88 KKPORT — 1881. 



cylindrical waves in circular vessels, have been investigated by Rayleigh ' 

 and compared -with his own experiments and those of Professor Guthrie^ 

 published in 187-5. The question has also been investigated by Giesen.^ 

 Kircbhoff'' has considered plane waves in a rectangular trough whose 

 sides are equally inclined to the vertical, the crests of the waves being 

 l^arallel to the sides. 



Report of the Cotnriilttee, consisting of Sir William Thomson, 

 Professor EoscoE, Dr. J. H. Gladstone, and Dr. Schuster 

 (Secretary), appointed for the piirpose of collecting information 

 tvith regard to Meteoric Dust, and to consider the question of 

 undertaking regular observations in various localities. 



This Committee was appointed for the double purpose of examining the 

 observations hitherto recorded on the subject of meteoric dust, and of 

 discussing the possibility of future more systematic investigations. 



With regard to the first point, we note that in a paper presented to 

 the Royal Astronomical Society ^ in 1879, Mr. Ranyard has given what 

 appears to be a j^retty complete account of the known observations as to 

 the presence of meteoric dust in the atmosphere. 



It appears that in the year 1852 Professor Andrews found native iron 

 in the basalt of the Giant's Causeway. Nordenskjold found particles of 

 iron, which in all probability had a cosmic origin, in the snows of Fin- 

 land and the icefields of the Arctic regions. Dr. T. L. Phipson, and, 

 more recently, Tissandier, found similar particles deposited by the winds 

 on plates exposed in different localities. Finally, Mr. John Murray dis- 

 covered magnetic particles raised from the deposits at the bottom of the 

 sea by H.M.S. Challenger. These particles were examined by Professor 

 Alexander Herschel, who agreed with Mr. Murray in ascribing a cosmic 

 origin to these particles. For fuller details and all references we must 

 refer to Mr. Ranyard's paper. 



Some interesting papers have also been published by Professors 

 Silvestri and Tacchini.^ 



There can be little doubt that magnetic dust, which in all probability 

 derives its origin from meteors, has often been observed, though it ought 

 to be mentioned that some writers have come to a contrary conclusion.^ 

 The question arises in what way we can exercise our knowledge on these 

 points to an appreciable extent. 



A further series of occasional observations would in all probability 

 lead to no result of great value unless the observations were continued 



' ' On Waves,' Phil. Mag. (5), i. p. 257 (1876). 



= 'On Stationaiy Liquid Waves,' Phil. Mag. (4), L pp. 290. 377(1875); see also 

 Eayleigli in Nature, xii. p. 251. 



' 'Versuch einermathematisclien Darstellung der Fliissigkeitswellen,' Schl. Zeits. 

 filr Math., xxii. p. 133. 



* ' Ueber stehende Schwingungen cincr schweren Fliissigkeit,' Wied. Ann., x. 

 p. 3i ; also Monatsber. d. It. ahad. d. Wiss. zu Bcrl., May 15, 1879. For experiments 

 bearing on this theory see a paper by Kircbhoff andHansemann in the same journal, 

 ' Versuche iiber stehende Schwingungcn des Wassers,' ih., p. 3;i7. 



* Monthly Notices, xxxix. p. 161 (1879). 



" Annali della Mcteorologia, Tarte III. 1879. 



^ Flogel, Zfitschrift fiir Mcteorologic, August 1881, 



