John Riley had e-mailed: Please see attached -- even a rough comparison indicates the similar sizes of all three wheel enclosures -- indicated in red on attached. The blue area is the location of the work shop cellar which extends below the level of the access road -- which I showed Bob on Saturday.

John Glithero commented: Thanks for your various emails. Unfortunately last week was hectic and I was not able to work on the measurements of the wheel pit that my friend and I took. I am off to a conference tomorrow and so it will be a while till I can get back to it. I would be grateful for John Riley's attachment with the red wheel pits and blue workshop cellar as below, and I would also be grateful for the relevant parts of the 2009 report. Corn mills usually did not require much power. I still stick with my guess as in my email of 8 May, i. e., Wellington 60hp, Waterloo 40hp,
south wheel 20 hp.

John Smeaton carried out a series of experiments on various types of wheel and he showed that the breast wheel was the most efficient. This knowledge was well diffused by the 1790s. However, if the corn mill was built before the cotton mill, the river could supply much more power than a corn mill would need and efficiency was of little importance. The south wheel might therefore have been undershot. If the corn mill was later than the cotton mill, efficiency was a consideration as the Wellington wheel would be using most of the available water and the wheel would be breast shot. Some form of bypass channel would have been needed to run the Waterloo wheel when the Wellington wheel was not working and this bypass channel must have come from the corn mill.

John Hearle added: If the corn mill was earlier, where did its water come from? It's not a sensible place to build a mill until Oldknow had made the millpond.

Bob responded: Here is what I think is a possible scenario for the relationship between Mellor Mill and the Corn Mill.

1. The location is on the flood plain of the river Goyt - good flat, fertile ground and source of water
2. Surrounding farmsteads growing corn - need for it to be ground to flour for sale, barter or personal use
3. Corn Mill is established and a head race (may have been from the stream down from Linnet Clough or the River Goyt) constructed for an undershot water wheel - basically not much more than a channel which then discharged via its tail race back to the river.  This would be a fairly crude way of using the potential of the river but as John G points out efficiency would not be that important so long as there was sufficient power to drive the mill wheel.  As John R points out the style of the corn mill is totally different from the very grand and formal architecture of Mellor Mill - why would you build something so different (even ugly by comparison) and divorced from the main building if it was intended to be another arm of the business to produce flour for selling to weavers to make size?
4. I am not aware of any detail of what was on the ground (other than well established farmsteads) as Oldknow bought up and leased land to make up the estate - I am not suggesting the corn mill had any great age when Oldknow established the estate - it could have been built just before he made his purchase - anybody's guess
5. Oldknow has decided on the optimum location for his mill and, conveniently it is next to the existing corn mill which is a substantial building with potential use for his industrial complex - why knock it down?
6. The mill is built but to maintain its grand design did not attach to the corn mill
7. As John R points out the, post Mellor Mill build, maps show a very large (almost the size of the other two) wheel house not what would be expected for a fairly low powered corn mill
8. The water wheel for the corn mill is converted to either overshot (unlikely) or breast shot and there is an increased power available for the corn mill - or could some of that power have been transmitted back into the Mellor mill??  There seems to be some evidence that the corn mill wheel was almost the size of the Wellington and the Waterloo (John R measurements of the depth of the tail race). Why would that be if it was only a simple wheel to drive the corn mill?
9. I think that John R has got a very valid point when it comes to the shape of the corn mill.  The "shot off" corner seem to be important to allow road access to the apprentice house and the farm.  I agree this is a likely alteration to make way for the roadway. Surely the original (if it pre-dates the Mellor Mill) corn mill would have been rectangular?
10. There is the canal route survey which doesn't give us much detail of the mill - it just appears as a block.
11. The North mill pond (from the cartographical evidence) was the only one showing as supplying the corn mill and Mellor Mill on the canal survey - so it maybe the South mill pond was a later addition to ensure better supplies of water as demand increased.

I am enjoying this!!  So has anybody any evidence to shoot me, and others, down in flames?  All comments welcome.