145:
261:
195:. He took a different approach from that of Harrison, believing that the way to achieve seaworthiness was to detach the escapement from the balance. He also differed from Harrison regarding his temperature compensation method, which used the variation of the rotation radius of the balance by modifying the diameter of the balance through bi-metallic components, a method which would become a standard in chronometers. His technique for temperature compensation was highly efficient in that it worked without changing the length of the spiral balance spring, which he had discovered to be
288:
276:
71:
56:
157:
300:
38:
219:
After having designed plans in 1754, he constructed his first chronometers by 1756, and accomplished his masterpiece in 1766. This remarkable chronometer incorporated a detached escapement, a temperature-compensated balance and an
241:
for the best method of measuring time at sea. He succeeded in giving his instruments the greatest possible regularity by the discovery of the isochronous spiral spring, in which he was in competition with
224:
balance spring, innovations which would be adopted in subsequent chronometers. Harrison demonstrated a reliable chronometer at sea, but these developments by Le Roy are considered by
260:
481:
486:
287:
172:: "The invention of the detached escapement belongs to P. Le Roy". This should not be confused with the detached ‘lever’ escapement which was invented by
144:
228:
to be the foundation of the modern chronometer. Pierre Le Roy's chronometer had a performance equivalent to that of the
Harrison H4 chronometer.
471:
437:
275:
267:
491:
442:
313:
He was the author of several valuable publications on the art and science of clock-making and chronography, among them the
232:
476:
299:
168:
In 1748, he invented a pivoted detent type of escapement, or detached escapement, which makes him the inventor of the
129:
173:
238:
149:
506:
501:
496:
121:
125:
70:
55:
325:
243:
188:
207:
runs at the same rate regardless of changes in its drive force, so it keeps correct time as the
133:
423:
392:
382:
361:
161:
156:
89:
20:
200:
199:
only at a precise given length (i.e. when frequency is independent of amplitude, so that a
333:
97:
465:
379:
Britten's Watch & Clock Makers' Handbook
Dictionary & Guide Fifteenth Edition
192:
109:
93:
324:
The work of Le Roy was not fully recognized in France however, and his contemporary
225:
221:
196:
184:
117:
208:
169:
85:
120:, in which place Pierre Le Roy succeeded his father. He had three brothers:
100:. His developments are considered as the foundation of the modern precision
37:
113:
179:
He was distinguished principally in his mastery and improvement of the
231:
In 1769, after his chronometre underwent testing aboard the corvette
332:, which left Le Roy disillusioned and led him to retire. He died in
204:
180:
143:
105:
101:
148:
Description of the Le Roy detent escapement mechanism by the
394:
A Journal of natural philosophy, chemistry and the arts
328:
became more famous, obtaining the prestigious title of
19:
For the French wine producer Baron Pierre Le Roy, see
191:, in which he carried forward the pioneering work of
420:
Biographical dictionary of the history of technology
63:
48:
28:
374:
372:
237:, he was awarded the double prize offered by the
8:
215:Development of the modern marine chronometer
69:
54:
36:
25:
482:Members of the French Academy of Sciences
155:
357:
355:
353:
351:
349:
345:
256:
438:hautehorlogerie.org: Longitude at Sea
415:
413:
411:
409:
407:
405:
403:
251:Le Roy's prototype marine chronometre
7:
458:(p. 3). Tours: Rouillé-Ladevèze
487:French scientific instrument makers
293:Pierre Le Roy chronometer mechanism
456:Notice sur Julien Le Roy, horloger
443:hautehorlogerie.org: Pierre Le Roy
140:Invention of the detent escapement
14:
266:Pierre Le Roy chronometer, 1766,
298:
286:
274:
259:
246:, but which he published first.
281:Pierre Le Roy chronometer, 1766
128:(1724–1803), an architect; and
94:temperature-compensated balance
16:18th-century French clockmaker
1:
472:18th-century French inventors
454:Dorange, Auguste Jean, 1880:
132:(1726–1779), a physician and
88:. He was the inventor of the
422:Lance Day, Ian McNeil p.429
305:Plans of Le Roy chronometer
523:
432:Sources and external links
124:(1720-1800), a physicist;
98:isochronous balance spring
18:
268:Musée des Arts et Métiers
84:(1717–1785) was a French
44:
35:
317:of 1760. He also became
315:Étrennes chronométriques
165:
153:
492:Scientists from Paris
365:Samuel L. Macey p.348
159:
150:Académie des Sciences
147:
104:. Le Roy was born in
363:Encyclopedia of time
122:Jean-Baptiste Le Roy
116:who had worked with
67:26 August 1785
187:, above all of the
126:Julien-David Le Roy
477:French clockmakers
330:Horloger de Marine
326:Ferdinand Berthoud
244:Ferdinand Berthoud
239:Académie française
189:marine chronometer
166:
154:
112:, a clockmaker to
170:detent escapement
162:detent escapement
152:, 14 August 1748.
90:detent escapement
79:
78:
514:
425:
417:
398:
390:
384:
376:
367:
359:
302:
290:
278:
263:
201:mechanical clock
108:, eldest son of
74:
73:
59:
58:
40:
26:
522:
521:
517:
516:
515:
513:
512:
511:
462:
461:
451:
434:
429:
428:
418:
401:
391:
387:
377:
370:
360:
347:
342:
319:Horloger du Roi
311:
310:
309:
306:
303:
294:
291:
282:
279:
270:
264:
253:
252:
217:
142:
68:
53:
31:
24:
17:
12:
11:
5:
520:
518:
510:
509:
504:
499:
494:
489:
484:
479:
474:
464:
463:
460:
459:
450:
447:
446:
445:
440:
433:
430:
427:
426:
399:
385:
368:
344:
343:
341:
338:
308:
307:
304:
297:
295:
292:
285:
283:
280:
273:
271:
265:
258:
255:
254:
250:
249:
248:
216:
213:
141:
138:
134:encyclopédiste
130:Charles Le Roy
77:
76:
65:
61:
60:
50:
46:
45:
42:
41:
33:
32:
29:
21:Château Fortia
15:
13:
10:
9:
6:
4:
3:
2:
519:
508:
507:Le Roy family
505:
503:
500:
498:
495:
493:
490:
488:
485:
483:
480:
478:
475:
473:
470:
469:
467:
457:
453:
452:
448:
444:
441:
439:
436:
435:
431:
424:
421:
416:
414:
412:
410:
408:
406:
404:
400:
397:
395:
389:
386:
383:
380:
375:
373:
369:
366:
364:
358:
356:
354:
352:
350:
346:
339:
337:
335:
331:
327:
322:
320:
316:
301:
296:
289:
284:
277:
272:
269:
262:
257:
247:
245:
240:
236:
235:
229:
227:
223:
214:
212:
210:
206:
202:
198:
194:
193:John Harrison
190:
186:
182:
177:
175:
171:
163:
158:
151:
146:
139:
137:
135:
131:
127:
123:
119:
115:
111:
110:Julien Le Roy
107:
103:
99:
95:
91:
87:
83:
82:Pierre Le Roy
72:
66:
62:
57:
51:
47:
43:
39:
34:
30:Pierre Le Roy
27:
22:
455:
449:Bibliography
419:
393:
388:
378:
362:
329:
323:
318:
314:
312:
233:
230:
226:Rupert Gould
218:
178:
176:circa 1755.
174:Thomas Mudge
167:
81:
80:
75:(aged 67–68)
502:1785 deaths
497:1717 births
222:isochronous
197:isochronous
185:chronograph
118:Henry Sully
466:Categories
340:References
211:unwinds).
209:mainspring
164:mechanism.
86:clockmaker
52:1717
336:in 1785.
321:in 1760.
114:Louis XV
96:and the
160:Le Roy
381:p.122
234:Aurore
92:, the
396:p.159
334:Vitry
205:watch
181:clock
106:Paris
102:clock
183:and
64:Died
49:Born
203:or
468::
402:^
371:^
348:^
136:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
