204 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[June, 



before Dr. Boucberie's was mentioned in Paris, which was in June 1840. 

 The specification filed by Mr. Bethell stated " that trees just cut down may 

 he rapidiv impregnated with the solution of the first class, hereafter men- 

 tioned (among which is included the pyrolignite of iron) by merely placing 

 the butt ends in tanks containing the solution, which will circulate with the 

 sap throughout the whole tree ; or it may be done by means of bags made of 

 waterproof cloth affixed to the butt ends of the trees and then filled with the 

 liquid."— Mr. Bethell found that some solutions were taken up more rapidly 

 by the sap and circulated with it more freely than others, and the pyrolignite 

 of iron seemed to answer best ; he had not hitherto introduced the process 

 in England, because it was much more expensive than the oil of tar, the py- 

 rolignite costing from 6d. to 9rf. per gallon, and the oil being delivered at 3rf. 

 per gallon.— Mr. Bethell had used similar tanks to those described in Mr. 

 Timperlev's paper for preparing wood with the oil of tar, but as the oil is 

 ver)' penetrating, previous exhaustion of the air had been found unnecessary, 

 the' hydrostatic power being sufficient. The mode of working the tanks was 

 to charge them with timber, close them and fill them with the oil ; a hydro- 

 static pressure of from 100 lbs. to 150 lbs. to the inch was applied by means 

 of the force-pumps, and kept up for about six hours ; this was sufficient to 

 cause the wood to absorb from 35 to 40 gallons per load. By this means a 

 charge of timber was easily prepared daily, the cost being about 14s. per 

 load. This was the plan pursued at Manchester for the Manchester and 

 Birmingham Railway, by Mr. Buck (upon the recommendation of Mr. Robert 

 Stephenson), and also' at Bristol and Bridgewater by Mr. Brunei. Mr. 

 Bethell preferred egg-shaped ends for the tanks as they resist the pressure 

 better than flat ends. The solution of corrosive sublimate used at Hull 

 appeared to Mr. Bethell to be very weak. The advice given by Sir Humphrey 

 Davy to the Admiralty many years since was, to use 1 lb. of corrosive sub- 

 limate dissolved in 4 gallons o'f water, and Mr. Kyan in the specification of 

 his patent states that strength, but according to the paper it appeared that 

 45 gallons of water were used to 1 lb. of the salt instead of 4 lbs. 



In answer to a question from Mr. Pellatt, Mr. Bethell stated that his ex- 

 periments on the use of silicate of potash or soluble glass for rendering wood 

 uninflammable were not yet concluded ; he had proved its efficacy in this 

 point — that as soon as the prepared timber was heated, the glass melted and 

 formed a filmy covering over the surface, which protected it from the oxygen 

 of the air and prevented its catching fire. The silicate also hardened the 

 wood and rendered it more durable. This process was included in his patent 

 of July 11, 183S. 



Professor Brande could add but little to what had been said on the sub- 

 iect, but he mentioned a curious appearance in a beech tree in Sir John Se- 

 "bright's park in Hertfordshire, which, on being cut down, was found perfectly 

 black all up the heart. On examination, it was discovered that the tree had 

 grown upon a mass of iron scoriae from an ancient furnace, and the wood had 

 absorbed the salt of iron exactly in the same manner as had been described 

 in the new process. The degrees of absorption of various solutions by difl'e- 

 lent woods demanded careful experiments, as some curious results would be 

 obtained ; it was a question whether a solution of corrosive sublimate in tur- 

 pentine, or in oil of coal tar would not be advantageous, as both substances 

 were so readily absorbed by timber. 



Mr. Defries explained the construction and action of his Dry Gas Meter, 

 which was exhibited before it was fixed in the Gallery of the Institution. 



The instrument consists of a hexagonal case with three solid partitions 

 radiating from the centre to the circumference, across each division thus 

 formed is a flexible partition, to the centre of which is fixed a plate, con- 

 nected by a lever and shafts with the valves on the top of the case ; by means 

 of a combination of levers and cranks with a worm and screw a circular 

 motion is given to dials indicating the quantity of gas which passes through 

 the machine. ■ 



The gas, on entering the upper chamber, passes through the valve into the 

 first division and distends the flexible partition until the lever is carried to a 

 certain point, when by means of the connecting shaft the inlet valve is closed, 

 the outlet valve is opened, and the second division commences its action, 

 which is continued by the third, thus producing an equal flow of gas, and an 

 uniform motion is given to the counter-dials, which necessarily indicate the 

 number of times the divisions have been inflated and emptied, and thus 

 measure the quantity which has passed through in a given time. 



The instrument which was presented to the Institution, had its sides 

 formed of glass in order to show the action of the machinery. 



lines of moulding than the secondary compartments inclosed within them ; 

 3rd, Parallelism, with relation to the mouldings, or groups of mouldings, 

 which form the common divisions between adjoining compartments ; 4th, 

 Symmetry, or a siinilaritv between the opposite sides of those divisions. In 

 complete' tracerv, where 'all these four principles are carried out, the com- 

 partments are c'ompactly fitted together, and the mouldings mitre wherever 

 they meet. In the tracerv of the early Gothic, these principles are only 

 partially developed ; thus, 'in the triforium of Salisbury Cathedral, we find 

 foliation and subordination, but neither parallelism nor symmetry. A seg- 

 mental arch incloses two pointed arches, and each pointed arch two others. 

 Here we have subordination, and foliation appears in the arches last men- 

 tioned, and in the openings in the spandrils; but there is no parallelism, the 

 forms of the open compartments being without reference to each other, and 

 having blank spaces without tracery between ; and symmetry is wanting, 

 since the mouldings of the secondary and tertiary compartments are treated 

 differently in different parts of the composition. All this is characteristic of 

 early Gothic tracery, and may be seen at Ely, Gloucester, and other edifices 

 in the same style. The tracery of the cloister and chapter-house at Salisbury, 

 the details of which Prof. Willis illustrated by several elaborate drawings, is 

 remarkable as forming a link between the early and late tracery, going a step 

 in advance of the former, without being complete. Parallelism is added to 

 the two first principles, but symmetry is still wanting, each corresponding 

 set of compartments being treated differently on each side of the dividing 

 mouldings. There is, therefore, very little mitring, although the compart- 

 ments fit together perfectly, without any blanks between them, as in the tn- 

 forium of the church. So great an independence in the mouldings, where 

 the principles of tracery are otherwise so perfectly developed, is very singular. 

 The same observations apply both to the inside and outside of the windows, 

 although these also differ from each other. . 



Another characteristic of eariy tracery is, that every compartment, princi- 

 pal or subordinate, has its separate hood-mould, as in the triforium already 

 cited ■ but in the cloister and chapter-house this is discontinued, and its 

 place supplied by a large double ogee. The Professor then made some re- 

 marks on the necessity of studying the true forms of the mouldings m Gothic 

 architecture. The ancient details will be found, on examination, to he drawn 

 with astonishing spirit and freedom of hand, whereas it is too much the 

 modern practice to draw all the curves with the compasses— a method totally 

 destructive of their real character, especially in the early Gothic style. In 

 conclusion, he exhibited an instrument by which such curves may be traced 

 with precision. It consists of a stylus, bent at one end in such a manner, 

 that while by turning it in different directions, it enters into the deepest 

 hollows, the point is always in one axis, at the extremity of which a pencil 

 traces the lines followed by the point. This portion of the instrument was 

 invented and exhibited at the Institute by Prof. Willis some time since, and 

 he has now added to it a parallel movement attached to a drawing-board ; 

 by this contrivance, the most intricate combinations of mouldings may be 

 traced with great facility and the most perfect accuracy. 



ROYAL INSTITUTE OF BRITISH ARCHITECTS. 

 May 16.— T. L. Donaldson, Esq., V. P., in the chair. 



A paper was read by Prof. Willis, " On Gothic Tracery, exemplified by the 

 Windows of the Chapter House at Salisbury," 



In the tracery of the Gothic style, four principles may be discerned, which 

 will be found universal when the tracery is perfectly developed. 1st, Folia- 

 tion, or the decoration of the compartments with those curves and points 

 which have been denominated cusps ; 2nd, Subordination, or the division of 

 the design into certain leading compartments, which are marked by bolder 



GERISH'S PATENT CYLINDRICAL MORTICE LOCK. 



This lock, as shown in the annexed engraving, which is drawn to 

 half the real size, merits general attention from the simplicity of 

 construction, and the easy manner in which it can be fixed to doors, 

 the portability of the key, and the security it affords. It will be seen 

 that by merely boring a hole with an auger in the door, it is at once 

 fixed, thereby saving considerable time in cutting a large mortice 

 which frequently injures the door. There is only one bolt, for the 

 purpose of locking it ; there is a contrivance at the back or end of 

 the bolt; by turning the key a lever or tumbler is let down which 

 prevents the latch bolt being turned back. The mortice lock before 

 us, strong enough for a room door, is 6 inches long and i of an inch in 

 diameter. 



