He made a grating for the altar, a network of bronze under its ledge, halfway up from the bottom.

You are to put it under the ledge of the altar below, so that the network will come ¹  halfway up the altar. ² 

From the base of the ground to the lower edge is 3½ feet, ¹  and the width 1¾ feet; ²  and from the smaller ledge to the larger edge, 7 feet, ³  and the width 1¾ feet;

The ledge is 24½ feet ¹  long and 24½ feet wide on four sides; the border around it is 10½ inches, ²  and its surrounding base 1¾ feet. ³  Its steps face east.”

You will take some of its blood, and place it on the four horns of the altar, on the four corners of the ledge, and on the border all around; you will cleanse it and make atonement for it. ¹ 

The priest will take some of the blood of the sin offering and place it on the doorpost of the temple, on the four corners of the ledge of the altar, and on the doorpost of the gate of the inner court.