35° 



THE TROPICAL AGRICULTURIST. 



[NOVEMEER I, 1884. 



delivered at the railway consigned to Colombo. Oue 

 objection to the clerihew is that the pipes wear out 

 sonn, and require occasional renewing, hut I have yet 

 to learu of a really better system of curing cacao. 

 The enemy of cacao, HrlopeHix, which has lately 

 had Dr. Trimen's attention, and for whose interesting 

 paper on this new pest we ail feel indebted, may or 

 may not be a recent importation to Ceylon. Some 

 planters affirm that they have seen it long ago in 

 the jungle in myriads. I know that the late Dr. 

 Thwaites had a fine contempt for the planter as a 

 scentific observer. "You muet be trained to observe. 

 You must be trained," the old man used to insist, 

 and doubtless he was right. If the late director has 

 laid it down that the fly is not a native, let those 

 decide who have the right and can do so. 1 do 

 not pretend to do ought else than record the "gup" 

 of highways and hedges. Pepper Corn. 



NEW FUEL: REFUSE OK SHALE AS A HEATING 

 MATERIAL. 



A former Ceylon planter sends us an account of an 

 " experiment with new fuel " at the Forth F>rid»e 

 Works. The new fuel is" the waste or residue 1 ft 

 in the manufacture of oil from shale, aud, with re- 

 ference, doubtless, to its efficacy as a heating agent, 

 our old friend writes on the slip : "Save the 80.000 

 acres jungle for coffee and tea." He means, of course, 

 that the new fuel will render forest reserves unnecess- 

 ary either for the railway or for tea preparation- 

 The question will be one of cost, and we have good 

 hopes that the new fuel oan be delivered cheaply 

 enough lo suit us here in Ceylon, iu view of the 

 computation that 400 tons of the waste shale product 

 would be not only the equivalent of, but preferable 

 to, 2,000 tons of coal, in the case of a sea-going 

 steamer. We sincerely trust that the new fuel will 

 answer all the expectations formed of it, for, aprrt 

 from the bearing of the discovery on our local enter- 

 prize, we have long felt and expressed our sense of 

 the deplorable opprobrium of modern scieuce involved 

 in the burning of raw coal as a force-generator, 

 volumes of dirty smoke being poured into the air in the 

 process. What a change a smoktless fuel would work 

 in the atmosphere of London, but especially of Man- 

 chester and other manufacturing towns of Britain ! 

 The inveution seems to be in an advanced stage, 

 looking at the letter from the Secretary of the Hydro, 

 carbon Syndicate which follows the account of the 

 experment nt the Forth Bridge : — 



THE FORTH BRIDGE WORKS— EXPERIMENT WITH NEW FUEL. 



Operations in connection with the two caissons, which 

 have been placed in position at the South Queensferry side 

 of the Forth Bridge works, are so advanced that yesterday 

 a body of men went down into the great pneumatic chamber 

 at the bottom of the south-weft caisson to commence the 

 process of excavation for the foundation of this part of the 

 structure. Sir Thomas Tancred and other gentlemen went 

 down two days ago. This chamber is one the floor of 

 which is the sea-bottom. The roof is completely air-tight. 

 As it is many fathoms under the sea, compressed air is 

 continually being pumped into the chamber, by powerful 

 engines placed on the stagingjjust beside the caisson, for 

 the purpose ol preventing the water from rising into it. 

 In other words, the constant pressure of air always present 

 in the chamber is sufficient to keep the water from rising. 

 Here men are to be employed day and night, air being 

 supplied by the meaus just indicated, aud light by electric- 

 ity generated in dynamos on the staging above. 



In the working of one of the engines used for pumping 

 compressed air into this chamber an interesting experi- 

 ment was conducted yesterday — an experiment with the 

 view of testing the substitution of crude shale oil for coal 

 in feeding the furnace. This crude shale oil may be said 



to be almost a waste substance : the manufacturers extract 

 the oil of commerce from the shale, and what was used at 

 the Forth Bridge works yesterday is the residue collected 

 in the process of distillation. It resembles coarse butter in 

 appearance, and is so crude that it will not burn by con- 

 tact with a match, a burning coal, or even a red-hot poker. 

 What was used yesterday was taken from the Dalmeny 

 oilworks just above the Forth Bridge. For application it 

 was stored in tanks or reservoirs near the furnace, and 

 these tanks are connected with the furnace by a series 

 of tubes. The grates or fire-bars of the furnace are 

 taken, out, aud instead of them a cylindrical retort is 

 suspended in the furnace, which retort is surrounded 

 by a spiral tube. From the reservoir of the oil, which 

 is always under pressure, aud from a water main, 

 two pipes and valves convey oil and water to the retort and 

 the coil or tube. The retort being warmed by any con- 

 venient method, the water valve is slightly opened, and a 

 fine stream passing into the retort is at once converted into 

 steam, which is carried through a superheating coil to a jet 

 or burner underneath the retort, from which jet it issues 

 in a powerful stream by the force of its own expansion. 

 The oil is then admitted in the same manner, and carried 

 by another heating tube to the same jet, which it reaches 

 in a nearly gaseous condition. It is then caught by the 

 superheated steam, and hurled against the convex bottom 

 of the retort, the force of the impact breaking up into finely 

 divided vapour any portion of the oil which the heat may 

 not have already converted into g.is. In a short time the 

 retort and heating tubes become red, and now begin a 

 chemical change and nearly perfect combustion. The steam 

 has become a dry gas, or oxygen and hydrogen, which is 

 thoroughly intermixing with heated carbon. The immedi- 

 ate effect of this appears to be the formation of carbonic- 

 oxide and free hydrogen. The force of the jet produces a 

 partial vacuum, and sucks into the centre of these flaming 

 gases a powerful current of air, which apparently com- 

 pletes their combustion, converting them into carbonic acid 

 and water vapour, without smoke, dirt, or residue. The 

 result of the whole process is almost perfect combustion— 

 an immediate and an intense heat which consumes all the 

 products, or, in other words, leaves practically speaking, no 

 residue to be cleared away. The advantages claimed by 

 the inventor of this system over other methods of burn- 

 ing hydro-carbon liquids are, that the retort acts, first as a 

 boder, or steam generator, to start the fire, while by other 

 methods a second boiler with steam up is necessary; second, 

 the retort is an atomiser, breaking all possible lumps into 

 atoms; third, the retort is a deflector or director of the flame, 

 distributing it equally toall parts of the furnace; and, fourth, 

 its internal cubic area acts like the air chamber of a pump to 

 keep a steady flow from the jet. Instead of taking moist 

 steam from the boiler to hurl the oil into the furnace, dry 

 superheated steam is furnished by the apparatus itself, mil 

 a directed forced air supply added to the natural draught, 

 the result being greater economy and better combustion. 

 The experiments yesterday were regarded as having been 

 perfectly satisfactory, and thus it is probable that the new 

 fuel may be applied to more than the one engine, and em- 

 ployed in various other directions in connection with 

 these gigantic works. Where, as at the Forth Bridge, coal 

 is cheap— possibly about the same cost as that of the crude 

 shale oil— there is still claimed for the use of the latter a 

 decided advantage on the side of economy. The wages of 

 labourers and stokers are saved, for there is comparatively 

 little labour required in connection with the use of oil ; 

 there is also an immense saving in the space required for 

 storing purposes; and a saving also in the labour of 

 keeping the furnace and machinery clean, heat with 

 cleanliness being a marked characteristic of this method. 

 Where coal is even moderately expensive a considerable 

 saving must be effected by the use of the oil experimented 

 with yesterday; and in case's in which the cost of 

 transit of coal is very heavy the saving must be corre- 

 spondingly large. The circumstance that the fire is put 

 out each night by simply cutting r.ff the supply of 

 oil and water is also an advantage on Ihe side of economy; 

 and the circumstance that the fire can be started in tho 

 morning by a process extending over five minutes is an 

 advantage on the side of facility in working. It is 

 estimated that the equivalent of this fuel to coal will 

 occupy less than one-fifth the space of coal. It w.s 

 pointed out yesterdaj that to an ocean steamer, whose 



