The above engraving is a facsimile of a cardboard protractor for primarygrades, wliich is used in many public schools with great satisfaction. This instrument is four inches in diameter and is made from cardboardprepared expressly for this purpose and graduated with a very accu-rately engraved die.… … The above illustration represents a practical instrument designed forpupils in the higher grades. The construction of the joint is peculiar,having two annular wearing surfaces milled from solid metal and so ac-curately adjusted to each other that a perfectly smooth and uniform move-ment of the legs…
Kindergarten -- Equipment and supplies · Schools -- Equipment and supplies · Color · Trade catalogs -- Schools -- Equipment and supplies
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