3^3 
it receives the attention which the subject demands. In 
order to secure this, it was thought expedient to print a 
number of blank charts, to be supplied to all persons em- 
ployed in measuring and delineating sections; so that, being 
bound in volumes on a regular and systematic arrangement, 
an easy reference might at any time be made. These blank 
charts are to be had on application to Mr. Jordan, at the 
Museum of Economic Geology, in Craig's Court, Charing 
Cross, London ; or to the Secretary of the Institution of 
Civil Engineers, 25, Great George Street, Westminster, 
by any parties who are willing to contribute any share of 
information in the form of sections drawn and coloured on 
these blank charts.* 
The scale on which these charts are constructed is 40 feet 
to an inch, which is as small as can be employed with clear- 
ness; and to have made it larger would have caused an incon- 
venient area to be occupied by the drawings. A stratum 
four feet thick thus appears one-tenth of an inch in thickness, 
according to this scale, and this is amply sufficient to repre- 
sent any seams of coal or other conspicuous objects. The 
chart extends 800 feet in length and 600 feet in height, 
according to this scale. At first sight it may appear that as 
a scale of length this is unnecessarily large, as nearly seven 
sheets will be required to represent one mile of section. It 
must be kept in mind, however, that it is only in a few 
particular places that the cuttings present instructive sections, 
and that the desired collection by no means involves a con- 
tinued drawing of many miles of cutting. If this were so, 
it would become necessary to adopt one scale for the hori- 
zontal distance, and a greatly enlarged scale of heights. 
Sections, thus constructed, are indispensable for engineering 
purposes, but ought to be avoided as much as possible in 
* These blank charts will be furnished by the Secretary to any one who will 
underlakc to fill them up 
