Principles of the mechanics of machinery and engineering, by Julius Weisbach

396 Pages·24.026 MB·English

by  Weisbach, Julius

THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
LOS ANGELES
GIFTOF
John S.Preil

\
PRINCIPLES
OP
THE MECHANICS
OF
MACHINERY AND ENGINEERING.
BY JULIUS WEISBACH,
PROFESSOROFMECHANICSANDAPPLIED-MATHEMATICSINTHEROYALMINING
ACADEMYOFFREIBERG.
FIRST AMERICAN EDITION.
EDITED
BY WALTER R. JOHNSON, A.M., CIV. & MIN. ENG.
WASHINGTON, B.C.
FORMERLYPROFESSOROFMECHANICSANDNATURALPHILOSOPHYINTHEFRANKLININSTI-
TUTE,ANDOFCHEMISTRYANDNATURALPHILOSOPHYINTHEMEDICAL
DEPARTMENTOFPENNSYLVANIACOLLEGE. AUTHOROFA
REPORTTOTHEUNITEDSTATESNAVYDEPART-
MENTONAMERICANCOALS,&C.&C.
IN TWO VOLUMES.
ILLUSTRATED WITH EIGHT HUNDRED AND THIRTEEN
ENGRAVINGS ON WC
VOL. II.
APPLIED ME
PHILADELPHIA:
LEA AND BLANCHARD.
1849.
ENTEREDaccordingtotheActofCongress,intheyear1849,by
LEA AND BLANCHARD,
intheClerk'sOfficeoftheDistrictCourtoftheEasternDistrictofPennsylvania.
PHILADELPHIA:
T.K.ANDP.G.COLLINS.PRINTERS.
Engmeeriflg
Library
TA
PREFACE BY THE AMERICAN EDITOR.
IN submitting to the American reader the second volume of
Weisbach's Mechanics of Machinery and Engineering, we cannot,
perhaps, better express our own appreciation of the value of this
%
part of his labors, than citing apassage from the advertisement
of the English translator, Prof. L. Gordon.
"Theusefulness of this secondvolume will be manifest from the
practicalinterest and importance ofthe subjects treated. The first
part of the volume, though far from giving a complete theory of
engineering and architectural construction, brings manyimportant
questions of practice before the studentin a simple form, and in a
light by which he will more readilyrecognize the bearings of the
mathematical calculations onthis subject,thanhasbeenusually the
case in English works. The second part of the volume contains
the only Theoretical Treatise onWater Power ofthe least practical
value hitherto printedinthe English language. The real import-
ance of such atreatise will be variously estimated; but as it is the
first publicationinwhicha systematic attemptismade tofamiliarize
English Machinists with the application of exact reasoning in deve-
lopingthe theory of the machines treated of, itis believed that it
must be interesting to them, and if so, it cannot fail to be useful
likewise."
The most available treatise on the numerous forms of reaction
wheels, and otherturbinestowhichtheAmericanstudenthas access,
is believed to be embraced in this volume. The author, it maybe
observed, has not contented himselfwith giving ageneraltheory on
that subject,butbyskillfullyanalyzing the several effectsproduced,
and computing separatelythe prejudicial and the useful resistances
713797
""- Engineering
Library
vi PREFACE BYTHEAMERICAN EDITOR.
to the action ofthewater,has presentedconclusions challenging the
highest confidence,especiallyastheystandconfirmed,inmost cases,
bytheresults ofnumerous directexperiments.
Inreferencetothewater-pressureengine,also,it maybe saidthat
the present volume will afford to the American student the most
directandpositiveinformation as totheuseful application of water
inthat species of motor.
In the original work of Prof. Weisbach, the secondvolume em-
braced the science applicable to the steam engine, but as that sub-
jecthasnowassumed sodistinctan importance,and as its numerous
topics andimprovements could scarcelybepresented with sufficient
clearness, in aless space than an entire volume,it hasbeen deemed
expedient, in imitation of the English translator, to reserve that
branch of the mechanics ofengineering for a separate treatise.
In assigning to their appropriate chapters the additions of the
translator, which had in the English edition been throwninto the
form of anappendix, wehave been guided by a desire of rendering
thework more serviceable to the student, byplacingbefore himthe
whole matterpertainingto each branchunderits appropriate head.
Wehave added afewarticlesparticularlyrelating to the strength
ofmaterials, which, we hope,maynot be found uninterestingto the
student. Indeed,whenwetakeinto viewthe lamentable,and often
wilfuland obstinatedisregardofthe truthswhichsciencehas elicited
relative to this department of our subject; whenwe see machines
and engines intendedto perform the most powerful operations, and
edifices, or monuments, designed to endurefor ages, constructed of
materials, either utterlyworthless, or, atbest, of veryinferior cha-
racter anddurability,orcontaining intheir compositiontheelements
of weakness and decay, we may estimate, with some justness, the
importance ofthoseresearches and computations, whichprove what
may be expected from the employment of good or bad materials
respectively, for any of the purposes of the architect and engineer.
The fact that the public has often been basely imposed upon by
reason of employing as architects and engineers those who would
pander to the cupidity of contractors for materials and labor, and