Book Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1862 edition. Excerpt: ...which shows a specimen of a series of cross arches, and pillars or piers. The particulars of the dimensions are as follows: --The span between the piers is 13 ft. The height of the piers is 11 ft. 6 in. The height of the shaft is 10 ft. The diameter of each pier is 23 in.; and their horizontal section is something of the form shown at b. The height of the masonry over the crown of each arch is 2 ft. Now, in 13 ft. there are 156 in., which, divided by 6, gives 26 in. for the diameter of each pillar: but the diameter is 23 in., therefore 2 in. too small; consequently, each pier requires the reduction of 1 ft. 3 in. in the height, taken from the dimensions of the span; thus leaving 11 ft. 9 in. for the balancing height pf the piers: but the piers aro 11 ft. 6 in. As their proportions approach so near to each other, it is probable that a mistake might have been made in the measurement of the diameter, by having allowed a trifle too much. The above proportions exactly coincide with those required for arches and piers running in a single series, as in Hartlip Church. In the Lady Chapel, it has been stated that several series of arches and piers cross each other at right angles; there fore, according to the experiment (fig. 65 p. 66), they will, thus circumstanced, carry double the weight of a single series. The architects were fully aware of this, and availed themselves of it to give lightness and beauty to the structure, which they have admirably accomplished by the concave section up the four sides of every pillar. The dotted line a d terminates at d on the outer edge of the pillar: c c are the walls. Rochester Cathedral.--Fig. 92 shows a part of the crypt under the choir of this cathedral, consisting of a series of arches and piers crossing..