B~id~,s used in: the construction of '~,luteg <C~umns~+ ~ ; ; :

[v~rOjecting from, and heel F, is firmly fix

E. This co~ wheelii lar is i~ two parts~ i which may be increas square pin projecting round, wliere it passe turn the pinion G~; an fi'eely upon: the pin 1 hole in the swivel K~ netted by a pin and socket.'" , , " ' '

tab~'e A, that it ma~ carry the [nuflar to the right distance.from, its edge, on eiVhe~- side.. " - Vf; J~ S

On the fo~'m hn'd,'ar~angement of Bri~: used @ it@~ ~i,i~e construclwn of Fluted, Columns,- ~~:~::~ ", :,;~!,, ,~.:,:~u:,

S t n ~ I n a late-visit to the city of:New ¥~rk~ m X attentien was attracted to the ehur6h now being built in Canal street.': I t s front appeared to be a copy of •that of the temple of Tl~seu~:at Athens. The ingenious arr~ingement of the bricks to prodnee"~he fluting of the col~mns,'~:ecalled to my memory t~e tbllo~ving eon~'ivance used by the ancients=: to. produce-the same effect, and which I send you~ with a hope that it may at]brd a useful hint to some of'our architects.

Ou 21¢~o~blin.g the ed.,yes of Books and Paper.

./"

In examinin% several years ago, the ruins of Pompeii, I notic'ed several do. ric columns broken ,ff a l~w feet from ~ \ ,he his ircu,n. ncogavo )- \ '. me an opportunity o f observing tbeir .¢~ internal structure. I found they were ~ ' - ~ . . / / composed of bricks of two diiti:rent,( ] forms and sizes, as in the atinexed d i a - ~ gram, The full lines show the form of ~ / ~ the bricks, and the dotted l ines show ).~ / the joints of the course next below, and - - " ~ the manner in which these joints were ~ , . ~

~46

broken so as to form a good bond. The gradual diminution of the Column was ett?cted by making, the

lateral joints between the bricks larger at bottom. The central part was filled by a circular brick. W.H.

on improvements in Marbling the edges of Books and Paper. [Trauslatcd froln the Diclionnalre TechnologCqu G for the Teclmoloffieat Reposi-

tory.] Tins art is confined to a few persons only, who take great pains

to preserve it secret, and will not make any communications thereolJ, but uMer considerable remuneratiom One of the most skiJful work- men m Pari% to whom I had rendered some essential ser vices~ was, however, willing in return, to initiate me in his mysteries, anti :exe- cute his processes before me; and he likewise furnished me with ~he necessary details~ to enable me to describe them; not~ however~ with, out my engaging to conceal his name, lest it might draw upon him the animadversions of his fellow-workmen. The tblt0wing iS the proeess:~

The utensils einptoyed by the marbier are not Very numerous:-- First, a vat, formed of oaken planks, well fitted together, so as to be perfectly water-tight. Secondly, a small cylindrical staE Third- ly, several earthen vessels, to Contain the eolom's and other prepa. rations. Fourthly, a small portable stove, or fire, ace. Anti fiftlfiy, a grinding stone, of porphyry or marble, a n d a mullar~ to grind tile eolours; these are indispensable requisites.

On the preparation of the gum,--2Put into a t)roner vessel, half a p~il full of ~ater, or a'bout eiff, ht or nine quarts', an'd dissolve in the c~td, about three ounces and [hree-quarte~'s of gum tragacanth, stir. ring it fi'equerltly tot six days : this is termed the couch, o," bed; and upon tliis bet[ a,'e to be spread the colours whicl~ serve to form the marbtin,.~. ~ the.y do not,. however, mino'le~, . with cacti other. T ~is qua0- t~ty of gum ~ suflicmnt for marbling tlie edges:of four hundred*'o- ]umes.

A soluti0n of ~um, ,nuch stronger tiian~ tim ab0v~ n,ust like,vise oe provided, in order to increase ilia ttuckne~s of the bcd, wheu