?66 



SCIENCE. 



[Vol. XX. No. 517 



In some weight-clocks the striking-train and tell comprise tbe 

 driving-weight. The striting mechanism is released by pins 

 projpclmg from the back of tbe little plates carrying the hour- 

 signs. These pins trip a small lever as the train passes Clocks 

 drawn by a spring have the spring-barrel located in the lower 

 part of the case 



A clock of this type in my possession has the general appear- 

 ance of a hall clock of our grandfathers' days except for its 

 diminutive size It is eight incVies high, three- fourths of an 

 inch deep, and one and one-fouith inches wide. The case is 

 beautifully made of dark wood. The upper part of it. enclosing 

 the works, has glass front and sides, the cap over the balance- 

 wheel, as well as the front plate of thf works, which are of brass, 

 is open-work of graceful design and is gilded. Another clock of 

 this type, also in my possession, is still more diminutive in size, 

 being only three and three-fourths inches hiah, one-fourth inch 

 deep, and three-fourths inch wide. It is made entirely nf brass 

 except the numerals, which are of silver, and is beautifully en- 

 graved and gilded. At the liottom of the case there is a small 

 compartment closed by a hinged door. This contains the key. 

 The numerals are fitted into a dovetail groove in the front of the 

 case, and the hand is carried on a sliding piece attached in the 

 manner before mentioned to the fusie chain. There are no di- 

 visions to indicate the fractions of the hour. 



Another interesting example of this type has a dial engraved 

 with a series of logarithmic curves. On the faces of these clocks 

 there are two rows of characters; when the dials are rectilinear, 

 the characters are arranged in two vertical columns; when cir- 

 cular, in two concentric circles. These rows are some little dis- 

 tance apart, and the characters are unequally spaced. Each 

 numeral is connected to its opposite one by a logarithmic curve. 

 The space between the columns is divided into twelve equal 

 parts by parallel vertical lines, each line having at its upper ex- 

 tremity the sign of a month. The space included between the 

 intei'sections of one of these lines with two successive logarithmic 

 curves, will indicate the length of the corresponding hour for the 

 first day of the month which is indicated by that line. In this 

 clock the index is borne on a cross-bar, vvhich extends across the 

 dial from one column to the other and is attached to the weight- 

 cord. The index is so affixed to this bar that it can be moved 

 along its length, thus passing from one line to the other as the 

 months elapse. When this kind of clock is provided with a cir- 

 cular dial, the logarithmic curves are laid out in the same man- 

 ner and intersected by parallel concentric circles. The hand 

 moves over the dial and is constructed so as to slide through its 

 attachment to its arbor, thus being lengthened and shortened. 



Another clock of this type has a much more complicated struc- 

 ture. Its circular dial revolves and is furnished with movable 

 hour-signs, which are arranged in concentric circular grooves on 

 its face. A pin pi-ojecting from the posterior face of each oppo- 

 site hour-sign enters the groove in a slotted arm which extends 

 across the back of the dial. These arms are acted upon by an 

 eccentric, which in its turn is driven by a train of wheels com- 

 pleting its cycle in a year. The action of this mechanism is such 

 that the opposite ends of the arms and consequently the hour- 

 signs are separated and approximated as the days and nights vary 

 in length. 



It only remains to describe the clocks of the second class, viz., 

 those in which the rate is made to vary in accordance with the 

 seasons. None of these clocks, as far as I am aware, have the 

 balance-wheel and hairspring, but they have its forerunner and 

 immediate ancestor, the escapement of Huygens, which consists 

 of a vertical staff suspended by a fine silk thread attached to its 

 upper end. This staff is provided with lugs which engage the 

 teeth of a crown-escapement wheel, and it bears a horizontal arm 

 from which small weights are suspended like a scale-beam. The 

 rate of the clock is regulated by the adjustment of these weights. 

 In general form, these clocks are rectangular or cube-shaped. 

 The gong is placed on top of the case. The dial is circular and 

 revolves from right to left, the hand being stationary. The case 

 is of brass and is usually highly ornamented. The variation of 

 rate in these clocks is accomplished in two ways, viz,, (1) en- 

 tirely by the adjustment of the weights borne on the arm of the 



escapement, and (2) partly in the foregoing manner and partly by 

 the mechanism itself; the latter form having a double escape- 

 ment, which will be described later. 



The specimen of the former kind which I have is two and one- 

 half inches wide, two and one-half inches deep, and seven inches 

 high over all. The case is of brass, and is beautifully ornamented 

 by chasing, and the wheels, which are cut by hand, are very ac- 

 curately made. The characters are engraved on the dial in two 

 circles, the outer one being composed of the signs of the Chinese 

 Zodiac, and the inner one, of the hour-signs. Below the dial, 

 on the face of the clock, are two openings, through each of which 

 may be seen an astrological character. These characters change- 

 once in twenty-four hours. The weight-cords run over spiked 

 pulleys and have small counter- weights. The clock has a strik- 

 ing-train and a going-train. 



Another clock of this form in my possession is of more compli- 

 cated construction, ft has two escapements, the horizontal armff 

 of which are t'f different lengths. In this clock the variation of 

 rate is accomplished partly by hand and partly by the automatic 

 operation of the mechanism itself. One escapement remains idle 

 during the day and the other during the night, the staff of one 

 being lifted from its engagement with the escapement-wheel at 

 the same time that the other is brought into gear. This is ac- 

 complished by two levers which lie directly below the ends of the 

 vertical staves of the balance. The opposite ends of these levers 

 are acted upon by two cams on the same arbor which cause one 

 of them to rise and the other to fall at the proper moment. 



I have omitted to say anything of the fantastic astrological 

 meanings of the various characters found on these clocks and of 

 the intimate connection between the astronomy, astrology, and 

 horology of the Japanese, and will only add that if they are 

 children in imagination they are certainly giants in mechanical 

 execution. 



Id wrltiua: this article I bave availed myself of tbe ai tides written by Emil 

 .James, Journal Science D'Horology, Vol. VIII.: Anee and Thomas Eggleston, 

 Pb.D. , In ibe School of Mines Quarterly lor July, 18^2. 



SOME BIOLOGICAL NOTES ON AMBLYSTOMA 

 TIGRINUM I, 



BY HENRY LESLIE OSBORN, PHD,, ST. PAUL, MINN. 



There is a salamander, most probably of the species named 

 above, which is very common in this vicinity. In the autumn 

 months, especially during September, it can be found abundantly 

 in cellars or in damp, dark, or semi-dark places about buildings, 

 I have often seen it on the railroad tracks imprisoned between the 

 rails, and many specimens whTch had been run over and killed bj' 

 the cars can be found at this season. Occasionally thej' are seen 

 creeping about on the walks or in the grass, where they are 

 frightened by man's approach and run actively away. They are 

 familiarly called lizards, and the use of that word among the peo- 

 ple of this vicinity can almost always be understood to refer to 

 this animal. It lives in aquaria for an indefinite time, remaining 

 on the bottom, and coming to the surface for renewal of air of the 

 lungs rarely. 



1. The markings of this salamander are vivid yellow spots ui^on 

 a ground of brown-black upon the back, giving place to faint 

 bluish ground and lighter color on the ventral surface. There is 

 a very great deal of variation in the shape and distribution of the 

 spots. In general, they are irregular, elongate figures of various 

 sizes from very small rounded ones up ta those of considerable 

 size, whose length may be equal to half an inch. The directions 

 of the long ones of the spots are not the same, while they are 

 chiefly antero-posterior, some are oblique from behind, forward 

 and inward, while others are oblique from behind, forward and 

 outward. The patterns of the two sides are not " mated," they 

 are entirely independent. Not only so, but there is a distinct 

 line which separates them, and in the middle a black line 

 often cuts directly through the spots, so that, while they meet, 

 they do not match. This last-named condition is very noticealile 

 in the tail, as shown in the accompanying figure. It is very con- 

 spicuous in many cases, but perhaps less noticeable in specimens 



