NA TURE 



[August 29, 1895 



the methods of calculation, and with the reduction of the 

 observations themselves. 



It is our lot to-day to say a few words about 

 another hard worker in astronomical science, whose 

 end has followed too soon after that of Dr. Tietjen. 

 This devoted student of astronomy has been an energetic 

 obsener in the same degree that Dr. Tietjen was an 

 ardent computer. We refer to Dr. Fricdnch Wilhelm 

 Gustav Sporer, the former chief assistant of the Astro- 

 Physical Observatory at Potsdam, and who died on 

 July 7 last. 



Dr. Sp<)rerwas bom in Berlin on October 23, 1S22, and 

 after spending some time at the Friedrich-Wilhelms Gym- 

 nasium, he entered the University of Berlin, making 

 mathematics and astronomy his chief studies. On 

 December 14, 1843, he gained his doctors degree, the 

 subject of his thesis being the comet of 1723. In the 

 following years he worked under Encke's direction at the 

 Berlin Observatory', and in 1846, after having made his 

 Staats exam., went as a teacher of mathematics and 

 natural science to the Gymnasium at Bromberg. In 1847 

 he proceeded to Prenzlau, and two years later to Anclam, 

 at which latter place he taught for twenty-five years, and 

 became eventually Pro-rector. 



It was during liis leisure hours there that Dr. Sporer 

 was able to turn his attention to astronomical observ- 

 ations, his instrumental equipment being of a very inferior 

 kind. Notwithstanding this hindrance, he was able, how- 

 ever, by great diligence and perseverance, to make useful 

 obscr\-ations with regard to the statistics of the solar 

 spots, which have made his name known to every worker 

 of solar physics. Through the attention of Prof. Schell- 

 bach, who was the teacher of the then Crown Prince 

 Friedrich Wilhelm, afterwards Kaiser Friedrich, Dr. 

 Sporer was equipped with a good 5-inch telescope, with 

 which he continued to make his solar observations by 

 the known method of projection. His .\nclam observ- 

 ations appeared from time to time in numerous articles 

 contributed to the Astronomisclicn Nac/iric/iten, and also 

 in two larger papers which came out in the years 1874 

 and 1876 in the Publicatiorwn dcr Astronomisclicn Gcscll- 

 schaft. The chief value of these pieces of work lies in 

 the careful determination of the elements of rotation of 

 the sun, and also in the more accurate settlement of the 

 then empirically known law of Carrington, namely, the 

 decrease in the velocity of rotation of the sun-spots 

 according to increase of solar latitude. 



In the year 1868, accompanied by Prof. Tietjen and 

 Dr. Engcimann, Dr. Sporer took part in the astronomical 

 expedition to observe the total eclipse of the sun visible 

 in the East Indies. Six years later (1874; he received 

 the appointment as observer at the Potsdam Astro- 

 Physical Observatory, and in the same year continued 

 his solar observations from the top of the tower of the 

 .Military Orphan Asylum, until the completion of the 

 obscr\ator)'. 



There Dr. Sporer, with untiring energy and with the 

 same ardour that he displayed m .\nclam, did a great 

 amount of work in collcctmg data on the subject of sun- 

 spots. The publications of the Astro- Physical Observ- 

 atory 'years 1879-1894} contain four valuable papers by 

 him, giving a rich quantity of accurate observations that 

 will remain a classical work for the study of the proper 

 motion of the solar spots. 



In 1882 Dr. Sporer became chief assistant, and tliis 

 position he held until October 1894, when he retired for 

 a wtllearncd rest. 



From Dr. Sporcr's observations of solar spots, the most 

 important deductions that have been made may be 

 ^ummed up as follows :— 



(i) That the period of rotation of the apparent surface 

 of the »un about the axis, is not the same for every 

 |>art. 

 (2) That the velocity of the spots is greater nearer the 



NO. 1348, VOL. 52] 



equator than further away from it, and that this velocity 

 can be approximately represented by a formula. 



(3) That the variation in latitude is periodical, and that 

 there are two series of spots. We learn thus that the true 

 sun-spot cycle is one extending over twelve to fourteen 

 years, and that another begins in high latitudes before 

 the former has ceased. 



(4) His observations of the quantity of spotted area 

 between the years 1 856- 18S0, show a length of period 

 of eleven years, this being the time between two consecu- 

 tive maxima. 



The maximum is reached when the mean latitude of 

 the spots is about 16" north and south. .A retreat then 

 takes place from about 30' to 16', that is, 14" in four years, 

 and a further retreat fro:n 16^ to S", that is, S' in eight 

 years ; or, in other words, we get a change of latitude of 

 over 3" a year to begin with, and one of \' a year to end 

 with. 



Such results as these, which have here only been briefly 

 summarised, are of fundamental importance, and form 

 valuable data for those attempting to in\ estigate the con- 

 ditions of atmospheric circulation at the surface of our 

 sun. Since the observations have been made consecutively 

 by such a diligent observer, and extend over a consider- 

 able period of time, they are strictly of a uniform nature, 

 and in consequence they are comparable inter sc. 



Happy in his work, and endowed with a strong con 

 stitution. Dr. Sporer was free from the ailings of old age 

 up to his last day. It was when on a journey to visit his 

 children that he was suddenly seized with paralysis of the 

 heart, without ever having had any previous sign of illness, 

 and died quietly and without pain. 



His loss not only aftccts the astronomical world, but 

 his large circle of friends, all of whom will mourn 

 deeply such a sudden and unexpected bereavement. 



W. J. S. L. 



NOTES. 



Co.NSlDERABl.E .nctivity has been displayed at the Plymoulh 

 laboratory of the Marine Biological Association during the 

 present summer, and general satisfaction has been experienced 

 by the naturalists who have visited the station for the purpose of 

 research. Progress has been made with the series of dredging 

 operations in the outlying grounds of the neighl)ourhood. The 

 unsettled weather of the past two months has been a somewhat 

 unfavourable condition in these expeditions ; but it is expected 

 that these operations may be carried on regularly and with 

 increased success during the autumn months. The following 

 naturalists have occupied tables at the laboratory during the 

 summer: Prof. Weldon, F.R.S., Mr. G. P. Bidder, Mr. W. 

 Garstang, Mr. T. II. Riches, Dr. Albrecht Bethe, Mr. \V. J. 

 Beaumont, Mr. Gilchrist, and others. 



A WEI.L-.MARKED earthquake disturbance was fell at Zcrmatl 

 on Wednesday, .Vugust 21. Many houses were severely shaken. 



Amo.nc the deaths of eminent scientific men abroad, we 

 notice the name of Dr. I''. Hoppe-Seyler, professor of physio- 

 logical chemistry in Strassljurg University, and also that of Dr. 

 S. Moos, professor of otology in Heidelberg University. 



We regret to record the death of Dr. J. S. Brislowe, F.K.S., 

 whose work on the "Theory and Practice of Medicine" is 

 recognised as a classic, while his other contributions to scientific 

 literature give him a high place among medical worthies. Dr. 

 Brisl(jwc had fdled the offices of President of the Me.lical 

 Society, of the Pathological Society, and of the Neurological 

 Society. Me was elected into the Royal Society in June 

 1881. 



