214 



NATURE 



{Jan. i, 1880 



RECORDING SUNSHINE 1 



SO far as I have seen there is in use at present but one 

 form of apparatus which effects an automatic regis- 

 tration of the duration and the times of sunshine, and 

 that is the instrument of Campbell, in which a sphere of 

 glass is so disposed as to burn a piece of wood or paper 

 by the concentration of his rays when the sun may chance 

 to shine. During the past few years I have devoted some 

 attention to this matter and devised a number of appli- 

 ances having the same object for their end but differing 

 materially both in their construction and in the manner 

 of their use from the apparatus I have named. 



One of these, with your permission, I will now describe. 

 It is an arrangement which places a lead pencil on a 

 sheet of paper and writes down therewith when and for 

 how long the sunshine lasts. 



It consists essentially of a differential thermometer with 

 a long horizontal stem, in which latter is contained 

 throughout the greater portion of its length some fluid 

 intended to operate by its weight. This thermometer is 

 attached to a scale beam or some equivalent device which 

 also carries the pencil by means of which the record shall 

 be made. 



The whole is so arranged that in its normal state it 

 rests gently — upon that side to which the pencil is not 

 attached' — on an embankment provided for that end. 



Close beneath the pencil point a disk of metal rotated 

 at the proper speed carries a paper dial whereon marks 

 and figures are engraved corresponding with the hours at 

 which the sun may shine. 



When using this instrument I have it inclosed within a 

 box which permits one bulb only of the thermometer — 

 that most distant from the clock — to be affected by the 

 radiance of the sun, which when it shines expands the air 

 contained therein, forces the fluid along the tube and by 

 altering the equilibrium of the beam brings some portion 

 of its weight to bear upon the pencil point, and so the 

 record is commenced. 



When the sun becomes obscured, the air expanded by 

 his rays contracts, the fluid in the tube returns, the normal 

 equilibrium is restored, and the pencil ceases to produce 

 its mark. 



In the instance of the instrument I use the stem of the 

 thermometer is 18 inches long and the eighth of an inch 

 or thereabouts in bore. 



Mercury in consideration of its weight is the fluid I 

 employ, and in conjunction with it some sulphuric acid is 

 inclosed, because of the mobility which is thereby gained. 

 I am aware that in these circumstances mercuric sulphate 

 is very slowly formed, but after two years' lapse of time no 

 inconvenience has been caused thereby and the mobility 

 of the mercury remains. 



The bulbs of the thermometer are 2 inches in diameter 

 or thereabouts, and that they may be more rapidly affected 

 the glass thereof is thin. Both are blacked, and the one 

 intended to receive the radiance of the sun projects above 

 the box in which the apparatus is contained into a dome 

 of glass. 



NOTES 



W. Hepworth Dixon died very suddenly early on Saturday 

 morning. He was be;t known to us as a brilliant writer and 

 speaker, and but comparatively few knew how profoundly, and 

 with what patient determination he would sift the truth, alike of 

 even the most well attested, as of the most apparently trivial 

 fact, before making use of it in his work. Only those within 

 the circle of his more intimate friends were aware how well he 

 followed and how easily he grasped the progress of scientific 

 thought. In this circle were several with whom and about 

 whose labours he delighted to converse, and none could listen 



' Paper read at the Literary and Philosophical Sjciety of Manchester by 

 Dawd Winstanley, l'.R.A.S., November 18, 1879. 



without benefiting by the practical views his vigorous intellect 

 suggested, the more so as they were possibly induced by quite 

 other claims of thought. These columns have called attention 

 to the ethnological value of his researches in America. His 

 travels, especially those in the Far West, in the wilder parts of 

 Russia, in the Holy Land, and in Cyprus, attended at times 

 with personal risk, are full of suggestive interest to the scientific 

 mind, and we may shortly to call ^attention to some of the 

 salient facts connected with natural science which they contain. 

 In his early days he studied astronomy and kindred subjects, 

 and it almost seemed at one period of his life that his bent would 

 have led him more deeply into these researches. That this early 

 inclination never forsook him, even those who knew him least, 

 may gather from his attendance at the meetings of the British 

 Association, his unremitting labours as chairman of the Palestine 

 Exploration Fund, and his presence at numerous anniversary 

 meetings of our learned societies. His surviving son, Harold, 

 is already known as a teacher of natural science at Oxford 

 University. 



The death, on December 1 8, is announced of Prof. Franz 

 Boll, who has filled the Chair of Physiology and Comparative 

 Anatomy in the Roman University ; he was only thirty years of 

 age. Born at New Brandenburg in February, 1849, he studied 

 at Berlin and took his Doctor's degree in medicine and surgery 

 in 1S69. When little more than twenty years old, he became 

 assistant to Dubois-Reymond in his physiological laboratory at 

 Berlin. Having been obliged on account of his health to seek 

 the warmer climate of Italy, he was in 1873 offered an appoint- 

 ment in the Roman University, and in 1877 was, by the 

 unanimous decision of the Commission of Examiners, elected to 

 the chair he has since held. His researches regarding the 

 arterial circulation of the retina are recognised as a most valuable 

 contribution to physiological science. 



General surprise is naturally expressed that Dr. William 

 Fair has not been appointed to succeed Major Graham as 

 Registrar-General. Dr. Farr's qualifications for the post are 

 known to all the world ; but it has been conferred upon Sir 

 Brydges Henniker, Bart., for what reason we have failed to 

 discover. It must be regarded as an almost national misfortune, 

 though it will surprise no one, that Dr. Farr has resigned his post 

 as head of the statistical department. 



The Hannoverschc Courier announces that Leibnitz's long- 

 lost calculating machine has been recovered. Leibnitz invented 

 and constructed this machine in 1672, during his stay in Paris. 

 It can add, subtract, divide, and multiply, and was the wonder 

 of the time. This machine became the property of the Hanover 

 public library, but long ago disappeared from among its treasures. 

 All that was known about its disappearance was that it had once 

 been sent to an instrument maker at Gbttingen to be repaired. 

 It has now turned up again in the Gbttingen library, and through 

 the efforts of Dr. Bodemann, the librarian of the Hanover 

 public library, has again come into the possession of the insti- 

 tution. 



It is only about a year since we gave some account (Nature, 

 vol. xviii. p. 361) of the railway bridge which spans the Firth of 

 Tay at Dundee, and on Sunday it was the scene of one of the 

 most terrible railway accidents on record. With the details of 

 this sad occurrence our readers are no doubt familiar ; for accu- 

 rate information as to the prime cause we must await the search- 

 ing inquiry which will no doubt be instituted. The structure 

 appears to have been subjected to the most rigid tests before 

 being opened to traffic, but we fear there must have been more 

 than one screw loose somewhere. Upwards of 3,000 feet of the 

 high girders are reported to have been swept away. One con- 

 jecture is that the train had got well upon the girders when a 



