the people of Athens from the character of his legislation and the miseries he attempted to mitigate. The Greeks had written language and they had literature-Homer, Hesiod, Sappho. They had a system of weights and measures and a coinage. They were prolific in political ideas. But the period just previous to Solon was marked by the tyranny of the oligarchs, the severity of whose legislation gave the term "Draconian" its significance, by widespread poverty, by slavery, by the decline of agriculture and industry, and by the unceasing war of factions. Athens was emerging from such conditions as these, under the reign of Pisistratus, at the moment when the Milesian philosopher is said to have introduced the sundial. We may conceive that the conditions were not favorable to the general adoption of any novelty of this character, but it is noticeable that this period was followed immediately by one of democratic ascendency under the constitution of Cleisthenes, in which the naval power and commercial importance of Athens were vastly augmented, and which continued without interruption until his invincible phalanxes laid all Greece at the feet of Philip of Macedon.

It was during this era of maritime vigor, of commercial prosperity, and of dominating influence at home and abroad, that Athens achieved that splendor in art which has made her a beacon light for all subsequent peoples and ages; and in this period timekeeping in common life had its first development. But the sundial is an instrument of limited capacity; however perfected, it was valueless in the hours of night and in the days of cloud and storm that even sunny Greece does not always escape. But, more than this, it was incapable of indoor use; and in the outgrowth of institutions under democratic order and among a litigious and voluble people a new and singular want had arisen demanding some means of checking time which, from its limitations, the sun-dial could not supply. With her other arts, that of oratory had developed in Athens; but every orator was not a Pericles, and whatever may have been the merits or defects of their performances the inordinate length of these was too great a tax on the tribunals. It therefore became necessary to limit and apportion the time of public speakers in the courts, and to do this equitably some practical means of indicating time was necessary. Hence arose the demand for another instrumentality whose origin and history are now to be traced.

It is proper to pause for a moment here to note a distinction between two kinds of instruments used to measure time. A continuous instrument like a clock, which marks off the hours of the day and night as they pass successively away, is what is called in common language a time-keeper; but there is a class of instruments which do not keep the record of continuous time, but are used only for the checking of brief periods; such an instrument is the glass by which the seaman observes his log or the cook boils her eggs. To such instruments, for the want of a better term, I give the name time-checks, to distinguish them from time-keepers. Their use is quite distinct from that of observing the time of day, and yet it is apparent at once that, by careful attendance, as by turning the hour-glass at the moment when its last sand has run out, the timecheck may be made to perform the office of a time-keeper. The allusions of ancient writers and of some modern ones to devices of these two classes are sometimes misleading and confusing because this distinction has not been kept in view. It is particularly important in the study of the clepsydra, which is originally a timecheck only, while the sun-dial is a true time-keeper.

The clepsydra or water clock, in its simplest form, is traced by historians no further than Greece, about 430 B. C., in the time of Aristophanes, whose familiar references to it show its use for certain purposes to have been common.

I confess I have been far from satisfied with stopping at this halfway house in seeking for the origin of this instrument. I have sought further, and what I have found, if conclusive of nothing, is at least suggestive.

If, taking our lives in our hands, we could step on board a Malay proa we should see floating in a bucket of water a cocoanut shell having a small perforation, through which the water by slow degrees finds its way into the interior. This orifice is so proportioned that the shell will fill and sink in an hour, when the man on watch calls the time and sets it afloat again. This device of a barbarous, unprogressive people, so thoroughly rude in itself, I conceive to be the rudest that search of any length can bring to light. It is in all aspects rudimentary. One can scarcely conceive of anything back of it but the play of children, and, as a starting point. for this history, it is much more satisfactory than what is disclosed in the polished ages of Greece. There is nothing in its structure, if we were to consider that only, to prevent it from being a survival

The protolithic age

of an age long antecedent to the use of metal. might have originated it if we can conceive that protolithic man could have had use for it.

Leaving our piratical friends, to whom we are so much indebted, and passing to their not remote neighbors in Northern India, we find the rude cocoanut shell developed into a copper bowl. Its operation is the same, but the attendant, who stands by and watches the moment of its sinking, now strikes the hour on the resonant metal. It is easy to see-in fact it would be difficult to doubt that this has been an improvement on an apparatus like that of the Malay and the natural result of improvements in other arts, eminently that of metal-working. It is more enduring, more perfectly accomplishes its purpose, and is in the precise direction that improvement on the ruder appliance might be expected to pursue.

Passing from Southern Asia to a people geographically remote, I next observe the water clock in use up to this day in China. We find the metal vessel with its minute perforation as before, but it has undergone a radical change in respect to its manner of use. It is now filled and the water flows from it in drops. Obviously enough the flight of time might be indicated by merely observing when the vessel has emptied itself and then refilling it, which, as will presently appear, was exactly the simplest Greek and Roman clepsydra and differs in no mechanical respect from the ordinary sand glass.

But in the days when the Chinese were a progressive people and developed inventions for which Europe had many centuries to wait, this water clock advanced far beyond the crude thing we have been considering. It would seem that the problem was to increase its usefulness by subdividing the unreasonably long intervals required for the complete emptying of the vessel. If this was done by marking graduations on the inside of the vessel and so noting the decline of the level the difference in its rate could not fail quickly to make itself manifest. The solution of this problem, not obvious at first, was found in so arranging the vessel that it should discharge into another, where the indication would be read in the rise of the surface, and contriving to hold the water in the upper vessel at a constant level. This was done by employing a third source, from which there was a constant flow into the first equal to its discharge. As the head in the middle vessel is thus maintained constant, the rise in the lowest is made uniform. Another radical improvement

enhancing the practical utility of the device was the arrangement of a float on the surface of the water in the lowest vessel. Upon this was an indicator or hand which, in its rise, traveled over an adjacent scale, and so gave a time indication visible at a distance.

To show what progress this structure implies in the development of the mechanical clock it is worth while to glance a moment at the. essential elements of such an instrument. Reduced to its lowest terms a clock consists of three elements only. These are a motor, or source of power, represented in our clocks by a spring or weight; an escapement, or a means by which the stored power in the motor is let off at a measured rate; and a dial, which is but the means by which the rate at which the power is let off is made visible to the eye. In this Chinese water clock we discover all these elements. Water, acted on by gravity, is a familiar form of motor; the small perforation through which it slowly trickles drop by drop is a true escapement, doing in its place just what our complicated mechanisms are doing in theirs; and, rude as it may appear, it is one which mechanicians of our time are not ready to dispense with. The visual indication is given by the rise of the float, causing the pointer to pass over the scale. Going backward from this Chinese clock we perceive, but less distinctly, the same elements in the Indian and Malay devices, in which the operation is reversed. In these the weight of the vessel, held up by the resistance of the water in which it floats, is the power; the perforation admitting the water by slow degrees is the escapement, and the only indicator is the visible sinking of the vessel itself.

The three devices described correspond in the degree of their perfection with the conditions of art and culture among the peoples to which they belong; and, as these conditions appear to have been unchanged for a long period, we hazard little in assuming that they date from a remote epoch. A description of the Hindoo instrument appears in a Sanscrit work on astronomy in which it is adopted for astronomical observations, and Chinese writers do not hesitate to ascribe the invention to Hwang-ti, who flourished, according to their chronology, more than twenty-five centuries before our era, and its later improvement by the introduction of the float to Duke Chau fourteen centuries later.

In describing these three devices in the order in which I have placed them I do not mean to be understood as intimating that they have followed the same order in respect to the time of their develop

ment nor that they have been transmitted from one people to another in the same order. I have, for convenience, proceeded from the lowest form to the highest; but it may well be true that the lower was an adaptation from the higher, fitting it for coarser needs, and so being in a certain sense an improvement. Consideration of the lines of commerce might, in fact, lead to the suspicion that the Malay got his notions from the Chinese, since they must for many centuries have sailed the same waters and been in frequent contact.

But we may come further west. Writers on this subject, while attributing to the Chaldeans the invention of the sun-dial, do not generally accredit them with the knowledge of any other instrument for measuring time. But if we may take as an authority Sextus Empiricus, who wrote near the end of the second century of our era, they had, as he tells quite minutely, the same device and used it in their astronomical observations. "They divided," says this author, "the zodiac into twelve equal parts, as they supposed, by allowing water to run out of a small orifice during the whole revolution of a star, and dividing the fluid into twelve equal parts, the time answering for each part being taken for that of the passage of a sign over the horizon." I see no reason for doubting this. In fact the division of the zodiac into twelve signs seems to require a means of measuring the passage of time at night, and this fact and the story just quoted tally with the conclusion that an instrument of the common generic character borne by all the forms I have described was known among widely distinct peoples of Asia before the dawn of European civilization.

Such an invention is not likely to be lost by political changes while supremacy in the exact sciences is maintained. We know that down to the Medo-Persian conquerors of Babylon each successive dominant race adopted, as has often happened in history, the dress, the manners, and the arts of the conquered; and we need not doubt that this instrument was in use in the Persian Empire when its sword first crossed that of the Greeks.

No record exists of the introduction of the clepsydra into Greece. We might infer from the absence of all reference to it by Herodotus that up to the period when his history ends, 478 B. C., it was not known. Fifty or sixty years later, when Aristophanes was writing his comedies, it was absolutely familiar in Athens. The interval named seems short in accounting for so radical a change in the habits of a people as is implied by the general introduction of such an appli