This is the inside of the Moody Street Feeder Gatehouse, one of many gatehouses in Lowell, MA. Built in 1848, the underground Moody Street Feeder was part of the northern canal project and was designed by well-known engineer James B. Francis.
The feeder drew water to meet the needs of the Merrimack Mills that were located at the end of the canal, and this is one of the three manually operated sluice gates. They were equipped with counterweighted rack and pinion equipment, which raised and lowered the gate to control the flow of water. These gatehouses were an integral part of the functioning mills in the late 19th century, and historians and scholars maintain that they are still very cool to look at. (I may have made that last part up, although I bet it’s true.)
Have a great weekend.