Lantern slide. Showing the First Catarct. This photograph was taken by Sgt. Johnson of the 436 Welsh Field Company c. 1917. It formed part of a lecture which he gave. The notes from his lecture read 'Here we have the first cataract. This shows you the water as it leaves the sluices of the barrage. By the way there are 120 sluices to the barrage which is 1 1/4 miles long and 40 feet wide at the base.' This view is similar to EC1789.