseus provides credit for all accepted changes, storing new additions in a versioning system.

hide Places (automatically extracted)

View a map of the most frequently mentioned places in this document.

Download Pleiades ancient places geospacial dataset for this text.

hide Display Preferences
Greek Display:
Arabic Display:
View by Default:
Browse Bar: