It seems well established that before the appearance of man on earth there were no bicycles, as demonstrated by the presence in that age of the dinosaurs: actually, since the extinction of the great reptiles is mainly due to the running downs by bicycles, it's obvious that the presence of the former rules out the latters. It seems on the other hand that the first Hominidae knew the bicycle, although they fell victim of frequent tumbles for their habit to ring the bell with their feet. It also seems that the typical supraorbital ridge prominence of Neandertal man had a traumatic origin, due to the frequent impacts caused by the tumbles face down from the bicycle.
Some attribute to the Sumerians the invention of the wheel, but according to recent researches the invention of the bicycle would have happened before, and the wheel would have been invented later as a velocipede's accessory, in order to improve its efficiency and comfort. It seems that the more frequent use of the vehicle by the Babylonians was to propitiate the arrival of rain, organizing Sunday trips for cycle tourists.
The riskiness of bicycle circulation in the ancient world is testified by the great number of helmets found, many of which were damaged, while the manufactures commonly known as shields actually were rudimentary windshields, being scarcely functional because they were not transparent.
The first models of bicycle had probably two places, with the two passengers pedaling in opposite direction; later, in the Roman Age, it was probably resolvhistoria de la bicicleta - Andrea Gaddinied to turn the two passengers in the same sense, with the invention of the tandem (the name means: "at long last"), so dear to Cicero, who in one of his orations described the patience needed to put the bicycle chain (in Latin "catilina") back in its place, once it comes out from the sprocket wheel ("Quousque tandem abutere, Catilina, patientia nostra?").
According to the tradition Leonardo da Vinci left a drawing representing a bicycle, but we should discredit this legend: in reality Leonardo invented the motorcycle, but he was forced to give up using it because it was impossible to find a filling station open in the Duchy of Milan, where he dwelt. This difficulty drove him to remove the engine and replace it with a pedal propulsion system. It seems that the genius of Vinci also invented the technique to place the left foot on the left pedal and the right foot on the right pedal, rather than the other way around, and this improved very much the push thrust efficiency and the cyclist's comfort.
We also owe to Leonardo the invention of the first bicycle lamps, consisting of small burning fireplaces, installed on the mudguards, that gave however some safety problem (the bicycles were made of wood), but also feeding problems, mostly in rainy or windy days.
In the sixteenth century the emperor Charles V, who was a cycling fan, was anyway tired of his long and exhausting climbs on the Dutch Alps, gave orders to level them to get a wide plain, nowadays known as The Netherlands.
An important technical improvement was the invention of the saddle, which was useful mostly for the bicycle couriers, accustomed to jumping on the byke and starting in a rush. At first they used horse saddles, equipped with stirrups, which made the push thrust hard, moreover the first cyclists were fitted with spurs, that they used to spur the bicycle on the slopes, causing frequent punctures. Later on the saddles underwent a progressive size reduction, till they reached the current size, not recommending again the habit to jump on the saddle in an exceedingly abrupt way.
Many great scientists and philosophers contributed to the improvement of the bicycle: between them Gottfried Wilhelm von Leibniz, who invented the first antitheft device, very effective, but not particularly handy, since it weighed 43 kgs (95 lbs) and it was built together with the bicycle itself; the same scientist invented the first braking device, composed by a lead anchor weighing about 60 kgs (132 lbs).
Benjamin Franklin invented the lightning conductor as a bicycle accessory, thinking it was useful in order to supply electric power for the lamps, but after some fatal accident occurred to the testers, he preferred to conceive the device as an autonomous invention. Even Søren Kierkegaard was keen on cycling and wrote his work "Either/Or" being urged by the indecision between purchasing either a classic bicycle or a mountain byke.
The French physicist Sadi Carnot invented a peculiar type
of bicycle (the Carnot cycle) running on a gas produced by the
cyclist himself (perfect gas), after the consumption of legumes.
Also Joseph-Ignace Guillotin designed
a model of bicycle, the célérifère,
lacking in brakes and steering, that in reality wasn't a means
of transport, but rather an instrument to administer death penalty,
as an alternative to the guillotine, when used on downhill roads
with hairpin bends.
In 1899 Leopold von Sacher-Masoch invented a simple model of dérailleur, bearing few cogs on the chain ring and many cogs on the cogset, allowing to make the push thrust much harder, but with a lower speed. Sacher-Masoch also took up again the ancient model of bycicle without saddle. Later on the dérailleur was improved, engineering the model now in use, which made the push thrust more efficient, but wasn't appreciated by Sacher-Masoch.
In the twentieth-century the figure of the biochemist Hans Adolf Krebs stands out: he studied the cellular respiration process, which is essential for the physical effort needed to pedal, and therefore named "Krebs cycle".
In the future the bicycle will be surely the kernel of many important technological innovations, as the air conditioning, the cabriolet body, the windscreen wiper, the remote central locking of doors and the Little Trees, as evidence of the age-long incitement action promoted by the velocipede on technology.