(c) The blocking of the small number of landing grounds by placing obstructions on them. The direction indicators and boundary marks could also be removed. (d) The destruction of petrol dumps and tanks along the routes. (e) The removal and replacement elsewhere of the marks which now indicated the line of the routes. CONCLUSION. Whilst we have no reason to modify our previously expressed opinion that owing to the difficulties of the country the scale of any attack from North Africa is likely at present to be limited to small raiding parties, we consider that it would be unwise to miss any opportunity that presents itself for preventing the enemy from making preparations for an attack at a later date.