THEORY OF WALLS. lOl 



tioned lead to improve a fubject the moft abftrufe 

 and difficult in the whole fcicnce of phyfics. Many 

 of our firft mathematicians, fmce the immortal New- 

 ton fliewed the way, have inveftigated, with the 

 greateft perfpicuity and elegance, a great variety of 

 theoremc concerning the reiiftance of bodies moving in 

 diflus; but for want of knowing the law of rcliliance, 

 their conclufions have differed very conliderably from 

 thofe experiments that were made to afcertain their 

 truth. Do6tor Mutton after making many experi- 

 ments at Woolwich^ in the year 1786, in order to prove 

 the refults of feveral interefting problems which he 

 has given in his fele8; exercifes, where he allows the 

 law of refiftance to be in the duplicate ratio of the 

 velocity, obferves, *' upon the whole, we find that the 

 refiftance of the air, as determined by our experiments, 

 differs very widely, both in refpect to the quantity of 

 it on all figures, and in refpcft to the proportions of it 

 on oblique furfaces, from the fame as determined by 

 the preceding theory, which is the fame as that of Sir 

 Isaac Newton, and moft modern philofophers." 

 And further, he fays, " we conclude therefore, that 

 all the theories of the refiflance of the air hitherto given 

 are very erroneous. And 1 have only laid down the 

 preceding one, till further experiments on this im-^ 

 portant fubjeft ihall enable us to deduce from them 

 another, that Ihall be more confonant to the true phe- 

 nomena of nature. ' 



Whether I have noticed every thing that ought 

 to be taken into confideration, in dcfcribing how the 

 experiment aforefaid ought to be made, will, perhaps 

 with fome, be a matter of doubt : but this 1 may ven- 

 ture to aver, that, if I have not, further difcoveries 

 on the fubje6l will tend to a greater redu6lion in the 

 dimenfions of the wall ; and as this enquiry has con- 

 tributed to that end, I Hiall remain fatisfied with the 

 correftnefs of the theory here ellablifhed, till more 

 data can be obtained. 



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