Year: 1886

page_text: I, HENRY HARINGTON LEIGH, practising as Phillips and Leigh, of 22, Southampton
Buildings, Chancery Lane, W.C., in the county of Middlesex, Engineer and Patent
Agent, do hereby declare the nature of this invention (as it has been communicated
to me from abroad by Bélisaire Dubois, of Bousignies, in the Republic of France)
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
-
Numerous attempts have been made to form upon columns of marble or other
hard substances ornamental spiral fillets by a process of addition, the .natural
inflexibility of these materials forbidding their being twisted.
The effect of a column constructed on this principle and in materials of different
colours is so beautiful that it is easy to understand why so many attempts have
been made to achieve success in this direction, but up to the present time the only
method of producing particolored columns has been that of cutting spiral grooves
therein and filling them with a material of a different colour.
In order that this invention may be thoroughly understood and carried into
practical effect, I will proceed to describe the same in detail, referring in so doing
to the accompanying drawings, which are to be taken as part of this specification
and read therewith, and in which like parts are marked throughout the figures in
which they occur with the same reference letter or number.
I cut prismatic bars A, Fig. 1, of which one angle a is determined as will be
hereafter explained, and these prisms serve as single elements for the construction
of the column. Two boxes or compound sockets, one for each end, contain a
number of openings corresponding to the number of bands in the column to be
made, and of the same shape respectively as the end elevation of the assembled
prisms. These openings are cut out in a circle around the centre of each compound
го...

page_text: socket, and the centres of the two sockets form the ends of the axis of the column.
The prisms are placed in the compound sockets, the angles a towards the centre.
These angles do not coincide with the axis of the column and are not even parallel
with it. Being inclined with respect to the axis, each angle has only one point of
contact with it, situated at the mid-length of the column, in such a manner that
the said angle forms with the said axis two acute angles subtended by radii of the
ends. It follows from this, that when all the prisms are put together the column
is only solid at its mid-length, whilst the two ends are hollow.
The prisms having been placed in the two compound sockets as I have just
explained, all the surfaces which touch are cemented together by means of a
suitable cement.
Figs. 2, 3, and 4, shew three horizontal sections of eight prisms united in the
position necessary to produce a twisted column consisting of eight bands of equal
width. Fig. 2 is a cross section of the upper end held in the upper compound
socket; Fig. 3 is a cross section taken at the mid-length; and Fig. 4 is a cross
section of the base through the lower socket. The prisms are marked from
I to VIII for the purpose of shewing their respective positions in the several
sections.
The dotted lines connecting the three sections of the prism I indicate the oblique
position of this same piece and of all the others. Fig. 5 is a vertical section
through the axis of the column, shewing that at the mid-length of this axis all the
prisms touch each other, therefore forming both above and below the plane of
contact a pyramidal space, the apices of both of these pyramidal spaces meeting in
the centre of the said plane of contact.
Fig. 6 is an elevation of the prismus put together, the Roman figures II, III, IV,
V, VI, and VII indicating the exterior angles of the corresponding prisms. The
two dotted lines shew the diameter of the column which is to be produced.
The circles in the three sections (Figs. 2, 3, and 4) shew the circumference of the
column. All that part of the prisms which is outside this circle is sawn off;
the column is then turned up, the inner part only of each prism remaining to form
a spiral band of the column and having the appearance therefore of inlaid work.
The sectioning of the prism I in the three sections shews the arrangement clearly.
After having cut the prisms down as above mentioned and polished the several
faces, their appearance is as shewn in Fig. 7, which is an elevation of the finished
column.
360°
the number of sides*
The column shewn in the drawings has eight spiral bands of equal width,
but the number and the width of these bands may be varied. The deter-
mining point is always the angle a. In the example chosen this angle is one
of 45°, i.e.
If a column is to be made with twelve equal bands,
the angle a will contain 30°. If I wish to produce a column containing, for
example, twelve bands of black marble separated by twelve of white marble of
double the width, I divide the circumference of the column into 36 equal parts;
the internal angle of the black prisms will be 10° and that of the white prisms 20°;
and so on.
All the angles set out around a common centre form the mid-length section of
the column, and the form of the two compound sockets is then obtained by the aid
of straight lines such as the dotted lines which are drawn between Figs, 2, 3, and 4.
The amount of twist varies according to the height determined upon.
Whilst speaking throughout this specification of prisms as the only elements of
the columns, I should explain that I have chosen this regular form because of the
ease with which it can be adapted to practical work. I wish it to be distinctly
understood that columns can be built up according to my invention from elements
of other form. All that is necessary is to have pieces of a sufficient length shaped
in such a manner as to have two flat longitudinal faces meeting each other at an
angle a determined according to the directions given above.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
The construction of columns by preparing a number of lengths of material
having two plane faces meeting at an angle decided by the relation of the cross
section of the particular length to the cross section of the finished column,
assembling them between two boxes in which they can be held with more or
less twist, and then reducing them by any convenient and well known process to
the shape of a column, substantially as and for the purpose described with reference
to the accompanying drawings.