^ On the Phenomena of the Morning and Evening Dew, 



But there is a very important confequence, which it feems allowable to draw from thefe 

 phenomena ; namely, that they muft influence the produ£tion and permanence of the trade 

 winds. For every day, almoft regularly, the air of the torrid zone being folicited to move 

 in two oppofite directions by forces very different in quantity, it muft tend in fa£t to ac- 

 quire and preferve a motion or current, in the diredlion of that ftrongefl: power, which 

 in this cafe is from the eaft, being the wind which brings the morning dew. This caufc 

 muft be the more effe£lual, as it a£ts in the lower part of the atmofphcre, where we feel 

 the trade winds, and becaufe it affe£ts the denfeft portion, and confequently muft the 

 more readily move the whole. 



Under the glacial zone, where particularly during the winter the fun fcarcely fkims the 

 horizon through the whole day, the precipitation of water will be very confidcrable, by 

 reafon of the coldnefs of the climate, and a thick fog will prevail, which will fCarcely be 

 diflipated in fummer ; but in winter will extend far into the temperate zones. Thus we 

 fee during the winter feafon, in our country, very confidcrable fogs, which have only a 

 feeble light even in the middle of the day. 



It would be curious to prefent in this place a numerous feries of accurate obfervations, 

 on the circumftances which accompany the morning and evening dews at different times 

 of the year, and in different countries, the hours at which thefe phenomena begin and end, 

 the intermiflions or irregularities, with which they are affefted in different fituations ; but 

 if the generality of the caufes to which they are here attributed, ftiould excite the attention 

 of philofopheis, the interefting talk here indicated will affuredly and fpeedily be per- 

 formed. 



X. 



Thoughts on Magnetifmf by Richard Kirwan, Efq; L.L.D. F.R.S. and M.R.I. A*. 



JL H E R E are two ways of explaining a natural phsenomenon ; the firft, is by dif- 

 covering the conditions and circumftances of its production and the laws by which its adlion 

 is governed ; the fecond, is by {hewing its analogy, fimilarity, or coincidence with fome 

 general fact with whofe laws and exiftence we are already acquainted ; this laft mode is by 

 far the moft perfeCt and fatisfa£lory. In the firft fenfe of the word cle£tricity and magne- 

 tifm have been in feme meafure explained, but in the laft fenfe neither ; the primary caufe 

 of magnetifm in particular has hitherto been fuppofed to relate to iron alone, or its ores, and 

 to ftand unconneded with all other natural phenomena. 



2. If therefore any other general faft or power can be difcovered to which it bears fome 

 analogy or fimilarity, it may fo far be faid to be explained. Now fuch fadt or power I think 

 may be affigned, namely, the power of cr^i/falization. 



• Tr,infaftions of the Royal Iri/h Academy. Vol, VI. 



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