I have copied here, from the "Derivation of Sundry Terms" (Section 5), the description of a Piscina and a Sedilium - simply because I thought that this was a good time to do it!

1. A piscina was a shallow basin or sink in which the priest washed his hands and rinsed the vessels.

2. A sedilium was a seat in the sanctuary for the priests.

Again, the sketches are copies of those appearing in the 1898 publication.