Story of first underwater photo taken in Weymouth

Born in Lake House, Hamworthy in 1822, William grew up to be a man of many talents. Eldest son of a wealthy father, he completed his education in France before returning to live at Yarrells, ( named after the naturist William Yarrell) , Lychett Minster.

He lived and practised in Weymouth as a solicitor from 11 Frederick Place where today is a plaque marking the fact.

The plaque in Frederick Place

One stormy day Thompson was weather-bound for several hours at the Portland ferry Bridge House where the recently demolished Bridge House Hotel once stood. Looking out towards the bridge itself Thompson began to consider the effect of the great force of water running in and out of The Fleet was having on the bridge’s piers. He envisaged that any underwater damage could only be discovered by sending a diver down. He then thought a camera might be a safer and cheaper way of monitoring the situation

He already owned a camera which he was in the habit of using in conjunction with his natural history studies. A carpenter now made him a wooden box large enough to contain the camera. The front of the box was made of plate glass and on the outside of the front there was a heavily weighted shutter, hinged at the top, that could be raised by a long string attached to it. Thumbscrews secured the back of the box so that when the camera had been placed in it, it could be made (Thompson hoped) reasonably watertight. The box was fitted on an iron tripod and provided with a rope for lowering it into the sea and pulling it up again.

William Thompson's home in Weymouth

The next problem concerned the camera itself. Thompson’s camera took a 5 x 4 inch plate which was prepared using the collodion process which required the liquid chemical be poured over the plate be exposed and developed within an hour or so. To solve the problem Thompson set up a tent on Weymouth beach where he prepared and developed the plate

He chose “ a nook in the bay of Weymouth which is bounded by rocks where the area within is of sand and boulders and thickly clothed with many species of seaweeds” to carry out trials.

Thompson and his friend Kenyon, having rowed out a sufficient distance from the beach, lowered the box into 18 feet of water. When he was sure that the apparatus was standing upright on the bottom, he pulled the string that raised the hinged shutter. Thompson made two attempts that day. For the first he allowed an exposure time of five minutes but found that the plate having been developed registered nothing.

The first underwater photograph taken by Thompson

For his second attempt he doubled the exposure time. Although by then the light had deteriorated, he obtained a reasonable satisfactory negative, from which he made a print on which it was possible faintly to discern the outlines of boulders and seaweed. Water had leaked into the camera but this, Thompson was pleased to see, had not seriously affected the quality of the picture. He also noted with surprise that the image had not been inverted, and came to the conclusion that the thick plate glass in front of the lens must have acted as a reversing mirror.

Thompson later designed a better apparatus, but he then lost interest and pursued the matter no further.

Thompson family grave

William Thompson died at 3 Gloucester Row on 15 April 1879. He lies with his wife and other members of the family in All Saints churchyard, Wyke Regis.

His wife Sarah Slade was a member of the important Poole family of Newfoundland merchants …. but that is another story