Fig. 9—Modern Sand Glass or “Hour Glass”
The most interesting of all water clocks is undoubtedly the “copper jars dropping water,” in Canton, China, where I saw it in 1897. Referring to the simple line sketch, which I make from memory, [Fig. 8], and reading four Chinese characters downwards the translation is “Canton City.” To the left and still downwards,—“Hon-woo-et-low,” which is,—“Copper jars dropping water.” Educated Chinamen inform me that it is over 3,000 years old and had a weather vane. As they speak of it as “the clock of the street arch” this would look quite probable; since the little open building, or tower in which it stands is higher than surrounding buildings. It is, therefore, reasonably safe to state that the Chinese had a weather and time station over 1,000 years before our era. It consists of four copper jars partially built in masonry forming a stair-like structure. Commencing at the top jar each one drops into the next downward till the water reaches the solid bottom jar. In this lowest one a float, “the bamboo stick,” is placed and indicates the height of the water and thus in a rude way gives the time. It is said to be set morning and evening by dipping the water from jar 4 to jar 1, so it runs 12 hours of our time. What are the uses of jars 2 and 3, since the water simply enters them and drips out again? No information could be obtained, but I venture an explanation and hope the reader can do better, as we are all of a family and there is no jealousy. When the top jar is filled for a 12-hour run it would drip out too fast during the first six hours and too slow during the second six hours, on account of the varying “head” of water. Now, the spigot of jar 2 could be set so that it would gain water during the first six hours, and lose during the second six hours and thus equalize a little by splitting the error of jar 1 in two parts. Similarly, these two errors of jar 2 could be again split by jar 3 making four small variations in lowest jar, instead of one large error in the flow of jar 1. This could be extended to a greater number of jars, another jar making eight smaller errors, etc., etc. But I am inclined to credit our ancient Chinese inventor with the sound reasoning that a human attendant, being very fallible and limited in his capacity, would have all he could properly do to adjust four jars, and that his record would average better than it would with a greater number. Remember, this man lived thousands of years before the modern mathematician who constructed a bell-shaped vessel with a small hole in the bottom, and proportioned the varying diameter in such a manner that in emptying itself the surface of the water sank equal distances in equal times. The sand glass, [Fig. 9], poetically called the “hour glass,” belongs to the water-clock class and the sand flows from one bulb into the other, but it gives no subdivisions of its period, so if you are using one running an hour it does not give you the half hour. The sand glass is still in use by chairmen, and when the oldest inhabitant gets on his feet, I always advise setting a 20-minute glass “on him.”
Fig. 10—“Tower of the Winds”—Athens, Greece
In the “Tower of the Winds” at Athens, Greece ([Fig. 10]), we have a later “weather bureau” station. It is attributed to the astronomer Andronicos, and was built about 50 B. C. It is octagonal in plan and although 27 ft. in diameter and 44 ft. high, it looks like a sentry box when seen from one of the hills of Athens. It had a bronze weather vane and in later times sundials on its eight sides, but all these are gone and the tower itself is only a dilapidated ruin. In making the drawing for this cut, from a photograph of the tower, I have sharpened the weathered and chipped corners of the stones so as to give a view nearly like the structure as originally built; but nothing is added. Under the eaves it has eight allegorical sculptures, representing wind and weather. Artists state that these sculptures are inferior as compared with Grecian art of an older period. But the most interesting part is inside, and here we find curious passages cut in solid stone, and sockets which look as if they had contained metal bearings for moving machinery. Circumstantial evidence is strong that it contained a complicated water clock which could have been kept running with tolerable accuracy by setting it daily to the dials on the outside. Probably during a few days of cloudy weather the clock would “get off quite a little,” but business was not pressing in those days. Besides, the timekeeper would swear by his little water wheel, anyway, and feel safe, as there was no higher authority wearing an American watch.
Some very interesting engravings of Japanese clocks and a general explanation of them, as well as a presentation of the Japanese mental attitude towards “hours” and their strange method of numbering them may be expected in the next chapter.
CHAPTER II
JAPANESE CLOCKS
Chinese and Japanese divisions of the day. — Hours of varying length. — Setting clocks to length of daylight. — Curved line dials. — Numbering hours backwards and strange reasons for same. — Daily names for sixty day period. — Japanese clock movements practically Dutch. — Japanese astronomical clock. — Decimal numbers very old Chinese. — Original vertical dials founded on “bamboo stick” of Chinese clepsydra. — Mathematics and superstition. — Mysterious disappearance of hours 1, 2, 3. — Eastern mental attitude towards time. — Japanese methods of striking hours and half hours.