ATMOSPHEROLOGV. — HOAR-FROST. 437 



as are borne by the breeze into contact with a ship's 

 rigging, affix themselves to the mndward side of the 

 different ropes, and form a thick fringe of fi-ozen 

 vapour. In some states of the atmosphere, the coat- 

 ing of hoar-frost resembles the coating of frost-rime, 

 consisting of an irregular fringe ; but in others, 

 every particle affixes itself in a determinate order, 

 so that the most delicate, and in some cases the most 

 beautiful crystals are produced. I have never, how- 

 ever, observed more than two different forms of these 

 crystals ; one, consisting of a combination of angular 

 cup-like figures, inserted into one another in an her- 

 baceous form, not unlike a species of erica or heath, 

 was seen upon the land ; the other, having the form 

 and texture of a feather, occurred when the ship was 

 in the midst of a compact body of ice. The circum- 

 stances under which the latter appeared were these. 

 Ice of the field kind encompassed the ship to an ex- 

 tent of many leagues ; the latitude was 78°9'; the lon- 

 gitude about 2f E. ; the wind easterly. At mid-day 

 a thermometer exposed to the sun's rays rose to 54", 

 while the air in the shade was only 18°. At mid- 

 night the temperature fell to 10", and the frozen va- 

 pour made its appearance. It soon increased to the 

 density of frost-rime, and was carried by the wind 

 in clouds or showers. In the course of the night, 

 the rigging of the ship was most splendidly deco- 

 rated with a fringe of delicate crystals. The general 

 form of these, was that of a feather having half of 



