RONALDS. 101 



nical Perspective.' With this machine he was enabled some years 

 afterwards (in 1835), assisted by Dr. Blair, to procure exact per- 

 spective projections taken from given noted stations, of the Celtic 

 remains at Carnac in Brittany. The result of these researches was 

 published by Mr. Ronalds and Dr. Blair in 1836, and was entitled, 

 ' Sketches at Carnac ; or, Notes concerning the present state of the 

 Celtic Antiquities in that and some of the adjoining Communes.' 

 In connection with this tracing apparatus, he likewise contrived a 

 hrxipod staff used for a support, and which has been much employed 

 for the support of instruments requiring great steadiness, such as 

 telescopes, theodolites, cameras, &c. In the year 1843 he became 

 the first and honorary director of the Kew Observatory, and while 

 occupying this office he supplied the observatory with various new 

 contrivances, for which he received a government reward from the 

 special service fund, and a small pension from the civil list. The 

 most considerable of these contrivances were his atmospheric elec- 

 trical conductor and its appendages, adopted at the Greenwich, the 

 Madrid, and the Bombay magnetic observatories ; his photo-baro- 

 graph, and two photo -thermographs, adopted at the Radcliff obser- 

 vatory, Oxford ; his photo-electrograph, arid three photo-magneto- 

 graphs. Besides the writings above-mentioned, Mr. Ronalds is the 

 author of an article in the Philosophical Magazine of 1814, entitled, 

 ' On Electro-galvanic Agency, employed as a moving power, with 

 descriptions of a Galvanic Clock;' and other articles in the same 

 journal, detailing his original experiments to illustrate the relations 

 of quantity and intensity in the electric pile. He also wrote four 

 Reports on the Kew observatory, which were fully illustrated and 

 printed in the reports of the British Association for the years 1845- 

 50-51 and 52 ; and one paper in the Philosophical Transactions on 

 * Photographic Self-registering Meteorological and Magnetical In- 

 struments,' written in 184G and printed in the year following. In 

 1856 Mr. Ronalds published in French, at Paris, a summary of these 

 reports, with some additions, entitled, ' Descriptions de quelques 

 Instruments Meteorologiques et Magnetiques,' intended to explain 

 his instruments at the French exhibition. 



Mr. Ronalds is now (April 1864) residing at Battle in Sussex, 

 and during the latter years of life has spent much time and part of 

 his small pension, in collecting and collating an electric library, 

 which might be conveniently available for the advancement of his 

 favourite science, and prove worthy of presentation or bequest to 

 some British public institution, so as to form the nucleus of one 

 which might approximate possibly to a complete electrical library. 

 particulars derived from authentic sources. 



