Upon this I may, however, perhaps venture to refer him to some brief remarks, addressed to you a good many years ago, and now to be found at pp.

101 and 105 of the new edition of my "Letters to _The Times_ upon War and Neutrality (1881-1918)." I am, Sir, your obedient servant, T.E.HOLLAND.
Oxford, April 24 (1914).
ATTACK FROM THE AIR THE RULES OF INTERNATIONAL LAW Sir,--In reply to Colonel Jackson's inquiry as to any rule of international law bearing upon aerial attack upon London, I referred him to the, now generally accepted, prohibition of the "bombardment, _by any means whatever_, of towns, &c., which are not defended." This rule has been growing into its present form ever since the Brussels Conference of 1874.

The words italicised were added to it in 1907, to show that it applies to the action of _aeronefs_ as well as to that of land batteries.

It clearly prohibits any wanton bombardment, undertaken with no distinctly military object in view, and the prohibition is much more sweeping, for reasons not far to seek, than that imposed by Convention No.ix.of 1907 upon the treatment of coast towns by hostile fleets.
So far good; but further questions arise, as to which no diplomatically authoritative answers are as yet available; and I, for one, am not wise above that which is written.

One asks, for instance, what places are _prima facie_ "undefended." Can a "great centre of population" claim this character, although it contains barracks, stores, and bodies of troops?
For the affirmative I can vouch only the authority of the Institut de Droit International, which in 1896, in the course of the discussion of a draft prepared by General Den Beer Pourtugael and myself, adopted a statement to that effect.