The slate is to write on. It's useful for younger children; they can practice their writing or work things out without using up good parchment or copybooks. I shall show you when we next see you, or he can.
The computer is going to prove an insurmountable problem, unfortunately. Never mind it, it was only an idea. I appreciate that you considered it. If you should ever alter your methods so that Mr Madrigal is doing the writing instead, we might look at it again.
O'Hara, if we carry out this plan, there isn't to be any paperwork. It's to be a private arrangement between us, with no records of any sort beyond those which are absolutely necessary for you in the course of your work, to be destroyed afterwards. Officially, I will not have done this, and if all goes well, Siri will drink whatever potion you devise, and never know just what it is for. I shall be placing my trust in you.