222 ANNUAL OF SCIENTIFIC DISCOVERY. 



to be maintained at a temperature below 32 of Fahrenheit's thermometer. 

 Mr. Spencer became desirous, in the study of snow crystals, to find some sub- 

 stance similar in its habits of crystallization, but of a less perishable nature, 

 and which would enable us to trace the progress of the crystals from the 

 simplest up to the most complicated forms, so that, reasoning by analogy, we 

 might be able to throw some light on the subject. Camphor crystallized slowly 

 does not wholly assume the form of hexagonal crystals ; but, like snow or ice, 

 takes the arborescent form, very similar to the fronds of ferns ; but does so 

 when the process is quick. The most convenient way to repeat the experi- * 

 ment on camphor is, to make a solution of this substance in alcohol, and add 

 thereto some water of ammonia. The field of inquiry thus opened by Mr. 

 Spencer has since engaged a portion of the author's attention. The process of 

 crystallization appears to proceed rapidly, and to commence simultaneously 

 with the action of the air upon the liquid, but to be by no means certain of 

 proceeding similarly under apparently similar conditions. The process of its 

 crystallization bears the closest analogy to that of snow, and the one of most 

 frequent occurrence presents an endless succession of little dots passing to and 

 fro with the restless movements of animalcula ; every instant these globules 

 very perceptibly increase in size, and develop points, generally six in number, 

 which continue to enlarge until they assume the character of arborescent 

 pinnae, the addition of the elementary figure being effected at an angle of 60. 

 The crystal, when arrived at perfection, immediately begins to simplify, and 

 continues to do so till it is evaporated. One main difference between these 

 figures and those of snow is, that they exhibit an entire want of angularity, 

 and only approximate, even when at their greatest perfection, to the snow 

 crystal just as it appears before finally dissolving. The author observed that 

 sometimes the figures were octagonal, and at times, when few were present, 

 many would be double, for they share in this respect a peculiarity of the snow 

 crystal, but differ in their being united by a point of contact common to the 

 two, instead of being united by a slender axis, as in the crystals of snow. 

 The author concluded by observing, that these bodies chiefly resemble the 

 crystals of snow in their hexagonal star shape and in the arborescent form of 

 their pinnas. If not, however, intimately allied, it is interesting to observe and 

 compare the manner of then* change ; and a continuation of these observations, 

 varied by experiments and the employment of other solutions, may yet give 

 increased information on a subject which, as Mr. Spencer remarks, is of pecu- 

 liar interest, as uniting the confines of meteorology and chemistry. 



NUMBERS IN NATURE. 



Physical science shows that numbers have a significancy in every department 

 of nature. Two appears as the typical number in the lowest class of plants, 

 and regulates that pairing or marriage of plants and animals which is one of 

 the fundamental laws of the organic kingdoms. Three is the characteristic 

 number of that class of plants which has parallel veined leaves, and is the 

 number of joints in the typical digit. Four is the significant number of those 

 beautiful crystals which show that minerals (as well as stars) have their geo- 

 metry. Five is the model number of the highest class* of plants, those with 



