Remarks on the Article " Strength rf Materials," &c. 483 



iFrom the top of the bridge the appearance of the water indi- 

 cated the same state of filth. Curiosity prompted a further 

 survey. The stream was followed to the lake, where the whole 

 mass of waters was found dirtier, if possible, than the stream 

 that flowed from it. From pretty accurate experiments, the time 

 necessary for the water just emptying itself from the lake, to 

 reach Auchmoor bridge, has been ascertained; and upon that 

 data we calculated, by the time the mud reached the field, at 

 what time the shock must have been felt in the lake, and marked 

 it to have taken place some time between eleven and twelve on 

 Tuesday night. 



Judge then our surprise, when the old man's remarks were 

 so fully confirmed by accounts from the north in so short a pe- 

 riod after. 



The agitation in the lake must have been dreadful, had it been 

 day-light to render it visible. The quantity of mud and sand 

 thrown up from the depth of 80 to 100 feet must have been 

 very extraordinary, when it continued so long dirty, though it had 

 the lake itself and the slow windings of a number of miles through 

 a flat country to subside in. The water continued to run dirty 

 for two days; so much so, that we coidd neither work nor put 

 our yarns through any operation during that period. 



LXXXVII. Remarks on the Article " Strength of Materials," 

 publishf-d in Dr. Rees's New Cyclopcediu, vol. xxxiv. part i. 

 Bij A Correspondent. 



1 HE author of the article " Strength of Materials," after stating 

 that we have two or three theories by different authors, proceeds ' 

 to sav, that " it unfortunately happens that we owe all these 

 theories to men who have not themselves made any experiments." 

 So far, perhaps, as respects Galileo, Leibnitz, .lames Bernoulli, 

 Euler, and Lagrange, the authors particularly alluded to, it is 

 correct ; but it is to Marriotte, whom the author has classed 

 with the experimental writers, that we are indebted for the first 

 outline of the true theory; and the whole of his experiments 

 were made with a view to illustrate and confirm the premises he 

 had a^iuned. Vlarriotte's mathematical investigation only ap- 

 plies to rectangular prisms ; therefore, his experim iits, being 

 made with cylinders, do not agree correctly with his theory. 

 Marriotie's theory was published in his Traite du Mouvemenl 

 des Euiix, sect. v. disc, ii."'' 



Marriotte and Leibnitz investigated the strength in a hori- 



* See Dusa{:urRrs's 'l'r:iiislation, p. 237. London 1718. 



Vol. 48. No. 224. Dec. 1816. E e zoiital 



