Thelonglingeringdeathof the longminglingspark...
The'long mingling spark'has been a laughing stock for almost 120 years, ever since his peers ridiculed Pennington's use of the term in conjunction with his 1890s creations. What those pioneers kept to themselves, and is now almost forgotten is that many of them quietly adopted long mingling sparks of their own for another 10years until the high tension magneto became commonplace, followed by the 'Kettering' style coil ignition (which came into general use much later on bikes than cars). Before that was the era of the 'trembler' coil.
The Belgian Etienne Lenoir, in his briefly successful non compressing engine, had adopted electric ignition and spark plugs in the 1860s.carl Benz (and let's have none of the Germanified 'Karl' here please the man signed himself Carl), isjust credited with beating Daimler to the first (successful and eventually marketed) 'horseless carriage; and he also used electric ignition. As far as Pubcan divine, this was of the'trembler coil'type, as certainly was that of the production Benztype cars widely licensed and copied by others.
Daimler adopted the fearsome 'hot tube' ignition system, with its exposed petrol burners, but there can hardly have been a longer more mingling ignition than a red hot tube throughout all four strokes. Hiram Maxim, the Pope company's first'horseless carriage' designer, recollects his first long trip with his prototype 'package carrier' tricycle, which reached its destination red hot and with barely any exhaust valve left. He expressed the opinion that only a hot tube ignition could have kept it firing at all.
In 1895 De Dion adopted a form of high tension electric ignition for hisvery popular engines .These ran at relatively high speeds as a result, and used a plain coil it is the large cylindrical lump that hangs from one side of the axle (often left in place on restored trikes, even though not in use).
Nevertheless its points were referred to in period literature as'the trembler'. This was unlike a modern contact breaker which aims for rigidity soasto follow the cam and not bounce the phenomenon that produced rogue sparksand wrecked the reputation of early Bsaspitfires*.
De Dion, however, fitted the moving point midway along a springy arm, with a heavy cam follower end on it , dropping into the cam recessto close the points
Above: Minerva 'contact maker' which was intended for use with trembler coils. It might work with conventional coil ignition, but the current could easily prove excessivefor the fragile points
then rapidly being lifted out again. As confirmed by a 1903 book , the idea seemsto have been that the follower would not only drop into its recess, but that due to its weight it would indeed bounce and reverberate, causing the points to open and close a time or two. In other words, it would intentionally produce more than one spark from a plain coil and also minimise current dra in in emulation of a trembler coil. If it was maladjusted, asalmost certainly happened unintentionally, it probably worked lesswell, for more current, but long pre dated the system attributed to 'Doc ' Kettering 's.
De Dion points were undoubtedly fiddly, and Ixion in his'remin iscences'said that it was rumoured that only three people in England knew how to adjust them correctly . He himself fondly recollects changing such a system on a primitive motorcycle for a 'wipe' contact and t rembler coil, and obtaining more reliable ignition as a result. A valuable additional benefit was that it also greatly eased fault finding. If the coil buzzed near TDC then all was OK, and if not then ➤ it was time to look for missing electricity electricity made audible in fact.
Diagrams of the ignition systems of an early Benz car, and a De Dion tricycle , taken from John Henry Knight's 1902 book on 'Light Motor Carsand Voiturettes; with the De Dion points referred to as a trembler (comments in brackets by PUB).JH Knight was himself the maker of a 'Horseless Carriage' before the repeal of the Redflag act in 1896, and thus unable to develop it