BUILDING CONSTRUCTION 111 



brass slots and having a hardwood slip on the working edge, upon 

 which the stock of the tee-square slides. 



The tee-square may be of pearwood, but must be strong. The 

 lust type of tee-square is that with a thin mahogany blade, ebony 

 drawing edge, and rebated ebony edge on stock. 



A 60 and 45 set-square are necessary. They may be of 

 mahogany, pearwood or celluloid. An extremely useful instrument, 

 that should be on every drawing-board, is a celluloid protracting 

 adjustable set-square, which facilitates the drawing of roofs and 

 enables the draughtsman to set off or divide any angle with speed. 

 Cheap drawing pins should be avoided. 



Unless one is prepared to lay out a considerable sum of money 

 on a case of first-class instruments, it is advisable to purchase only 

 those likely to be of most use and of good quality. Cheap instru- 

 ments are invariably of little use, and will only result in bad and 

 inaccurate work. The following instruments may be purchased : 



(1) A pair of 6-inch compasses, with pen and pencil points. 



(2) A pair of dividers. 



(3) Spring bows for pencil and ink, for the purpose of drawing 



small circles. 



(4) .A good drawing pen for inking-in the completed work if 



desirable. 



(5) A 12-inch scale (boxwood), divided into twelfths, and con- 



taining the following scales : On one side inch to 

 the foot, inch to the foot, -J inch to the foot, and 1 inch 

 to the foot. And on the other side f inch to the foot, 

 f inch to the foot, 1 inches to the foot and 3 inches to 

 the foot. 



(6) Good lead pencils graded H and HB are probably all that 



will be found necessary, but the taste of the user settles 

 this matter, as well as the kind of work being done and 

 whether paper is rough or smooth. 



Good cartridge paper is usually employed for ordinary work, 

 although hand-made paper is desirable for plans which must stand 

 considerable wear or be kept for reference for some time. 



For working plans clear tracing linen is indispensable, although 

 for small works tracing paper may fulfil all the requirements, if 

 taken care of. 



In ordinary architectural practice it is found that a great many 

 of the drawings are only in use for a very short period, during the 

 execution of the work, and do not warrant the use of an even 

 moderately expensive paper. For those who have such work to 

 do, rolls of thin, tough, vegetable paper, sometimes called " bank- 



