1854.] 



THE GREENWICH OBSERVATORY. 



311 



Tlie GrccaivkH Observatory.* 



The Annual Visitation of the Royal Observatory took place 

 on Saturday last, when the Board of Visitors inspected this 

 national establishment. The Astronomer Royal, in his Report,' 

 states that he trusts to be able to report at a very early date, 

 the conclusion of the very important operation of determining 

 the longitude difference between the observatories of Greenwich 

 and Paris. 



In his last report, Mr. Airy alluded to the erection of a time 

 sigual ball at Deal, to be dropped every day by a galvanic 

 current from the Royal Observatory. The ball has now been 

 erected by Messrs. Maudslay & Field, and the galvanic con- 

 nexion with the Observatory, through the telegraph wires of 

 the South Eastern Railway, is perfect. The automatic changes 

 of wire communications are so arranged that, when the ball at 

 Deal has dropped to its lowest point, it sends a signal to Green- 

 wich to acquaint Mr. Airy, not with the time of the beginning 

 of its fall (which cannot be in errorj, but with the fact that it 

 really has fallen. The ball has several times been dropped 

 experimentally with perfect success, and some small official and 

 subsidiary arrangements alone are wanting for bringing it into 

 constant use. 



No step has yet been taken for the galvanic determination 

 of the longitude of the Oxford Observatory, but the necessary 

 preparations within that building are now complete. 



The normal clock, with its small adjusting apparatus, has 

 been in constant use. It drops the Greenwich ball and the 

 Strand ball ; it sends daily signals along several railways, and 

 it maintains in sympathetic movements various clocks by 

 galvanic currents. Among other clocks thus moved, one is in 

 the chronometer-room, one at the Observatory entrance gate, 

 and one at the South-Eastern Railway offices, London Bridge. 



The barrel apparatus for the American method of transits, 

 has been practically brought into use, not, however, as Mr. 

 Airy states, without having met with a succession of difficulties 

 which happily have been overcome. Still Mr. Airy considers 

 the apparatus troublesome, consuming much time in the gal- 

 vanic preparations and other details. But its high astronomical 

 merits of general accuracy render the method very far superior 

 to the former mode of observing by the eye and ear. 



The beautiful system of registering magnetical and meteoro- 

 logical changes by means of photography continues to be 

 employed, and efforts have been made to multiply copies of the 

 Photographic Registers. After many experiments, it was 

 found that, by the agency of sunlight upon the back of an 

 original photograph, whose face was pressed closely, by means 

 of a glass plate, upon proper photographic paper belo ,v, there 

 would be no difficulty in preparing negative and inverted 

 secondaries, and, from them, positive tertiaries. Thus, beyond 

 the trouble, which the process involves, Mr. Airy anticipates 

 that it will be easy to multiply copies to any extent which may 

 be desired. 



The changes among the Observatory instruments have been 

 so trifling during the past year as not to require definite notice. 

 A fire-proof room, for the preservation of valuable documents 

 will shortly be constructed, a sum having been granted by the 

 Admiralty for that purpose. 



* Athencnum. 



Under the head of " General Remarks," the Astronomer 

 Royal thus concludes his Report: — -"The past year has, on the 

 whole, been felt as a laborious one. This has arisen from accu- 

 mulation of several perfectly distinct causes. The order of 

 our printing has been disturbed, and this has produced great 

 disarrangement of all our ordinary daily work. The establish- 

 ment of our galvanic system, and its application to American 

 transits, to public time-signals, and more especially to the 

 longitude determination, has caused to the establishment in 

 general, and to myself in particular, a great consumption of 

 time. The preparation of the Observatory Regulations, and of 

 the description of the Transit-Circle, and the closing of the 

 business of the Standard Commission, have required a great 

 amount of writing which could be entrusted to no one but 

 myself. I may confidently hope that in the next following years 

 several of these causes will not be in action. Still I am im- 

 pressed with the feeling that the strength of our establishment 

 is now loaded to the utmost that it can bear. A brief review 

 of the progress of the science of Astronomy and of the arts 

 related to it will show that this must be expected. The number 

 of kuown planets has been largely increased : and I cannot 

 think that in this National Observatory the neglect of any one 

 of the bodies of the Solar System is permissible. The Amer- 

 ican method of transits adds to our labours; but it appears 

 likely to contribute to accuracy, and it will give facilities for 

 the record of the observations made at other Observatories, 

 upon our registering barrels; and if these advantages are estab- 

 lished by experience, the method must be maintained. The 

 public dissemination of accurate time brings some trouble ; 

 but it is a utilitarian application of the powers of the Obser- 

 vatory so important that it must be continued. The galvanic 

 determination of difference of longitude brings with it a mass 

 of work in negotiations, in preparations, and in calculations; 

 but it produces results of such unimpeachable excellence, and 

 of such value to astronomy and geodesy, that it must in any- 

 wise be preserved as part of our system. Time is consumed 

 in experiments for the improvement of our photographic pro- 

 cess', and in measures for the multiplication of copies; but 

 these are worthy objects of attention, which it would be wrong 

 to neglect. All these are additions to the labours of the 

 Observatory as they existed a few years ago, unbalanced by 

 any corresponding subtraction." 



Notices of Books* 



The Book of Nature, an elementary introduction to the Sciences of 

 Physics, Astronomy, Chemistry, Mineralogy, Geology, Botany, 

 Zoology, and Physiology, by Fkiedrich Shoedler, Ph. D. ; trans- 

 lated from the Sixth German Kdltion, by Henry Medlock, F.C.S. ; 

 illustrated by 679 engravings on wood — pp. 691, 8vo ; Philadelphia, 

 Blanchard and Lea, 1853. 



A very complete and exact popular exposition of Natural Science ; 

 well printed, well illustrated, and supplied with a valuable and copious 

 glossary of Scientific terms. The Book of Nature has met with an 

 extensive circulatiou in Germany and England, and is not only well 

 suited to the higher schools, but is particularly to be recommended to 

 that numerous class whose occupations do not permit them to devote 

 a large share of their time to books. We can imagine no better com- 

 panion for the winter evening study of intelligent farmers, and none 

 whicli will be so constantly furnished with practical lessons and exam- 

 ples in their daily walk of life. 



