Vitamin D is the collective term for a group of fat-soluble compounds, which occur in two major forms: ergocalciferol or vitamin **D2**, and cholecalciferol or vitamin D3.

This supplement contains vitamins C, **D2**, E, B1, B2, B3, B6, B12, folic acid, iodine, zinc, copper and magnesium, along with PABA, Fenugreek, Aloe Vera and silica.

To operate with **D2** upon (213) (214) (15), we have D (2)f = (13) (214) (15) + (213) (14) (15), D c1 2)f = (122) (213) (15) +(213) (213) (14) + (212) (214) (14), and hence **D2f** = (214) (15) (13) +(213) (15) (14) +(213) (212) (15) +(213)2(14) +(214) (212) (14).

If a is the distance shown by the normal triplets the type of separation observed in the line **D2** shows distances from the central line equal to a /3, 3a/3, 5a/3, while the type of D 1 gives 2a/3, 4a/3.

Then, since Hp, the force at M due to m and - m, is the resultant of d, and - m2, we have (L Hp m d **d2** 2ml H = d3, the direction being parallel to AB.

If in the identity f =f l f 2 ...fm we introduce a new root A we change a 8 into a8+/la8_l, and we obtain (1 +AD1 2 **D2**+...

3 tan 8, d l - I _ idlv j d23 **d2**/ I - 1d12H tan ©.

We then have approximately for the field at M due to the rod 4 HP= (dm1)2 (d + 1) = m (d 2 _ M Therefore 2m1= = (**d2** - 12)2Ht, - (**d2-**12)2HEtan 0 2d 2d (44) M (**d2-**12)2HE (45) And I = v - 2dv tan 0, whence we can find the values of I which correspond to different angles of deflection.

The logarithm is then obtained by use of the formula d l **d2** l d3 2 log e (x+d) = log e x-f- - x2+3 x3 - &c., in which of course the object is to render dlx as small as possible.

It is clear that direct transmission through the plate at a point where the thicknesses of the prisms are d 1 and d 2 will introduce a relative retardation of (µ,; -, u o) (d l - **d2**) between streams polarized in planes parallel and perpendicular to the edges of the prisms,, u o, and being the ordinary and the extraordinary refractive indices; and it is hence possible by an adjustment of the thickness to reduce elliptically polarized to plane polarization at an assigned point marked off by two parallel lines.