I notice that Theodore Lawrence, of Ogdensburg, N. Y., says that he has succeeded in removing coal tar from hot-water pipes by swab-ing them with hot lye. I apprehend that in that case either the surface of the pipes must have been unusually smooth - as in wrought iron - or else the "painting" must have been done with the tar when cold; for if applied while hot (as is usually the case) it permeates the grain of the iron, almost through it, and in such instances hot lime, lye and a dozen other things, which I know to have been tried in the case of James Park, Brooklyn, L. I., failed to remedy the mischief, and nothing was left to do but to take down the pipes and burn it out.