The governor left town so immediately after my return from Monticello that I had only time to send you two small specimens of the shale; the one burnt. The other as it was taken from the earth. I now send by Mr Cabell some more pieces for your inspection, the difference of colour is produced by the degree of heat. The powder in the papers sent by the boat man are of the same material. The one marked “Basalt Powdered” contains the shale not well burnt. If you will take the trouble to have the specimens powdered, and mix 4 measures of the powder with five of quick lime powdered, make it moist, let it lay two days, and then bring it into order by a little more water, and a good deal of beating, I think that you will find it to answer well. The cement in the barrels requires to be treated in the same way.

I shall be gratified to hear your opinion, after you shall have made some experiments.