Since sending you my experience with gas on roots of trees, I have come across the following article in the Gardeners' Magazine, which some of your readers may not see. It says : " Cuttings of willows, the lower ends of which were placed in flasks containing a little water and filled with coal gas, developed only short roots, and the buds on the upper part died shortly after unfolding in the air. Of ten plants in pots, amongst the roots of which coal gas was conducted through openings in the bottom of the pots, seven died in four months. To show that the plants were killed, not by the direct action of the gas, but in consequence of the poisoning of the soil, several were made with earth through which coal gas had passed for two or three hours daily for two and a half years. The rootlets of seeds sown in this soil remained very short and soon rotted. These results sufficiently account for the fact that trees planted near gas pipes in streets so often die. The enclosing of gas pipes in wider tubes having openings to the air, through which currents could be maintained by artificial means, has been recommended as a remedy." This is similar to my suggestion offered about enclosing the pipes in some kind of cement.

Openings could be left to the surface in the same manner, by insertion in the cement of short lengths of pipes. There is no doubt where the soil has been once impregnated with the gas, it is fatal to vegetation, and its renewal for a large space around will be necessary to ensure success after this precaution is taken; and, perhaps, if your complainant will remove as much of the soil as he possibly can, and renew it, he may yet save his trees. Sup't Gov't Grounds, Canada.