TIHE greater part of t, hc sub cct m atter of t, his book appeared in a series of articles in the Tfechnr ica II l T orld. The purpose in writing it is so fullv ex lainetl in thc Introduction that a Preface is hardlv V C d required. As the forms gi-en to the various parts of a machinc or er gine are on analysis invariably found to be combinst, ions of certain geometrical solids. s knowledge of how each of these should be drawn c3 when in any posihon should first acquired by the student draughts man. To this end a series of problems is giwn in the folloxving pages, coinmencing with the construction of those simple geometrical figures which form the surfaces of the solids which give shape to mechanical rletails, and subsequently the rnetliotl. aclopted in representing the solids themselves, singly and in combin a t lon. As no amount of copying rlrawinga of mechanical dehils -ill . ever i v oth e student a knowledw of the reasons whv thev are rnadc to tal the special forms given to Them, so in t, he earlik sGgrs of the study of mechanical drawmg it ip, impossible for him to acquire the pou-er to draw the simplest solids in different positions correctly without a knowledge of t, he principles of 01. thographic Projection, which is the basis of the representation of all solid objech. In this part of the subject an extended series of problems is given, the solution of which should enable t, he student to draw any simple object without further hela. In the kethod of studying the contents of this work, the student is advised to tako the different pm-ts of the subject in the orcler in which they are arranged, as he will thereby be led to acquire a mwtery of it in a way that mill impress upon hisnund the connection that each part bears to that which follows. The order of study may not be that usually followed, but it js such as an association of many ears with draughtsmen and studentt has p r o d ta the author to be t g e bcst for the acquisition of the preliminary knowledge necessary ta the successful practice of the draughtsmans art. This work ix not, intender1 a6 a treatise on either Plane or Solid Geometry, but m much of these subjects is given as will be required by the student ta attain to an easy comprehension of the first principles of mechmical drawing as herein exemplified. Their actual application to the delineat, ion of machine elements and engine details may possibly form the subject of a further work. H. HOLT-BUTTERFILL. CONTENTS Infrcduetiwt.-THE V ALUE O F A KSOWLEDO O E F DRAWIN T Q O THE STUUEST FAOF. CHAPTER I THE TOOLS A XD IATERIA R L E S Q UIRED BP THE STUDEST Drawing-Board-Tee-Sq sre-Adjustable Blded SquareSet-Squares-Pencils-Dmwing - Pitis-Paper-Rubber-Ink-Drawing Instru ments . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11 CHAPTER IT MECHANICAL A ND FREEHAKDRDA WISG THEIR D IFFERENCE . ASD USEB Tho mearlirig of Freehud Drawing-How 01 jecta are made visible-Ilrhat a Perspective is-How a Perspective Dwwing is obtained-Tlle use of a Perspective Drawing to thc workman-An Oi-thographjc Projection, and how obtained-The nleaning of Plan and Elevntiotl 12-16 CHAPTER 111 PRACTICA G L EOMETRY AS D IECHANIC D A n L a w sa Tho mertni of g tlie term Geometry-The difference between Plane and Solid Geometry-Definition of Geometrical terms used in the work-Plane Geometrical Figures . . . . . . . . . . . ...