These have been the primary underwater photographs to disclose the ocean ground—in full coloration

One downside which needed to be solved was to synchronize the discharge of the flash-light powder with the digicam shutter, in order that the latter can be huge open on the prompt that the flash had reached its illumination peak. 

A pound of magnesium powder was used for each cost. The ignition of such an quantity of dazzling explosive on a dory piloted by two males, who have been compelled on the identical time to observe the shadowy actions of the diver along with his digicam far under, was greater than human nerves may stand. Especially was this true when it generally occurred that the lads within the boat needed to wait for 2 or three hours, each second anticipating the blinding and deafening detonation. They may by no means know at what prompt the diver would discover his quarry within the desired place with respect to his lens. 

To overcome this nerve-racking suspense, three small pontoons have been constructed to help a dry-cell battery, the flash-light powder, and the reflector. The contrivance, floating upon the floor and guided right here and yon, might be dealt with by the diver himself, leaving the lads within the dory free to observe their colleague underneath sea at a secure and comfy distance from the highly effective explosive, but close to sufficient to keep up the mandatory move of air pumped to the person beneath the floor. The mere setting of {the electrical} connections, nevertheless, inside just a few toes of the massive cost of powder was a hazardous endeavor. 

(How to take photographs underwater.)