=^26 



NA rURE 



[September 29, 1892 



nitrate of soda. He had spread one half of a newly -sown lawn 

 with a mixture consisting of one part of sulphate of ammonia 

 to three parts of nitnite of soda — four cwt. to the acre— and 

 had grass an inch long, whilst the unspread part was quite bare. 

 The next paper taken was that of Prof. Roberts Austen, in 

 which was described a modification of the Le Chatelier pyro- 

 meter, which has been introduced for the purpose of securing 

 autographic records of temperature. The apparatus was 

 exhibited at the council table, and has been constructed under 

 the directions of the author for Mr. E. P. Martin, of Dowlais, 

 in order that a continuous record might be kept of the tempera- 

 ture of the stoves in which the blast is heated for the iron 

 smelting furnaces. It will, of course, be understood that the 

 apparatus is suitable for recording temperatures under other con- 

 ditions, and it can hardly fail to afford valuable assistance to 

 those engaged in many branches of manufacturing industry, 

 and in the scientific invei^tigating of processes ; in fact, in 

 many branches of metallurgical inquiry, and also in the 

 study of steam engine economy, there has been no want more 

 widely felt in times past than that of a trustworthy means of 

 ascertaining high temperatures. The author had previously 

 described an apparatus he had before devised, and that shown 

 was the result of a desire to simplify the design. The original 

 apparatus consisted of a camera containing a reflecting galvano- 

 meter of the Deprelz and D'Arsonval type of about 200 ohms 

 resistance. A thermo-junction is connected with this galvano- 

 meter, and the amplitude of the deflection of a spot of light from 

 the mirror affords the basis in calculating the temperature to 

 which the thermo-junction has been raised. An autographic 

 record of the temperature may then be readily obtained if the 

 spot of light from the mirror falls into a sensitized photographic 

 plate actuated by an astronomical clock, or by other suitable 

 mechanism. Such an appliance as this, though well adapted for 

 conducting investigations, is not sufficiently simple for industrial 

 purposes, and the author determined that it was necessary to 

 simplify the part which receives and records the spot of light ; 

 and also to arrange for attaching several thermo-junctions, so 

 that there would be one for each furnace, and each might be 

 brought in connection with the recoiding apparatus in turn. In 

 order to effect these changes the original moving plate was re- 

 placed by a clockwork- revolved cylinder, to which was attached 

 sensitized paper. In the apparatus shown provision was made 

 for placing any one of six centres of heat, such as hot-blast stoves 

 or furnaces, in connection with the galvanometer, and for obtain- 

 ing within the period of the revolution of the cylinder a record 

 of the temperature of any one, or of all the six sources of heat. 

 The records will, of course, be intermittent, the duration of the 

 test in any particular case being subject to the will of the 

 operator ; or the shifting of the electrical contact from furnace 

 to furnace could be carried on by clockwork. The apparatus 

 would then be entirely independent of manual adjustment. 



In the discussion which followed the reading ol the paper the 

 most important point was that raised by Dr. W. Anderson, the 

 Director-General of Ordnance Factories, who asked what was 

 the durability of the thermo-couple, and whether the intensity 

 of the current would alter owing to changes in the metals after 

 exposure to high temperature. It will be remembered that the 

 metals used are platinum and rhodium. Mr. T. Parker also 

 asked if the couple was protected. Sir Lowthian Bell, who has 

 had considerable experience with the Le Chatelier pyrometer in 

 practical use at the Clarence Iron Woiks, said that in regard to 

 durability and constancy of record, the device was most success- 

 ful. He had only had to renew three or four couples, and they 

 certainly would give accurate readings for the space of several 

 weeks. He had proved this by comparing new and old couples, 

 and also by testing at known temperatures. The author sub- 

 sequently stated that the couples were put naked in the blast, 

 and did not require protection unless subject to the impact of a 

 shower of metal, in which case they were placed in a porcelain 

 sheath. 



Mr. Greathead next read his paper on the Liverpool Over- 

 head Railway. This is a new railway which follows the "Line 

 of Docks," and extends for a distance of about six miles. It 

 is composed, for the whole distance, with the exception of a 

 length of a few hundred feet, of an iron viaduct of uniform 

 height, and which is continuous from end to end ; unless some of 

 the swing bridges on its course be open. The railway itself has 

 been previously described, but the rolling stock has not, we 

 believe, before been dealt with. Electricity will supply the 

 motive power, there being a generating station situated about 



NO. II 96. VOL. 46] 



the middle of the line, where there will be four engines working 

 up to 400 horse-power, each driving a separate Elwell Parker 

 dynamo. The current will be carried along the line by a steel 

 conductor placed on porcelain insulators. Hinged collector? of 

 cast iron, sliding upon this conductor, will make the connection 

 between the motors on the train and the generating dynamos. 

 There will be no separate locomotives, the motors being on the 

 cars, two cars forming a train to seat fifty-six passengei-s, the 

 total weight being about forty tons. The signals will be worked 

 h)y the trains themselves through an automatic device. The total 

 cost of the railway is to be £85,000 per mile. 



The second day, Wednesday, September 21, was opened by 

 the reading of Mr. Hadfield's paper. This is a production of 

 the kind that brings despair to the heart of those who prepare 

 brief notices of these meetings. It consists, with the appendices, 

 of over eighty-three pages, besides numerous sheets of tables, 

 diagrams, &c. It begins with Vauquelin, and ends with a biblio- 

 graphy— rt*^ ovo usqtie ad mala, as the author himself says ; but 

 the difficult part of the matter is that throughout the whole 

 treatise there is not a part that could well be left out without 

 disadvantage to the reader. Having said so much it -will be 

 evident that we can give but a very faint indication of the con- 

 tents of Mr. Hadfield's paper. It is well known that he has 

 madeaspecial study of the alloys of iron and chromium, generally 

 known as chrome-steel, and his success a? a practical steel maker 

 has been most marked. He has now put the results of long 

 research and experiment at the dispo.-al of all steel makers, and 

 we cannot do better than refer those interested in the subject to 

 the original work, which will duly appear in the volume of the 

 proceedings of the Institute. It is noteworthy that chromium 

 appears not to be in itself a hardener of steel, but that it acts 

 indirectly by influencing the action of carbon upon the iron. 

 Some of the photographic reproductions of chromium steel pro- 

 jectiles attached to the paper are very interesting, as showing 

 what punishment this metal will stand. The shells go through 

 nine inches of compound armour and eight feet of oak backing 

 without apparent damage, the points being as sharply 

 defined as in the shell as it comes from the shops. At a range 

 of eighty yards two six-inch shells went through the thickness of 

 armour mentioned, the striking velocity being 1825 feet per 

 second, and the energy 2250 foot tons. One projectile altered 

 •oi" in diameter and the second '013." One of these 

 I projectiles was fired through another 9" plate without 

 apparent damage. A 13 '5" projectile, also of Hadfield's 

 make, was fired at a target consisting of two armour 

 plates with 20" of oak between. The first plate con- 

 sisted of 18" of compound armour backed by 6" of wrought iron. 

 !Next came the 20" of oak, and then a io|-wrought iron, and 

 finally a 2" wrought-iron plate. This gave a total of 365" of steel 

 and iron, besides the oak. The penetration was complete, but 

 the illustration shows the projectile to have been broken into 

 three parts. The striking velocity was 1950 feet per second, 

 and the energy on impact 34,280 foot tons. The weapon was a 

 63-ton B.L. gun. 



In the discussion which followed this paper — which the author 

 read in abstract, having previously distributed printed copies — 

 Prof. Roberts-Austen pointed out that the author's researches 

 supported the views taken by himself and Osmond as to the dual 

 form in which iron exists. This was shown by the diagrams 

 showing the rate of cooling which accompanied the report. In 

 these, when the cooling was from a high temperature, 1320° C, 

 the curve was continuous throughout, but when the cooling was 

 from about a thousand degrees, there was a point of recovery 

 indicating recalescence. The diagrams formed part of a report 

 by Mr. Osmond on Hadfield's chromium steel, which the author 

 had incorporated in his paper. Prof. Roberts-Austen said he 

 had arrived at the same results working independently. An- 

 other point worth recording is that remarked upon by Mr. 

 Vickers, who dwelt upon the difficulty of deciding whether the 

 effects noted in the steel were due to carbon or chromium, as it 

 seemed impossible to separate the one from the other, the 

 chromium invariably disappearing with the carbon. Mr. Vickers 

 also started the old question of hardening by oil or water, a pro- 

 cess which he advocates. Dr. Anderson put the matter in its 

 true light by pointing out the danger from untrustworthinessdue 

 to the hardening process, defects being sometimes set up of 

 which there was no outward indication. This, of course, refers 

 to metal in large masses, such as gun-hoops, &c. Mr. F. W. 

 Webb, the Mechanical Engineer to the London and North- 

 western Railway, gave high praise to chromium steel, saying 



