These are the huge cogs and wheels on one end of a spinning machine. You can see from this how big an issue health and safety would have been in a Victorian mill. There don't appear to be any guards on the machinery. Workers, especially women and children, were frequently injured or killed by the machinery - hair, clothes and scarves got caught, fingers trapped and limbs crushed, and there were reports that some children - who worked long hours until factory reforms were eventually brought in - were scalped when they crawled under the machines or killed when they went to sleep and fell into the machinery.
Thankfully, Titus Salt was not at all uncaring about his workers. In 1868, he built Salts Hospital - originally as a two-storey building with a six-bed casualty ward for accidents at the mill. In time, this grew into a cottage hospital for the whole community. (I haven't yet shown you a good picture of the hospital. I hope to remedy that before too long.)
It's interesting to see that the manufacturer of the spinning machine in the photo was a company in Keighley (pronounced Keethley!), a few miles up the Aire Valley from Saltaire. When textile production in this area died out, it affected many more than those who actually worked in the textile mills themselves.
Visit The Monochrome Weekend site for more B&W photos.