cxx 



NATURE 



\August 7, 1879 



STANDARD AND OBSERVATORY TIMEKEEPERS. 



TRADE, 



£Jy[^R'< MANUFATURED BY E. DENT & C 0. ■^«'^°^^^|y|^R'< 



Guineas. 

 Standard Clock, suitable for Private Residences in Town 

 or Country, or Public Institutions, beating seconds and 

 going eight days with once winding; in carved and 

 decorated oak or mahogany case ... ... from 35 



(a) The same, but going one month with once 



winding ... ... ... ... ... from 40 



Standard Observatory Mean-time Clock 80 



(rt) The same, but furnished with electrical contact 

 apparatus with eccentric screw adjustments for 

 dropping a time ball, or transmitting hourly 

 signals ... ... ... ... ... ... 92 



Standard Observatory Sidereal Clock 



80 



(a) The same, but furnished with electrical contact 



apparatus with fine vertical and horizontal screw 

 adjustments for transmitting seconds, currents 

 for controlling other clocks, &c. .. ... 95 



(b) The same, but arranged to omit the current at 



every 6oth second, for pricking on chronograph 

 barrel, &c. 97 



Guineas. 



Standard Observatory Clock, of the most refined con- 

 struction, with barometric compensation, &c. ... 160 

 (a) The same, with Sir Geo . Airy's escapement ... 170 

 {b) The same, with M. Leverrier's electrical contact 



system 200 



The Nroj Standard Clock (the primary standard thnekeeper of 

 the United Kingdom) of the Royal Observatory, Greenwich, wns 

 constructed by £. Dent iSr" Co., and precisely similar instruments 

 are new being made for the Royal Observatories of Spain and 

 Belgium, Standard Clocks of less refined construction for the Ob- 

 servatories of Edinburgh (Royal), Dunsink (Royal Irish), Oxford 

 (University), Pulkowa (Russian Imperial), Geneva (National 

 Swiss); and many others. Foreign and Colonial, have been 

 manufactured. 



Galvanic Chronographic Apparatus, for registering 



the time of occurrence of transits and other astrono- 

 mical phenomena from 120 



The Great Galvanic Chronograph of the Royal Observatory, 

 Greenwich, and the still more powerful Apparatus for the Royal 

 Observatory, Brussels, and other smaller ones for other Observa- 

 tories were constructed by E. Dent <&= Co. 



E. DENT & CO., 



^WATCH. CLOCK, AND CHRONOMETEE MAKERS, 

 61, STRAND, & 34, ROYAL EXCHANGE. FACTORY, GERARD STREET, LONDON. 



THE TELEPHONE COMPANY, LIMITED, 



36, COLEMAN STREET, LONDON, E.G. 



TESTIMONIALS. 



14S to 149, Tottenham Court Road, Lindon, W., 14/A May, 1879 

 To the Telephone Company, Limited, 36, Coleman Street, E.C. 



Dear Sirs, — You will be pleased to hear that the forty Telephones you supplied answer admirably, and are of great con- 

 venience, communicating as they do in some cases with our workshops a mile away. 



The simplicity and ease with which they work, being able to be used by any one, and the great advantage over the Telegraph 

 system in rapid communication and recognition of the voice, must create a great demand for Telephones everywhere. — We remain, 

 dear Sirs, yours faithfully, (Signed) J. MAPLE & Co. 



Midland Railway Telegraph Department, Superintendent's Office, Derby, 28lh April, 1879 



Dear Sirs, — In reply to your inquiry of the 2Sth inst, I have the pleasure to inform you that the Telephones which have 

 been erected on the Midland Railway are working very satisfactorily. — Yours faithfully, (Signed) W. LANGDON 



The Telephone Cojipany, 36, Coleman Street, London, E. C. 



Application for Price Lists or further information to be made to the Manager. 



MICROSCOPIC SPECIALITIES. 



Series 



Series V. — 24 Preparations from the Frog, in 



Case £2 2 o 



„ VI. — 24 Surgical Pathological Preparations 220 



„ A. — 48 Diatomacea; (selected) 2 10 o 



,, B. — 24 ,, (very rare) I II 6 



Pathological and Physiological Preparations in great and constantly increasing variety, and of most valuable descriptions. 15/. to 



30J. per doz. 



I. — 24 Medical Pathological Preparations, 



in Case £2 2 o 



II. — 24 Physiological Preparations, in Case 220 

 III. — 24 Educational ,, „ 220 



IV. — 48 Physiological ,, ,, 440 



Descriptive Lists and full particulars on application to 



ARTHUR C. COLE & SON, 



ST. DOMINGO HOUSE, OXFORD GARDENS, NOTTING HILL, LONDON, W. 



LATE OF 62, ST. DOMINGO VALE, EVERTON, LIVERPOOL. 



Printed by R. CtAv. Sons, and Taylob, at 7 and 8, Bread Street Hill, Queen Victoria Street, in the City of Londjn, .nnd piWisked by 

 '■Macmillan a.\d Co., at the Office. 29 and 30, Bedford Street, Covent Garden. — Thursday, August 7, 1S79. 



