Page:An introduction to linear drawing.djvu/19

vi dividers, square, and protracter or graduated semicircle. The rule should be a good one, with the inches and tenths of inches marked on it, that, when the pupils have become expert in making the figure, the difficulty may be increased by requiring the whole, or some part of the figure, to be of a given length or dimension.

On most rules in common use, the inches are divided into quarters and eighths, but as it is our plan to apply Geometry to decimal arithmetick, such rules as are divided into tenths should be preferred. When the simplicity of decimal calculations is so evident, it is to be regretted that all our measures are not subdivided into decimal parts, as our currency is, and why our government should set so good an example in one particular, and neglect all he rest, it is not easy to determine.

Although this treatise was originally designed for schools of mutual instruction, still a slight examination of it will show that there is nothing which unfits it for use in schools on any other plan. If the pupils are all taught, and their drawings examined by the instructer, they will do well; but if they are likewise required to examine and correct each other's work, they will do better; they will acquire a familiarity with the figures, and an exactness in execution, to which mere learners seldom attain.