T I D 



To convert the degrees of Reaumur into those of Fahrenheit, and the 

 ontrary. 



r = * + 320-and R t= (Zl^OJl* 

 To convert the centrigrade to Fahrenheit and the contrary. 



F = ^V 32 o _ and C ^ (F-^?X5 

 convert the Centrigrado to Reaumur and the contrarj'-. 



K = S->L* .ndc=*. 



5 4 



To 



THERMOMETRICAL barometer. See Heat. 

 TIDE3. ( Fhice and Racism from Bernouilli.) 



1. If a fluid sphere at rest be attracted by a distant body S also at rest, 

 it will put on the form of a spheroid ; and if P and Q represent respec- 

 tively the attraction of the spheroid at the extremities of the minor and 

 major axes,z be the addititious force of S upon P, and n that upon the 



point E 



Major axis : Minor I : P 4. m : F, 2 n. 



Cor. If the sphere were the earth, and S the sun or moon ; then, upon 

 the above supposition, the difference of the diameters or height of the 

 tide, as caused by the sun, would = 2,033 feet ; and the height, as caused 

 by the moon, r= 5,412 feet; .'. in syzygy the height would be 7,445 feet. 



2. Tha altitude of the high tidj above the level of the water, if thero 

 had been no tidi?, is double of the. depression of the low tida below. 



3. Find (1) The elevation of the water at any point above the natural 

 level of the undisturbed ocean. (>) The depression below the natural 

 level at any point. (3) The falling 1 of the water from the highest point, 

 and (4) The rising of the water from the lowest point. 



Put angular distance of the point from the place of high water, or 

 the hour / from the time of high tide ; m perpendicular height of high, 

 above low water ; then the equations will stand thus : 



(1) Elevation = 2!^1=J x . 



o 



(>) Depression = ^^ -^- X m. 

 J 



(3) Fall ......... m X sin. 3 0. 



(I) Rise ......... = m X cos.s 0. 



203 



