## The American House Carpenters' and Joiners' Assistant: Being a New and Easy System of Lines, Founded on Geometrical Principles, for Cutting Every Description of Joints, and for Framing the Most Difficult Roofs; to which is Added a Complete Treatise on Mathematical Instruments. Also, Mensuration, Tables of the Weights and Cohesive Strength of the Several Materials Used in the Construction of Buildings, &c |

### From inside the book

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Page 46

... the following ; viz . , Whole and halves .

... the following ; viz . , Whole and halves .

**Proportional**compasses . Triangular Compasses . Marquois's scales . ( Beam Compasses . Plotting scales . The pantagraph . Sliding Rule . ON DRAWING COMPASSES . - This instrument consists of two. Page 48

... These compasses are also useful for dividing lines by continual bisections .

... These compasses are also useful for dividing lines by continual bisections .

**PROPORTIONAL**COMPASSES . - By means of this ingenious instrument drawings may be reduced or enlarged , so that all the lines 48 MATHEMATICAL INSTRUMENTS . Page 50

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**proportional**between two numbers , being the square root of their product , may be found by multiplying the numbers together , and then taking the square root of the product in the manner explained above . The numbers of the scale of ... Page 61

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**proportional**compasses be set in the proportion of the sine 90 ° on the line of sines to the radius of the prim- itive , one pair of points will give , reduced to this radius , the sines taken off by the other pair of points . The ... Page 64

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**proportional**to their real mag- nitude . Another and more exact method is , to make the meridian passing through the center of the map , and all the parallels of latitude , straight lines , as in the last method . Then all the degrees ...### Other editions - View all

### Common terms and phrases

26 Spruce St angle rib beam beam compasses bevel breadth Cast Iron circle circumference colatitude constructed copy cube root cubic feet depth describe the arc diagonal diameter divided draw the lines edge Eighths elevation ellipsis extent will reach Figure floor frame girders given line given number gnomonic projection half hypothenuse inches instrument Invented and Drawn jack-rafters Join joists length in feet limb line of chords line of numbers line of sines Lith 26 Spruce meridian method of finding multiplied nail number of degrees number of equal pencil perpendicular plane Plate polygon primary divisions proportional purlin quadrant quarter girt quotient radius regular polygons represent right angles right line roof rule Rule.-Multiply screw secants sector Shows the method slider sliding soffit square root straight line stroke subdivision tangents thickness transverse distance triangle truss vernier scale weight