Adrian Wenner submitted:
>"The depth of the brood-cells of drones and working Bees is about half
>an inch; their diameter is more exact, that of the drone-cells being three
>lines and one third, that of the workers two lines and three fifths.
>These, says Reaumer, are the invariable dimensions of all the cells, that
>ever were, or ever will be made."

 From "Manual of the Apiary", by A. J. Cook, published in 1880:

>Contemporary with Linnaeus and DeGeer was Reaumur, of France, whose experiments and researches are of special interest to apiarists. Perhaps no entomologist has done more to reveal the natural history of bees. Especially to be commended are his method of experimenting, his patience in investigation, the elegance and felicity of his word pictures, and, above all, *his devotion to truth.* [ italics for emphasis in the original ]
>
>The diameter of the worker cells averages a little more than one fifth of an inch -- Reaumur says two and three-fifths lines or twelfths of an inch. But this distinguished author was quite wrong when he said: "These are invariable dimensions of all cells that ever were or ever will be made."
>
>The most promising use of foundation is in the brood chamber. It is astonishing to see how rapidly the bees will extend the cells, and how readily the queen will stock them with eggs if of the right size, five cells to the inch.

Comment:
If you study Reaumur's statement, you will realize several things can be learned. One is a high level of precision. He says the cell is .217 inches wide, two and one sixth inches per ten, or 55.04 mm per ten cells. He also indicates that he has looked at a lot of cells and finds them very consistent ("These are invariable dimensions"). Well, we know he didn't look at enough because we know they *do* vary. By the way, Reaumur did his work around 1740, before foundation was even invented.

Sometime in the late 1800s, foundation was invented and various cell sizes were tried. Obviously, bees construct a range of sizes and will accept a range of sizes. Doolittle writes: "We tried to improve upon the bee as to make them take cells 4 1/2 to the inch [5.64 mm], but we had to give it up, and believe God knew best when he taught them five was right." From this we have the upper limit that bees will accept. The range that I found measuring three old mills was 5.08 to 5.4  mm per cell.

Now accept for a moment that it doesn't matter what size they are, as long as they are in this range. What size would you pick? Some might pick 5 cells to the inch, because this is a nice neat figure (I suspect this is what Cook has done). Some might prefer the larger size because you could get slightly bigger bees (this was thought of as a good thing at the time). Further, as we all know, the cells become smaller with age so starting out with cells at the large end of the range would possibly increase the useful life of the comb.

Now, I have no way of knowing what size cells were before foundation was used. Reaumur says 5.4, Cooke says 5.1. But I have yet to see any proof that it makes any difference at all, as long as they are within the range of 5 to 5.5 mm.

Reports from Africa are that mites can reproduce in 4.9 cells. They reproduce in Apis cerana comb (around 4.9 mm) but cerana has ways of controlling them. As far as them reproducing less in old comb, we bought 15 hives from a beekeeper last spring which had quite old comb in the brood nest. These received no chemical treatments (we were running a test of screened bottom boards). By the end of September, the had all fizzled out due to mites.

PB