The scale of decorative development is, like the scale of tones in music, _absolute_. It is the principle upon which Nature herself works, and this principle may be as well illustrated by means of the pot-hat as by anything else, as the principle holds good, and may be applied to any "demned thing," as Mr. Mantalini would say. [Illustration: THE DEVELOPMENT OF THE CHIMNEY-POT HAT.] We have, then, the two primal, elemental forms to work with, the straight line and the curved. Fig. 1 represents the pot-hat in what may be called its primordial state, in which state it stands in the same relation to headgear generally as did Millbank Prison to architecture; it would not be possible to produce less variety except by reducing its height and making its shape an exact parallelogram. In the next figure, by substituting the curved line for the straight lines of the sides and brim, we get a hint of those delicate and subtle curves for which the pot-hat is famous. In Fig. 4--not to weary the gentle reader with a long dissertation, he will at once perceive the principle--the degree of curvature is carried as far as is consonant with dignity or propriety; to carry it further would be to border upon buffoonery; such vagaries could not by any possibility be entertained in a work of such gravity and seriousness as the present. The same may be said of development in the direction of _height_. It only remains to develop the hat by means of reducing the width of its crown at the top, since the dimension AA is absolute, as the article must conform itself to the human cranium, which for present purposes is a fixed quantity. It is at this point that we take an affectionate and regretful leave of the pot-hat proper. Fig. 5 represents the high-crowned hat of the reign of James I., and which, in fact, was worn during the greater part of the Stuart period. "I send you," writes the King (James I.) to his son, in 1623, "for youre wearing, the three bretheren that ye knowe full well, but newlie sette, and the mirroure of Fraunce, the fellow of the Portugall dyamont, quiche I wolde wishe you to weare alone in your hatte, with a little blakke feather"; and to Buckingham he says, "As to thee, my sweete gossippe, I send thee a faire table dyamont, quiche I wolde once have givin thee before if thou wolde have taken it, and I have hung a faire pearle to it for wearing on thy hatte or quhaire thou plaisis, and if my Babie will spaire thee the two long dyamonts in forme of an anker, with the pendant dyamont, it were fit for an admiral to weare.... If my Babie will not spaire the anker from his mistresse, he may well lend thee his rounde broocke to weare, and yett he shall have jewells to weare in his hatte for three great dayes."