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ING THE WEIGHT AND DIMENSIONS OF BALLS AND SHELLS,
WITH THEIR APPROPRIATE QUANTITIES OF POWDER.
REVISED AND CORRECTED BY JOHN D. CRAIG,
PROFESSOR OF MATHEMATICS.
V. Robinson, Printer.
District of Maryland, to wit:
BE IT REMEMBERED, that on the first day of
May, in the thirty-seventh year of the Inoependence
junr, of the said district, hatb deposited in this
“uring Being a plain and comprehensive treatise on
“John D Craig, professor of Mathematics.”
And also to the act, intitled "An act supplementary to the act intitled, 'An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprietors of such copies during the times therein mentione di'w di-stending the benefits thereof to the arts of de& igning, eagraving, and etching historical and other pr.nts
BY THE EDITOR.
The many editions which Mr. Hawner's Treatise on Mensuration has gone through, are evident proofs of its general utility. But at the time when this work was first published, it was not the practice in schools for each scholar to have a printed book by him, while engaged in the study of arithmetic and mensuration; consequently Mr. HAWNEY
gave no particular examples as exercises for La learner, without working them at full length, »> and explaining every step. Thongh this was perhaps originally an advantage to the book, it precluded the use of it in our modern
schools ; for with such assistance, a boy of ry good abilities would naturally become indo
lent, for want of something to exert his genius ; and a boy of a heavy disposition would be in luced to copy all his work from the book.
To remedy these inconveniences, the preprietors of the work engaged the present editor to make such alterations and additions as would render it useful in schools, without diminishing its former plainness and perspicuity.