Jani'aky. 1912. 



KXOWLF.Dr.i:. 



I- II 



many jjcrfcct talnilar forms aiich as we rwjiiired. 

 It is <iiiite certain, however, tiiat all general 



storms ])ossess 

 favourable quad- 

 rants (the western 

 ones) furnishing 

 perfect tabular 

 forms, their failure 

 to furnish these at 

 any one time or 

 place being due to 

 the fact that their 

 paths fail to bring 

 these productive 

 (|uadrants o\er the 

 locality in question. 

 The student of 

 thesnow findsmuch 

 to marvel at in a 

 study of these peer- 

 less crystals. What 

 perhaps causes the 

 greatest amazement, is their almost i?ifinite di\ersit\' 

 of form and interior. Yet one is 

 almost equally impressed with the 

 almost unbclic\able beaut\- and 

 perfect symmetry of the choicer 

 forms. Among the man\- remark- 

 able things about them is their habit 

 of very freely enclosing within them- 

 selves the solvent (air) wherein the\ 

 form. 



This is doubtless largelv due to 

 their frequent habit of constanth 

 changing form and acquiring new 

 branches and adornments as growth 

 progresses, accom[)anied, in man\ 

 cases, with progressive solidification. 

 The merging of branch with branch 

 and segment with segment as growth 

 progresses and solidification occurs, 

 accomplishes the bridging over and 

 inclusion of tiii\' i|u:mtities of air. 

 and the forniatinn. in many cases. l'i<u 



of a vast ninid)er of tiny air 

 tubes and chambers, which add vastK' to the beaut\- 

 and complexity of the internal structure. 



The air-tubes possess a further and most fascinat- 

 ing interest, because they outline, in part or whole, 

 transitionary stages of growth, and thus enable us to 

 trace out man\- of the pre-c.xisting forms of the 

 crystals while growing in cloudland. Another 

 remarkable habit concerns their manner of growth. 

 The tabular crystals usualh" grow simultaneously 

 outward, in the form of six-raved stars, or six- 

 petalled flower-like forms, from a common nucleus. 

 Each of these sc\eral parts mav, and often does, 

 have but a tiny connection with the others at the 

 nucleus, and hence the whole structure is for all 

 practical purjioses. a group of six separatelv-growing 

 crystals. These rays or segments oft-times undergo 

 a multitude of changes of form, as thev momentarih- 



rayed starry 

 eeneral. in 



accjuire ad'.litions here autl adoninients I'lsi'where, 

 as grow th progresses. 



But, marvellous to state, grow th proceeds, in most 

 cases, after a common [)lan, as though at the behest 

 of some central controlling influence. A branch or 

 other adornment forming at any given moment and 

 point upon one of the rays or segments, is often 

 instantly and exactly duplicated, as regards time, 

 form, location, and so on, upon all the others, so that 

 perfect symmetrv is always maintaini'd. 



More marvellous still, growth usualK i)nKi-eds a 

 little differenth- in individual cases, so that it is 

 rarel\- the case that aii\- two are just ahki- when 

 completed. 



.\ further study and analysis of tin- tonus and 

 habits of growth of these marvellous snow cr\stals 

 as revealed in the photo-micrographs, and directh' 

 under the microscope, discloses much of great 

 interest. 



One fact relates to the characteristic manner of 

 formation of the main and secondary rays of the six- 

 forms. The secondary rav'S occur, in 

 airs, and directly op|)osite each other 

 upon the main ra\s. But, strange to 

 say, exceptions are not rare, for we 

 occasionally find secondary ravs 

 without corresponding mates on the 

 ojiposite side of the main ra\'. It 

 adds much to the interest of these 

 exceptional cases that their frequenc\- 

 increases with distance from the 

 nucleus. 



.\notluT interesting thing is the 

 way the secondarv rays behax'e 

 toward each other whenever they 

 grow so far outward as to meet. 

 In most cases, if the rays are short, 

 as when the\- spring outward and 

 meet close to the nucleus, the tips 

 merely merge, and growth ceases 

 thereafter, in the manner adopted b\- 

 the first set of branches as shown 

 in I'igure 1.5. 

 . -'-'■. lUit oft-times in cases in which the 



secondar\' raj's form far outward 

 f II 111 the nucleus, a seeming crossing of the secondary 



rays takes place, after which each continues growth 

 in the original direction, as shown in Figure 15. 



