IV PREFACE TO THE FIRST EDITION.
Complex and difficult formulæ have as far as
possible been avoided, and, in many cases, to the
formulæ have been added an easy approximate
rule Throughout the book there is scarcely a
formula which cannot be mastered by any one
possessing little more than a mere knowledge
X arithmetic. To facilitate the calculations of
hydraulic formulæ, the crushing strains on columns
and other formulæ, I have calculated the 5th, 4Ü
3-6th and l’7th powers for those numbers wbic
are most likely to be required; and, that the book
may in itself be complete for use when no» othei
reference is at hand, I have added short; t
Logarithms, Natural and Logarithmic femes, kc„
Square and Cube Roots, Areas and Circumfer-
ences of Circles, &c., which are quite euihcient for
all ordinary calculations. . .
Many of the formulæ, though appearing in a
new shape, are not original, but merely siniphhed
by me, so as to give the same results as before
vrtth less labour and complication. Some aie i -
serted unchanged. Others I have deduced from
practical experience of their usefulness.
P While in justice making a general acknow-
ledgment to many authors who have been con-
sulted, but whose names could not be conve-
nient! v enumerated, I cannot deny myself the
satisfaction of recording my special ^bgations
to iny friend, Mr. Henry Warmer; not only for
many kind and useful suggestions m the region
of this book for publication, but for much valuable
and practical information, which I have derived
from him in the course of my professional con-
nection with him in past years.
Guilford L. Moleswostii.
November^ 1862-