Down, June 5th [1859].
I thank you much for your letter.

Had I seen the interest of my remark I would have made many more measurements, though I did make several.
I stated the facts merely to give the general reader an idea of the thickness of the walls.

(73/1.

The walls of bees' cells: see Letter 173.) Especially if I had seen that the fact had any general bearing, I should have stated that as far as I could measure, the walls are by no means perfectly of the same thickness.

Also I should have stated that the chief difference is when the thickness of walls of the upper part of the hexagon and of the pyramidal basal plates are contrasted.