ov 
260 National Geographic Magazine. 
The author had the rare privilege of spending three months at 
the Southampton office in 1888, through the introduction of the 
director of the Geological Survey, and the request of our recent 
minister in London, Mr. Phelps. 
Nothing could have exceeded the courtesy and hospitality of 
the director of the survey, Sir Charles W. Wilson, and the offi- 
cers in charge of the various departments, not alone in granting 
the necessary authority to inspect every branch of the work, but 
in lending personal aid and men for that purpose. 
Great interest was also expressed in the topographic surveys of 
this country which differ so essentially from the Ordnance Sur- 
vey. In the former, field work and methods are directly adapted 
to the scale of publication ; in the latter, the largest scale of 
publication governs the operations of the survey, and the smaller 
scales are reduced by photography, with a gradual elimination of 
unnecessary details from the larger to the smaller scales until 
finally the topographic map of the country, on the scale of one 
mile to one inch is produced, which possesses an accuracy and 
character that could be obtained by no other method. 
To illustrate this important subject there are exhibited a 
series of experimental and complete maps and diagrams which 
will well repay careful examination. They were prepared and 
collected at the Ordnance Survey at Southampton expressly for 
this purpose and with the kind permission of the present director, 
Colonel Sir Charles W. Wilson, R. E., C. B. 
The author desires to state that many of the paragraphs of the 
paper, particularly those relating to the history of the Ordnance 
Survey, have been extracted from the following works and re- 
ports on the subject : . 
1. The Ordnance Survey of the United Kingdom, by Lieut.- 
Col. P. Pinkerton White, R.E. 
2. The Ordnance Suryey of the.:Kingdom, by Capt. H. 8. 
Palmer, R.E. 
3. Methods and processes adopted for the production of the 
maps of the Ordnance Survey, by Lieut.-Genl. Sir Henry James, 
R.E., F.R.S. 
4, Reports of Col. Colby and others in the Blue Books presented 
to Parliament—1850-1860. 
