# Aircraft in Warfare (1916)/Appendix 2

APPENDIX II.
The discussion of the radius of action of aeroplanes presented in § 125 and 126, and as affecting the Naval outlook in § 128, may be helpfully illuminated by the accompanying sketch map (Fig. 21).
This map gives in outline the British Isles and the nearest adjacent portions of the Continental littoral; a few towns and places, important from the present standpoint, are indicated by their initial letters (block capitals) from which there will be no difficulty in identification. Positions have been chosen on salient points of the Continental coast, and indicated by circles identified by numerals, thus:—
| Cherbourg | is denoted by | .... | 1 |
| The region of Calais | by„ | .... | 2 |
| North Holland or Texel | by„ | .... | 3 |
| Heligoland | by„ | .... | 4 |
| Stavanger (Norway) | by„ | .... | 5 |
From the above points as centres, arcs of circles hare been struck of 400 miles radius, as indicating the probable extreme radius or limit of raid by aeroplane. It is to be understood that raids by aeroplane at so great a radius in the face of reasonably good defensive measures will rarely be pushed home, and still more rarely successful. We may take it that any point or place in or beyond this radius is to be regarded as out of the effective reach of the enemy, and points 50 or 100 miles within this as reasonably safe. Thus, referring to the figure, station 5 may be ignored as not seriously threatening any point of importance not otherwise imperilled. The only station ​which brings any portion of Ireland within danger is number 1, that is to say, the French coast from Cherbourg westward. Under all conditions the region of the North Channel, including Belfast and the Clyde, and extending as far as the Naval Station at Rosyth (R on the map) may be taken as out of range.
Fig. 21.
In addition to the above, the nearest point situated on the German frontier, taken to be Dusseldorf (D), has also been considered a centre of danger, and an arc of 400 miles inscribed. This brings such important centres as Newcastle, Liverpool and Manchester, Bristol and Weymouth, almost, but probably not as an actual fact ​within danger. Such centres as Southampton and Portsmouth. Birmingham and the Midlands, and last but not least. London, are, however, clearly threatened.
As representing more closely the conditions of the moment, a point (B) has been taken as representing Belgian territory at present in enemy hands. From this point arcs have been struck at radii 100, 200 and 300 miles, the latter representing the probable present-day limit of raiding distance. The degree of the existing danger to our Midland and South-East Counties can be fairly judged from these indications, taken in conjunction with the discussion in the text.
The suggested ship canal from Clydebank to the Forth River is indicated in the map by the heavy line C. Apart from its strategic import, such a canal could not fail to be of great value as a commercial asset, though from that point of view alone it could not be justified to a greater extent than a mere fraction of its probable cost. Whether from a National point of view the need will justify its being carried out is a question which the future alone can determine; its strategic value would be considerable in any case, but if at any time the French littoral were to fall into enemy hands the importance of a canal such as proposed would be greatly increased.
At the moment of going to Press it has come to the author's notice that the proposal for a Ship Canal from the Firth of Forth to the West of Scotland has already been seriously considered; both the route herein suggested and an alternative route through Loch Lomond and Loch Long having received attention. For full particulars vide Royal Commission on Canals and Waterways; Fourth and Final Report; England. Wales and Scotland; page 183. The computed cost given in the said report, viz., twenty millions sterling, is decidedly optimistic.