1140 REPORT—1885. 
but they failed to follow it. One could actually get a clearer idea of the relative 
density of the population throughout the different parts of the United Kingdom 
from Petermann’s map than from anything that had since been published. Jn this 
matter of applied cartography, Scotland (and it might be added England also) was 
deplorably behind most foreign countries—notably Germany, France, and Italy. 
To some extent this might be the fault of the cartographers, but to a larger extent 
it was due to the small attention that was bestowed on the systematic collection of 
statistical information in such a form as can be tabulated or ‘ graphicised.’ Nothing 
was more difficult in many cases than to obtain statistical facts for any smaller 
totality than the United Kingdom. It was time that an attempt should be made 
to compile, under the auspices of some authoritative institution, such as the Royal 
Society of Edinburgh, a new statistical account of Scotland: though such a work 
as Mr. Groome’s ‘ Ordnance Survey Gazetteer’ did much to supply the desideratum, 
the enterprise was too difficult for private accomplishment. 
6. On Bathy-hypsographical Maps, with special reference to a Combination 
of the Ordnance and Admiralty Surveys. By E. G. Ravensretn, F.R.G.S. 
The bathy-hypsographical map, which exhibits the vertical configuration of the 
solid surface of the earth aboye as well as below the ocean-leyel, is a product of 
modern times. It was Gerard Mercator who first inserted soundings upon a chart 
in 1585, but nearly two centuries passed away before Cruquius, in 1728, introduced 
the fathom-lines with which we areall familiar. Buache, and after him Ducarla, 
first suggested the introduction of contours upon maps, and their idea was realised 
in 1791 by Dupain-Triel on a map of France. The combination of these two 
descriptions of contoured maps we owe to modern German geographers, and more 
especially to Berghaus, von Sydow, and Ziegler. Cartographers in effecting this 
combination had hitherto quite lost sight of the fact that the heights on maps are 
referred to high or mean water, whilst the depths on charts represent soundings 
reduced to low water. This rough method gave satisfactory results when dealing 
with maps on a small scale, but a more rigid method would have to be applied when 
it was desired to combine accurate surveys like those made by the Ordnance and 
Admiralty departments. The so-called mean level of the sea was not a suitable 
datum level, and it would be necessary to carry on tidal and other scientific obser- 
vations on a far more comprehensive plan than had been done hitherto if a really 
satisfactory bathy-hypsographical map of the British islands were to become attain- 
able. These various supplementary surveys, tidal observations, &c., it was to be 
hoped, would expand into a comprehensive scientific survey of the British seas. 
