An Odometer, Pedometer, Perambulator, or Way-measurer, is an instrument or machine by which the steps of a person who walks, or the revolutions made by the wheel of a carriage, can be counted, and by which the distance that one has travelled can be ascertained. Vitruvius, in his tenth book15, describes a machine of this kind for a carriage, and which, in his opinion, would answer for a ship. We are told by Capitolinus, in the life of the emperor Pertinax, that among the effects of the emperor Commodus exposed to sale, there were carriages of various kinds, some of which “measured the road, and pointed out the hours;” but whether by these words we are to understand an odometer, cannot with certainty be determined.

That this instrument was known even in the fifteenth century, can be proved from the carving on the ducal palace at Urbino—an edifice erected in an uncommon style of magnificence, by duke Frederic, who died in 1482. The ornaments here employed form, almost, a complete representation of all the warlike apparatus used at that period, both by sea and land; and among these is the figure of a ship, which seems to be furnished with an odometer; but whether the wheels and springs, carved out apart, be intended to show the construction of it, I will not venture to decide16.

The celebrated John Fernel, physician to Catherine of Medici, queen of France, measured with an instrument of this kind, in 1550, a degree of the meridian between Paris and Amiens, and found it to be 68,096 geometrical paces, or about 56,747 toises (364,960 English feet); that is, 303 toises less than Picard found it to be; or about 300 toises less than later measurements have made it. Picard himself, in his mathematical measurement, assisted by the newest improvements, erred 123 toises. It is therefore very surprising that Fernel should approach so near the truth with such an instrument. The manner of constructing it however, as far as I know, appears to be lost17.

Levin Hulsius, in his Treatise of mechanical instruments, published at Frankfort in 1604, describes an odometer, but without naming the inventor. It appears, however, that it was the production of Paul Pfinzing, born at Nuremberg in 155418; and who, besides other works, published, in 1598, Methodus Geometrica, or a Treatise on measuring land, and how to use proper instruments for that purpose, on foot, on horseback, or in a carriage. This treatise, which was never sold, but given away by the author, contains a description of the same instrument described by Hulsius, and which, as Nicolai says, is still preserved in the collection of curiosities at Dresden.

In the same collection is an odometer which Augustus, elector of Saxony, who reigned between the years 1553 and 1586, employed in measuring his territories. This instrument is mentioned by Beutel19, without naming the inventor; but I think it very probable that it was made by Martin Feyhel, who was born at Naumburg, and resided at Augsburg; as Von Stetten20 relates, in his History of the Arts at Augsburg, that Feyhel made a way-measurer (probably odometer) for the elector of Saxony, and that he himself called it a new instrument never before heard of. This artist was an intimate friend of the celebrated Christopher Schissler, also of Augsburg, who in 1579 constructed a quadrant, still to be found at Oxford; and in 1606 an armillary sphere, still preserved at Augsburg.

The emperor Rudolphus II., who reigned from 1576 to 1612, and who was fond of, and acquainted with, the mechanical arts, possessed two very curious odometers, which not only pointed out distances, but also marked them down on paper by the way. The description and use of one of these is given by De Boot21, who was that prince’s librarian; and what he says has been copied by Kircher22, and illustrated with a coarse figure. It is not improbable that the before-mentioned Schissler was the maker of this instrument, as we are informed by Stetten that he constructed a great many machines and automata for the emperor Rudolphus II. The other odometer, which was much more curious, appears to have been constructed by that emperor himself23.

About the end of the 17th century, an artist in England, named Butterfield, invented an odometer which met with great approbation. In the first volume of the Philosophical Transactions there are two papers written by this ingenious man; but of his odometer I have not yet been able to find a description.

In the beginning of the last century, Adam Frederick Zurner, to whom we are indebted for good maps of the electorate of Saxony, invented also an odometer, or geometrical carriage, a description and figure of which, taken from Schramm’s Saxonia Monumentis Viarum illustrata, is given by Nicolai. This instrument is not now to be found in the Dresden collection.

In Bion’s Treatise on the construction of mathematical instruments, improved by Doppelmayer, there is a description of a pedometer, and the author praises a new invention by one Sauveur.

In the year 1724 Meynier laid before the Royal Academy of Sciences at Paris an odometer, a short account of which, without a figure, is given in the history of the Academy for that year. This machine was afterwards improved by Outhier; and a description of the improvements, but without any figure, is to be found in the history of the Academy for 1742. A full description, together with a figure, may however be seen in a work, entitled Machines et Inventions approuvÉes par l’AcadÉmie, t. vii.

Perhaps the most perfect machine of this kind was that made at Berlin by an artist named Hohlfeld, a short account of which may be found in the ninth volume of the Hamburg Magazine. A complete description I have not seen; but I learn from Professor Bernoulli’s Tour through Brandenburg, Pomerania, &c., that a model of it is preserved in the excellent collection of Count de Podewils at Gusow24. The inventor of it was a man of such rare talents, and rendered such benefit to the public, that the following anecdotes of his life may prove not unacceptable to many readers. It was written by Professor Muller at Berlin, and transmitted to me by Dr. Bloch.

Hohlfeld was born of poor parents at Hennerndorf in the mountains of Saxony, in 1711. He learned the trade of lace-making at Dresden, and early discovered a turn for mechanics by constructing various kinds of clocks. From Dresden he removed to Berlin to follow his occupation. As he was an excellent workman, and invented several machines for shortening his labour, he found sufficient time to indulge his inclination for mechanics; and he made there, at the same time that he pursued his usual business, air-guns and clocks.

In the year 1748 he became acquainted with the celebrated Sulzer, at whose desire he undertook the construction of a machine for noting down any piece of music when played on a harpsichord. A machine of this kind had been before invented by Von Unger; but Hohlfeld, from a very imperfect description, completed one without any other assistance than that of his own genius. Of this machine, now in the possession of the Academy of Sciences at Berlin, Sulzer gave a figure, from which it was afterwards constructed in England. This ingenious piece of mechanism was universally approved, though several things may be wanting to render it complete; but no one was so generous as to indemnify the artist for his expenses, or to reward him for his labour.

About the year 1756, the Prussian minister, Count de Podewils, took him into his service, chiefly for the purpose of constructing water-works in his magnificent gardens at Gusow. There he invented his well-known thrashing machine, and another for chopping straw more expeditiously. He also displayed his talent for invention by constructing an apparatus, which, being fastened to a carriage, indicates the revolutions made by the wheels. Such machines had been made before, but his far exceeded every thing of the kind. Having lost this machine by a fire, he invented another still simpler, which was so contrived as to be buckled between the spokes of the wheel. This piece of mechanism was in the possession of Sulzer, who used it on his tour, and found that it answered the intended purpose.

In the year 1765, when the duke of Courland, then hereditary prince, resided at Berlin, he paid a visit to Hohlfeld, and endeavoured to prevail on him to go to Courland, by offering him a pension of 800 rix-dollars; but this ingenious man was so contented with his condition, and so attached to his friends, that he would not, merely for self-interest, quit Berlin. His refusal, however, obtained for him a pension of 150 dollars from the king.

Besides the before-mentioned machines, he constructed, occasionally, several useful models. Among these were a loom for weaving figured stuffs, so contrived that the weaver had no need of anything to shoot through the woof25; a pedometer for putting in the pocket; a convenient and simple bed for a sick person, which was of such a nature, that the patient, with the least effort, could at any time raise or lower the breast, and when necessary convert the bed into a stool; and a carriage so formed, that if the horses took fright or ran away, the person in it could, by a single push, loosen the pole and set them at liberty. The two last models have been lost.

Every machine that this singular man saw, he altered and improved in the simplest manner. All his own instruments he made himself, and repaired them when damaged. But as he was fonder of inventing than of following the plans of others, he made them in such a manner that no one except himself could use them. Several of his improvements were, however, imitated by common workmen, though in a very clumsy manner. It is worthy of remark, that he never bestowed study upon anything; but when he had once conceived an idea, he immediately executed it. He comprehended in a moment whatever was proposed, and at the same time saw how it was to be accomplished. He could therefore tell in an instant whether a thing was practicable; if he thought it was not, no persuasion or offer of money could induce him to attempt it. He never pursued chimÆras like those mechanics who have not had the benefit of education or instruction; and though this may be ascribed to the intercourse he had with great mathematicians and philosophers, there is every reason to believe that he would have equally guarded against them, even if he had not enjoyed that advantage. The same quickness of apprehension which he manifested in mechanics he showed also in other things. His observations on most subjects were judicious, and peculiar to himself; so that it may be said, without exaggeration, that he was born with a philosophical mind.

A little before his death he had the pleasure of seeing a curious harpsichord he had made, which was purchased by his Prussian Majesty, and placed in an elegant apartment in the new palace at Potsdam. As he had for some time neglected this instrument, the too great attention which he bestowed on putting it in order contributed not a little to bring on that disease which at last proved fatal to him. His clock having become deranged during his illness, he could not be prevented, notwithstanding the admonition of his friend and physician Dr. Stahls, from repairing it. Close application occasioned some obstructions which were not observed till too late; and an inflammation taking place, he died in 1771, at the house of Count de Podewils, in the 60th year of his age.

[The instrument now generally used in this country for measuring the distance gone over, is that invented by Mr. Payne, watchmaker, of Bond-street. In this ingenious contrivance motion is communicated from the traveller to the machinery of the pedometer, by means of a horizontal lever, which is furnished with a weight at one end and a pivot or axis at the other; under the lever is a spring, which keeps the lever when at rest close up to a regulating screw; the spring is so arranged as to be only just sufficiently strong to overcome the weight of the lever and to prevent its falling downwards.

When the body of the traveller is raised in progression, the lever is impelled downwards by the jerk, and immediately returned to its place by the spring, and so long as the motion is continued the lever is constantly in a state of vibration. A small ratchet-wheel is fixed to the axis of the lever, and beneath it is another and larger ratchet-wheel which fits on the same axis, but is not attached to it. These two wheels are connected by a ratchet or pale in such a manner, that when the lever falls, both wheels are moved forward one or more teeth, but when the lever rises again from the force of the spring, the larger ratchet-wheel is held stationary by a ratchet. The larger wheel is connected with a series of toothed wheels and pinions, by means of a pinion fixed on its under-surface. The centre wheel carries an index or hand, which points to figures on the dial-plate. The whole apparatus packs into the case of a watch26.]