In setting out a drawing, this fixing of certain salient points is the first thing for the student to do.  The drawing reproduced on page 90 [Transcribers Note:  Plate XVIII] has been made to illustrate the method of procedure it is advisable to adopt in training the eye to accurate observation.  It was felt that a vertical line drawn through the pit of the arm would be the most useful for taking measurements on, and this was first drawn and its length decided upon.  Train yourself to draw between limits decided upon at the start.  This power will be of great use to you when you wish to place a figure in an exact position in a picture.  The next thing to do is to get the relative heights of different points marked upon this line.  The fold at the pit of the stomach was found to be exactly in the centre.  This was a useful start, and it is generally advisable to note where the half comes first, and very useful if it comes in some obvious place.  Other measurements were taken in the same way as our points A B C D E in the diagram on page 87 [Transcribers Note:  Diagram IV], and horizontal lines drawn across, and the transverse distances measured in relation to the heights.  I have left these lines on the drawing, and also different parts of it unfinished, so as to show the different stages of the work.  These guide lines are done mentally later on, when the student is more advanced, and with more accuracy than the clumsy knitting-needle.  But before the habit of having constantly in mind a vertical and horizontal line with which to compare positions is acquired, they should be put in with as much accuracy as measuring can give.

[Sidenote:  Blocking in your Drawing.]

The next thing to do is to block out the spaces corresponding to those occupied by the model in the field of your vision.  The method employed to do this is somewhat similar to that adopted by a surveyor in drawing the plan of a field.  Assuming he had an irregular shaped one, such as is drawn in Fig.  X, page 87 [Transcribers Note:  Diagram IV], he would proceed to invest it with straight lines, taking advantage of any straightness in the boundary, noting the length and the angles at which these straight lines cut each other, and then reproducing them to scale on his plan.  Once having got this scaffolding accurately placed, he can draw the irregularities of the shape in relation to these lines with some certainty of getting them right.

You should proceed in very much the same way to block out the spaces that the forms of your drawing are to occupy.  I have produced these blocking-out lines beyond what was necessary in the accompanying drawing (page 87 [Transcribers Note:  Diagram IV]), in order to show them more clearly.

[Sidenote:  How to observe the Shape of Curves.]