aqueduct

article on the process of photochrom: en.wikipedia.org/wiki/Photochrom "A litho stone is coated with a thin layer of purified bitumen dissolved in benzene. A reversed half-tone negative is then pressed against this light-sensitive coating and an exposure in daylight made (taking from 10–30 minutes in summer, to several hours in winter). The bitumen hardens and becomes resistant to normal solvents in proportion to the light. The coating is then washed in turpentine solutions, removing the unhardened bitumen. It is then retouched in the tonal scale of the chosen color to strengthen or soften the tones as required. Each tint needs a separate stone bearing the appropriate retouched image, and prints are usually produced by at least six, and more commonly from 10 to 15 tint stones.[4]"

Correct spelling is Pontcysyllte. (Now a World Heritage Site) en.wikipedia.org/wiki/Pontcysyllte_Aqueduct

hefhoover: Thanks for pointing out the correct spelling. We'll fix the description next time we update.

No problem, thanks for posting these superb photographs. :-)

The aqueduct today. www.flickr.com/photos/speedtree/3488388724/

In August 1913, three men were killed and 62 others trapped in a tunnel in Harlem, part of the Catskill Aqueduct, when a fire started in a blacksmith's shop at the head of the shaft. It was especially dangerous because 900 pounds of dynamite were stored in the tunnel. There was no light, no fresh air, and a lot of smoke, but eventually the trapped men were rescued.

pennylrichards: Thanks for the additional information. We'll include the event and date next time we update the record.

Tremendous sense of scale with the human figures in the image.