May 8, 1884] 



NA TURE 



by Messrs. Pease, in which case the sulphate of ammonia and tar 

 were worth about 3-r. per ton of coal used. As theoretically live 

 times this amount of sulphate of ammonia might be obtained from 

 the coal, it seems probable that a large quantity of nitrogenous 

 compounds may eventually be secured in this manner. 



In the discussion on the paper, the fact of coal and coke being 

 practically equal in heating power was confirmed by several 

 speakers ; and some interesting facts as to the anthracite blast 

 furnaces of the United States were elicited. The advantages of 

 calcining the limestone (which seem in most cases to be nil) and 

 of mixing coke with coal in the charge were also discussed ; 

 ami the important question of raw coal as an iron-smelting 

 material may thus be said to be fairly opened. 



The next two papers were taken together. The first was by 

 Mr. R. Smith Casson on the system worked out by himself and 

 M. Bicheroux for gas puddling and heating furnaces. This 

 system, which has been worked with most satisfactory results in 

 Belgium, is simpler and cheaper than that introduced by Sir 

 William Siemens, and as regards efficiency and economy has 

 much to recommend it. The other paper, by Mr. W. S. 

 Sutherland, was on the most recent results in the application 

 and utilisation of Gaseous and Liquid Fuels. It appears that 

 Messrs. Baird and Co. are now recovering the tar and ammonia 

 from the gases of no less than sixteen of their blast furnaces, 

 consuming about loo tons of coal daily. They manufacture the 

 ammonia into sulphate and distil the' tar, the actual yield per 

 ton of coal varying from 18 lbs. to 25 lbs. of sulphate of 

 ammonia, and from 180 lbs. to 200 lbs. of tar. The 

 found to be perfectly clean and free from moisture, and is thus 

 better adapted than before to such purposes as raising steam, 

 heating the blast, iVx. In addition to this the paper described a 

 new method of working the producers employed for generating 

 gas in the Siemens or other systems of gaseous fuel, and for 

 abstracting from the gas so obtained the tar and ammonia it 

 comprises. It appears that a generator gas of high quality can 

 now be got with certainty, at the same time yielding 20 lbs. 

 of sulphate of ammonia with ten to twenty gallons of good tar 

 per ton of coal. A net saving of from 2s. 6d. to 4?. per ton 

 may thus be effected, and with the same result as in the case of 

 the blast furnace, viz. that the gases are improved instead of 

 being damaged by the removal of their valuable products. The 

 using of such substances as tar and ammonia merely for fuel can 

 only be considered barbarous, and it now seems probable that in 

 a very few years it may be a thing of the past. 



On Thursday the first paper read was by Mr. Walter R. 

 Browne on Iron and Steel Permanent Way. ' It described the 

 system of iron sleepers, successfully introduced by Mr. Webb of 

 the London and North- Western Railway, and pointed out the 

 many advantages that 'would result, especially to the iron trade 

 "I this country, if the use of metallic sleepers became a recog- 

 nised fact. In Germany it is -.,, already, thousands of miles 

 being now laid with metallic sleepers ; and it is to be hoped that 

 a vigorous effort will be made to develop their use both in 

 England and in our colonies. 



The second paper, by Capt. C. Orde-Browne, R.A., dealt 

 with the behaviour of Armour of different kinds under fire. Four 

 kinds of armour were specified: first, wrought iron ; secondly, 

 compound armour or wrought iron with a steel face ; thirdly, 

 solid steel ; fourthly, chilled cast iron. The different modes in 

 which these yield to the impact of a shot were clearly described. 

 Wrought iron is punched with a clean hole, the rest of the target 

 hardly suffering any damage. As complete penetration is neces- 

 sary, hardness and rigidity of metal are the essentials for a pro- 

 jectile, and not tenacity. Hence the extended use of Palliser's 

 chilled shot. In compound armour the hard steel face severely 

 tries the tenacity of the metal, so that the shot frequently breaks 

 to pieces ; at the same time the plate yields by cracking in 

 radiating lines from the point of impact, and sometimes in con- 

 centric lines. Solid steel does not yield at the point of impact, 

 but as the shot enters, it wedges and sets up the metal round it, 

 the plate swelling and yielding by radiating cracks. Such cracks 

 are much more likely to extend through the metal than is the 

 case with compound plates. Chilled iron is broken up bodily by 

 the direct blows of heavy shots, cracks radiating from the point 

 of impact, which is never pierced even to a single inch of depth. 

 Details were then given of the experiments carried out in 1882 

 at Essen, at Spezia, and at Ochta near St. Petersburg ; in 1883, 

 at Shoeburyness, and at Buckau on chilled cast iron ; and 

 finally experiments by Capt. Palliser and Sir Joseph Whitworth. 

 Stress was laid on the necessity for dividing armour into two 



distinct classes, soft and hard : the former signified armour which 

 was perforated, and the latter armour wdiich must be broken up. 

 The difference was illustrated by a simple dropping apparatus, 

 in which a model of a shot with a heavy weight behind it was 

 allowed to fall either upon millboard, to represent soft iron, or 

 upon brick, to represent hard iron. The likeness of the results 

 to those found in practice with hard and soft armour respectively 

 is very remarkable. It is therefore altogether a mistake, when 

 attacking hard armour, to use the data obtained for perforation 

 as a measure of the shot to be employed. The energy in the 

 shot per ton of the weight of the shield is another measure which 

 may be useful, but is not theoretically correct. To work out the 

 problem mathematically is very- difficult, and it is suggested that 

 much might be learnt by firing steel bullets against plates of 

 steel and chilled iron, keeping all conditions uniform except 

 those whose relation is the object of investigation. Certainly 

 some such experiments are needed, as are also actual trials 

 against the hard armour, solid steel, or chilled iron, which is much 

 used abroad ; otherwise, should we be involved in a war. we 

 might find that our calculations, based only on soft armour, 

 would land us in disastrous failure. 



The first paper on Friday was on Recent Improvements in 

 Iron and Steel Shipbuilding, by Mr. William John of Barrow- 

 in-Furness. This paper gave some remarkable statistics of steel- 

 built vessels during the last few years. It appears that between 

 1879 and 1883 the proportion of steel vessels built and registered 

 in the United Kingdom increased from 4-38 per cent, in 1879 to 

 157 per cent, in 1S83 ; wooden vessels being left out of account 

 in each case. It is evident that steel as a material for shipbuild- 

 ing has passed entirely out of the experimental stage, and must 

 be judged by the results of its working in the shipyards, and the 

 performance of the ships already afloat. The experience of 

 those shipbuilders who have paid most attention to steel is that 

 it has now become a much more uniform and satisfactory mate- 

 rial than iron, so that workmen actually complain if they are put 

 to work upon iron, from the trouble and annoyance it involves. 

 The only point of practical importance left is the deterioration 

 which occasionally occurs when thick plates of steel are punched. 

 On this further information is necessary, as also on the real cause 

 of the failures that took place some years ago, especially those 

 in the boilers of the Livadia. In some cases, metal of which 

 the chemical analysis showed nothing abnormal, and which 

 would bend double when the edges were carefully prepared, 

 broke off like glass when the edges were rough, or when holes 

 were punched in it. The paper then went on to consider the 

 difference in cost between vessels built of iron and steel, which 

 at the present rate appears to be practically insignificant. On 

 the other hand, strength is decidedly in favour of steel ships, 

 even with the present reduction of scantlings sanctioned by 

 Lloyd's. The case was mentioned of the Duke of Westminster, 

 a vessel 400 feet long, which bumped for a week at the back of 

 the Isle of Wight on stony ground without making a drop of 

 water. This was owing to the elasticity of the steel, and o nild 

 not possibly occur with an iron ship. With regard to corro- 

 sion, Mr. Johns considered that this was a matter to be 

 overcome by increased knowledge and care in maintenance, 

 while there was no evidence to show that the difference in 

 corrosion between steel and iron is sufficient to stop the progress 

 of steel shipbuilding. Finally he observed that great attention 

 had been paid of late to the longitudinal strains on very large 

 ships, much greater use being made of iron decks, longitudinal 

 stringers in the bottom, &c, so that he could no longer show, as 

 he had in 1874, that vessels grew steadily weaker as they in- 

 creased in size. In the discussion, Mr. Martell, Inspector of 

 Lloyd's, confirmed the view that steel is infinitely superior to 

 ordinary iron, and that there is no reason to suppose that it 

 deteriorates faster. He mentioned a ship built in 1S7S for the 

 iron ore trade, which as yet showed no sign of deterioration. On 

 the other hand, Mr. Jeremiah Head mentioned that, despite the 

 progress of steel, more iron had been used in shipbuilding 

 during the last year than ever before, and that steel plates were 

 still much more expensive than steel rails from the necessity of 

 hammering them after rolling. He maintained that common iron 

 did not corrode so much as best iron or steel : the Great 

 Britain, built in 1845, is still in existence, and so is a collier 

 built in 1S31. Mr. Riley confirmed the necessity of hammer- 

 ing, owing to the increased number of failures if this was 

 neglected. Sir Henry Bessemer and others also took part in 

 the discussion. This concluded the business of the meeting, the 

 remaining papers being adjourned. 



