January 27, 19 16] 



NATURE 



.603 



hawn from the reservoir, there is provided a very 

 arge Venturi meter, 410 ft. long, formed in reinforced 

 oncrete, with bronze throat castings and piezometer 

 ring. The protection of the surrounding area has 

 been effected by planting the banks with Arhor vitce. 

 with pine and spruce seedlings in the rear, which 

 will also serve the purpose of minimising the evil of 

 drifting deciduous leaves. ^ 



We are asked by Mr. J. Reid Moir to state that the 

 urangement of the collection of flint implements 

 which, as announced last week (p. 572), has recently 

 rome into the possession of the Ipswich Museum, is 

 . ntrusted to the curator, Mr. Frank Woolnough, and 

 himself, and not to Mr. J. Reid Moir alone. 



OUR ASTRONOMICAL COLUMN. 



Comet 19156 (Taylor).— The following is a con- 

 linuation of the ephemeris based on the orbit given 

 hist week : — 



. in. s. o < ^- ^^- *• o / 



21 295 



22 144 

 22 582 



It will be seen that the comet is moving on the 

 line 15 Orionis-n4 Tauri, and should be close to the 

 latter on February 5. According to an observation 

 made at the Hill Observatory on January 22, the 

 ephemeris required corrections of -22 sec. in R.A., 

 and — 15' in declination. The former has more than 

 doubled since January 13, but the latter has remained 

 practically unchanged. 



The Notation of Star Colours. — ^The combination 

 of photographic and photovisual photometry, as well 

 as more direct methods, provide a measure of the 

 colour index which can be expressed as a sum of 

 terms due to the spectrum of the star, its absolute 

 magnitude, and its distance. To break up into defined 

 groups the numerical colour indices Prof. F. H. 

 Seares proposes colour classes corresponding to 

 the means for the typical spectra of classes B, A, F, 

 etc., with the designations b, a, f, etc. By making 

 certain numerical definitions, the difference between 

 the colour symbols and the spectrum symbols expresses 

 the abnormality of the individual as regards luminosity 

 and distance. Such colour symbols may be termed 

 " hypothetical spectra." 



Saturn's Rings. — Speculation is only beginning to 

 become again active in regard to the ring system of 

 Saturn since Keeler elucidated the mystery of its 

 constitution. Thus there is the question of its 

 origin, perhaps indeterminate, as it admits of a 

 number of almost equally plausible suggestions. A 

 more limited problem concerns the subdivisions. 

 What is the meaning of the manifold "rings"? In 

 bringing forward this problem. Dr. Lxjwell (Lowell 

 Observatory Bull., No. 68) suggests, and advances 

 proof in the form of filar micrometer measures of 

 their dimensions, that many of the newly-detected 

 divisions on ring B are due to the perturbative action 

 of Mimas (the nearest of Saturn's satellites, half the 

 diameter and half as far away as the moon is from 

 the earth). The proof offered is the fact that most of 

 the new divisions occur where a particle of the ring 

 would have a period of revolution commensurate with 

 that of Mimas in some simple ratio. New divisions 

 ire situated 1/4, 3/7, 4/7, 1/3 — and 1/3 + way out 

 from the inner edge of ring B respectively, and the 

 corresponding periods would be 3/8, 2/5, 3/7, 4/9, 

 and 5/1 1 that of Mimas. Dr. Lowell some time ago 

 directed attention to simple rommensurabilities among 



NO. 2413, VOL. 96] 



planetary periods (Nature, July 24, 1913). The ques- 

 tion naturally arises whether Mimas is making new 

 satellites for Saturn out of the meteoritic material 

 of ring B. 



Stereoscopic Me.asurement of Proper Motions. — 

 M. Comas Sola recently gave an example of the use 

 of an ordinary stereoscope for the detection of proper 

 motions (Nature, August 26, 1915). Apart from Prof. 

 Barnard's criticism of the results, this simple instru- 

 ment obviously cannot yield quantitative information. 

 This deficiency, however, appears to be removed by 

 the addition of an arrangement M. Comas Sol^ has 

 named a stereogoniometer {Comptes rendus, clxii., 

 p. 39). This is a device by which the two properly 

 oriented plates under comparison may be simul- 

 taneously rotated through a measured angle. As the 

 plates rotate so the apparent "relief" of the proper 

 motion star alters, the position of maximum relief 

 giving the direction of the star's movement. It may 

 be pardonable to add that the obvious experiment is 

 very interesting. 



PROF. GUI DO BACCELLI. 



WE are indebted to the British Medical 

 Journal for the following particulars of 

 the career and work of Prof. G. Baccelli, 

 whose death was announced in Nature of Janu- 

 ary 13. Prof. Baccelli was born in Rome on 

 November 25, 1832, and took his doctor's degree in the 

 university of his native city in 1852. Four years later 

 he was appointed to the chair of forensic medicine 

 in the University of Rome, but resigned his position 

 after two years, and devoted himself to the study of 

 morbid anatomy. When a chair of that subject was 

 founded in the University Baccelli was appointed the 

 first professor. In that capacity he had a great influ- 

 ence in turning the minds of his pupils in the direction 

 of modern scientific methods. In 1863 he was ap- 

 pointed lecturer on clinical medicine, and in 1870, when 

 Rome became the capital of Italy, he was appointed 

 professor of clinical medicine, a post which he con- 

 tinued to hold until the end of his life. In 1875 he 

 entered the Italian Parliament as one of the deputies 

 for Rome, and soon took a leading place as a poli- 

 tician. In 1881 he became Minister of Public Instruc- 

 tion, and held that portfolio four times in all, doing 

 great service to his country by the promotion of far- 

 reaching reforms, both of primary and university edu- 

 cation. To him Rome chiefly owes the Policlinico, a 

 magnificent pile of buildings, fully equipped for the 

 study of disease. He was also once Minister of Agri- 

 culture, Industry, and Commerce. He was prominent 

 as a sanitary reformer, and was at one time President 

 of the Board of Health. He took an active part in the 

 sanitary improvement of the Campagna ; for his efforts 

 in that direction he received the thanks of the Italian 

 Parliament. He was a Senator of Italy. Prof. Bac- 

 celli was president of the eleventh International Con- 

 gress of Medicine held in Rome in 1894, and at that 

 congress he made a powerful appeal for the introduc- 

 tion of Latin as a universal spoken language which 

 could be understood all over the world. A little modi- 

 fication in the teaching of Latin in schools as a spoken 

 and not merely as a dead language would give all 

 the advantage of the attempts which have been made 

 to construct a universal language, while it would not 

 disorganise the present curriculum and would render 

 available for general use all the stores of wisdom and 

 knowledge contained in Latin books and at present 

 unavailable for common use. Besides a monograph 

 on Roman malaria, published in 1878, in which his 

 views on the sanitary improvement of the Campagna 

 were embodied, Prof. Baccelli was the author of many 



