Atigusi 7, 1879] 



NATURE 



349 



detent shown in the drawing to fall ; this closes the 

 circuit, and a hook attracted by the coil, catches a 

 tooth cut in the escape-wheel, and holds it till the stan- 

 dard clock reaches the hour. At the hour the standard 

 clock, Fig. 10, allows the lower detent to fall, and so 

 breaks the circuit. Consequently the clock. Fig. 11, 

 starts off side by side with the standard. 



Mr. Ritchie, to whom we have referred before, has also 

 devised a plan for correcting clocks by hourly currents. 

 His clock, to be corrected in like manner, gains some 

 second or two per hour. Fifteen seconds before each 

 hour the lever D B (see Fig. 12) is attracted by the electro- 

 magnet A, and a pin in the arm D would thereupon enter 

 and catch a tooth of the escape-wheel, did the disc M 

 allow the other arm of the lever E to move. When the 

 hand reaches the hour, E falls, then D catches S and holds 

 it till the cessation of the current at the sixtieth second of 

 the governing clock. 



Generally the use of a long telegraphic wire can only 

 be commanded for a few minutes daily. Fig. 13 shows a 

 very suitable arrangement to be adopted when this is the 

 case. By means of the 24-hour disc the line wire is 

 held in communication with the telegraph office until a 



TELEGRAPH 



^ 24 HOUR. 



Fig. 13. 



few minutes before the clock current is going to be de- 

 spatched. The notch in the 24-hour disc will at last 

 allow the system of levers to fall, but then the i-hour 

 disc supports them until about one minute before the 

 clock current is coming ; so that, till then, the line is 

 being used for messages. The line wire has not been 

 allowed to fall into circuit with the battery wire ; this is 

 still prevented by the i-minute disc. At the sixtieth 

 second precisely the I -minute disc allows the line wire to 

 join the battery wire, and out goes the clock current. 

 Some seconds afterwards the i-hour disc lifts the line 

 wire back into communication with the telegraph office, 

 where it stays for another twenty-four hours. 



The Great Westminster Clock reports its own time 

 to Greenwich by the following arrangement : — Some 

 minutes before a signal is due, a lever is lifted by a slow 

 wheel into such a position that a pin in the next wheel at 

 its coming rotation will catch it.» The second wheel lifts 

 it so much further that a pin in the escape wheel reaches 

 it, presses two slight springs together, and sends off the 

 signal. 



A method of driving an electric dial was contrired by 

 the late E. J. Dent. A powerful magnet was lifted through 



a coil of insulated wire by a strong tower clock movement. 

 Every half minute the magnet was dropped a current was 

 generated in the coil, which proceeded to the dial and 

 moved the hands. A plan on the same principle has 

 lately been used for driving a number of small dials. A 

 pendulum having a hollow coil of insulated wire for a bob, 

 is by a heavy weight kept oscillating over a system of mag- 

 nets. Currents are generated in the coil which proceed 

 to the dials and work them. 



Only the principal inventions in electrical clocks and 

 clock-work have been indicated in this article. Since the 

 year 1843 upwards of thirty patents have been applied for 

 for improvements in such clocks and clockwork. It will 

 be seen from this the subject, though not a wide one, is 

 extensive. 



Mr. Ritchie kindly lent diagrams 5, 6, 9, 12, and 13 to 

 illustrate his plans, and M. Collin 10 and 11. Figs, i and 

 3 have been arranged to exhibit their working with clear- 

 ness. Henry Dent Gardner 



TAUNTON COLLEGE SCHOOL 



X^V/^E are sorry to chronicle the extinction of a school 

 » '' once watched with interest by all supporters of 

 scientific education. The company which formed it is 

 insolvent ; the school buildings with the fine library and 

 all the collections and apparatus which the late head- 

 master amassed will be sold for the benefit of the creditors ; 

 the shareholders will lose their money ; and the town will 

 fall back for its higher education on the old, dilapidated, 

 unhealthy grammar school. 



The directors of the company, who constituted the 

 council of the school, have performed no ordinary feat. 

 Four years ago the school was nearly full, its annual 

 profits considerable, its distinctions, and consequent 

 reputation, unprecedented in so young an institution ; 

 public lectures in literature and science attracted to its 

 hall large classes from the town and neighbourhood ; and 

 its systematic teaching of science to all its pupils was 

 studied and imitated by many other schools. The council 

 exhibited sudden activity ; they starved the teaching- 

 staff, interfered with the discipline and management, 

 thwarted, harassed, humiliated the head-master. Warn- 

 ings from parents and old pupils fell upon them unheeded. 

 The last term of 1877 saw two open scholarships at Ox- 

 ford, two places in Cooper's Hill, and a host of minor 

 honours gained by the boys ; but it saw also the head- 

 master bullied into resignation, and all but a handful of 

 the pupils withdrawn by their indignant friends. The 

 fate of the school was clear to all except the council ; it 

 has lingered on only to add to the liabilities of the share 

 holders, who have now met to learn from their directors 

 the history of a great scheme blighted, of insolvency far 

 beyond the value of the mortgaged property, of their 

 ancient school relapsed into the feeble, obsolete, pro- 

 vincial position from which Mr. Tuckwell rescued it. 



ON SUPERS A TURA TION 



A SOLUTION is a case of adhesion overcoming co- 

 hesion ; and when these two forces are in equilibrium 

 the solution is said to be saturated. 



In general the adhesive force is diminished by lowering 

 the temperature, and a portion of the solid, a salt, for 

 example, is thrown down ; but it is increased by raising 

 the temperature, so that the liquid can take up an addi- 

 tional portion of the solid. 



In the case of a large number of salts, but for the most 

 part those that are hydrated, a solution saturated at a 

 given high temperature can be reduced to a lowqr one 

 without depositing any salt, in which case the solution is 

 said to be supersaturated, because it contains more salt 

 than it can take up at the reduced temperature. 



For example, 100 parts of water at 194° F. will 



