of "F. Goldstein" in
the visitors' book, went forth on his cycle to explore the beauties of
the Highlands, the thaw having now cleared the roads, and on each
occasion I managed by dint of many subterfuges to watch his proceedings.
His gaze was ever in the distance, and each time he gained high ground
he swept the surrounding country with a pair of powerful prismatic
field-glasses.

I confess I was rather annoyed at Ray's conduct in thus abandoning me at
the very moment of my discovery, for here was the ballooning expert
Straus bent upon seeing and photographing our newest arm of defence.

As the days passed I exerted every precaution, yet I followed him
everywhere, sometimes using the car, and at others the motor-cycle.

The spy, a bespectacled, round-faced Teuton who spoke with a strong
accent, was ever active, ever eager to discover something in the air.
Yet, to my intense satisfaction, he seemed to be utterly unaware that I
was keeping so strict a watch upon his movements. Purposely I avoided
speaking to him in the hotel, for fear of arousing his suspicions.

One day Mr. Goldstein did not appear, and in response to my inquiry the
waiter informed me that he had caught cold and was confined to his room.

A spy with a cold! I laughed within myself, and the afternoon being
bright, I took a run south through the Abernethy Forest down to Loch
Pityoulish. On my return I crossed Dulnan Bridge, where the turbulent
Dulnan River hurtles along over the stones on its way down to the Spey.
I dismounted, hot and tired, and propped up my cycle against the parapet
to rest and admire the dark pine-clad gorge which opened to the north.

My reflections were suddenly cut short by a loud humming sound which
seemed to come from the road which I had just traversed. Instinctively I
looked round for the approaching motor-car. The sound came nearer, but
instead of a car, I saw in the air, above the tops of the firs against
the distant hill in the background, a splendid aeroplane with two men
aboard. Swiftly it swept over the stream with the ease and majesty of an
enormous albatross!

Next instant it had disappeared from my gaze. Yet in that brief moment I
had had ocular demonstration that the secret trials were in progress in
the neighbourhood.

I waited on tiptoe with excitement. Again the whirring sound came
nearer, the occupants of the neighbouring cottages being undisturbed,
believing it to be a motor-car. Once again I saw the new