SECTIONAL TRANSACTIONS.—E. 497 
Lt.-Col. A. B. CLoucu, O.B.E.—The preparation of maps and illustrations 
for geographical articles and theses (12.15). 
Geographers wishing to illustrate their articles by maps can either : 
(1) Draw the map de novo from their own survey material or by copying 
or tracing from existing maps ; or 
(2) Use an existing map as a topographical base on which to overprint 
their special information. 
In all such cases where they are preparing drawings in any form for 
reproduction, some knowledge regarding the processes of reproduction will 
be found very helpful. 
In the case of (2) above, the Ordnance Survey can supply impressions in 
non-photographic blue of detail or water or contours or of any combination, 
on which the special material can be drawn in its correct position. This 
special drawing can then be reproduced as an overprint in any colour on 
the chosen map sheet, the basic topographical detail being printed either in its 
normal colouring or in grey, dependent on whether it is desired to emphasise 
or not the special information in comparison with the topography. 
For Great Britain a choice of Ordnance Survey maps ranging between 
the large scale 1/2,500 to the small scale 1/million is available. 
When compiling material for subsequent reproduction in conjunction 
with an Ordnance Survey map, it is wise to use the appropriate Ordnance 
Survey map as the key and not to use other maps of nominally the same 
scale. Otherwise subsequent difficulties in register may ensue. 
AFTERNOON. 
Prof. Lt. RopweEtt Jones and Mr. F. H. W. Green.—Rainfall in Kenya 
and Uganda (2.15). 
In Kenya there are some 230 rainfall stations, of which only 80 have 
records for a period of more than fifteen years. 'The corresponding numbers 
for Uganda are 35 and 14. 
In both countries the stations are unevenly distributed, and in some cases 
the records obviously unreliable. Even so it seemed possible to construct 
maps which should aid a rapid assessment of the rainfall conditions and do 
no serious injustice to the general facts. 
A 1/250,000 contoured map exists for much of the area, and the isohyets 
were drawn with constant reference to the relief. The usual methods of 
interpolation were used in respect of the records of short-period stations. 
Maps showing distribution by months for the long-period stations have 
also been prepared. Amongst much else it emerges definitely that a rain 
shadow is formed by the Eastern Highlands, and that there is a difference 
in the distribution type for places in the same latitude but on opposite sides 
of the Northern Rift. 
From hourly velocity readings windroses were prepared for the three 
first-class stations for selected months. 
At Kampala the chief influence appeared to be the land and sea breezes 
of the northern verge of Lake Victoria. 'The same phenomenon, for definite 
hours, causes a deflection in the otherwise monsoon directions evinced at 
Zanzibar. 
Mr. E. W. GiLBert.—The human geography of Mallorca (3.0). 
Mallorca, the largest of the Balearic Islands, is 1,350 square miles in 
extent, almost the same size as the county of Cornwall, and contained about 
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