One volume of my war-journal completed, and I must confess it is dull reading. I could not help smiling as I read my enthusiastic remarks at the outbreak of war when we visualized battles by the week. What a contrast between our expectations and the actual facts.

Months of monotony, and I haven't even seen an Englishman yet.

Our battle cruisers have had a little amusement with the coast raids at Scarborough and elsewhere, but we battle-fleet fellows have seen nothing and done nothing.

So I have decided to volunteer for the U-boat service, and my name went in last week, though I am told it may be months before I am taken, as there are about 250 lieutenants already on the waiting list.

But sooner or later I suppose something will come of it. I shall have no cause to complain of inactivity in that Service if I get there.

This excerpt is most likely from what kind of source?