To the real estate editor: I suggest Mr. Isherwood check through the alternative-energy publications at his loca library -- the Whole Earth Catalogue, for example.
He might also try the Cumberland General Store, RR 3, Crossville, Tenn. 38555 , which supplies by mail order a great variety of similar hardware.
Finally, Mr. Isherwood might like to read through C.H. Stoner's "Producing Your Own Power" (Rodale Press, Emmaus, Pa.) which devotes several pages to explaining the operating principles of rams and includes instructions and diagrams for constructing a ram on-site from ordinary fittings.
My thanks for an interesting and helpful column. It's one of my favorite parts of the Monitor. John A. Schultz Durham, N.C.