Saturday, 3 November 2012

Job's Hooker: of fish, birds, mice, and men

Christopher Hogue seems to have been travelling a parallel trajectory to mine concerning an interest in mouse trap history. We both embarked in 2006 on peculiar and parallel enquiries. Though I do not know the cause for this coincidence, I have a hunch. On December 20, 2005 Judge Jones ruled that teaching Intelligent Design in biology classes at US schools is unconstitutional. Possibly the media hype following on this prompted both of us to take a closer look at ID claims, such as Behe's claim that mouse traps cannot have precursors that worked with one part less, because a current trap cannot work with one part lacking. 

Unlike others producing mere just-so stories of how the common flat snap mouse trap might have evolved from simpler precursors, we dug ourselves into the historical records. However, that's where the parallels end. Whereas I got into contact with David Drummond, Christopher's mouse trap expert was Rick Cicciarelli.

Spring loaded flat animal traps existed long before the 19th century and in cultures that did not protect ideas by patents. For example, I have found links to early 19th century tinkeres and peddlers from Slovakia and Germany, to medieval torsion traps, and to ancient Egyptian bird traps. Nevertheless, the traps recorded in the form of patents are of special interest, because their records are exceptionally detailed and exactly dated.

Summary of Hogue's findings
Rick pointed Christopher to a very rare flat snap rat trap (fig. 1) by Job Johnson in his collection, which bears a stamp advertising a patent of 1847. The given US patent number 5256, however, turned out to relate to a spring loaded fish hook by Job Johnson. Hence, even this micro-history of rodent traps is very complex and we need more than just the patents as records, in order to reconstruct it.
Fig. 1: Spring loaded rat trap with a fish hook set/release mechanism patented in 1847
Enter Todd Larson, who has published a book on the hisotry of American fish hooks and come accross an article in The Prairie Farmer of 1847. It reviewed the spring loaded fish hook of Job Johnson and concluded:
"Those who wish to catch rats have got the machinery here." 
According to Larson, the fish hooks were actually used to catch rodents by farmers. Job Johnson, being a prodigious inverntor, seems to have taken the challenge and stuffed the set/release mechanism of his patented fish hook into a wooden platform adding a barbed striker and thus turning a veritable fish trap into a veritable rat trap.

As the fish hook was patented, Job Johnson's advertise his patent of 1847 on his rat trap as well. The stamp on the specimen in Rick's collection, however, does not necessarily give us the exact date, when Johnson invented this rat trap. Nevertheless, Johnson's rat trap has one part less than current flat snap traps, because the bait hook and holding bar were made of one wire part.

Johnson's invention of a rat trap is analoguous to the way Slovakian tinkerers turned a veritable bird trap into a veritable mouse trap by mounting spring, striker, and set/release mechanism of a common bird trap (fig. 2) on a wooden platform (fig. 3). Hence, the conversion of a fish trap on the one hand and a bird trap on the other into similar rodent traps is a convergence in mouse trap history.
Fig. 2: Bird traps of a very old design still (illegally) used in the Mediterranean
As with all evolutionary convergences, there are structural differences to be gleaned from a closer inspection. For example, the Johnson rat trap (fig. 1) has its set/release mechanism sunk into a hole in the wooden platform, whereas the tinkerers mounted the set/release mechanism on top of the wooden piece (fig. 3).
Fig. 3: Slovakian tinker tap
In this respect, the tinker trap (fig. 3) is closer in design to the direct precursor of all current flat snap mouse traps, Hooker's 'Out O' Sight' (fig. 4). As you can see, both the tinker trap (fig. 3) and Hooker's trap (fig. 4) have a holding bar fixed on top of the wooden platform, and it hinges the striker, when set, from above the striker. In Johnson's rat trap (fig. 1) the bait hook and holding bar are made of one wire that runs through a hole in the wooden base, and it hinges the striker from below. Unfortunately, this part is difficult to discern in figure 1. This difference in design suggests that Johnon's rat trap is a distant relative in terms of disign similarity.
Fig. 4. Hooker's 'Out O' Sight' made according to his patent of 1894.
Nevertheles, Johnso's trap (fig. 1) is similar to the bird trap (fig. 2) and the tinker trap (fig. 3) in that their spring and striker are made of two parts, whereas Hooker's 'Out O' Sight' (fig. 4) has its spring and striker formed of one wire. (Hence, both Johnson's and Hooker's trap worked with one part less than current flat snap traps.) Mouse traps with a spring-striker unit were common in renaissance traps. Furthermore, Hooker had previously patented a mole trap that consisted entirely of only two wire parts with the frame, striker and spring being all made of one wire.

Convergence, hybridization, or work-around
Anyway, a distant relative is still a relative whereas evolutionary convergence is a concept usually applied to similar adaptations in non-relatives. This raises the question whether we have here, two convergent but not related inventions of spring loaded flat rodent traps, or whether Hooker drew some inspiration from Johnson's trap as well.

Unfortunately, iventors are secretive about their sources of inspiration lest the patent application might be rejected. Furthermore, an inventor might even draw inspiration from an example used to work out a different design. For example, a trap might be a source of inspiration in some general features (flat, spring loaded) but differ in other respects (set/release mechanism) on purpose. This is known as the Hannah principle (Temkin and Eldredge 2007). It means the purposeful working around a certain design, either to evade a patent protection or to circumvent other drawbacks of the design that serves as inspiration. Here, the best indication of what Hooker wanted to improve is the text of his own patent:
"The object of the present invention is to provide, for catching mice and rats, a simple, inexpensive and efficient trap adapted not to excite the suspicion of an aniumal, and capable of being arranged close to a rat-hole, and of being sprung by the animal passing over it when not attracted to the bait. [...] The particular construction of the catch forms a very sensitive trap, [...] The slightest pressure on the trigger will cause the springing of the trap." Hooker (1894)
Clearly, Hooker had some existing traps in mind that were more complex, more expensive to produce, and would not spring when an animal only passed over it without being attracted to the bait. That is, Hooker himself described his invention in terms suggesting that he had applied the Hannah principle and worked around some drawbacks of traps existing at his time.

Johnson's rat trap, the bird trap, and the tinker trap all have a bait hook that needs to be pulled by the animal, in oder to release the catch. The animal needed to be attracted by the bait and pull it, in order to get it from the hook. Furthermore, Johnson's trap must have been more difficult and expensive to produce, since it required drilling a hole into the base, running a wire through the hole and forming that wire into a bait hook at one end and into a holding bar at the other.

The way to decide questions about sources of inspiration in cultural ecolution should be the oppposite of the rule deciding about homology in biological evolution. In biology, a similariy is taken to be convergent unless further evidence for homology is available. In cultural evolution, the patent officer's rule should be applied (Dagg 2011), that is, an invention is not taken to be new unless evidence for its novelty is being provided. Otherwise, a common culture pool can be assumed as a general source of inspiration. Accordingly, we must include Johnon's trap among the sources inspiring Hooker, if only as flat, spring loaded rodent trap that requires working around some of its drawbacks.

Priority issues and urban legends
So far, the first known to have patented a flat spring loaded mouse trap has been William C. Hooker. He patented his seminal trap design in 1894 and produced and sold it with the name 'Out 'O Sight.' Despite the evidence on Hooker's priority being available all the time, various later inventors have also been celebrated as THE ones to invent THE flat snap mouse trap as we know it. For example, John Mast's patent filed in 1899 and granted in 1903 is regularly mentioned, although the patent text leaves no doubt that he only improved Hooker's design by adding a safety setting mechanism preventing the trap from hitting the fingers of the person trying to set it. James H. Atkinson's UK patent of 1899 produced and sold as the 'Little Nipper' is also often mentioned.

Anyway, Hooker's priority for patenting (not making) the first flat, spring loaded snap trap must now be passed on to Johnson. However, we do not know when exactly Johnson stuffed his fish hook mechanism in a wooden platform. Simply citing Johnson's patent of 1847 would be as false as citing Mast's or Atkinson's. The mere act of transferring a patented mechanism into a wooden platform was probably not patent worthy or Johnson did not see the need to apply for one. Furthermore Johnson's patent of 1847 was only an improvement of earlier spring loaded fish hooks, such as the invention of the 16 year old George Washington Griswood, which has been patented by Englbrecht and Skiff (1846).

We here have step by step lineages of artefacts flowing so smoothly from fish hooks, bird traps, and other artefacts into rodent traps that such priority issues as above are exactly the wrong way to look at its history. The general picture that now emerges from the records is gradual and reticulated, where giving priority to any one inventor for inventing THE flat, spring loaded mouse trap as we know it would simply be silly.

P.S.: For more on mouse traps from this blog click on the LABEL "mousetraps" in the left side bar. Some hard to get sources are in the link list called SOURCES in the left side bar. You will not see those in the dynamic views of blogger.

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