hiff of departed
menhaden smote his nose forcefully and he added grimly, "Believe me,
it'll be a pleasure!"

CHAPTER VIII

The Old Tower

Rick tightened the last screw that held the searchlight-telescope unit
to his camera and looked at it with satisfaction. "I _should_ get a
picture," he murmured. There were still quite a few unknown factors.
He knew the theoretical power of the infrared searchlight, but only an
actual test would tell whether it gave enough light for the rather
slow infrared film emulsion. He was sure that it wouldn't give enough
light at its extreme range of eight hundred yards. In all probability,
he would not get an image on the film at a distance greater than two
hundred.

It was a little strange to think in terms of light. True, infrared was
light. But it was not visible to the human eye. The searchlight would
cast no beam that could be seen, although anyone close to it would be
able to see dimly the hot filament of the bulb.

Another unknown was the ability of the film emulsion to register the
reflected infrared rays of his particular searchlight. The emulsion
had been designed originally for infrared flash bulbs. The
motion-picture film had been made at his special order. It was not a
stock item. He wished Professor Gordon were at Spindrift. Gordon could
have measured the wave length of the searchlight on the lab equipment.
Rick wasn't skilled enough to use the delicate spectroscopic wave
analyzer as yet and Hartson Brant was busy with a problem in the
library and couldn't be disturbed. He hoped he would have a chance to
ask his father before he tested the camera.

He rechecked the data that had come with the film and started to do
some figuring.

Scotty came in just as the phone rang downstairs. Both boys waited
expectantly, and in a moment Mrs. Brant called. "It's an out-of-town
call, for either one of you."

"We'll take it up here, Mom," Rick called back. He and Scotty raced
for the landing.

Scotty reached the phone first. "Hello?" He nodded at Rick. "It's
Cap'n Mike."

Something had told Rick that the call would have to do with the
Seaford case. He glanced at his watch. It was almost noon.

Scotty held his hand over the mouthpiece. "He wants to know if we're
coming down today. Says he has something to talk over with us."

Rick said quickly, "We'll be down by boat right after lunch."

Scotty relayed the information and hung up. "He didn't say what it
was, but he so