

OBSERVATIONS ON THE WEATHER. 281 



running water being warmer than the land, a mitt or' fog may 

 be feen rifing above the rivers, particularly when the air is cold 

 and clear ; but this vapour is no longer vifible when the river 

 is frozen, for though the ice be fubject to evaporation, it does 

 not yield fo much vapour as water, and the water, in parting 

 With its caloric in the moment of freezing, warms the fur- 

 rounding air. 



To the philofopher all obi efts in nature, both animate and Amufement and 



~ , , ,, r i • n n.- i* inftru&ion from 



inanimate, may afford both amulement and lnltruction, parti- the fo ,- lCary rort . 



cularly in meteorology ; but to obferve them with due atten- templation of 



tion, we muft quit the bufy fcenes of life ; " and thus our naturc * 



"> lives exempt from public haunts, find tongues in trees, 



*' books in rnnning brooks, fermons in ftones, and good in 



" every thing. " 



VIII. 



Defcription of a Cheap, Simple, and Portable Instrument, for 

 determining the Pofitions of Objeels in taking a Picture from 

 the Life. By R. L. Edgeworth, Fjq. 



JL HAT active and intelligent philofopher and journaliit, Inftrument for 

 €if. Pictet, author of the Bibliotheque Brittanique, on his late ^^f^thc**' 

 return from London to Paris, prefented various instruments National Infti- 

 brought from this country to the National Inftitute of France. tute > 

 Among them was the instrument here to be defcribed, and 

 fince publifhed in the Bulletin des Sciences ; on infpection of 

 which my attention was excited to my notes, where, among 

 other communications to be made to my readers, I find this 

 initrument, as publifhed in the excellent work " On Practical 

 Education" by Maria Edgeworth and her father, to whom I 

 have afcribed the contrivance in the title. The authors of the 

 Bulletin affirm, that it was invented and executed by the chil- 

 dren under the parental care of Mifs Edgeworth ; but I find 

 no fuch intimation in the original work. The initrument of was not as per- 

 Profeflbr Piclet is in various refpe&s inferior to that which I inal i nvent i oa . 

 have here copied ; infomuch that Cit. Cloquet has propofed 

 an amendment, for giving the index an horizontal pofition 

 when it is required to transfer the obfervation to paper, which 

 is in fact lefs effectual than the provisions made for that pur- 



pofe, 



