WAV 



" Philofophical Eflays on various Subjefts, with Remarks 

 on Locke's EfTay on the Human Underitanding ;" and " A 

 brief Scheme of Ontology." His other works are chiefly 

 theological, confiding of Sermons, Difcourfes, EiTays, and 

 Controverfial Trads, &c. His fcheme of theology was 

 undoubtedly that which is ufually called orthodoxy, and, to 

 fay the leaft of it, approaching to Calvinifm. His temper, 

 however, was kind and gentle, and his moderation was in- 

 creafing as he advanced in years, and the maturity of his 

 judgment reftrained and controlled the fervour of his feehng3 

 and paffions. Some have faid that towards the clofe of life 

 his fentiments, with regard to the doSrine of the Trinity, 

 were materially altered. This, however, is a queftion Jul 

 jtidice. Whilft it is needlefs in this place to enter into the dif- 

 pute, and to examine the allegations pro and con, we incline 

 to think, as far as we have had an opportunity of examining 

 the evidence, that the fuppofition of fome degree of change 

 is not improbable. The printed Works of Dr. Watts, to- 

 gether with thofe which were left in M.S. for the revifion of 

 Dr. Jennings and Dr. Doddridge, were publiflicd colledively 

 by Dr. Gibbons, in 6 vols. 410. 1754. We (hall conclude 

 this article with the words of one of iiis biographers. " To 

 whatever clafsDr. Watts belongs," ranked by this biographer 

 among the decided advocates for orthodoxy," he muft always 

 be regarded as one of thofe whofe whole heart was devoted 

 to the promotion of the bell interefts of mankind, and whofe 

 life would have done honour to any fyltem of opinions." 

 Gibbons's Memoirs of Watts. Johnfon's Lives of the Poets. 

 Gen. Biog. 



Watts, in G«ofra/i^j;, a town of Virginia ; 30 miles N.W. 

 of Alexandria. — Alfo, a town of the ftate of Georgia. N. 

 lat. 34°~22'. W. long. 86° 25'. 



Watts IJland, a fmall ifland in the Chefapeak. N. lat. 

 37° 54'. W. long. 76° 3'. 



WATTUSKIFLET, a channel of the Baltic, between 

 the ifland of Aland and the coaft. of Finland, abounding with 

 fmall iflands. 



WAT VV EILE R, or Watterweiler, a town of France, 

 in the dapartment of the Upper Rhine. Near it is a medi- 

 cinal fpring ; 16 miles S. of Colmar. 



WAU, a town of Hindooftan, in the circar of Wcrrear ; 

 24 miles N. of Radunpour. 



WAU-CA-HATCHO, or Cow-Tail Ri-ver, a river of 

 Louifiana, which is the laft llream of any conlequence that 

 enters the Sabine. 



WAVE, Unda, in Phyfics, a cavity in the furface of 

 the water, or other fluid, with an elevation on its fides. 

 Or, it is a volume of water elevated by the adlion of the 

 wind upon its furface, into a ftate of fluftuation. 



The origin of waves may be thus conceived. The fur- 

 face of a ftanding water being naturally plam, and parallel 

 to the horizon, (allowing for that fmall degree of curvature 

 which refults from its gravitation to the centre,) if by any 

 means it be rendered hollow, as at A, {Plate 'X.Y. Hy- 

 draulics, Jig. II.) its cavity will be furrounded with an ele- 

 vation B B ; for if a certain quantity of water be deprefled 

 below the ufual level, an equal quantity muft rife in fome 

 other place above that level, and the water which ftands 

 clofeft to the place of the original impreffion will of courfe 

 be moved. The raifed water will defcend by its gravity, 

 and, with the celerity acquired in defcending, will form a 

 new cavity ; by which motions, the water will afcend at the 

 fides of this cavity, and fill the cavity A, while there is a 

 new elevation towards C ; and, when this laft is deprefled, 

 the water rifes anew towards the fame part. Thus arifes a 

 fucceflive motion in the furface of the water ; and a cavity, 

 which carries an elevation before it, is moved along from A, 



WAV 



towards C. Thus the alternate rifing and falling of the water 

 in ridges will extend all round the original fource of motion ; 

 but as they recede from that place, fo the ridges, as well as the 

 adjoining hollows, become fmallcr and fmaller, until they 

 vanilh. This diminution of fize is produced by three 

 caufes ; viz. by the want of perfeft freedom of motion 

 amongft the particles of water, by the refiftance of the air, 

 and by the further ridges being larger in diameter than thofe 

 which are nearer. It is likewife on account of the friftion, 

 or adhefion, among the particles of water, and of the refift- 

 ance of the air, that, in the fame place, the alternate eleva- 

 tions and depreflions diminifti gradually, until the water re- 

 aflumes its original tranquillity, unlefs the external impref- 

 fion be renewed or continued. This cavity, with the eleva- 

 tion next it, is called a luave ; and the fpace taken up by 

 the wave on the furface of the water, and meafured accord- 

 ing to the direftion of the wave's motion, is called the 

 breadth of the -wave ; which is evidently equal to the dif- 

 tance between the tops of contiguous ridges, or between 

 the loweft parts of two contiguous hollows ; and a wave is 

 faid to have run its breadth, when Us elevated part is arrived 

 at the place where the elevated part of the next wave ftood 

 before, or (the fituations of two contiguous waves being 

 given ) when one of them is arrived at the place of the other ; 

 and the time which is employed in this tranfition is called 

 the time of a -wave's motion. 



Waves, the Motion of, forms an article in the new phi- 

 lofophy ; and its laws being now pretty well determined, 

 we fhall give the reader the fubftance of what is taught on 

 this fubjeft. 



1 . The cavity, as A, is encompafled every way with an 

 elevation ; and the motion above-mentioned expands itfelf 

 every way : therefore the waves are moved circularly. 



2. Suppofe, now, AB [Jig. 1 2.) an obftacle, againft 

 which the wave, whofe beginning is at C, ftrikes ; and we 

 are to examine what change the wave fufFers in any point, 

 as E, when it is come to the obftacle in that point. In all 

 places through which the wave pafles in its whole breadth, 

 the wave is raifed ; then a cavity is formed, which is again 

 filled up ; which change while the furface of the water un- 

 dergoes, its particles go and return through a fmall fpace : 

 the direftion of this motion is along C E, and the celerity- 

 may be reprefented by that line. Let this motion be con- 

 trived to be refolved into two other motions, along G E and 

 D E, whofe celerities are refpedlively reprefented by thofe 

 lines. By the motion along D E, the particles do not aft 

 againft the obftacle ; but, after the ftroke, continue their 

 motion in that direftion with the fame celerity ; and this 

 motion is here reprefented by E F, fuppofing E F and E D 

 to be equal to one another ; but by the motion along G E, 

 the particles ftrike direflly againft the obftacle, and this 

 motion is deftroyed : for though the particles are elaftic, 

 yet, as in the motion of the waves they run through but a 

 fmall fpace, going backward and forward, they proceed fo 

 (lowly, that the figure of the particles cannot be; changed by 

 the blow ; and fo are fubjeft to the laws of percumon of 

 bodies perfeftly hard. See Percussion. 



But there is a refleftion of the particles from another 

 caufe : the water which cannot go forward beyond the ob- 

 ftacle, and is puftied on by that which follows it, gives way 

 where there is the leaft refiftance ; that is, it afcends ; and 

 this elevation, which is greater in fome than other places, is 

 caufed by the motion along G E ; becaufe it is by that mo- 

 tion alone that the particles impinge againft the obftacle. 

 The water, by its defcent, acquires the fame velocity with 

 which it was raifed ; and the particles of water are repelled 

 from the obftacle with the fame force in the direftion E G, 

 B b 2 as 



