Ars Magica spell rules are a critical part of the game, and Fifth Edition guidelines for spell design are the best yet published for Ars Magica. It is a shame that "official" published spells in Fifth Edition supplements don't always conform to them (Covenants especially has many such mistakes). This section is intended to clarify or correct some of the more problematic published spells for use in the Bohemian Rhapsody Saga.

This spell violates the Touch range guidelines. It is useful to touch the weed, as that identifies the kind of plant to destroy, and the properties of Similarity can be used to then destroy like plants. However, Voice range is required to affect all such plants in a 15 pace range - that is, at standard Voice range. This makes the level of the spell 25, not 20.

This spell is especially problematic, as it appears to adhere to the 5th Edition Guidelines. The problem is that the spell imparts knowledge that neither the caster nor the target knows: what action to take for specific properties of the wood. Without a Mentem requisite and a nearby skilled carpenter, that just isn't possible. Without the advice component of the effect, however, the spell is still quite useful, even to a skilled carpenter.

This spell is clearly incorrect, as the Target should correctly be a Group of objects. Re-defining the spell as Base 15, +1 Touch, +2 Group, +1 Complexity, the spell can create the equivalent of a Group of precious metal, or approximately one cubic foot (10 individuals). One cubic foot of silver is 651 pounds of metal (density of 10.5 grams/cubic centimeter). Creating coins would normally require some adulteration with copper (around 5%), for an approximate value of 600 pounds of silver, or around 170,000 Mythic Pennies. This is quite a bit less than the 2,000 Mythic Pounds posited by the Covenants book, but is still enough to last 300 magus-years at the "legal" rate referred to in Covenants. As such it is excessive, and probably a waste of vis (and would not have fit into a single chest in any event).

The above calculation assumes a standard of silver content similar to that of English coinage of the period. As an alternative calculation, one can postulate that the Mythic Pound (and thus the Mythic Penny) is not based on English coinage, which was "sterling" silver, but on more of an average silver penny, such as the French denier tournois. Throughout much of the 13th century, the tournois and the denier parisis were intentionally of comparable value in terms of silver content, and many other coinages in France began to copy their content, if not their form. Thus, the tournois might be used as a basis for a "Mythic Penny" of typical silver content. Using an actual silver content of 1/3 silver for each Mythic Penny, this (corrected) spell would create roughly 900,000 Mythic Pennies (rounding the result), an even greater mass of coinage ( ~ 3,750 Mythic Pounds) and thus even more excessive.

Creating nearly a million Mythic Pennies, however, is not only excessive in terms of the value of coin created, but also in the sheer quantity of objects. Creating grossi, larger coins worth 12 deniers (one sous), would be more efficient and would create coins with a higher proportion of silver content. In terms of grossi, the value of the silver created would not change, but the quantity of coins would be vastly reduced, from 900,000 coins to only 75,000. This would still equal 3,750 Mythic Pounds, and still an excessive amount, but would at least not require an enormous room just to hold it all.

Note: the original ruling stated in Heirs to Merlin (4th Ed.) allowed two pounds of silver per year per resident, "magus or mundane." Using this ruling, magically created silver could be much more prevalent, and a covenant could theoretically subsist on such a ritual every year or three (depending on the size of the covenant). Depending on how one interpreted "two pounds" of silver, it could vary from two Mythic Pounds per resident (assuming the "pounds" refers to Mythic Pounds directly), up to six Mythic Pounds per resident (if the weight refers to the weight of raw silver, and the above alternative using tournois is applied).

However, there is another complication. Conjuring silver coins through magic, even if otherwise permissable in Hermetic law, is counterfeiting, and thus technically illegal. Even if the coins created are not copying any existing coinage, but are a "new" coinage, doing so without minting rights from the local authorities would be illegal as well. In most areas of Mythic Europe, an argument could be made in Hermetic law that such flagrant violations of mundane law interfere with the mundanes, and thus violate the Oath. This issue could in theory be side-stepped by conjuring the silver, not in the form of coins, but in ingots of some standard of silver content. This would not alter the overall value of silver created, but would make it more easily stored and transported in any large quantity. Such ingots were often used in long-range trade for this reason. If local coinage is needed, ingots can be traded for local currency where needed. Thus, a spell to create coins is probably a waste of complexity. Creating a raw lump of metal requires less vis to begin with, and the metal could be transformed readily into suitable ingots by a smith or even through Rego magic.

This spell's design is needlessly complicated by the "+1 size" designation. No matter how many feathers you transform, you're not likely to exceed the weight of 10 ponies, which is what Group Target buys you. No increase in size is necessary, enabling the version with Rego requisite to be merely level 15

Although this spell is listed as PeAn3, it cannot be primarily a Perdo spell, because the net result is an improvement to the quill. ReAn2 is actually easier, and avoids this fundamental flaw in spell design. One could include a Perdo requisite if one wished, but it isn't strictly necessary, since magical crafting using Rego alone is a standard method. A Per + Finesse roll (3+) is ordinarily sufficient to achieve the intent of this spell.

The base guidelines for ReAn are fairly brief, but by comparison with ReCo, the base guideline for level 1 "manipulate items made from animal products" should not be interpreted as encompassing any possible manipulation (and other published spells bear out this distinction: see the spell immediately following). A better base guideline for "as fast as a running man" would be three magnitudes higher, based upon comparable Corpus guidelines. Thus, the base effect for this spell should be 4, not 1, making the final level 25.

Just as with the last spell, the base guidelines are best determined when compared with Corpus - but not taken wholesale from Corpus (going from one extreme to the other). ReAn allows large-scale manipulation of products at base 1. Corpus, however, does not allow large-scale manipulation of bodies until base 4. Thus, the guidelines for movements in ReCo should be reduced by three magnitudes when applied to animal products (as opposed to living animals, where direct level to level equivalence is more appropriate). The base level for this spell should be 5, not 20, making the final level 25.

This is one of the more egregious errors, as there is a specific Corpus guideline for "ward a Target against other human beings" at level 15. Why exactly it is so much harder to ward against humans than animals is left open to question, but the guidelines are clear in this regard. This makes the spell base 15, not 3, for a final level of 30.

Just as with The Scribe's Touch, above, this spell violates the fundamental guideline that Perdo cannot improve. This should be Creo or Rego (either would work). The Creo version is more direct: base 5 (to affect metal implements), +1 Touch, +3 Month, +2 Room, for a final level of 35. Casting requisites to affect items of Herbam or Animal Forms may be required.

Although this spell is listed as level 4, with Target: Individual, that is not possible. The Target of this spell is the ground. Since an Individual Target with Size of the entire earth is unmanageable, Part Target should be used (just as for other Terram effects targeting the ground). This raises the level of the spell to 5.