A few of these are specifically based on true lineages (which I was rereading) and I'll try to note such.
pg 68 TL. Being a Terrae Magus..."many posses the divinatory ability geomantia...learn to summon and bargain with earth elementals..." I admit I only browsed sections of the divination chapter in mysteries and i'm with out that book currently, is this ability covered in more detail there or anyplace else?
If your longevity ritual expires can you have children again or are you permenantly steril?
pg 85 TL. the vis exchange rate. It says "...follow a simple system of exchange...1 for 2. One pawn vis tenta is generally valued the same as two pawns of vis forma...generally adhere to the following exchange rates"
but then the examples have 1 muto=1 corpus, 2 Aquam=1 Ignem, 2 Intelligo=1 Creo, 4 Vim=1 Rego
Is there a typo here (i didn't find errata) and dont see the connection of 2:1
If you are holding a non talismen staff (1 hand) do you suffer from motionless casting? 2hands?
I'm away from my books but it seems to me that you could use the Hermetic Divination Mystery even if it isn't explicitly written up in the Divination chapter of Mysteries Revised
Summoning Earth elementals is covered in the Curious Ccommon Magics chapter of Mysteries revised.
I know of no baganing rules coverage outside of the main book.
I'd think permanently sterile but I have no rules quote to back this up.
No you don't but once again I don't have a citation to back that up.
1 pawn of a Technique is considered to be worth 2 pawns of a Form, and the Redcaps exchange at 2:1.
So if you have a pawn of Muto (value 2), you can get a pawn of Corpus (value 1).
If you have two pawns of Aquam (value 2), you can get a pawn of Ignem (value 1).
If you have two pawns of Intellego (value 4), you can get a pawn of Creo (value 2).
Finally, if you have four pawns of Vim (value 4), you can get a pawn of Rego (value 2).
I am not certain of the RAW either, but I prefer to rule that wielding a talisman, a casting tool, the material for a Potent spell, vis being expended, Touching the target, etc, does not necessitate motionless casting.
Holding a non-talisman object I would in most cases penalise as Subtle gestures.
As I see it, the most basic part of the gestures of any spell is the forming of the technique with the left hand and the form with the right. If you're holding something, then this should be difficult... Using only one hand should at the very least give you a penalty equal to subtle gestures.
I do not share your opinion, you can still make gestures with that hand in fact if you are gesturing with a wand or staff it could be argued that your gestures are more pronounced. The technique / form hand gestures were art not rules and they've been gone for two editions.
Unless someone has a rules citation this discussion is only about opinion.
However to expand on my opinion (you know, the important one ).
I would find it contrary to the feeling I want to evoke in my games to have a magus put down his magical staff before casting a spell in order to get a bonus. It would be another (albeit minor) complication for my players to tell them they recieve a -2 penalty for subtile gestures because their character is holding a staff. New players have enough to remember as it is.
Well, this really isn't about new players is it? ( ) But even so that's what the SG is there to help them with, and even if those silly -2 are forgotten it really isn't that big a deal (I don't think it makes a difference with most spells). In fact I think the rules are more streamlined - and thus easier to remember - if you stick to 'something in your hand influences your magic'. He might as well be holding a sword and bulky shield or holding on to someone else, as a staff. I nkow you say it is contrary to the feeling, but on the other hand I can think of many nice touches of sorcerors throwing their staff to the ground (maybe turning them to snakes ) or sticking it in the ground before starting to chant. On the other hand I'll still maintain that the little -2 penalty would probably only cause them to do so when about to do really big things (compared to their skills). On the other hand, magical items or things used in conjecture with magic I have no qualms about at all - so if the staff is the magus' trusted talisman or enchanted staff then I see no need for it to distract from his gestures.
We use the Technique/Form hand ideas as inspiration, even if outdated - not out of rules (or in anyway penalizing if done otherwise), but as an 'incharacter tool' for us to use as an acting effect.
ahem... the short answer officially is "no", but...
I've actually written a 7000 word article 6 months ago before The Mysteries was released, entitled "Societas Guernici: Scholae Petrae, Students of the Stone" which dealt with the Terrae magi cult within House Guernicus and their associated lineages, spells and earth elemental summoning rituals / geomantia.
The article is meant to appear in the last issue of Hermes Portal (Hermes.Portal@wanadoo.fr). I extrapolated from the brief introduction in HoH:MC for the Mystery mechanics and Ordeals etc.
Sadly, it's looking like it may never be published.
In about 2 months the publishing agreement with Eric will expire, unless he wants to release me from this earlier, in which case I'll post the article to Sanctum Hermeticum Revisited and/or the forum if people are interested. I'd really like the last issue of HP to come out, but its looking less and less likely and I'm getting tired of bugging Eric. I'll ask him again.
Here's a summary of my take on the Guernicus Mysteries you mention:
Based on a comment by the original author of the Guernicus chapter in HoH:TL, the ability to summon earth elementals was a Mercurian Ritual, similar to the Fenicil's Rituals presented in HoH:TL, page 76-77. I cover this in the article (it's a Lesser Ritual) and also suggested a mechanic to produce temporary elementals similar to the Merinitia Faerie Mystery of Summon Animae.
Geomantia was never more than an idea in the original Guernicus seciton draft and never fleshed out beyond what appears in HoH:TL, but in my article I used the mechanics for Divination from the Ars Notoria chapter of Realms of Power: the Divine, which are similar to the old ArM4 mechanic for the old non-Hermetic Divination Virtue. They were the only "official" mechanics I had available and I didn't want to create a whole new mechanic - I didn't have the Mysteries at the time and so wasn't aware of how Neil had redesigned the Augury Mysteries into Hermetic Divination.
If I reworked the article now that I've read Th Mysteries, I'd probably change it to Hermetic Divination, but have access to learning Puissant Hermetic Divination to make it more usable as it was one of the later Inner Mysteries and any magus who achieved it would have already developed an appreciable Intellego score. The focus on Terram +5 is obvious, but the +2 bonus to "Kingdoms" would seem particularly appropriate to a House that deals with politics and law. I'd probably also suggest a few enchanted devices developed by the cult or enchanted locations (beneath the covenant of Magvillus, the walls of the ruins of Petra etc.) where Guernicus geomancers could gain bonuses to their geomancy totals.
).
) But even so that's what the SG is there to help them with, and even if those silly -2 are forgotten it really isn't that big a deal (I don't think it makes a difference with most spells). In fact I think the rules are more streamlined - and thus easier to remember - if you stick to 'something in your hand influences your magic'. He might as well be holding a sword and bulky shield or holding on to someone else, as a staff. I nkow you say it is contrary to the feeling, but on the other hand I can think of many nice touches of sorcerors throwing their staff to the ground (maybe turning them to snakes 
) or sticking it in the ground before starting to chant. On the other hand I'll still maintain that the little -2 penalty would probably only cause them to do so when about to do really big things (compared to their skills). On the other hand, magical items or things used in conjecture with magic I have no qualms about at all - so if the staff is the magus' trusted talisman or enchanted staff then I see no need for it to distract from his gestures.