Part 5 (2/2)

THE RIGHT NAME FOR EVERYTHING.--Always make it a point to apply the right term to each article or portion of a structure. Your explanation, to those who do know the proper technical terms, will render much easier a thorough understanding; and to those who do not know, your language will be in the nature of an education.

PROPER DESIGNATIONS.--Every part in mechanism, every point, curve and angle has its peculiar designation. A knowledge of terms is an indication of thoroughness in education, and, as heretofore stated, becomes really the basis of art, as well as of the sciences. When you wish to impart information to another you must do it in terms understood by both.

Furthermore, and for this very reason, you should study to find out how to explain or to define the terms. You may have a mental picture of the structure in your mind, but when asked to explain it you are lost.

LEARNING MECHANICAL FORMS.--Suppose, for example, we take the words _segment_ and _sector_. Without a thorough understanding in your own mind you are likely to confuse these terms by taking one for the other.

But let us a.s.sume you are to be called upon to explain a sector to some one who has no idea of terms and their definitions. How would you describe it? While it is true it is wedge-shaped, you will see by examining the drawing that it is not like a wedge. The sector has two sides running from a point like a wedge, but the large end of the sector is curved.

If you were called upon to define a segment you might say it had one straight line and one curve, but this would not define it very lucidly.

Therefore, in going over the designations given, not only fix in your mind the particular form, but try to remember some particular manner in which you can clearly express the form, the shape or the relation of the parts.

For your guidance, therefore, I have given, as far as possible, simple figures to aid you in becoming acquainted with structures and their designations, without repeating the more simple forms which I have used in the preceding chapters.

[Ill.u.s.tration: _Fig. 55.-Fig. 65._]

55. _Arcade._--A series of arches with the columns or piers which support them, the spandrels above, and other parts.

56. _Arch._--A curved member made up, usually, of separate wedge-shaped solids, A. K, Keystone; S, Springers; C, Chord, or span.

57. _b.u.t.tress._--A projecting ma.s.s of masonry. A, used for resisting the thrust of an arch, or for ornamentation; B, a flying b.u.t.tress.

58. _Chamfer._--The surface A formed by cutting away the arris or angle formed by two faces, B, C, of material.

59. _Cotter or Cotter Pin._--A pin, A, either flat, square or round, driven through a projecting tongue to hold it in position.

60. _Crenelated._--A form of molding indented or notched, either regularly or irregularly.

61. _Crosses._--1. Latin cross, in the Church of Rome carried before Bishops. 2. Double cross, carried before Cardinals and Bishops. 3.

Triple or Papal cross. 4. St. Andrew's and St. Peter's cross. 5. Maltese cross. 6. St. Anthony or Egyptian cross. 7. Cross of Jerusalem. 8. A cross patte or ferme (head or first). 9. A cross patonce (that is, growing larger at the ends). 10. Greek cross.

62. _Curb Roof._--A roof having a double slope, or composed on each side of two parts which have unequal inclinations; a gambrel roof.

63. _Cupola._--So called on account of its resemblance to a cup. A roof having a rounded form. When on a large scale it is called a dome.

_Crown Post._--See _King Post_.

64. _Console._--A bracket with a projection not more than half its height.

65. _Corbels._--A ma.s.s of brackets to support a shelf or structure.

Largely employed in Gothic architecture.

[Ill.u.s.tration: _Fig. 66.-Fig. 79._]

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