Appletons' Cyclopædia of Drawing: Designed as a Text-book for the Mechanic, Architect, Engineer, and Surveyor, Comprisng Geometrical Projection, Mechanical, Architectural, and Topographical Drawing, Perspective, and Isometry

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William Ezra Worthen
Appleton, 1857 - 410 من الصفحات
 

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الصفحة 3 - A circle is a plane figure contained by one line, which is called the circumference, and is such that all straight lines drawn from a certain point within the figure to the circumference, are equal to one another.
الصفحة 2 - When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a Right Angle; and the straight line which stands on the other is called a Perpendicular to it.
الصفحة 2 - When several angles are at one point B, any one of them is expressed by three letters, of which the letter that is at...
الصفحة 20 - ... the beginning of this division, or zero point, a distance equal to one of the subdivisions. Now divide the extent thus set off into ten equal parts, marking the divisions on the opposite side of the divided line to the strokes marking the primary divisions and the subdivisions, and number them 1, 2, 3, &c., backwards from right to left Then, since the extent of eleven subdivisions has been divided into ten equal parts, so that these ten parts exceed by one subdivision the extent of ten subdivisions,...
الصفحة 33 - Then press downwards the branches ee, which will cause the points to make punctures in the paper at opposite sides of the circle; which being afterwards connected, the line will pass through the given angular point, if the instrument was first correctly set. In this manner, at one setting of the instrument, a great number of angles, or a complete circular protractor, may be laid off from the same point. THE T SQUARE AND SEMICIRCULAR PROTRACTOR.
الصفحة 200 - V4, the exhaustion valve, for opening or closing the communication between the lower part of the cylinder and the condenser. The nozzle chamber above the valve communicates with the cylinder by the lower port n, while to the bottom of the nozzle, under the valve, is attached the eduction pipe H.
الصفحة 115 - VIII, leads to the following remarkable conclusion, easily fixing itself in the memory, that with the unguents, hogs* lard and olive oil interposed in a continuous stratum between them, surfaces of wood on metal, wood on wood, metal on wood, and metal on metal, when in motion, have all of them very nearly the same co-efficient of friction, the value of that co-efficient being in all cases included between 0,07 and 0,08, and the limiting angle of resistance therefore between 4° and 4° 35'.
الصفحة 62 - XXXVIII. length AD, the polygon may be completed. The constructions for inscribing regular polygons in circles are suitable also for dividing the circumference of a circle into a number of equal parts. To supply a means of dividing the circumference into any number of parts, including cases not provided for in the foregoing problems, the annexed table of angles relating to polygons, expressed in degrees, will be found of general utility. In this table the angle at TABLE OF POLYGONAL ANGLES.
الصفحة 111 - To find the weight that will be supported by a known amount of power, the position of the fulcrum being given : Multiply the distance between the power and the fulcrum by the power, and divide the product by the distance between the fulcrum and the weight.
الصفحة 20 - ... or 2-53, according as the primary divisions are taken as hundreds, tens, or units. General Rule. — To take off any number to three places of figures upon this vernier scale. Increase the first figure by one; subtract the third figure from the second, borrowing one- from- the first increased figure, if necessary, and extend the compasses from the division upon the vernier -scale, indicated by the third figure, to the subdivision indicated by the number remaining after performing the above subtraction.

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