Oct. 30, 1879] 



NATURE 



620 



and certain of his chapters are in the highest degree interesting. 

 His chapter on the origin of coal is perhaps more interesting than 

 any other, and is full of suggestive reasoning. I have not seen 

 the work cited in any of our treatises on geology, and yet the 

 opinions of such an eminent chemist must have some weight in 

 the treatment of problems wherein chemistry alone can furnish a 

 satisfactory solution. J. P. O'Reilly 



Dublin, October 22 



Suicide of Scorpions 



The self -destraction of the scorpion when hard-pressed is tin- 

 qnestionable. I have on several occasions invited sceptics to 

 witness the tragedy (!) in this part of Europe. 



The scorpion we frequently meet with in and about " Sierra 

 Morena" under stones and in crevices, is a large light-brown 

 species often more than tuio inches from head to sting. 



Having procured one I have placed it in a circle of glowing 

 charcoal embers a foot or so in diameter ; after vain attempts to 

 get away it raises its tail over its back, pierces its head with its 

 ■ting and dies, precisely in the way described by Dr. Thomson 

 (Nature, vol. xx. p. 577). F. Gillman 



Provincia Jaen, Linares, Spain, October 20 



Superficial Earthquakes 



Can any correspondent oblige me with an explanation of the 

 following facts ? The earthquake which took place at Virginia 

 City some time ago was not felt by the workmen in the mines. 

 Some years ago a much more violent earthquake shook the town, 

 breaking chimneys, overthrowing houses, and so on. But it was 

 hardly to be noticed in the mines; indeed, not at all in the 

 deeper shafts. E. Burke, Jun. 



October 16 



Coloured Lightning 



About 4 P. M. to-day we had a pretty severe thunderstorm, 

 accompanied by heavy rain, and the entire heavens were overcast 

 by one unbroken cloud ; three or four flashes of lightning were 

 of a distinct blue colour, and then followed a flash of beautiful 

 rose colour, succeeded by more flashes of blue lightning. Will 

 some of your correspondents explain the cause of change of 

 colour ? and oblige A Constant Reader 



Welland, Ontario, Canada, September 28 



" Memoria." — The correspondent who signs herself thus 

 urast send her name if she wishes her letter to be inserted. 



OUR ASTRONOMICAL COLUMN 



The Satellites Mimas and Hyperion.— The 

 loUowing are approximate times of the greatest 

 western elongations of Mimas during the first week 

 in November : — 



h. m. h. m 



Nov. 



Observations of Hyperion during the present opposition 

 ^re required before a reliable ephemeris of this satellite 

 can be furnished. The true motion of the pcri-saturnium 

 is yet doubtful, unless Prof. Asaph Hall has been able to 

 decide upon it from later observations than have been 

 published. As we have stated before, Mr. Marth some 

 years since conjectured that it might be as great as + 75° 

 annually, and this rate of motion accords with Bond's 

 determination of the place of the peri-saturnium in 1848 

 and Hall's results from Mr. Lassell's observations in 1852, 

 and his own in 1 875. So far as we know the Washington 

 measures of 1878 are not yet published; probably they 

 may throw more light upon the subject. 



AnUARIO del OnSERVATORlO DE MADRID.— The 



seventeenth volume of this compilation (for 1879) reaches 

 us late in the year. It is one of those useful compendiums 

 of which the Annuaire du Bureau des Lon_^itudes is 



probably the oldest, and may be taken as the type. 

 Astronomical phenomena and details occupy a consider- 

 able space, and the volume is therefore fitly noticed in 

 this column, but there is a great amount of miscellaneous 

 information, geographical, meteorological, physical, and 

 otherwise, which will recommend it to a larger class of 

 readers. We remark some few points to which exception 

 might be taken on the score of want of accuracy or 

 completeness ; thus the independent discovery of Hyperion 

 by Mr. Lassell is not recorded, and the number of 

 Uranian satellites is set down as eight, though four are 

 queried with good reason. The discovery of Tuttle's 

 comet is dated in 1858, no mention being made of its 

 appearance in 1790. It is doubtless through a misprint 

 that Encke's comet is stated to have appeared in 1695. 

 Many of the miscellaneous tables are very full, as, for 

 example, those of the altitudes of mountains in all parts 

 of the world, the length of rivers, and the meteorological 

 conditions in various parts of the peninsula, and as 

 regards Spanish science, &c., the volume is no doubt to 

 be considered authoritative. There are many who have 

 occasion to consult works of this kind, who may like to 

 have their attention directed to the present publication of 

 the Royal Observatory at Madrid. 



A New Private Observatory. — Observatories 

 erected, equipped, and maintained in activity by private 

 individuals are numerous in this country, and, as will 

 appear from Prof. Holden's recent report, there are many 

 of them in the United States ; but the number of known 

 observatories of this class upon the continent of Europe 

 is not great, and the more interest therefore attaches to 

 the addition of a new one to the list. Dr. Jedrzejewicz gives 

 some account of an observatory he has constructed at 

 Pl(5nsk, about 37 miles from Warsaw, or in lat. 52° 37' 39*, 

 and long. 20° 30' 59" E. of Greenwich. The princi- 

 pal instrument is an equatorially-mounted refractor by 

 Steinheil, of 64 inches aperture, to which are attached 

 filar and other micrometers, and a spectroscope. Acting 

 upon the advice of Dr. Vogel of Potsdam, Dr. Jedrzeje- 

 wicz has the intention of devoting his time mainly to the 

 measurement of double-stars, selecting such objects as 

 are well within the power of his telescope; indeed, he 

 has already made a considerable advance in this direc- 

 tion, having secured 860 complete observations of 170 

 double or compound stars, the result of some 8,500 

 separate measures, and with the view to enable astrono- 

 mers to judge of the amount of confidence to be placed 

 in the observations that may be published from Pldnsk, 

 he has given a comparison of his measures of a number 

 of stars, which do r^r,^ c-i.iuit change, with those ol 

 Struve and others, and the comparison will tend to 

 induce reliance upon his work. One remark we may 

 make which bears generally upon the selection of objects 

 for measurement with such an aperture as Dr. Jedrzeje- 

 wicz possesses : it appears to have been too much the 

 custom with the generality of observers who devote them- 

 selves to double-star astronomy, to accumulate a large 

 number of measures of well-known, we may almost say, 

 historical binaries, to the neglect of other objects, equally 

 within the scope of their instruments, and equally deserv- 

 ing of attention. A carefully-considered list of stars is 

 an essential in the actual slate of this branch of the 

 science, if the labours of the observer are to possess 

 their utmost attainable value, in the future. The nume- 

 rous discoveries of Mr. Burnham in particular confirrn us 

 in this view ; his various lists exhibit many stars which it is 

 highly desirable to keep under observation, and which do 

 not yield in point of interest to other better-known binaries. 



GEOGRAPHICAL NOTES 

 The Japan papers report, with expressions of great 

 regret, the loss, of which we have already had news by 

 telegraph, of the A. E. Nordenskjold, the little vessel 



