a student's slate

©iStockphoto.com/Bruce Lonngren

slates & blackboards

Slates are the smaller versions of blackboards, used with chalk, before cheap paper.



In England the dimensions of school slates and their names were the same as those used for roofing slates.

Designation Size in inches
Princess 24 × 14
Duchess 24 × 12
Marchioness 22 × 12
Countess 20 × 10
Viscountess 18 × 10
18 × 9
Ladies 18 × 10
16 × 8
15 × 8
14 × 12
14 × 8
Plantation 13 × 11
Double 13 × 18
12 × 20

Frederick Danvers Power.
A Pocket-Book for Miners and Metallurgists, comprising Rules, Formulae, Tables and Notes for Use in Field and Office Work.
London: Crosby, Lockwood and Son, 1892.
Page 43.


Blackboard shops are generally operated independently. When finished the standard boards are about 3/8 in. in thickness and 3, 3½, and 4 ft. wide and any lengths desired. Of late the Bangor blackboard business has been of small account. At the Enterprise Slate Works, East Bangor, W. J. Jacobs has the only marbleizing plant in this section now in operation. It is a small affair. All told the value of the structural output, including blackboards, of this locality in 1897 was $98,000.

There are six concerns engaged in the making of school slates in Bangor and vicinity. Of these the Hyatt and the Weller factories are the most important. When working at full capacity they all employ over 600, many being girls. Every variety of school slate is made. The season of activity is the summer and fall.

The greater part of the blackboards used in the United States are made in Slatington [PA] and vicinity. Last year there were eleven factories operating, including the Hower at Danielsville, which ships from this point. Each made from 45,000 to 153,000 sq. ft., or in all 930,500 ft., which at 10c. would be $93,050. The factories buy stock delivered from the quarries at 7c. per foot for inch material, and each foot makes two feet of blackboards, the latter being 3/8 in. thick. With the exception of the Consolidated Lehigh and Slatington companies little attention is paid to structural material, though several other mills do more or less, but this is destined to be a more important factor of the Lehigh slate trade, as clear stock is corning into better demand. For 1897 the production was 325,000 ft.

For school slates this region supplies the best material, which should be soft, smooth, and of even grain, the greater portion used in the Northampton County factories coming from here. It is probable the time is not far distant when most of the school-slate factories will be near the quarries supplying the raw material, but of the ten operating last year eight are in Northampton County and two in Lehigh County. The factory of Edwin L. Kraus at Slatington is the most complete. It averages 15,000 slates per day, and next to the Hyatt, at Bangor, is the largest in the country. David Williams' Sons, also at Slatington, make about 2,000,000 per year; their product is handled by the Hyatt School Slate Co., excepting exports. A promising trade is being built up in England, Denmark,and Germany. In quality, finish, and price American school slates are superior to the foreign, but evidence of a strong prejudice against them is not wanting, simply because they are American. Ordinarily, in summing up the different slate products, school slates are overlooked, though they form a considerable item, the business in 1897 amounting to $255,000. The production last year was 10% greater than in 1896, but prices were lower. Prior to 1897 there was a school-slate pool.

H. L. J. Warren.
Richard P. Rothwell, ed.
The Mineral Industry, vol. 6.
New York: The Scientific Publishing Co., 1898.
Page 596 & 598.

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