The cut was made by photographing a page of the Census Abstract which was printed on rather rough paper. With an original cut made directly by the Ben Day process the distinction

GRAPHIC METHODS

between the different shades would be considerably clearer than it is in Fig. 179. A cut of this size and complexity is rather expensive when the Ben Day shading is used. Anyone wishing a cut made with Ben Day work would do well to get a rough cost-estimate from his engraver before actually giving the order.

It will be noticed in Fig. 179 that the numerical scale-steps for different degrees of shading are uniform except at the smaller end of the scale. It would probably not be wise to show as white area all of the land valued at from $10 to $25 an acre, since such land makes

Nombre

de maisons

Bertillon's "Course elementaire de StaiistiQue Administrative"

Fig. i8o. Height of the Houses in the Different Districts of Paris

The scale for this illustration should have been indicated on the chart so that actual numbers of houses could be read. The vertical dimension of the group of bars for each district shows the relative total number of houses. The horizontal dimension shows the relative number of houses of each height by stories

up about half of the whole United States. A uniform scale varying by $25 per acre would give an erroneous impression regarding those important areas which contain land valued at less than $25 per acre but in which there is a large amount of farming.