1813.] Scientific Intelligence. -171 



V. Freezing of Alcohol. 



A correspondent informs me that the process followed by Mr. 

 Hutton to freeze alcohol, and which he thought proper to con- 

 ceal, was as follows. The alcohol is put into a condensing 

 vessel, and air condensed on it as fur as can be done with safety. 

 The vessel is then reduced to as low a temperature as possible by 

 means of freezing mixtures, and the air being allowed suddenly 

 to make its escape increases the cold so much that the desired 

 effect is produced. 



VI. Situation of Cryolite in Greenland. 



I received from Mr. Allan the following correction of his ac- 

 count of Greenland from Mr. Giesecke too late for insertion in 

 the last number of the Annals of Philosophy ; — 



" Cryolite occurs in two small detached beds, resting on 

 gneiss ; one of them is composed entirely of the fine white 

 cryolite uncontaminated with any mixture ; in the other, the 

 brown variety occurs mixed with galena, pyrites, &c. They 

 are situated very near each other. The first is touched at high 

 water by the tide. It varies from 1 to 2\ feet in thickness. 

 From the decompositions which this curious mineral has under- 

 gone, it could not be procured attached to the rock on which it 

 rests. It is, besides, divided from it by a thin layer of mica, 

 always in a state of disintegration. Mr. Giesecke is inclined to 

 consider the cryolite as belonging to a floetz formation." 



VII. Meteorological Apparatus. 



In answer to the correspondent who wishes for correct infor- 

 mation respecting Mr. Luke Howard's meteorological apparatus, 

 I have only to refer to the wrapper of Number li. of the Annals 

 of Philosophy, where every thing respecting it with which 1 am 

 acquainted has been noticed. As to evaporation, he will find 

 useful observations on it in Saussure, and in a paper by Mr. 

 Dalton published in the Manchester Memoirs. The part of the 

 apparatus most frequently wrong is the rajin-gage, which never 

 can give correct information unless it be placed within a few feet 

 of the ground, and detached from all buildings. 1 believe the 

 mean temperature indicated by the thermometer in most journals 

 is too high. It must always be so, unless the lowest point to 

 which the thermometer falls in the night be marked. This, in 

 :ummer, is usually about sun-rise; in winter, it is irn cular, 

 depending on the wind. A good Six's thermometer I conceive 

 to be a necessary appendage to every meteorological apparatus. 



VIII. Bidden/ Hare. 

 I have been favoured by Pr. Wilkins with the following 



