462 



SCIENCU. 



[Vol. I., No. 16. 



I. Scholia et emendationes in Halienticon 

 P. Ouidii Nasonis. [pp. 1-11.] 

 [Second title.] P. Ovidii Nasonis Ha- 

 lievticon liber. 

 II. Aqvatilivm Animantium Enumeratio iuxta 

 Pliniiim, emendata et explicata serie 

 literarum. [pp. 12-92.] 

 [Running titles] Catalogvs Aqvatili- 

 vm, and Divisio Aqvatilivm. 

 III. Eoi'vndeni NomenclatorGermanicus longe 

 copiosissimus. Et alia quaedam ad 

 Pisciiim historiam pertinentia. [pp. 

 93-280.] 

 [ Ennning title.] Teiitsche namen der 

 Fisclie vnd Wassertliieven. 

 Tigvri apud Andream Gesnernm F. 

 [Date of Prefaces 1556.] 

 In consequence of the foregoing, after 

 Ovidhis Nuso (Pnblius), "Halienticon: hoc 

 est, de piscibus libelhis, mute qnam ante hac 

 emendatior et scholiis ilkistratus . . . per 

 Conradum Gesnerum. Tiguri apud Gesneros 

 fratres [1530 r] 8°" should give place to the 



following: Part I. of Gesner's De piscibvs 

 et Aqvatilibvs, "Scholia et emendationes in 

 Halienticon P. Ovidii Nasonis." "P. Ovidii 

 Nasonis Halienticon liber." pp. 1-11. Tigvri 

 apud Andream Gesnerum F. [1556.] 



The date for the first Frankfort edition of 

 Aldrovandi is 1623 instead of 1629 ; and 

 Gronow gives that of the second as 1640 

 instead of 1645. That given by the latter as 

 Venice, 1616, is omitted. Three editions of 

 Aelian (1556, 1611, and 1616), given by some 

 authorities, do not appear. Future revision of 

 the work will probably introduce the names of 

 such works as those of Schomburgk's Fishes 

 of British Guiana (1852), and Spix and 

 Agassiz' Fishes of Brazil ( 1 829) , both of which 

 give information on angling. The latter fig- 

 ures on plates A to G the various methods of 

 capture in use among the natives. 



Our authors have given ns a work of great 

 importance to all interested in the subjects of 

 which it treats. 



WEEKLY SUMMARY OF THE PROGRESS OF SCIENCE. 



ASTRONOMY. 

 Mass of a planet from observation of two 



satellites. — M. Struve reconimeiids measurement 

 of tlie positive, angle and distance of a satellite from 

 another satellite, and not from the primary planet. 

 A series of sucli measurements on satellites of Ju- 

 piter has heeii betjnn at Pulkova. The observations 

 occupy (ine-thii'd the time, and are considered two or 

 three times as accurate as those by direct reference 

 to the centre of the planet. They are free, more- 

 over, fi-oiii the unknown constant errors inseparable 

 from the latter, — an advantage which Prof. A. Hall, 

 in this paper, considers clieaply pnrcliased at tlie 

 price of gi-eater ditBciilties in computation. He 

 shows, that, while the solution of si.K normal equa- 

 tions requires seventy-seven auxiliary quantities, that 

 of twelve (the elements of both orbits l)eing involved 

 by the new iiieihod) lequires four hundred and forty- 

 two, and tlierefoie nearly six times the Labor. But 

 these twelve equations give the period and mean dis- 

 tance of eacli satellite, and hence two values of the 

 planet's mass. Mr. \V. B. Taylor objected to such 

 special designations as ' peri-Saturn ian,' ' apo-Jovi- 

 an,' for the apsides of satellites' orbits when general 

 names were needed. He suggested ' peri-apsis' and 

 ' apo-apsis.' — [Phil. soc. Waah., math. sect. ; meetlnri 

 April 2(1) [919 



Periodicity of auroras. — Professor Sophus 

 Tronihiilt has discussed the observations of auroras 

 made by Prof. S. ICleinschuiidt at Gotihaab, in 

 Greenland, from ISO") to 1880. together with olher 

 observations in nortliern latitudes, and finds that 

 for polar regiims the maximum of auroras cor- 

 responds with the miuimum sun-spot period, the 

 reverse of what has been noted in temperate zones. 

 The yearly maximum is at the winter solstice, while, 

 in lower latitudes, maxima occur at the equinoxes. 



Weyprecht has shown tliat the yearly maximum is 

 due to an oscillation of the auroral zone toward 

 the south at the equinoxes, and toward the north at 

 the solstices. The same explanation is given of the 

 eleven-year period, corresponding with the sun-spot 

 period. Prof. Lemstrom's production of an arti- 

 ficial aurora is mentioned. — {Observ., April, 1883.) 

 M. Moif. [920 



Report of -work of the Royal observatory, 

 Cape of Good Hope. — In the report for 1882, Di-. 

 Gill states that the observations for the difference 

 of longitude between the observatory and Aden are 

 completed. The great comet was observed on every 

 clear night from Sept. 7, and photographs were ob- 

 tained on six nights. The heliometer measures for 

 the parallax of certain southern stars are nearly 

 concluded. Ill connection with observations in the 

 northern liemispliere, Victoria and Sapitho have 

 been observed for determining the solar parallax 

 by Galle's method. Time of contact at the tr.ansit of 

 Venus was noted by six observers, and heliometer 

 measures were made during the transit. — [ilimlhly 

 not., March, 1883.) M. mcn. [921 



MATHEMATICS. 



Infinitesimals. — Mr. M. H. Doolittle looks on 

 infinitesimals, differetitials, and zero as having the 

 same denotation, but different connotations. He 

 proposes, in cases wliere the value of a function 

 becomes indeterminate, to call that value which is 

 continuous with those for preceding and succeeding 

 values of the variable the serial value. The differ- 

 ential coeiiicent, in this view, is the serial value of 

 the ratio of two increments when those increments 

 become zero. — (Phil. soc. Wash., math, sect.; weet- 

 iwj May 9.) [922 



