Improvement connected with Sewer Ventilating Shafts.

摘要

6851. Ham, F. G. S., and Spinks, F. I. March 20. Ventilating. - The ventilating-standard D is seated in a socket B of a casing A, in which is placed a box U to receive dirt, dust, &c. This box may be chained up, supported on brackets, or made integral with the casing.