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Report of the Kew Committee of the British Association for the Advancement of Science for 1870-71.
The Committee of the Kew Observatory submit to the Council of the British Association the following statement of their proceedings during the past year:
(A) WORK DONE BY KEW OBSERVATORY UNDER THE DIRECTION OF THE
1. Magnetic work.-In their last Report the Committee stated the plan on which they proposed to reduce their Magnetic observations; they now report that with reference to the reduction of the Magnetic Disturbances from January 1865 to December 1869, the period following that which has already been published, the discussion of Declination and Horizontal Force Disturbances is nearly ready for presentation to the Royal Society, and that of the Vertical Force is in progress; when that is completed, the whole period, 1865 to 1869 inclusive, will have been discussed at Kew. The tabular statement, which is herewith presented (see Appendix I.), exhibits the exact state of the reduction.
Two Dipping-needles by Dover and one by Adie have been tested for Mr. Chambers, Superintendent of the Colaba Observatory; and one needle has been procured from Dover and tested for Prof. Jelinek, of Vienna.
A Dip-circle by Dover has been verified and forwarded to Prof. Jelinek, who ordered it on behalf of the K. K. militär-geographisches Institut.
Major-General Lefroy, Governor of Bermuda, having applied for the loan of a Dip-circle, one has now been prepared for his use, and will be forwarded to Bermuda as soon as possible. A Dip-circle has been obtained from Dover, and, after verification, will be forwarded to the Survey Department, Lisbon.
At the request of Prof. Jelinek the Committee have undertaken to examine a Dip-circle by Repsold. It is of a large size and has eight needles, but Prof. Jelinek reports that the results obtained by them are very discordant.
Copies of certain specified magnetograph. curves have been made and forwarded to the late Sir J. Herschel, M. Diamilla Müller, of Florence, and Senhor Capello, of Lisbon, at the request of those gentlemen.
The usual monthly absolute determinations of the magnetic elements continue to be made by Mr. Whipple, the Magnetic Assistant.
The Self-recording Magnetographs are in constant operation as heretofore, also under his charge.
2. Meteorological work. The meteorological work of the Observatory continues in the charge of Mr. Baker.
Since the Liverpool Meeting, 113 Barometers (including 17 Aneroids) have been verified, and 2 rejected; 1320 Thermometers and 215 Hydrometers have likewise been verified.
Two Standard Thermometers have been constructed for Owens College, Manchester, one for the Rugby School, one each for Profs. Harkness and Eastmann, of the Washington Observatory, four for Dr. Draper, of the New York Central Park Observatory, one for Major Norton, of the Chief Signal Office, Washington, one for Mr. G. J. Symons, and three for the Meteorological Committee.
Three Thermograph Thermometers have been examined for Mr. Chambers, of the Colaba Observatory, and three for the Meteorological Committee.
Two Standard Barometers have been purchased from Adie, and tested at Kew, one of which has been forwarded to the Chief Signal Office, Washington, and the other to Prof. Jack, of Fredricton, New Brunswick.
Tubes for the construction of a Welsh's Standard Barometer on the Kew pattern, together with the necessary metal mountings, and a Cathetometer, have been made under the superintendence of the Committee for the Chief Signal Office, Washington.
The Committee have likewise superintended the purchase of meteorological instruments for Owens College, Manchester, and for the Observatory attached to the University of Fredricton, New Brunswick.
The Kew Standard Thermometer (M. S. A.), divided arbitrarily by the late Mr. Welsh, and employed for many years past as the standard of reference in the testing of thermometers, was accidentally broken on the 3rd of January. Since then a Kew Standard, of the ordinary construction, made in 1866, and which had been compared on several occasions with M. S. A., has been used to replace it.
Copies of some of the meteorological observations made at Kew during the years 1869 and 1870 have been supplied to the Institution of Mining Engineers at Newcastle-upon-Tyne, and the Editor of Whitaker's Almanac, the cost of the extraction being paid by the applicants in both instances.
A set of self-recording meteorological instruments, the property of the Meteorological Committee, have been erected in the Verification-house, and are now undergoing examination.
The self-recording metereological instruments now in work at Kew will be again mentioned in the second division of this Report. These are in the. charge of Mr. Baker.
3. Photoheliograph.-The Kew Heliograph, in charge of Mr. Warren De La Rue, continues to be worked in a satisfactory manner. During the past year 362 pictures have been taken on 205 days. The prints from the negatives alluded to in last Report have been taken to date, and the printing of these has become part of the current work of the establishment. A paper by Messrs. Warren De La Rue, Stewart, and Loewy, embodying the position and areas of sun-groups observed at Kew during the years 1864, 1865, and 1866, as well as fortnightly values of the spotted solar area from 1832 to 1868, has been published in the Philosophical Transactions, and distributed to those interested in solar research. A Table exhibiting the number of sun-spots recorded at Kew during the year 1870, after the manner of Hofrath Schwabe, has been communicated to the Astronomical Society, and published in their Monthly Notices.'
An apparatus is being constructed under the direction and at the expense of Mr. Warren De La Rue, and it will shortly be erected on the Pagoda in Kew Gardens, in order to be employed in obtaining corrections for optical distortion in the heliographical measurements.
4. Miscellaneous work.-Experiments are being made on the heat produced by the rotation of a disk in vacuo.
A daily observation has been made with the Rigid Spectroscope, the property of Mr. J. P. Gassiot.
Observations have been made with two of Hodgkinson's Actinometers, the property of the Royal Society, in order to compare them with the Actinometers deposited at the Observatory, for reference, before forwarding them to India.
The Committee have superintended the purchase of optical apparatus, chemicals, &c. for the Observatories at Coimbra and Lisbon.
An inventory has been made of the apparatus, instruments, &c. at present deposited in the Observatory, and forms Appendix III. of the present Report. In Appendix II. a list is given of the books at present in the Observatory, the property of the British Association.
List B (Appendix II.) is a rough inventory of books, the property of the British Association, which have been transferred from the Observatory to the rooms of the Association in London for the purpose of being catalogued.
(B) WORK DONE at Kew as the CENTRAL OBSERVATORY OF THE
1. Work done at Kew as one of the Observatories of the Meteorological Committee. The Barograph, Thermograph, Anemograph, and Rain-gauge are kept in constant operation. Mr. Baker is in charge of these instruments.
From the first two instruments traces in duplicate are obtained, one set being sent to the Meteorological Office and one retained at Kew. As regards the Anemograph and Rain-gauge, the original records are sent, while a copy by hand of these on tracing-paper is retained. The tabulations from the curves of the Kew instruments are made by Messrs. Page and Rigby.
2. Verification of Records.-The system of checks devised by the Kew Committee for testing the accuracy of the observations made at the different Observatories continues to be followed, as well as the ruling of zero lines in the Barograms and Thermograms suggested by the Meteorological Office. Messrs. Rigby and Page perform this work, Mr. Baker, Meteorological Assistant, having the general superintendence of the department.
3. Occasional Assistance.-The Meteorological Committee have availed themselves of the permission to have the occasional services of Mr. Beckley, Mechanical Assistant at Kew; and he has lately been visiting the various Observatories of the Meteorological Committee.
The self-recording Rain-gauge, as mentioned in the last Report, has been adopted by the Meteorological Committee, and instruments of this kind have been constructed for the various Observatories.
A series of comparative observations was commenced in April 1870 of two Anemometers erected in the grounds attached to the Observatory, in order to compare the indications of a large and small instrument; but as a discussion of the result showed them to have been greatly affected by the influence of the neighbouring buildings, the instruments were dismounted in January last and re-erected in an open part of the Park, at a distance from the Observatory. Three months' observations were made in this position, and as these proved satisfactory, the instruments have been dismounted. The cost of this experiment has been defrayed by the Meteorological Committee. Owing to his duties in Manchester, and to a railway accident, Dr. Stewart has not been able during the last year to devote much time to the Observatory. During his absence his most pressing duties were discharged by Mr. Whipple in an efficient manner.
The Observatory was honoured on the 9th of July by a visit from the Emperor and Empress of Brazil. Their Majesties were received, on behalf of the Committee, by Sir E. Sabine and Mr. W. De La Ruc.
In the unavoidable absence, through illness, of Dr. Balfour Stewart, the Emperor was conducted over the Observatory by the above-named gentlemen, and the various instruments &c. were explained by Mr. Whipple and the other members of the staff of the Observatory.
Tabular statement showing state of Magnetic Reductions at the present date.
The reduction of the tabulations for the year 1870 is being performed in Sir E. Sabine's office.
BOOKS AT PRESENT IN THE KEW OBSERVATORY,
THE PROPERTY OF
THE BRITISH ASSOCIATION.
Books to be retained at Kew for reference. British Association Reports, 1 vol. for the following years:1831-32, 1833, 1834, 1835, 1836, 1837, 1838, 1839, 1840, 1841, 1842, 1843, 1844, 1845, 1846, 1847, 1848, 1849, 1850, 1851, 1852, 1853, 1854, 1855, 1856, 1857, 1858, 1859, 1860, 1861, 1862, 1863, 1864, 1865, 1866, 1867, 1868, 1869.