458 



KNOWLEDGE. 



December, 1913. 



The Moon.— First Quarter 4 d l h 9 m e ; Full 12 d 5 h 9 m m ; 

 Last Quarter 19 d h 30 m m. New 26 d 6 h 34 m m. Apogee 

 3 d 9 h e. Perigee 15" 6 h e. Apogee 31 d 5 h e, semi-diameter 

 14' 48", 16' 17", 14' 47" respectively. Maximum Librations, 

 9 d 6° E, 9 d 7° S, 22 d 7° N, 23 d 5° W. The letters indicate the 

 region of the Moon's limb brought into view by libration. 

 E. W. are with reference to our sky, not as they would 

 appear to an observer on the Moon. (See Table 89.) 



Mars is in opposition 5 d 6 h e. Nearest Earth on 1st, 

 distance 0-622. This is an unfavourable opposition as 

 regards distance, but favourable as regards planet's 

 declination. It will be seen that both hemispheres of Mars 

 are observable, but the Northern one is best placed. The 

 semi-diameter during January, diminishes from 7b" to 6£". 

 The unilluminated lune is on the East : its width increases 

 from to rV'. The Planet is in Gemini : 2° N. of e, on 22nd. 



Jupiter is invisible, being in conjunction with the Sun on 

 20th. 



Saturn is very well placed for observation, having been in 

 opposition on Dec. 7th. Polar semi-diameter 9J". P. is 

 -4°-2; B-26°-7. Ring major axis 47", minor 21". The ring 

 is approaching its maximum opening, and projects beyond the 

 poles of the planet. It is interesting to measure the exact 

 amount of overlap. The absolute maximum opening will 

 occur on July 1st, but the Planet will then be too near the 

 Sun to see. 



East Elongations of Tethys (every fourth given), 2 d h -0e, 

 10 d l h -2m, 17 d 2 h -4e, 25 d 3 h -6m; Dione (every third given), 

 2 d 2 h -7e, 10 d 7 h -8e, 19" h -7m, 27 d 5 h -7w; Rhea (every 

 second given), 2 d 2 h -8m, ll d 3 h -5m, 20 d 4 h -3m, 29 d 5 h -0m. 

 For Titan and Iapetus E.W. mean East and West Elonga- 

 tions; I. Inferior (North) Conjunctions, S. Superior (South) 

 ones. Titan, 5 d 6 h -2m I.; 9 d 2 h -6m W., 13 d l h -9m S., 

 17 d 4 h -6m E., 21 d 4 h -2m I., 25 d h -6w W., 28 d 12 b -0e S; 

 Iapetus, 6 d l h -9e I., 25 d l h -4e W. 



Uranus is invisible, being in conjunction with the Sun on 

 28th. 



Neptune is in opposition on the 17th. Semi-diameter 1". 

 Possessors of small telescopes may easily recognise it by its 

 motion, if they make a sketch map of the stars in the region, 

 and observe it night by night. 



Westphal's Comet. — See the ephemeris given last month. 

 The R.A. will be some 20" greater than the ephemeris value, 

 the declination 4° less. 



Meteor Showers (from Mr. Denning's List) :— 



Double Stars 

 given 



of 



these 

 are 



and Clusters. — The tables 

 given two years ago are again available, and reai 

 referred to the corresponding month of two years ago 



Variable Stars. — The list will be restricted to two hours 

 of Right Ascension each month. The stars given in recent 

 months continue to be observable. 



Table 90. Non-Algol Stars. 



Star. 



X Aurigae 

 i) Geminorum 



V Aurigae 



V Monocerotis 



V Lyncis 

 R Lyncis 



S Canis Min. ... 



V Geminorum 

 S Geminorum 

 U Puppis 



Right Ascension. 



Declination. 



+ 50 • 2 

 + 22 -5 

 + 47 -8 



-2-1 

 + 6l '4 



+ 55 '5 

 + 8-5 

 + 20 -7 

 + 23 -7 

 — 12 6 



Magnitudes. 



8-1 to 130 

 3'3to 42 

 83 10 ii- 7 

 7.7 to io- 2 

 8'6 to 9-4 

 65 to 14- o 

 7 - 7 to 12 7 

 8-5 to 9-2 

 83 to 145 

 8'5 to 145 



Period. 



d. 



i62'6 

 233 

 352 

 332 



72 

 379 '2 

 33o "3 

 286 

 293-8 

 315 



Date of Maximum. 



Feb. 4. 

 About January. 

 Dec. 22. 

 Jan. 7. 

 Feb. 1. 

 Mar. 27. 

 Dec. 21. 

 Jan. 27. 

 Feb. 4. 

 Dec. 16. 



Principal Minima of /3 Lyrae Jan. 12 d 7 h m, 25 d 5 h w. Period 12 d 21 h -8. 



Algol minima Jan. 7 d 4 h 5 m m, 10 d h 54 m w, 12 d 9 h 42 m e, 15 d 6 h 31 m e, 18 d 3 h 20 m e, 30 d 2 h 36 m w. 



Mira Ceti will reach maximum in March. 



CORRESPONDENCE. 



THE FLOWERING OF PLANTS IN SOUTH 

 GERMANY IN 1911 AND 1913. 



To the Editors of " Knowledge." 



Sirs,— Everyone knows the delights of botanists who, in the 

 month of August, have wandered through the Austrian and 

 Italian Tyrol. Edelweiss and Alpine roses form only a small 

 part of the treasures which they bring away, and they never 

 forget the fragrance of those Alpine meadows where the 



flowers bloom and the bees fertilise them close under the ice 

 and snow. What is not generally realised is the wealth of the 

 Odenwald and the Schwarzwald especially so far as the fungi 

 are concerned, and these have been particularly abundant in 

 damp years, like 1912 and 1913. Unfortunately the orchards 

 and gardens have neither been so profitable nor so interesting. 

 So far as the plant-world of South Germany is concerned, 

 the annus mirabilis was the year 1911. The vineyards 

 were of more importance than the orchards. The grapes 

 were small but as sweet as sugar, and the tourist now in the 



