"Time measures all things, but I measure it."

So far as we at present know there were four forms of time-measuring instruments known to antiquity—the sun-dial, the clepsydra or water clock, the hour-glass, and the graduated candle.

The sun-dial, by which time was measured by the shadow cast from a pin, rod or pillar upon a graduated horizontal plate—the graduations consisting of twelve equal parts, in which the hours of the day were divided, were, both as to the instrument and the division of the day into hours, invented by the Babylonians or other Oriental race, set up on the plains of Chaldea, constructed by the Chinese and Hindoos—put into various forms by these nations, and adapted, but unimproved, by the learned Greeks and conquering Romans. It appears to have been unknown to the Assyrians and Egyptians, or if known, its knowledge confined to their wise men, as it does not appear in any of their monuments.

The clepsydra, an instrument by which in its earliest form a portion of time was measured by the escape of water from a small orifice in the bottom of a shell or vase, or by which the empty vase, placed in another vessel filled with water, was gradually filled through the orifice and which sank within a certain time, is supposed by many to have preceded the invention of the sun-dial. At any rate they were used contemporaneously by the same peoples.

In its later form, when the day and night were each divided into twelve hours, the vessel was correspondingly graduated, and a float raised by the inflowing water impelled a pointer attached to the float against the graduations.

Plato, it is said, contrived a bell so connected with the pointer that it was struck at each hour of the night. But the best of ancient clepsydras was invented by Ctesibius of Alexandria about the middle of the third century B. C. He was the pupil of Archimedes, and adopting his master's idea of geared wheels, he mounted a toothed wheel on a shaft extending through the vessel and carrying at one end outside of the vessel a pointer adapted to move around the face of a dial graduated with the 24 hours. The vertical toothed rod or rack, adapted to be raised or lowered by a float in a vessel gradually filled with water, engaged a pinion fixed on another horizontal shaft, which pinion in turn engaged the larger wheel. It was not difficult to proportion the parts and control the supply of water to make the point complete its circuit regularly. Then the same inventor dispensed with the wheel, rack, and pinion, and substituted a cord to which a float was attached, passing the cord over a grooved pulley and securing a weight at its other end. The pulley was fixed on the shaft which carried the hour hand. The float was a counterbalance to the weight, and as it was lifted by the water the weight stretched the cord and turned the pulley, which caused the pointer to move on the dial and indicate the hour. The water thus acted as an escapement to control the motive power. In one form the water dropped on wheels which had their motion communicated to a small statue that gradually rose and pointed with a rod to the hour upon the dial.

Thus the essential parts of a clock—an escapement, which is a device to control the power in a clock or watch so that it shall act intermittently on the time index, a motive power, which was then water or a weight, a dial to display the hours, and an index to point them out—were invented at this early age. But the art advanced practically no further for many centuries.

The hour-glass is too familiar to need description.

The incense sticks of the Chinese, the combustion of which proceeded so slowly and regularly as to render them available for time measures, were the precursors of the graduated candles.

With the ungraduated sun-dial the Greeks fixed their times for bathing and eating. When the shadow was six feet long it was time to bathe, when twice that length it was time to sup. The clepsydra became in Greece a useful instrument to enforce the law in restricting loquacious orators and lawyers to reasonable limits in their addresses. And in Rome the sun-dials, the clepsydras and the hour-glass were used for the same purpose, and more generally than in Greece, to regulate the hours of business and pleasure.

The graduated candles are chiefly notable as to their use, if not invention, by Alfred the Great in about 883. They were 12 inches long, divided into 12 parts, of which three would burn in one hour. In use they were shielded from the wind by thin pieces of horn, and thus the "horn lantern" originated. With them he divided the day into three equal parts, one for religion, one for public affairs, and one for rest and recreation.

Useful clocks of wondrous make were described in the annals of the middle ages, especially in Germany, made by monks and others for Kings, monasteries and churches. The old Saxon and Teutonic words cligga, and glocke, signifying the striking of a bell, and from which the name clock is derived, indicates the early combination of striking and time-keeping mechanism. The records are scant as to the particulars of inventions in horology during the middle ages and down to the sixteenth century, but we know that weights, and trains of wheels and springs, and some say pendulums, were used in clockwork, and that the tones of hourly bells floated forth from the dim religious light of old cathedrals. They all appear to have involved in different forms the principle of the old clepsydra, using either weights or water as the motive power to drive a set of wheels and to move a pointer over the face of a dial.

Henry de Vick of France about 1370 constructed a celebrated clock for Charles V., the first nearest approach to modern weight clocks. The weight was used to unwind a cord from a barrel. The barrel was connected to a ratchet and there were combined therewith a train of toothed wheels and pinions, an escapement consisting of a crown wheel controlled by two pallets, which in turn were operated alternately by two weights on a balanced rod. An hour hand was carried by a shaft of the great wheel, and a dial plate divided into hours. This was a great advance, as a more accurate division of time was had by improving the isochronous properties of the vibrating escapement. But the world was still wanting a time-keeper to record smaller portions of the day than the hour and a more accurate machine than Vick's.

Two hundred years, nearly, elapsed before the next important advance in horology. By this time great astronomers like Tycho Brahe and Valherius had divided the time-recording dials into minutes and seconds.

About 1525 Jacob Zech of Prague invented the fusee, which was re-invented and improved by the celebrated Dr. Hooke, 125 years later.

Small portable clocks, the progenitors of the modern watch, commenced to appear about 1500. It was then that Peter Hele of Nuremberg substituted for weights as the motive power a ribbon of steel, which he wound around a central spindle, connecting one end to a train of wheels to which it gave motion as it unwound.

Then followed the famous observation of the swinging lamp by the then young Galileo, about 1582, while lounging in the cathedral of Pisa. The isochronism of the vibrations of the pendulum inferred from this observation was not published or put to practical application in clocks for nearly sixty years afterward. In 1639 Galileo, then old and blind, dictated to his son one of his books in which he discussed the isochronal properties of oscillating bodies, and their adaptation as time measures. He and others had used the pendulum for dividing time, but moved it by hand and counted its vibrations. But Huygens, the great Dutch scientist, about 1556 was the first to explain the principles and properties of the pendulum as a time measurer and to apply it most successfully to clocks. His application of it was to the old clock of Vick's.

The seventeenth century thus opened up a new era in clock and watch making. The investigations, discoveries, and inventions of Huygens and other Dutch clock-makers, of Dr. Hooke and David Ramsey of England, Hautefeuille of France, and a few others placed the art of clock and watch making on the scientific basis on which it has ever since rested.

The pendulum and watch-springs needed to have their movements controlled and balanced by better escapements. Huygens thought that the pendulum should be long and swing in a cycloidal course, but Dr. Hooke found the better way to produce perfect isochronous movements was to cause the pendulum to swing in short arcs, which he accomplished by his invention of the anchor escapement.

The fusee which Dr. Hooke re-invented consists of a conical spirally-grooved pulley, around which a chain is wound, and which is connected at one end to a barrel, in which the main actuating spring is tightly coiled. The fusee is thus interposed between the wheel train and the spring to equalise the power of the latter.

To Dr. Hooke must also be credited the invention of that delicate but efficient device, the hair-spring balance for watches. His inventions in this line were directed to the best means of utilising and controlling the force of springs, his motto being "ut tensio sic vis," (as the tension is so is the force.) Repeating watches to strike the hours, half-hours and quarters, made their appearance in the seventeenth century. In the next century Arnold made one for George III., as small as an English sixpence. This repeated the hours, halves and quarters, and in it for the first time in the art a jewel was used as a bearing for the arbors, and this particular one was a ruby made into a minute cylinder.

After the discovery and practical application of weights, springs, wheels, levers and escapements to time mechanisms, subsequent inventions, numerous as they have been, have consisted chiefly, not in the discovery of new principles, but in new methods in the application of old ones. Prior to the eighteenth century, however, clocks were cumbrous and expensive, and the watches rightly regarded as costly toys; and as to their accuracy in time-measuring, the cheaper ones were hardly as satisfactory as the ancient sun-dials.

With the coming of the machine inventions and the new industrial and social ideas of the eighteenth century came an almost sudden new appreciation of the value of time. Hours, minutes and seconds began to be carefully prized, both by the trades and professions, and the demand from the common people for accurate time records became great. This demand it has been the office of the nineteenth century to supply, and to place clocks and watches within the reach of the poor as well as the rich. While thus lessening the cost of time-keepers their value has been enhanced by increasing their accuracy and durability.

Among the other ideas for which the eighteenth century was famous in watch-making was that of dispensing with the key for winding, thus saving the losing of keys and preventing access of dust, an idea which, however, was perfected only in the last half of the nineteenth century.

The eighteenth century was chiefly distinguished by its scientific improvements in time-keepers, to adapt them for astronomical observations and for use at sea, in not only accurately determining the time, but the degrees of longitude. Chronometers were invented, distinguished from watches and clocks, by means by which the fluctuation of the parts caused by the variations in temperature are obviated or compensated. In clocks what are known as the mercurial and gridiron pendulums were invented respectively toward the close of the eighteenth century by Graham and Harrison, and the latter also subsequently invented the expanding and contracting balance wheel for watches. The principle in these appliances is the employment of two different metals which expand unequally, and thus maintain an uniformity of operation.

The Dutch, with Huygens in the lead, were long among the leading clock-makers. Germany ranked next. It was in the seventeenth century that a wonderful industry in clock-making there commenced, which lasted for two centuries. The Black Forest region of South Germany became a famous locality for the manufacture of cheap wooden clocks. The system adopted was a minute division of labour. From fourteen to twenty thousand hands twenty years ago were employed in the Schwarzwald district. Labour-saving machines were ignored almost entirely. The annual production finally reached nearly two million clocks, of the value of about five million dollars.

Switzerland in watch-making followed precisely the example of Germany in clock-making. It commenced there in the seventeenth and culminated in the nineteenth century. Many thousands of its population were engaged in the business and it flourished under the fostering care of the government—by the establishment of astronomical observations for testing the adjustment of the best watches, the giving of prizes, and the establishment and encouragement of schools of horology conducted on thorough scientific methods. A quarter of a century ago it was estimated that in Switzerland 40,000 persons out of a population of 150,000 were engaged in watch-making, and that the annual production sometimes reached 1,600,000 completed movements. The whole world was their market. The United States alone was in 1875 importing 134,000 watches annually from that country.

As in Germany, so one characteristic of the Swiss system was a minute sub-division of the labour. Individuals and entire families had certain parts only to make. It is said that the Swiss watch passed through the hands of one hundred and thirty different workmen before it was put upon the market. The use of machines was also, as in Germany, ignored. By this national devotion to a single trade and its sub-division of labour, the successful production of complicated watches became great and their prices comparatively low.

The United States in the commencement of its career and at the opening of the century had no clocks or watches of its own manufacture. But it soon followed the example of Germany and Switzerland and established cheap clock manufactories, first of wood, and then of metal, which became famous and of world-wide use. But it could make no headway against the cheap labour of Europe in watch-making, and the country was flooded with watches of all qualities, principally from Switzerland and England. Finally, at the half-way mark in the century, the inquiry arose among Americans, why could not the system of the minute sub-division of human labour followed in watch-making countries so cheaply and profitably, be accomplished by machinery? The field was open, the prize was great, and the government stood ready to grant exclusive patents to every inventor who would devise a new and useful machine. The problem was great, as the fields abroad had been filled for generations by skilled artisans who had reduced the complicated mechanism of watch-making to a fine art. Fortunately the habit had been established in America in several of the leading industries, principally in that of fire-arms, of fabricating separate machinery for the independent making of numerous parts of the same implement, whereby uniformity and interchangeability were established. Under such a practice, which was known as the American system, a duplicate of the smallest part of a complicated machine, lost or worn out thousands of miles from the factory, could soon be furnished by simply sending the number or name of such required part to the manufacturer, or to the nearest dealer in such machines.

With such encouragement and example the scheme of watch-making was commenced. Soon large factories were built, and by the time of the Centennial Exhibition in 1876, the American Watch Company of Waltham, Massachusetts, were enabled to present an exhibit of watch movements made by machinery, which astonished the world. Other great companies in different parts of the country soon followed with the same general system. Machines, working with the apparent intelligence and facility of human minds and hands, and with greater mathematical accuracy than was possible with the hands, appeared:—for cutting out the finest teeth from blank wheels stamped out from steel or brass; for making and cutting the smallest, finest threaded screws by the thousands per hour and with greatest uniformity and accuracy; for jewel-making; for cutting and polishing by diamonds, or sapphire-armed tools, the rough, unpolished diamond and ruby, crysolite, garnet, or aqua-marine, and for boring, finishing and setting the same; for the formation of the most delicate pins or arbors; for the making of the escapements, including forks, pallets, rollers, and scape wheels; for making springs and balances, including the main-springs and hair-springs; for making and setting the stem-winding parts; for making the cases, and engraving the same, etc. The list would be too long to simply name all the ingenious machines there exhibited and subsequently invented for every important operation.

It was the aim of these manufacturers to locate every great factory in some quiet and attractive spot, free from the dust of town, and city, and divide it into many departments, from the blacksmithing to the packing and transportation of the completed article; and to conduct every department with the best mechanical and mathematical skill that money and brains could provide.

The same system was followed with equal success in producing the first-class pocket-chronometer for the nicest work to which chronometers can be put.

Thus with every watch and its every part made the exact duplicate of its fellow, uniformity in time-keeping has been established; and the simile of Pope is no longer so correct, "'Tis with our judgments as our watches, none go just alike, yet each believes his own." A simple statement of this system illustrates with greater force than an entire volume the revolution the nineteenth century has produced in the useful art of horology. And yet the story should not omit reference to the application of the electric system to clocks, whereby clocks at distant points of a city or country are connected, automatically corrected and set to standard time from a central observatory or other time station.

Great as were the advances in horology during the seventeenth and eighteenth centuries, the number of inventions that have been made in the nineteenth century is evidenced by the fact that in the United States alone about 4,000 patents have been granted since 1800, which, however, represent not only American inventors but very many of other countries.

Registering Devices.—Devices for recording fares and money have employed the keenest wits of many inventors and is an art of quite recent origin. Attention was first directed to fare registers in public vehicles, the object of which is to accurately report to the proper office of the company at the end of a trip, or of the day, the number of passengers carried and the fares received. Portable registers, to be carried by the conductor and operated in front of the passenger have been almost universally succeeded by stationary ones set up at one end of the vehicle in open view of all the passengers and operated by a strap and lever by the conductor. These fare registers have been called "A mechanical conscience for street car conductors."

Cash Registers, intended to compel honesty on the part of retail salesmen, are required to be operated by them, and when the proper lever, or levers, or it may be a crank handle, is or are touched, the machine automatically records the amount of the sale, the amount of change given, and the total amount of all the sales and money received and paid out.

Voting Machines—designed to overcome the difficulties, expenditure of time, and the commission of errors and frauds experienced in the reading and counting of votes—have received great attention from inventors, and are not yet in a satisfactory condition. The problem involves the dispensing of printing the ballots, the prevention of fraudulent deposition of ballots, the automatic correct counting of the same, and a display of the result as soon as the balloting is closed.

Successful electrical devices have been made for recording the votes of a great number of persons in a large assembly by the touch of an "aye" or "nay" button at the seat of the voter and the recording of the same on paper at a central desk.

The invention and extensive use of bicycles, automobiles, etc., have given rise to the invention of cyclometers, which are small devices connected to some part of the vehicle to indicate to the rider or driver the rate at which he is riding, and the number of miles ridden.

Speed Indicators.—Many municipalities having adopted ordinances limiting the rate of speed for street and steam cars, bicycles, automobiles, and other vehicles, a want was created, which has been met, for devices to indicate to the passengers, drivers or conductors the rate at which the vehicle is travelling, and to sound an alarm in case of excess of speed, so that brakes can be applied and the speed reduced. Or to relieve persons of anxiety and trouble in this respect, ingenious devices have been contrived which automatically reduce the speed when the prescribed limit has been exceeded.

Weighing Scales and Machines.—"Just balances and just weights" have been required from the day of the declaration, "a false weight is an abomination unto the Lord." And therefore strict accuracy must always be the measure of merit of a weighing machine. To this standard the inventions of the century in weighing scales have come. Until this century the ordinary balance with equal even arms suspended from a central point, and each carrying means for suspending articles to be weighed, or compared in weights, and the later steelyard with its unequal arms, with its graduated long arms and a sliding weight and holding pan, were the principal forms of weighing machines. Platform scales were described in an English patent to one Salman in 1796, but their use is not recorded. The compound lever scale on the principle of the steelyard, but arranged to be used with a platform, was invented and came into use in the United States about 1831. Thaddeus and Erastus Fairbanks of St. Johnsbury, Vermont, were the inventors, and it was found to meet the want of farmers in weighing hemp, hay, etc., by more convenient means than the ordinary steelyard. They converted the steelyard into platform scales. The leading characteristics of such machines are, first, a convenient platform nicely balanced on knife edges of steel levers, and second, a graduated horizontal beam, a sliding weight thereon connected by an upright rod at one end to the beam, and at its opposite end to the balance frame beneath the platform.

The modification in size and adaptation of this machine for the weighing of different commodities amounted to some 400 different varieties—running from the delicately-constructed apparatus for weighing the fraction of a grain, to the ponderous machines for weighing and recording the loaded freight car of fifty or sixty tons, or the canal-boat or other vessel with its load of five or six hundred tons. The adaptation of a balance platform on which to place a light load, or to drive thereon with heavy loads, whether of horses, steam, or water vehicles, was a great blessing to mankind. No wonder that they were soon sold all over the world, and that monarchs and people hastened to heap honors on the inventors.

Spring weighing scales have recently been invented, which will accurately and automatically show not only the weight but the total price of the goods weighed, the price per unit being known and fixed.

In the weighing of large masses of coarse material, such as grain, coal, cotton seed, and the like, machines have been constructed which automatically weigh such materials and at the same time register the weight.

Previous to this century no method was known, except the exercise of good judgment in the light of experience, of accurately testing the strength of materials. Wood and metals were used in unnecessarily cumbrous forms for the purpose to which they were put, in order to ensure safety, or else the strength of the parts failed where it was most needed.

The idea of testing the tensile, transverse, and cubical resisting strength of materials has been applied to many other objects than beams and bars of wood and metals; to belts, cloths, cables, wires, fibres, paper, twine, yarn, cement, and to liquids. Kiraldy, Kennedy, and others of England, Thomasset of France, Riehle of Germany, and Fairbanks, Thurston and Emery of the United States, are among the noted inventors of such machines.

In the Emery system of machines, consisting of scales, gages, and dynamometers, the power exerted on the material tested is transmitted from the load to an indicating device by means of liquid acting on diaphragms. The same principle is employed in his weighing machines.

By one of these hydraulic testing machines the tensile strength of forged links has been ascertained by the exertion of a power amounting to over 700,000 pounds before breaking a link, the chain breaking with a loud report.

The most delicate materials are tested by the same machine—the tensile strength of a horsehair, some of which are found to stand the strain of one and two pounds. Eggs and nuts are cracked without being crushed, and the power exerted and the strain endured automatically recorded. Steel beams and rods have been subjected to a strain of a million pounds before breaking.

Governments, municipalities, and the people generally are thus provided with means by which they can proceed with the greatest confidence in the safe and economical construction and completion of their buildings and public works.