August 12, 1897] 



NATURE 



.53 



and which is in use on the Tyne, consists of a series of belts or 

 creepers and a continuous chain, with leaves attached, working 

 in a trunk. The coal is lowered on to the belts, and is thus 

 conveyed any required horizontal distance until it reaches the 

 end of the staith or pier against which the ship is moored. One 

 end of the trunk, in which the continuous chain or belt 

 works, is lowered into the hold of the ship, and by 

 means of the trays the coal is lowered down and 

 gently deposited in the required position. The action of the 

 lowering part of the apparatus is similar to that of a grain 

 elevating machine, or of a bucket and ladder dredger ; but of 

 course the working is reversed, the material being lowered in 

 place of being raised. The machine in use was said to be 

 capable of dealing with 400 tons of coal an hour, and as, 

 presumably, a machine could be used for each hatch, a vessel of 

 say 2400 tons dead weight, and having three hatches could, we 

 suppose, be brought to her bearings in a couple of hours. In 

 the discussion that followed, the arrangement was rather sharply 

 criticised, but it must be remembered that Cardiff is the home 

 and birthplace of a rival scheme that has been in successful 

 operation for some years. Naturally those who have used the 

 older method and have experienced the benefit of it as compared 

 with the primitive shoots, are loath to change, and it is also natural 

 that the maker of the original apparatus should not welcome a 

 competing scheme with too great enthusiasm. It would seem, 

 however, that the Wrightson invention ought necessarily to 

 have an advantage in point of speed because it is continuous, 

 whilst the work with the older method is intermittent. 



Mr. George B. Hammond's contribution, "On the Manufacture 

 of Tin-plates," was an omnibus paper dealing with the subject 

 at large — historically, commercially, and technically. From the 

 historical and technical point of view, there was very little new 

 to say, and indeed the commercial side of the question is 

 already a thrice-told tale of sadness and decay. America was our 

 great customer for tin-plates, and under the enormous impetus 

 given to the industry by the spread of the canning trade in pro- 

 visions fortunes were made in South Wales, and enormous 

 wages were paid. The inevitable reaction followed. The 

 United States, pursuing their protectionist policy, put an im- 

 port duty on tin-plates which was absolutely prohibitive, and 

 that market was lost. There were, however, other outlets for 

 the commodity, and had both employers and employed recog- 

 nised the need of hard work and frugality the trade need never 

 have fallen to the low ebb it has. Over-prosperity had, how- 

 ever, destroyed the moral fibre of those who had experienced 

 it. There were large profits, high wages, antiquated methods, 

 and artificial restrictions to output which no one wished to 

 forego, and the consequence is that South Wales sees every 

 prospect of American competition in neutral markets. This, 

 however, is somewhat beside Mr. Hammond's paper; but it 

 would be difficult for us to deal with the technical part without 

 the illustrations of machinery which accompanied the paper. 



On the following day, Wednesday, the first paper taken was 

 that of Prof. Honore Ponthiere, " On a Thermo-chemical 

 Study of the Refining of Iron." It was read in brief abstract 

 by Mr. Brough in the absence of the author. From its title it 

 will be seen how impossible it would be to abstract such a 

 subject within anything approaching the limits of space at our 

 disposal. It began with a discussion on the conditions under 

 which the elements exist in iron, and treated of the various 

 possible or probable reactions which take place during the pro- 

 cess of steel-making by the two chief processes, and of puddling. 



Mr. E. H. Saniter's paper "On Carbon and Iron" followed, 

 being read in full by the author. This was the most important 

 contribution to the meeting. It discussed the thermal treatment 

 of tri-basic carbide of iron ; the saturation point of iron with carbon 

 by fusion in contact with excess of carbon ; the saturation point of 

 iron with carbon by heating without fusion in contact with excess 

 of carbon ; and the etching of pure carbon alloys at a red-heat 

 in order to ascertain their structure by means of the microscope 

 at that temperature. The last branch of the subject brought 

 forward points of considerable interest, and the paper raised the 

 old, and it would seem interminable, controversy on the alpha 

 and beta states of iron. Mr. Saniter, we gather, is more of a 

 carbonist than an allotropist, and his reasoning seemed to sup- 

 port the former party. Unfortunately there were no allotropists 

 present, or if there were they were silent ; so the discussion 

 went all one way. The photo-micrographs attached to the 

 paper were interesting, and in some respects this new method 

 of treatment showed unexpected results. Mr, Saniter made a 



NO. 1450, VOL. 56] 



strange mistake in his paper. He attributed to so competent an 

 authority as Edward Riley the statement that the saturation- 

 point of iron for carbon was 4 per cent. Mr. Riley, who was 

 present, naturally exclaimed against this, and asked Mr. Saniter 

 for his authority, which the latter gave as the Journal of the 

 Institute for the year 1877. What the saturation-point may be 

 has not, we believe, been exactly determined, but at any rate it 

 is higher than 4 per cent. Mr. Saniter's mistake, of course, 

 was that he did not verify his authority when the statement was 

 so questionable and the reference to the original so easy. 



The last paper read at the meeting was Mr. Henning's con- 

 tribution on a recorder of stretching, which was taken charge of 

 by Mr. Wicksteed, in the absence of the author. The portable 

 recorder referred to consists of a pair of clamps attached to the 

 two ends of the specimen rod. To one of these clamps is 

 attached a parallel motion with a projecting arm. at the end of 

 which is a pencil. The motion is worked by rod from the other 

 clamp, so that when the .specimen stretches, and the clamps are 

 thus pulled apart, the arm moves. In this way a record can be 

 obtained on a card which is mounted on a revolving drum, 

 which is actuated by a cord from the poise weight. It will be 

 seen that in construction the apparatus bears a resemblance to a 

 steam engine indicator, both in regard to the parallel motion and 

 the paper-drum. It was objected during the discussion that the 

 poise could not be moved fast enough to give true indications 

 when the specimen ultimately gave way ; but probably if a 

 record can be obtained within the elastic limit, that will be 

 sufficient for the majority of engineers, as a material strained 

 beyond this limit is very little good for structural purposes. 



Five other papers were on the agenda, but were not read at 

 the meeting. 



The excursions and entertainments during this meeting were 

 numerous and the hospitality profuse. Several of the large iron 

 and steel works were visited, the Cardiflf and Newport docks 

 were inspected, and also other places of industrial interest. 

 There were lunches, dinners, soirees, a Welsh concert, garden 

 parties, and illuminations packed in as close as time would 

 permit ; but the culminating point in all these delights was the 

 Marchioness of Bute's ball. To this over three thousand guests, 

 including all the members of the Iron and Steel Institute and 

 the ladies acconipariying them, were invited. 



ON PRACTICALLY AVAILABLE PROCESSES 



FOR SOLDERING ALUMINIUM IN THE 



LABORATORY. 



TT seems that ever since the metal aluminium has been used in 



construction, difficulties have arisen in soldering it. Further, 



from contemporary literature it appears probable that some 



perfectly satisfactory methods of getting over the difficulty are 



known, but not published in sufficient detail to be available. 



Hence it seems well to put on record any advance towards 

 the solution of this somewhat troublesome problem. In the first 

 place, my experience is that it is not easy to solder aluminium 

 simply by using an alloy of definite composition without a flux. 

 Also that the only other process which does not require special 

 apparatus, that based upon the use of silver chloride, is very 

 troublesome indeed unless the local fusion of the aluminium be 

 immaterial. I find, however, that cadmium iodide is distinctly 

 more satisfactory. If it be fused on an aluminium plate, de- 

 composition of the salt occurs long before the melting point of 

 the aluminium is reached. The result is generally the violent 

 evolution of iodine vapour and formation of an alloy of cadmium 

 and aluminium on the surface of the metal. 



The decomposition of the cadmium iodide is, however, too 

 rapid to be convenient, and the pulverulent white residue is in 

 the way. It is, therefore, of advantage to add some other body 

 which, if possible, will obviate these defects. I find that zinc 

 chloride answers fairly well. Thus I mix concentrated zinc 

 chloride solution with a little ammonium chloride, evaporate 

 in a round porcelain dish, and ignite a low red heat till a part 

 of the ammonium chloride is volatilised. The fused chlorides are 

 now mixed with cadmium iodide. The proportions of zinc 

 chloride and cadmium iodide are best adjusted experimentally. 



The final result, when the salts are completely fused together, 

 is a flux which readily enables tin (or other soldering alloy) to 

 unite perfectly with aluminium. The melted flux can be taken 

 up in a pipette with india-rubber teat, and dropped on to the 

 surface of the metal to be soldered. Some powdered metallic 



