56 PHILOSOPHICAL TRANSACTIONS. [aNNO 1673. 



stone which Boetius calls Astroites. All these I say are rare, the first described 

 being the general figure. 



As for the configurations of other bodies, we shall find that there are divers 

 which have some a less, others a more near resemblance to snow. Nitre is 

 formed into long cylindrical shoots, as also all lixivial salts for the most part, 

 resembling the several points of each starry icicle of snow. Salt of hartshorn, 

 sal ammoniac, and some other volatile salts, besides their main and longer shoots, 

 have others shorter branched out from them ; resembling as those the main, so 

 these the collateral points of snow. But the icicles of urine are still more near: 

 for in salt of hartshorn, although the collateral shoots stand at acute angles with 

 the main, yet not by pairs at equal height : and in sal ammoniac, although they 

 stand diametrically opposite, or at equal height, yet at right angles : whereas in 

 the icicles of urine, they stand at equal height, and at acute angles both; in both, 

 like those of snow. And it is observable, that the configuration of feathers is 

 likewise the same. The reason whereof is, because fowls have no organs for 

 evacuation of urine, and the urinous parts of their blood are evacuated by the 

 habit of skin, where they produce and nourish feathers. 



From hence it should seem, that every drop of rain, containing in itself some 

 spirituous particles, and meeting with others in their descent, of a saline, and 

 that partly nitrous, but chiefly urinous, or of an acido-salinous nature ; the said 

 spirituous parts are intercepted by them, and with those the watery, and so the 

 whole drop is fixed. 



On the Strange Freezing noticed in Numb. QO. By Dr. TVallis. N° 92, 



p. 5196. 



The extraordinary freezing which happened in Somersetshire in Dec. last, 

 was similar with us at Oxford. It was rather a raining of ice, or at least rain 

 freezing as it fell ; which made strange icicles hanging on trees, and a noise by 

 the rattling of them on the boughs moved by the wind. Yet more in the coun- 

 try about us it seems, than with us here. And the great warmth soon after 

 was also with us; insomuch that not only blossoms, but as it is said, green 

 apples on divers trees; particularly in the parish of Holywell. 



An Account of two Books. N° 92, p. 51 97. 



I. Tracts written by the Honourable Robert Boyle, containing New Experi- 

 ments touching the Relation betwixt Flame and Air, and about Explosions : An 

 Hydrostatical Discourse, occasioned by some Objections of Dr. Henry Moore, 

 &c. ; To which is annexed an hydrostatical Letter, about a way of weighing 



