What is "long primer"

Primer \Prim"er\, n. [Originally, the book read at prime, the first canonical hour. LL. primae liber. See Prime, n., 4.]

1. Originally, a small prayer book for church service, containing the little office of the Virgin Mary; also, a work of elementary religious instruction.

   The primer, or office of the Blessed Virgin.
   --Bp. Stillingfleet.

2. A small elementary book for teaching children to read; a reading or spelling book for a beginner.

   As he sat in the school at his prymer.
   --Chaucer.

3. (Print.) A kind of type, of which there are two species; one, called long primer, intermediate in size between bourgeois and small pica [see Long primer]; the other, called great primer, larger than pica.

   Note: Great primer type.

n. (context printing dated English) The size of type between bourgeois and small pica, standardized as 10-point.