dz dz

dz Sentence Examples

• Thus so that z 1 J1 2 (z) = - 2 Jo 2 (z) - qz.h2(Z), (' an n z 1 J i 2 (z)dz = 1 -Jo (z) - J 1 2 (z).

• J 1 2 (z)dz.

• If we suppose that the force impressed upon the element of mass D dx dy dz is DZ dx dy dz, being everywhere parallel to the axis of Z, the only change required in our equations (I), (2) is the addition of the term Z to the second member of the third equation (2).

• (b2V2 + n2) (a2 - b 2) = - z It will now be convenient to introduce the quantities a l, a 2', 7731 which express the rotations of the elements of the medium round axes parallel to those of co-ordinates, in accordance with the equations Ty - 1 = dz ' 3= - dy 2 = dx - In terms of these we obtain from (7), by differentiation and subtraction, (b 2 v 2 + n 2) 7,3 = 0 (b 2 0 2 +n 2) .r i = dZ/dy (b 2 v 2 +n 2)', , 2 = - dZ/dx The first of equations (9) gives 3 = 0 (10) For al we have ?1= 47rb2, f dy e Y tkr dx dy dz

• Thus f (= 4-rb 2;JJ Z dY (e r) dx dy dz.

• These equations can be made to represent the state of convective equilibrium of the atmosphere, depending on the gas-equation p = pk =RA (6) where 0 denotes the absolute temperature; and then d9 d p R dz - dz (p) n+ 1' so that the temperature-gradient deldz is constant, as in convective equilibrium in (I I).

• The integral equation of continuity (I) may now be written l f fdxdydz+ff (lpu+mpv+npdso, (4) which becomes by Green's transformation (dt +d dz dy dx (p u) + d (p v) + d (p w) l I dxdydz - o, dp leading to the differential equation of continuity when the integration is removed.

• Taking the fixed direction parallel to the axis of x, the time-rate of increase of momentum, due to the fluid which crosses the surface, is - f'fpuq cos OdS = - f f (lpu 2 -+mpuv+npuw)dS, (1) which by Green's transformation is (d(uiu 2) dy dz dxdydz.

• The time rate of increase of momentum of the fluid inside S is )dxdydz; (5) and (5) is the sum of (I), (2), (3), (4), so that /if (dpu+dpu2+dpuv +dpuw_ +d p j d xdyd z = o, (b)` dt dx dy dz dx / leading to the differential equation of motion dpu dpu 2 dpuv dpuv _ X_ (7) dt + dx + dy + dz with two similar equations.

• These equations may be simplified slightly, using the equation of continuity (5) § for dpu dpu 2 dpuv dpuw dt dx + dy + dz =p Cat +uax+vay+waz?

• dp dpu dpv dpw -z)' reducing to the first line, the second line vanishing in consequence of the equation of continuity; and so the equation of motion may be written in the more usual form du du du du d dt +udx+vdy +wdz =X -n dx' with the two others dv dv dv dv i dp dt +u dx +v dy +w dz - Y -P d y' dw dw dw Z w dw i d p dt +u dx +v dy +wd - -P dz.

• = dx dy dz the equations of motion may be Written du - 2v?

• 2wr { a 0, dt2WE+2UC+ dz = o, dw dt - 2un+2v+ dH = 0, where H = fdp/p +V +1q 2, (7) 2 2 +v 2 2 (8) and the three terms in H may be called the pressure head, potential head, and head of velocity, when the gravitation unit is employed and Zq 2 is replaced by 1q 2 1 g.

• Eliminating H between (5) and (6) DS du dv dw (du dv d1zv dt u dx n dx udx' 5 -, dzi =°' and combining this with the equation of continuity Dp du dv dw p iit dx+dy+ dz = °' (10) D i du n dv dw_ dt (p p dx p dx p dx - o, with two similar equations.

• d o, dx dy dz dx dy dz so that, at any instant, the surfaces over which tk and m are constant intersect in the vortex lines.

• dz =o.

• Equation (5) becomes, by a rearrangement, dK dmdm dm din dx dt +u dx + dy +Zee dz + dx (dt +u dx +v dy +w d) = o,.

• d - K dK dK _ dK dK dK ?dx n dyd °, udx dz - ° and K=fdp/o+V+2q 2 =H (3) is constant along a vortex line, and a stream line, the path of a fluid particle, so that the fluid is traversed by a series of H surfaces, each covered by a network of stream lines and vortex lines; and if the motion is irrotational H is a constant throughout the fluid.

• = 0, dz = O.

• So far these theorems on vortex motion are kinematical; but introducing the equations of motion of § 22, Du + dQ =o, Dv+dQ =o, Dw + dQ dt dx dt dy dt dz and taking dx, dy, dz in the direction of u, v, w, and dx: dy: dz=u: v: w, (udx + vdy + wdz) = Du dx +u 1+..

• u '= - dx -md x, ' - dy -m dy, w = - dz-mdz' as in § 25 (I), a first integral of the equations in (5) may be written dp V + 2q 2 - d - n dt +14-14) (dx + m dz) +(v-v') (+m) +(w - w) (+m) =F(t), (7) in which d4, do, d?

• dt-(u)dy- (w-w) dz = d - (U-yR+zQ) dy - (V-zP+xR)d -(W-xQ+yP) d z (8) is the time-rate of change of 49 at a point fixed in space, which is left behind with velocity components u-u', v-v', w-w'.

• d t dy dz where _ oo abcdA A, B ' C ' - (a 2 +A, b 2 ±x, A, c 2 +A) P P 2 = 4(a 2 -F-A) (b 2 ±A) (c2+A).

• Let us apply the above theorem to the case of a small parallelepipedon or rectangular prism having sides dx, dy, dz respectively, its centre having co-ordinates (x, y, z).

• Let this rectangular prism be supposed to be wholly filled up with electricity of density p; then the total quantity in it is p dx dy dz.

• Hence the total flux is - (+ d2V d 2 V d2V dye + dz2) dy dz, dx2 and by the previous theorem this must be equal to 4'rrp dxdydz.

• Consider the integral W dx dy dz .

• Hence 8?rJJJ.dx l i 2 + i dy) 2 2 dxdydz= 8 Jfv d s_JJJvvvdx dngr dy dz.

• I by the whole area B"DZ'VO under the isothermal 9"D and the adiabatic DZ', bounded by the axes of pressure and volume.

• DZ, representing the loads taken in their order.

• These circuital relations, when expressed analytically, are then for a dielectric medium of types = (dt + x) (f',g',h')+dt(f,g,h), dR dQ = da dy dz dt' ' I See H.

• Here, then, is a case specially adapted to the isotropy of the quaternion system; and Hamilton easily saw that the expression i d x +j - + k dz could be, like ix+jy+ kz, effectively expressed by a single letter.

• If x, y, z be the co-ordinates of P it is easily proved that dx ~ dz = V = di W =~ (1)

• ~s Now, suppose a tracing point T Pa to be fixed to the cord, so as to be carried along the path of con- Dz a tact P11P2, that point will trace on a plane rotating along with the wheel I part of the involute of the base-circle DfD1, and on a plane rotating along with the wheel 2

• If we take the axis of z normal to either surface of the film, the radius of curvature of which we suppose to be very great compared with its thickness c, and if p is the density, and x the energy of unit of mass at depth z, then o- = f o dz, (16) and e = f a xpdz,.

• zpzL(z)dz, where, in general, we must suppose p a function of z.

• The surface-density of this stratum is a = cp. The energy per unit of area is e = f xpdz=cp(X' -4lrpe(o))+27rp'f c 0(z) dz+27rp fee(c - z)dz.

• Hence the surface-tension =e - =47rp 2 (f 0(z)dz - ce(c)).

• Integrating the first term within brackets by parts, it becomes - fo de Remembering that 0(o) is a finite quantity, and that Viz = - (z), we find T = 4 7rp f a, /.(z)dz (27) When c is greater than e this is equivalent to 2H in the equation of Laplace.

• If the density be a, the attraction between the whole of one side and a layer upon the other distant z from the plane and of thickness dz is 27r6 2 P(z)dz, reckoned per unit of area.

• The expression for the intrinsic pressure is thus simply K= 2 iro 2 f 1,G(z)dz (28) In Laplace's investigation o- is supposed to be unity.

• We may call the value which (28) then assumes Ko, so that as above Ko =27rf (z)dz.

• If a i, a 2 represent the densities of the two infinite solids, their mutual attraction at distance z is per unit of area 21ra l a fZ '(z)dz, (30) or 27ra l 02 0(z), if we write f 4,(z)dz=0(z) (31) The work required to produce the separation in question is thus 2 7ru l a o 0 (z)dz; (32) and for the tension of a liquid of density a we have T = a f o 0 (z)dz.

• For f0(z)dz =0(z).z - fz d dz) dz =0(z).z+fz4,(z) dz.

• Since 0(o) is finite, proportional to K, the integrated term vanishes at both limits, and we have simply f 0(z)dz f: (z)dz, (34) and T= ref: z1,1,(z)dz (35) In Laplace's notation the second member of (34), multiplied by 27r, is represented by H.

• Integrating by parts, we get J l'(z)d z = zI, G (z) + 3 z 3 I I (z) 3 f z3Cb(z)dz, fzqi(z)dz = J z21 '(z) + k z41 I (z) + a fz4(1)(z)dz.

• In all cases to which it is necessary to have regard the integrated terms vanish at both limits, and we may write f o (z)dz = 3f2' z 3 4(z)dz, f o z(z)dz = 'a' z4 cb(z)d z; (36) so that Ko = 3 f o z3 ?(z) dz, To = \$?

• o z 4 0(z)dz A few examples of these formulae will promote an intelligent comprehension of the subject.

• We may write T'12 = rQio f ° B(z) dz = bra i v 2 f 04 z 4 (z)dz;..

• Remember to do the three checks; Airspace, Alti and DZ, before starting any exercises and to respect all other canopy flyers.

• dz, by the hydranths, each with dactylozoid; gz, gastrozoid; b, mouth and tentacles; and, blastostyle; gon, gonophores; secondly, the " coenosarc," or rh, hydrorhiza.

• One class g g of polyps, the dactylozoids of branching in the Plumularia-type; (dz), lose their mouth and compare with fig.

• Thus so that z 1 J1 2 (z) = - 2 Jo 2 (z) - qz.h2(Z), (' an n z 1 J i 2 (z)dz = 1 -Jo (z) - J 1 2 (z).

• J 1 2 (z)dz.

• According to this notation, the three equations of motion are dt2 = b2v2E + (a2 - b2) d.s dt =b2v2rj+(a2 - b2) dy d2 CIF - b2p2+(a2_b2)dz It is to be observed that denotes the dilatation of volume of the element situated at (x, y, z).

• If we suppose that the force impressed upon the element of mass D dx dy dz is DZ dx dy dz, being everywhere parallel to the axis of Z, the only change required in our equations (I), (2) is the addition of the term Z to the second member of the third equation (2).

• (b2V2 + n2) (a2 - b 2) = - z It will now be convenient to introduce the quantities a l, a 2', 7731 which express the rotations of the elements of the medium round axes parallel to those of co-ordinates, in accordance with the equations Ty - 1 = dz ' 3= - dy 2 = dx - In terms of these we obtain from (7), by differentiation and subtraction, (b 2 v 2 + n 2) 7,3 = 0 (b 2 0 2 +n 2) .r i = dZ/dy (b 2 v 2 +n 2)', , 2 = - dZ/dx The first of equations (9) gives 3 = 0 (10) For al we have ?1= 47rb2, f dy e Y tkr dx dy dz

• Thus f (= 4-rb 2;JJ Z dY (e r) dx dy dz.

• Phil.): - Let x, y, z be the coordinates of P in the orbit,, r t, those of the corresponding point T in the hodograph, then dx dy _ dz c= ' 71 - a' - at therefore Also, if s be the arc of the hodograph, ds = v = V V1 1) j dt + (dt2) dt Equation (1) shows that the tangent to the hodograph is parallel to the line of resultant acceleration, and (2) that the velocity in the hodograph is equal to the acceleration.

• These equations can be made to represent the state of convective equilibrium of the atmosphere, depending on the gas-equation p = pk =RA (6) where 0 denotes the absolute temperature; and then d9 d p R dz - dz (p) n+ 1' so that the temperature-gradient deldz is constant, as in convective equilibrium in (I I).

• On another physical assumption of constant cubical elasticity A, dp = Ad p /P, (p - po)IA= lo g (P/Po), (18) dp _ A dp (I 1 zd p dz - P ' A Po-p -z, I - p -k, A kPo ' (19) (3) P dx Pdy Pdz -., (I) When the density p is f un dp/ iform, this becomes, as before in (2) § 9 P pp ==Pzz++pao constant.

• The integral equation of continuity (I) may now be written l f fdxdydz+ff (lpu+mpv+npdso, (4) which becomes by Green's transformation (dt +d dz dy dx (p u) + d (p v) + d (p w) l I dxdydz - o, dp leading to the differential equation of continuity when the integration is removed.

• Taking the fixed direction parallel to the axis of x, the time-rate of increase of momentum, due to the fluid which crosses the surface, is - f'fpuq cos OdS = - f f (lpu 2 -+mpuv+npuw)dS, (1) which by Green's transformation is (d(uiu 2) dy dz dxdydz.

• The time rate of increase of momentum of the fluid inside S is )dxdydz; (5) and (5) is the sum of (I), (2), (3), (4), so that /if (dpu+dpu2+dpuv +dpuw_ +d p j d xdyd z = o, (b)` dt dx dy dz dx / leading to the differential equation of motion dpu dpu 2 dpuv dpuv _ X_ (7) dt + dx + dy + dz with two similar equations.

• These equations may be simplified slightly, using the equation of continuity (5) § for dpu dpu 2 dpuv dpuw dt dx + dy + dz =p Cat +uax+vay+waz?

• dp dpu dpv dpw -z)' reducing to the first line, the second line vanishing in consequence of the equation of continuity; and so the equation of motion may be written in the more usual form du du du du d dt +udx+vdy +wdz =X -n dx' with the two others dv dv dv dv i dp dt +u dx +v dy +w dz - Y -P d y' dw dw dw Z w dw i d p dt +u dx +v dy +wd - -P dz.

• To determine the component acceleration of a particle, suppose F to denote any function of x, y, z, t, and investigate the time rate of F for a moving particle; denoting the change by DF/dt, DF = 1t F(x+uSt, y+vIt, z+wSt, t+St) - F(x, y, z, t) dt at = d + u dx +v dy+ w dz and D/dt is called particle differentiation, because it follows the rate of change of a particle as it leaves the point x, y, z; but dF/dt, dF/dx, dF/dy, dF/dz (2) represent the rate of change of F at the time t, at the point, x, y, z, fixed in space.

• To integrate the equations of motion, suppose the impressed force is due to a potential V, such that the force in any direction is the rate of diminution of V, or its downward gradient; and then X= -dV/dx, Y= -dV/dy, Z= -dV/dz; (I) and putting dw dv du dw dv du Ty - dz -2 ' dz - dx -2n ' dx - dy2?, d -{- d ' v ?

• = dx dy dz the equations of motion may be Written du - 2v?

• 2wr { a 0, dt2WE+2UC+ dz = o, dw dt - 2un+2v+ dH = 0, where H = fdp/p +V +1q 2, (7) 2 2 +v 2 2 (8) and the three terms in H may be called the pressure head, potential head, and head of velocity, when the gravitation unit is employed and Zq 2 is replaced by 1q 2 1 g.

• Eliminating H between (5) and (6) DS du dv dw (du dv d1zv dt u dx n dx udx' 5 -, dzi =Ã‚°' and combining this with the equation of continuity Dp du dv dw p iit dx+dy+ dz = Ã‚°' (10) D i du n dv dw_ dt (p p dx p dx p dx - o, with two similar equations.

• d o, dx dy dz dx dy dz so that, at any instant, the surfaces over which tk and m are constant intersect in the vortex lines.

• dz =o.

• Equation (5) becomes, by a rearrangement, dK dmdm dm din dx dt +u dx + dy +Zee dz + dx (dt +u dx +v dy +w d) = o,.

• d - K dK dK _ dK dK dK ?dx n dyd Ã‚°, udx dz - Ã‚° and K=fdp/o+V+2q 2 =H (3) is constant along a vortex line, and a stream line, the path of a fluid particle, so that the fluid is traversed by a series of H surfaces, each covered by a network of stream lines and vortex lines; and if the motion is irrotational H is a constant throughout the fluid.

• The osculating plane of a stream line in steady motion contains the resultant acceleration, the direction ratios of which are du du, du d i g d g 2 _ dH dx +v dy + dz - 2v?

• = 0, dz = O.

• So far these theorems on vortex motion are kinematical; but introducing the equations of motion of § 22, Du + dQ =o, Dv+dQ =o, Dw + dQ dt dx dt dy dt dz and taking dx, dy, dz in the direction of u, v, w, and dx: dy: dz=u: v: w, (udx + vdy + wdz) = Du dx +u 1+..

• Now if k denotes the component of absolute velocity in a direction fixed in space whose direction cosines are 1, m, n, k=lu+mv+nw; (2) and in the infinitesimal element of time dt, the coordinates of the fluid particle at (x, y, z) will have changed by (u', v', w')dt; so that Dk dl, do dt dt dt dt + dtw +1 (?t +u, dx +v, dy +w, dz) +m (d +u dx + v dy +w' dz) dw, dw +n (dt ?dx+v?dy +w dz) But as 1, m, n are the direction cosines of a line fixed in space, dl= m R-n Q, d m = nP-lR an =1Q-mP dt dt ' dt ' so that Dk __ du, du, du, du dt l (dt -vR+ wQ+u + v dy + w dz) +m(..

• u '= - dx -md x, ' - dy -m dy, w = - dz-mdz' as in § 25 (I), a first integral of the equations in (5) may be written dp V + 2q 2 - d - n dt +14-14) (dx + m dz) +(v-v') (+m) +(w - w) (+m) =F(t), (7) in which d4, do, d?

• dt-(u)dy- (w-w) dz = d - (U-yR+zQ) dy - (V-zP+xR)d -(W-xQ+yP) d z (8) is the time-rate of change of 49 at a point fixed in space, which is left behind with velocity components u-u', v-v', w-w'.

• d t dy dz where _ oo abcdA A, B ' C ' - (a 2 +A, b 2 ±x, A, c 2 +A) P P 2 = 4(a 2 -F-A) (b 2 ±A) (c2+A).

• Let us apply the above theorem to the case of a small parallelepipedon or rectangular prism having sides dx, dy, dz respectively, its centre having co-ordinates (x, y, z).

• Let this rectangular prism be supposed to be wholly filled up with electricity of density p; then the total quantity in it is p dx dy dz.

• Hence the total flux is - (+ d2V d 2 V d2V dye + dz2) dy dz, dx2 and by the previous theorem this must be equal to 4'rrp dxdydz.

• Consider the integral W dx dy dz .

• We have by partial integration ff1 fV dd - ' 2 dy JJ dx y JJ y dxd dz = V - d dzdxd dz, and Itwo (similar equations in y and z.

• Hence 8?rJJJ.dx l i 2 + i dy) 2 2 dxdydz= 8 Jfv d s_JJJvvvdx dngr dy dz.

• I by the whole area B"DZ'VO under the isothermal 9"D and the adiabatic DZ', bounded by the axes of pressure and volume.

• DZ, representing the loads taken in their order.

• These circuital relations, when expressed analytically, are then for a dielectric medium of types = (dt + x) (f',g',h')+dt(f,g,h), dR dQ = da dy dz dt' ' I See H.

• Here, then, is a case specially adapted to the isotropy of the quaternion system; and Hamilton easily saw that the expression i d x +j - + k dz could be, like ix+jy+ kz, effectively expressed by a single letter.

• The confusion of (3 with v necessitated the invention of a new symbol B in the Cyrillic, E in the Glagolitic for b, while new symbols were also required for the sounds or combinations of sounds z (zh), dz, Ã¯¿½t (sht), c (ts); c (ch in church), Ã¯¿½ (sh), u, i, y (u without protrusion of the lips), e (a close long e sound), for the combination of o, a and e with consonantal I (English y) and for the nasalized vowels e, q (nasalized o in pronunciation) and the combinations je and ja (English yg, ye).

• If x, y, z be the co-ordinates of P it is easily proved that dx ~ dz = V = di W =~ (1)

• ~s Now, suppose a tracing point T Pa to be fixed to the cord, so as to be carried along the path of con- Dz a tact P11P2, that point will trace on a plane rotating along with the wheel I part of the involute of the base-circle DfD1, and on a plane rotating along with the wheel 2

• If we take the axis of z normal to either surface of the film, the radius of curvature of which we suppose to be very great compared with its thickness c, and if p is the density, and x the energy of unit of mass at depth z, then o- = f o dz, (16) and e = f a xpdz,.

• zpzL(z)dz, where, in general, we must suppose p a function of z.

• Hence if we write K =27rf o,/i(z)dz, H =27rf o zi/i(z)dz, the pressure of a column of the fluid itself terminating at the surface will be p2{K+1H(I/Rid-I/R2)}, and the work done by the attractive forces when a particle m is brought to the surface of the fluid from an infinite distance will be mp{K+zH(I/Ri+I/Ro)} If we write (.0 J then 27rmpo(z) will express the work done by the attractive forces, while a particle m is brought from an infinite distance to a distance z from the plane surface of a mass of the substance of density p and infinitely thick.

• The surface-density of this stratum is a = cp. The energy per unit of area is e = f xpdz=cp(X' -4lrpe(o))+27rp'f c 0(z) dz+27rp fee(c - z)dz.

• Hence the surface-tension =e - =47rp 2 (f 0(z)dz - ce(c)).

• Integrating the first term within brackets by parts, it becomes - fo de Remembering that 0(o) is a finite quantity, and that Viz = - (z), we find T = 4 7rp f a, /.(z)dz (27) When c is greater than e this is equivalent to 2H in the equation of Laplace.

• We have given several examples in which the density is assumed to be uniform, because Poisson has asserted that capillary B (25) e = c p (X' - 4 7rpe (0) ) -I-474Ã‚°o(z)dz.

• If the density be a, the attraction between the whole of one side and a layer upon the other distant z from the plane and of thickness dz is 27r6 2 P(z)dz, reckoned per unit of area.

• The expression for the intrinsic pressure is thus simply K= 2 iro 2 f 1,G(z)dz (28) In Laplace's investigation o- is supposed to be unity.

• We may call the value which (28) then assumes Ko, so that as above Ko =27rf (z)dz.

• If a i, a 2 represent the densities of the two infinite solids, their mutual attraction at distance z is per unit of area 21ra l a fZ '(z)dz, (30) or 27ra l 02 0(z), if we write f 4,(z)dz=0(z) (31) The work required to produce the separation in question is thus 2 7ru l a o 0 (z)dz; (32) and for the tension of a liquid of density a we have T = a f o 0 (z)dz.

• For f0(z)dz =0(z).z - fz d dz) dz =0(z).z+fz4,(z) dz.

• Since 0(o) is finite, proportional to K, the integrated term vanishes at both limits, and we have simply f 0(z)dz f: (z)dz, (34) and T= ref: z1,1,(z)dz (35) In Laplace's notation the second member of (34), multiplied by 27r, is represented by H.

• Integrating by parts, we get J l'(z)d z = zI, G (z) + 3 z 3 I I (z) 3 f z3Cb(z)dz, fzqi(z)dz = J z21 '(z) + k z41 I (z) + a fz4(1)(z)dz.

• In all cases to which it is necessary to have regard the integrated terms vanish at both limits, and we may write f o (z)dz = 3f2' z 3 4(z)dz, f o z(z)dz = 'a' z4 cb(z)d z; (36) so that Ko = 3 f o z3 ?(z) dz, To = \$?

• o z 4 0(z)dz A few examples of these formulae will promote an intelligent comprehension of the subject.

• 4,(z) =0 from z = a to z=co, Equations (37) now give 2 it " ira4 Ko = - z i dz = 6, 3 0 _ 7r fa 4 sra5 T o 8 fo zdz=40 The numerical results differ from those of Young, who finds that " the contractile force is one-third of the whole cohesive force of a stratum of particles, equal in thickness to the interval to which the primitive equable cohesion extends," viz.

• We may write T'12 = rQio f Ã‚° B(z) dz = bra i v 2 f 04 z 4 (z)dz;..

• dz, by the hydranths, each with dactylozoid; gz, gastrozoid; b, mouth and tentacles; and, blastostyle; gon, gonophores; secondly, the " coenosarc," or rh, hydrorhiza.

• One class g g of polyps, the dactylozoids of branching in the Plumularia-type; (dz), lose their mouth and compare with fig.

• According to this notation, the three equations of motion are dt2 = b2v2E + (a2 - b2) d.s dt =b2v2rj+(a2 - b2) dy d2 CIF - b2p2+(a2_b2)dz It is to be observed that denotes the dilatation of volume of the element situated at (x, y, z).

• We have by partial integration ff1 fV dd - ' 2 dy JJ dx y JJ y dxd dz = V - d dzdxd dz, and Itwo (similar equations in y and z.

• (11), where r is the distance between the element dx dy dz and the point where a l is estimated, and k = n/b = 27r/X (12), X being the wave-length.

• (11), where r is the distance between the element dx dy dz and the point where a l is estimated, and k = n/b = 27r/X (12), X being the wave-length.