The Clay Door Spring John H. Clay, manufacturer of fire department supplies, Philadelphia, Pa., has just recently patented a spring door. It is the Clay No. 400 spring, which the Clay house guarantees to hold doors open so they will not sway no matter how strong the wind is. This was patented November 14th, 1916. In conjunction with the Clay No. 252 door bolt, this spring makes an ideal outfit for fire engine house doors, opening out. The John H. Clay concern specializes in quick opening door devices for doors opening in or out, and also manufactures a four-fold device.