HentyoiHiI Structure formed in CooUng lieestra.r. 123 



1'.5 inillim. tliirk ami of utiiform deptli, and the atmosphere of 

 even temiicratnrf, otlierwise the hexagcjn.s will \nt i^^e^Mlla^ iti 

 siz*' and shape. 



It is inimatirial how thin the phite of wax is, as the 

 hexaKons arc formed in any case ; hut their size is undoubtedly 

 regulated by the thickness of the plate of wax, the rule being 

 the thinner the plate the more n)inute the individual iiexagon. 

 The same result may be obtained on a much smaller scale, so 

 as to jjroduce only one or two hexagonal forms; but the 

 operator will then find that the difficulty lies in the rapid 

 cooling at the* sides of so small a mass of wax. 



The explanation of the forn)ation of these crystalline bodies 

 is as follows : — 



On cooling, the wax at first forms into nuclei of nearly 

 equal size. On the shrinking of the wax by further cooling, 

 these nuclei or spheroids are pressed together, forming pIuMes 

 at their points of contact (see longitudinal section, fig. 2). 

 Should the wax be rapidly chilled before these spheroidal 

 bodies are fully formed, they are then prevented from coming 

 into contact one with another by the intervening nebulous 

 masses of " uncentralized " particles of wax *. In this state 

 the nuclei appear when cold as solid circular bodies. 



Tlic crystals appear very distinctly above and below the 

 surface while the wax is cooling. When it is actually solid 

 their forms are often very indistinctly seen or may be alto- 

 gether invisible, but they are none the less present. 



The bases of these hexagons, which lie midway between 

 those visible at the to|) and those at the bottom, are pointed 

 and are arranged so that the point of the base of the upper 

 hexagon coincides with the points of contact of the lower 

 hexagons, as in the honeycomb (see perpendicular sections, 

 figs. 3). 



These bases can be observed by making a very thin micro- 

 scopic section ; but several hundred sections had to be 

 examined before they were made out with certainty. 



\\ hen a small amount of resin and turpentine is added to 

 beeswax and melted, and the mixture is allowed to cool, 

 the outlines of the planes of contact on the hexagons are more 

 distinct and are to be seen raised upon the surface. Under 

 these circumstances they may be easily rubbed with black- 

 lead, which still further increases their visibility. 



Our chief exjieriment was next to put our theory to a 

 practical test, and observe iu what manner the bees would 



• It would appear from microscopic examinatiun that the.'»e particles are 

 also sniuUer nuclei whioii become absorbed in the larger. They also, like 

 the larger, assume hexajiouul form. 



