Sept. 22, 1887] 



NATURE 



487 



dial up (flat) position. Want of isochronism would also 

 cause it to vary its rate considerably as time went on. 

 Isochronism is obtained by a careful adjustment of the 

 weight of the balance to the motive power ; and by suit- 

 ing the length, number of coils, and forms of the curves 

 at the terminations of the balance-spring to circumstances, 

 as may be required. For example, A, Fig. 12, shows the 

 contour of the curves which terminate the spring of 

 a marine chronometer ; B and C, the contours of a 

 pocket chronometer spring. It must not be supposed 

 that all marine or pocket chronometer springs are alike. 

 The correct form is generally arrived at after prolonged 

 trial and patient fashioning. 



Technical education has not been neglected in recent 

 years by English watch-makers. Indeed, the necessity 



Fig. 13. — Loseby's Balance. 



for it has been too keenly felt to allow them to forget it. 

 But for a long time there was nobody to help or even to 

 advise them. Under such conditions a small party took 

 the matter into their own hands, and founded the Horo- 

 logical Institute. With very little encouragement they at 

 first worked on, but have now the satisfaction of seeing 

 their efforts successful to an extent which they could have 

 scarcely anticipated. Workshops, science and drawing 

 classes are to be found at the Institution ; and examina- 

 tions, under the auspices of the City and Guilds of London 

 Institute, are periodically conducted, and certificates of 

 proficiency granted. 



Before concluding we give two diagrams which may be 

 of interest. They refer to the subject of secondary com- 

 pensation, one of them, Fig. 13 (Loseby's), representing 



Fig. 14. — Kullberg's Balance. 



one of the oldest, and the other, Fig. 14 (Kullberg's), one 

 of the most recent forms of balance for the purpose. It 

 will be seen that Loseby's object was effected by means 

 of curved mercurial thermometers — the lower the tempera- 

 ture the more indirectly the mercury receded from the 

 centre, checking the action of the compensation : with 

 Kullberg's the supplementary compensation screws are 

 checked directly. 



There have been many improvements in the lever 

 escapement. Fig. 1 5 shows one of the most remarkable. 

 In this case the discharging is effected by means of two 

 pins in the roller, and the impulse given by means of a 

 pin in the lever working into the notch on the roller. The 

 effect is that the unlocking takes place at about the line 

 of centres, and the impulse is given more advantageously. 



Resilient escapements are those which will enable the 

 watch-balance to make several turns in the same direc- 

 tion without injury to the escapement. They often save 

 a breakage in the case of a blow or jerk ; their invention 

 is due to Mr. Cole. We ought not to close this article 

 without mentioning the fact that the manufacture of the 



Fig. 15. — Savage's Two-pin Lever Escapement. 



duplex escapement, which was at one time reckoned the 

 very first, has been completely abandoned. Besides its 

 liability to stop, it was found that the wear in the pivot- 

 holes made its timing and adjustment exceedingly pre- 

 carious. 



Henry Dent Gardner. 



THE BRITISH ASSOCIA TION. 

 SECTION F. 



ECONOMIC SCIENCE AND STATISTICS. 



Opening Address by Robert Giffen, LL.D., V.P.S.S., 

 President of the Section. 



The Recent Rate of Material Progress in England. 



In coming before you on this occasion it has occurred to me 

 that a suitable topic in the commercial capital of England, and 

 at a time when there are many reasons for looking around us 

 and taking stock of what is going on in the industrial world, will 

 be whether there has been in recent years a change in the rate 

 of material progress in the country as compared with the period 

 just before. Some such question is constantly being put by in- 

 dividuals with regard to their own business. It is often put in 

 political discussions as regards the country generally, with some 

 vague idea among politicians that prosperity and adversity, good 

 harvests and bad, in the most general sense, depend on politics. 

 And it must always be of perennial interest. Of late years it 

 has become specially interesting, and it still is so, because many 

 contend that not only are we not progressing, but that we are 

 absolutely going back in the world, while there are evident signs 

 that it is not so easy to read in the usual statistics the evidence 

 of undoubted growth as it was just before 1870-73. The general 

 idea, in my mind, I have to add, is not quite new. I gave a 

 hint of it in Staftbrdshire last winter, and privately I have done 

 something to propagate it so as to lead people to think on what 

 is really a most important subject. What I propose now to do 

 is to discuss the topic formally and fully, and claim the widest 

 attention for it that I possibly can. 



There is nwxch pri?>id facie evidence, then, to begin with, that 

 the rate of the accumulation of wealth and the rate of increase 

 of material prosperity may not have been so great of late 

 years, say during the last ten years, as in the twenty or 

 thirty years just before that. Our fair-trade friends have 

 all along made a tactical mistake in their arguments. What 

 they have attempted to prove is that England lately has not been 

 prosperous at all, that we have been going backwards instead of 

 advancing, and so on ; statements which the simplest appeal to 

 statistics was sufficient to disprove. But if they had been more 

 moderate in their contentions, and limited themselves to showing 

 that the rate of advance, though there was still advance, was 

 different from and less than what it was, I for one should have 

 been prepared to admit that there was a good deal of statistical 

 evidence which seemed to point to that conclusion, as soon as a 



