Spark

The Spark, short for "the spark of genius", is the mental attribute which is the sine qua non of a mad scientist, who is therefore referred to as "a spark". To quote the Professors Foglio, the Spark is "whatever it is that makes Mad Scientists what they are. A poorly understood concept that identifies and incorporates a batch of personality traits shared by those who have it." There can be competent, even brilliant, engineers and researchers who are nevertheless not sparks and therefore will never make the intuitive leaps necessary to "truly warp the laws of nature" and arrive at such creations as Dr. Jekyll's formula, Dr. Frankenstein's monster, a Strong AI implemented in clockwork, or even the absolutely perfect cup of coffee. (However, some apparently sparky creations — such as nuclear submarines equivalent to Captain Nemo's Nautilus, heavier-than-air flying machines, Google AdSense, and mortgage-backed securities — actually do exist in our world.)

It is a rare hereditary trait found mostly within a small number of families - most of the common population that "break through" are either relatively weak or unknowingly related to one or more of these families. Most of those who survive quickly gain minions through sheer charisma, and eventually gather tremendous support unless killed by rival Sparks. Those that survive this process of attrition become the power players of their fictional world, and if they successfully reproduce they begin lineages that are nothing less than royalty – right down to personal heraldic sigils: the Heterodyne Trilobite, the Sturmvoraus Sword-and-Gear, and the Wulfenbach Winged Rook, for example. However, this does little to satisfy their obsessions, and they spend most of their time dueling rivals when not engaging in dangerous experiments — which is what makes the world of Girl Genius one of unending conflict and cataclysm.

They are thus almost always generally despised, and are colloquially called "madboys" and "madgirls". But calling one this to his or her face is generally considered.

Breaking through
The first trip into the madness place is the definitive point at which one may be called a Spark. Prior to breaking through, the individual may have not shown any particular signs; afterwards, there's no turning back. This is usually traumatic for the Spark and dangerous for bystanders, since breakthrough devices are notoriously destructive (with few exceptions).

If the breakthrough device does not kill its creator and everyone in the general vicinity, and the new spark also survives the retribution of other survivors, he or she becomes part of the incessant power politics of the Gifted, usually as the pawn of an existing power who noticed the chaos, but sometimes (especially with appropriate protection and mentoring) they become players in their own right.

The crazy
"Main article: The madness place"

Even if they're not actually driven insane by the breakthrough, Sparks often lose rationality while they're working. This state tends to be marked by megalomania, increased aggression (especially if interrupted), and a serious loss of perspective.

Personality
Sparks tend to inspire loyalty (or at least obedient fear) in lesser mortals and thus acquire a coterie of minions. This intuitive ability and associated charisma come at a price, however: sparks are mad scientists who lose awareness of practical and ethical concerns in their pursuit of technical apotheosis.

The fact that most of the musical characters are also Sparky suggests that the Spark may be associated with musical ability.

Each Spark's characteristic style
One of the features of the Spark is that each mad scientist has a unique style. At the grossest level this refers to the spark's preferred medium — which is often fairly easy to describe: Agatha Heterodyne works mainly with clanks and small-to-medium sized weaponry, for example; while Dr. Dimitri Vapnoople appears to have worked primarily with small furry animals.

"See also: List of sparky styles"

There's more to it than that, however. A Spark's style seems to remain consistent and recognizable (at least to those who know what they're looking for) across projects, types of project, and technology levels. It has been compared to the distinctive style of a painter, except that artistic styles are generally not inherited. Sparky styles can be.

Distribution of the Spark
Apparently, only a small minority of the European population have the Spark.

Degrees and limitations
While most of the Girl Genius main characters (Agatha, Tarvek, Gil, the Baron) who are obviously sparks are clearly "major", or strong, sparks, there are many minor sparks as well. Although sparks generally have the ability to "warp the laws of nature", their actual effectiveness — and which laws they can get handle on — can be limited either by the unique characteristic style of their spark or even, apparently, by a simple lack of education. The Chef from the Circus is such a spark. In addition, Dr. Dimitri Vapnoople was apparently incapacitated by the Baron's brain coring.

Null sex correlation
It is (or has become) generally understood that, despite the title Girl Genius, there is no (measurable) inherent difference in probability of males and females breaking through. But there are many more male than female sparks in Agatha Heterodyne's Europa, but this is apparently due to external forces.

Physical hardiness
Sparks are known for generally having a stronger constitution than ordinary human beings. For example, Othar Tryggvassen, Gentleman Adventurer, has repeatedly survived falling off airships. Sparks are also capable of rejecting or resisting ordinary slaver wasps.