302 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[June, 



of preparation, and of laying tlie road, to be the most perfect hitherto 

 executed. 



Some years since, Mr. Home had made a series of experiments on the 

 form of timber beams, which presented the greatest amount of strength with 

 the least quantity of timber ; he found that a triangular beam placed with 

 the base upwards was one-third stronger than a.y other form. 



Mr. Colthurst inquired whether the trenails and wedges had been found to 

 have lost strength by compressing. He imagined that they would not bear 

 a transverse strain so well as before compression. 



Mr. May replied that no experiments had been tried as to the relative 

 transverse strength of timber before and after compression. 



Mr. S. Seaward thought it was probable the timber did suffer somewhat 

 from compression, but that did not militate against the system, as there 

 must necessarily be an original excess of strength in the trenails, so that no 

 inconvenience could result from tlie process. 



The President observed that although uncompressed trenails do draw out 

 of the stone blocks, they hold fast in wood sleepers. The round trenails 

 used to fasten the chairs to the sleepers on the Hull and Selby Railway, were 

 of a proper size to fit the hole in the chair, and at the end a square head 

 was left, which held the chair down. 



Mr. Cubitt had frequently seen trenails or plugs driven into stone blocks 

 to receive the iron spikes which fastened down tho chairs ; he believed they 

 had also been used for driving through the chairs into the blocks, but he was 

 not aware that they had been used in wood sleepers until he employed them 

 no the South-Eastern Railway. 



In answer to a question from the President, Mr. Lynde explained, that 

 upon the HuU and Selby Railway, trenails were certainly used in conjunction 

 with wooden sleepers, a portion of them were uncompressed, but the greater 

 part were compressed like the wedges ; the latter were supplied by Mr. Wil- 

 liam Cubitt. 



Mr. William Cubitt only supplied the wedges, they were compressed as he 

 had previously explained ; he believed that the trenails and wedges generally 

 used upon the London and Birmingham, and other railways, were compressed 

 by being driven through steel rings, liy heavy mallets, or by a press ; they 

 were most frequently used in the stone blocks to receive the iron spikes. 



March 8. — The President in the Chair. 



" Description of the Tanis for Kyanizing the Timber for the permanent 

 way of the Hull and Selhy Railway." By John Timperley. 



Upon the recommendation of Messrs. Walker and Burges, the Engineers, 

 it was determined that the sleepers of this railway should be kyanized in 

 close vessels, using exhaustion and pressure, instead of in the open tanks 

 usually employed. The present communication, which includes a description 

 of the kyanizing vessels, and an account of the various circumstances con- 

 nected with the operation, commences by describing the apparatus, as shown 

 by the accompanying drawing, to consist of two tanks, a reservoir, two force 

 pumps, and a double air pump. The tanks are cylindrical, with flat ends, 

 and are made of wrought iron plates, nearly half an inch in thickness ; they 

 are 70 ft. in length, and 6 ft. in diameter : at each extremity is a cast iron 

 door, flat on the outside, and concave on the inner side, provided with 

 balance weights for raising and lowering it. Each end is strengthened by 

 five parallel cast iron gu'ders, whose extremities are held by wrouglit iron 

 straps rivetted on to the circumference of the tanks. Notwithstanding the 

 great strength of these girders, several were broken by the pressure applied 

 during the process. The vessels are lined with felt, upon which is laid a 

 covering of close jointed fir battens, fastened with copper rivets ; this pre- 

 caution is nccessarj' to prevent the mutual deterioration which would arise 

 from the contact of the iron and corrosive sublimate. There was originally 

 only one brass force pump, 2 in. diameter, and 6 in. stroke ; this being found 

 insufficient, another was added of 4 in. diameter, and henceforward a pressure 

 of 1001b. per square inch was easily obtained. The air pump is 10 in. dia- 

 meter, and 15 in. stroke. Its construction is of the ordinary kind. Tlie 

 author gives in au appendix to the paper a minute description of the various 

 parts of the apparatus, with the details of their dimensions and weight. 

 The process is simple and rapid ; the corrosive sublimate is first mixed with 

 warm water in a trough, in the proportion of 1 lb. of the former to 2 gallons 

 of the latter ; the clear solution is then poured off into the reservoir, where 

 water is added till it is diluted to the proper point, which may be ascertained 

 by an hydrometer : a more perfect test is the action of the solution upon 

 silver, which it turns brown at the requisite degree of saturation. The 

 operations of exhaustion and pressure employ eight men for five hours, the 

 whole process occupying about seven hours, during which time from 17 to 20 

 loads are kyanized in each tank. It is desirable that the timber should 

 remain stacked for two or three weeks after kyanizing before it is used. It 

 was found that about | lb. of corrosive sublimate sufficed to prepare one load 

 (50 cubic feet) of timber. About 337,000 cubic feet of timber were kyanized, 

 the average expense of which, including part of the first cost of the tanks, 

 was about 5</. per cubic foot. The timber was tested after the process, and 

 it was found that the solution had penetrated to the heart of the logs. 



The paper contains some interesting tables exhibiting the quantity of 

 solut'on taken up by different kinds of wood with and without exhaustion ; 

 fom these it appears tliat the saturation per cubic foot in the latter case did 

 I o£ exceed 2'25 lb. with specimens of Dantzic timber, whereas it ranged 

 I etween 12'24 lb. and 15.25 1b. with pieces of home-grown wood. The 

 iutbor observes that this striking difference may be partly due to the greater 



compactness of the foreign timber. Appended to this communication is a 

 correspondence between Mr. J. G. Lynde and Mr. James Simpson relative to 

 the best tests of the presence of corrosive sublimate, accompanied by letters 

 from Mr. Colthurst and Dr. Reid ; the former of these describes the process 

 of kyanizing adopted on the Great Western Railway, and the latter suggests 

 the three following tests; — 1st, dilute hydro-sulphuret of ammonia; 2nd, 

 a strong solution of potassa ; dilute nitric acid and proto-muriate of tin, 

 also gold-leaf with this solution ; and 3rd, iodide of potassium. Directions 

 are given for the application of these tests. 



Mr. Lynde also mentions the use of a solution of nitric acid, and by the 

 application of hydriodate of potash detecting the presence of mercury in a 

 specimen taken from the heart of a log of timber 10 in. by 5 in., and 9 ft. 

 long. lie also details appearances of the destructive action of the corrosive 

 sublimate upon the iron-work with which it came into contact, which would 

 be prejudicial to the use of iron bolts in kyanized sleepers. 



A drawing explanatory of the whole apparatus accompanied the com- 

 munication. 



Remarks. — In answer to questions relative to the process of exhausting 

 the air from the receiver in which the bank-note paper was wetted at the 

 Banks of England and Ireland previously to being printed, Mr. Oldham 

 stated that as an experiment a packet of 1000 sheets of paper had remained 

 a whole day in water without being wetted through : whereas by exhausting 

 the air from the vessel containing them to a partial vacuum of 22 inches of 

 the barometer, and admitting water, they had been perfectly saturated in five 

 minutes ; the edges of the paper in simple immersion would rot away before 

 the mass was saturated ; by the exhausting process 5,000 sheets of bank-note 

 paper would absorb 16 lb. of water. 



Mr. Simpson conceived that exhaustion would facilitate the process of 

 kyanizing ; but he believed that if time was allowed, pressure would accom- 

 plish the same end as perfectly, for he had observed that pieces of wood 

 which had remained four or five days in a water-main under pressure had 

 become perfectly saturated. Captain Scoresby, in his account of the whale- 

 fishery, remarks that when a whale carries a boat down it rarely rises again' 

 most probably because the fish plunges to such a depth that the extreme 

 pressure water-logs the boat : instances had been known of the specific gravity 

 of the planking being doubled by being carried down. 



Mr. Newton remarked that immersion of timber in close tanks had been 

 practised by Mr. Langton many years since for bending timber ; a boiling 

 fluid was used in the tanks, and the wood was subjected to heat for a con- 

 siderable period. He had understood that Mr. Newmarch of Cheltenham 

 was the first person who used corrosive sublimate for preserving timber, and 

 that he had prepared and employed considerable quantities of wood. Mr. 

 Kyan snbseq\iently revived the system. 



In Mr. Oldham's process of wetting paper, pressure was not requisite, on 

 account of its open texture. About the year 1819, Mr. Oldham had tried 

 the same process with perfect success for preserving meat. 



Exhaustion had been tried by Mr. Harris for cleansing wool. The cops 

 of wool were put into an exhausted receiver, a solution of an alkali was then 

 admitted ; after remaining a short time in the liquid, a sufficient quantity of 

 diluted acid was added to neutralize the alkali, and the wool was washed out 

 in clean water. The process succeeded perfectly, but was too expensive. 



Mr. Palmer had employed the kyanizing process for large pieces of timber, 

 for the ribs of lock gates, but had no means of ascertaining the depth to 

 which the mercury had penetrated. The use of corrosive sublimate was first 

 suggested by Sir \l. Davy in his lectures at the Royal Institution, as a means 

 of destroying the vegetating process in timber by the combination of the 

 chlorine in the former with the albumen of the latter. Mr. Palmer mucli 

 doubted whether the means used for exhausting the capillary tubes effected 

 the object, unless the timber was in a dry state, and he considered it equally 

 doubtful whether the solution could be forced to any considerable depth by 

 compression, especially if any moisture actually filled the capillary tubes. 

 The application of pressure in the process of salting meat suggested by Mr. 

 Perkins many years ago, was a complete failure. 



Mr. Simpson observed that in the experiments of Messrs. Donkin and 

 Bramah pressure alone had been used, and it could easily be understood that 

 owing to the cellular formation of meat, the pressure, instead of forcing the 

 salt through it, caused the substance to collapse and the brine was prevented 

 from penetrating. 



Mr. Braithwaite explained that in Payne and Elmore's process, although 

 pressure had been found indispensable, tlie meat was more perfectly prepared 

 when exhaustion was also employed, therefore both were now combined. 



Mr. May reverted to the subject of kyanizing timber; he believed that 

 exhausting the air from the tanks previously to the admission of the solution 

 was a loss of time — the fluid should be admitted first, or at least while the 

 exhaustion was proceeding; labour and time would thus be saved, and the 

 air would be more completely expelled from the capillary tubes before pres- 

 sure was applied. It was essential that the timber should be as far as 

 possible deprived of its sap as well as dried : as either sap or moisture 

 appeared to prevent the proper action of the corrosive sublimate. 



Mr. Cubitt regretted that experiments had not been made on the same- 

 kinds of wood both with and without exhaustion. The experiments on small 

 pieces of foreign (Memel and Dantzic) timber with SO lb. to 100 lb. pressure 

 without exhaustion, showed an increase of weight of from 11 to 2 oz. in 

 pieces of about ^'^ part the size of a sleeper, and that result agreed very 

 nearly with bis practice with sleepers of Memel and Dantzic timber, when 

 kvanized without exhaustion under a pressure of 80 lb. to the inch ; sleepers 



