354 



KNOWLEDGE. 



September. 1910. 



all over the heavens, whilst there are very few of the 

 oblate spheroidal form, such as the hypothesis of 

 Laplace assumed to be met with in the sky. This 

 was pointed out by Proctor and Ranyard (Old and 

 New Asfronoiny § 1445). Such nebulae as we see 

 have a greater analogy with the solar corona than 

 with the fiery condensing mist conceived of by 

 Laplace. The opposite branches often seen on 

 photographs of spiral nebulae, are considered to 

 represent the " original streams of cosmical dust 

 coiling up and forming spiral systems." If the 

 streams converge and the mass becomes very dense 

 at the centre, a double star ma}- be formed. 



The theor\- of the action of a resisting medium 

 gives results exactly the opposite of tidal friction. 

 The latter usualh" increases the major axis and 

 eccentricity of a planetary orbit ; the resisting medium 

 decreases both these elements. "In the actual 

 universe both causes are at work, sometimes one 

 predominating, sometimes the other." 



In the growth and development of our system 

 all these various agencies may have been called into 

 plav, so true is it that here, as elsewhere, no single 

 explanation is self comprehensive and exclusive of 

 other hypotheses. The mind of man is so constituted 



that it cannot help speculating on such topics, but it 

 is well to remember that all our knowledge, both 

 of time and space, is essentially relative and con- 

 ditioned ; no absolutely undisputed truth is admitted 

 by all philosophers alike, so that in some respects 

 we seem less advanced than \\as thought to be the 

 case a century ago. The Sun was supposed to have 

 an absolute velocit\' of about fifteen miles per second 

 ■" towards a point in the constellation of Hercules," 

 but, as has been pointed out, this result has been 

 overthrown bv the work of Kapteyn. Numerous 

 optical and electrical experiments have been made at 

 difterent times with the view of determining the 

 absolute velocit\- of the Earth, but such effects have 

 alwavs failed to appear. 



" The vast masses of observational data accumu- 

 lated b\" the persevering industry of self-denying 

 men of science," together \\ith the mathematical 

 researches we have outlined above, are leading to 

 more accurate views than anv that have been held 

 hitherto, and the results already obtained should give 

 us encouragement in our eftorts to trace " the process 

 of Creation," but we must more than ever feel how- 

 little after all is vet known compared with what 

 remains to be learned. 



QUERIES .AND ANSWERS. 



Readers arc invited to send in Questions and to ansicer the Queries icJiieJi are printed on tin's pai^e. 



QUESTIONS. 

 2 and 6 still reiiiaiii unanswered. iSee pages 288 and 301 ). 



7. SCIENTIFIC IDE.\S OF TO-DAV.— In Mr. (~,ibson's 

 instructive booic, Scientific Ideas of To-day. I find the 

 following statement, on p. 207 : — 



" Picturing the electron revolving around it? atom and setting up 

 other waves of definite length (definite colour), we can imagine 

 readily that if the atom itself were caused to vibrate at an abnormal 

 speed, the revolutions of the electron might be very materially affected. 

 We Iiave evidence of such occurrences. For instance, a certain cheniical 

 compound — tlie double iodide of mercurv and silver — appears yellow 

 at normal temperatures. If we hasten the vil)rations of its alonis liy 

 increasing the temperature to about one hundred-and-ten degrees 

 Fahrenheit the substance appears red.'" 



Again, on page 157 we read: — 



" By applying heat to a body we hasten the speed of these revolving 

 electrons. . . . In a lump of iron at ordinary temperature the motion 

 of these electrons is disturbed by molecular collisions, so that the 

 resulling rates of revolution cause very long waves in the aelher. . . . 

 To. return to the very simple experiment of striking a piece of iron by a 

 heavy hammer, we are able, by repeated blows, to cause the molecules 

 to vibrate more rapi.-ily, and this enables these revolving electrons to 

 quicken their pace." 



Now if by means of heat the revolving electrons of the 

 chemical compound are forced to quicken their pace, why 

 should the other waves produced be " red " ? That is a colour 

 produced by the electrons re-.olving at a slower pace than 

 those producing the original colour, yellow. From the above 

 statement I should have expected that the colour produced by 

 heating the compound would rather have been higher up the 

 colour scale than the yellow. '• PERPLF:XED." 



8. H.^IR COLOURS. — There are cases where the hair at 

 birth is dark coloured or almost black in the case of human 



babies. When the child is four years old or so the hair 

 becomes bright golden, while in adult life a shade of colour 

 intermediate between the two previous ones is acquired. Has 

 anyone studied this question, and has any theory been brought 

 forward as to the colours ha\ing been inherited from any 

 particular ancestral races (sav in the case of English people) 

 as are the spots on voung lions and tapirs ? 



R. R. 



REPLIES. 



4. For the information of Mr. Sandeman it may be pointed 

 out that queen wasps are the only ones that survive the 

 winter. Hence it stands to reason that they must be 

 fertilised before hibernation, and that they must fulfil the 

 duties of founding a new nest and rearing the first larvae. 



"BIOLOGIST." 



3. In reply to Mr. Jeftery's enquiry with regard to Barometer 

 readings, my Barograph, which is set Ath higher than the 

 Standard at Victoria Park, Portsmouth, registered at 10 p.m. 

 on the 26th of January, 1905, 30, r'rrths. 



At 9 a.m. on the 27th, it registered 31 (7 degrees of frost 

 during the night) and at 9 a.m. on the 29th, it registered 

 31 and iVth. This is the highest reading my Barograph has 

 ever recorded in my experience of about eight years. It is set 

 accurately for its height above the sea level, but seems to 

 differ iVth from the Standard at Portsmouth. 



Harmsworth's Encyclopaedia states (Art. Barometer) the 

 highest pressure ever observed was 3F717 at Irkutsk, 20th 

 December, 1896, and in the British Islands at Ochtertyre, 

 Perthshire on the morning of 9th January, 1896. 31 '108. The 

 Royal Observatory at Greenwich would probably be the best 

 authority on this subject. 



JOHN GLAS. SANDEMAN. 



