NATURE 



[July 28, 1910 



Naturally the detection of products which may indi- 

 cate decomposition actually occurring or likely to 

 occur is important, and for this purpose Abel's heat 

 lest, first introduced for gun-cotton about 1875, is 

 employed for cordite. The test depends on the libera- 

 tion of iodine from potassium iodide by the action of 

 nitrogen peroxide, the principal decomposition gas. 

 The ground explosive is heated to 180° F. in a tube, 

 and the time noted for discoloration of the test paper 

 to a certain standard tint. The question at once sug- 

 gests itself. Does the test show decomposition products 

 which were present in the explosive, or have they 

 resulted from heating during the test, or both con- 

 ditions acting together? Very divergent opinions are 

 held as to the value of the Abel test as an indication 

 of the stability or '• life " of gelatinised explosives. 

 Certainly a powder giving a bad test must be re- 

 garded with suspicion, but it is obviously not an easy 

 matter to fix a time limit for a test which is subject 

 to adverse criticism. 



One of the most important considerations with any 

 explosive is its stability. The question naturally 

 arises, Is the molecular arrangement in such sub- 

 stances as nitrocellulose and nitroglycerine stable 

 under ordinary conditions of temperature? Their 

 explosive properties depend entirely on molecular re- 

 arrangement, which is practically instantaneous 

 when detonation occurs. Certainly slow decomposi- 

 tion occurs in most nitro-compounds of the explosive 

 class at temperatures not greatly above the normal 

 with the production of oxides of nitrogen, and it has 

 been shown that these oxides act catalytically on the 

 explosive ; in other words, their effect becomes cumu- 

 lative and mav lead to ignition. In order to avoid 

 this catalytic action, "stabilisers" have been intro- 

 duced in many explosives, substances capable of 

 absorbing these nitrogen compounds. As already 

 mentioned, the vaseline in cordite appears to perform 

 this useful function. 



THE SHEFFIELD MEETING OF THE 

 BRITISH ASSOCIATION. 

 "pOR the last few months the various committees 

 -*■ dealing with the local arrangements for the 

 meeting of the association have been hard at work 

 and the general outlines are settled. The hardest 

 task, perhaps, has fallen to the lot of the hospitality 

 committee in finding accommodation for the large 

 number of visitors expected, the city being notorious 

 for its small hotel accommodation. A first list of 

 hotels and lodgings is now ready, and members should 

 lose no time in engaging rooms. To meet the e.x- 

 pected demand, the committee has arranged for the 

 two training colleges' hostels for women to receive 

 members, the larger one for gentlemen, with a 

 limited number of married people in an annexe, and 

 the University Hostel for single ladies. The list may 

 be obtained from the secretary of the hospitality com- 

 mittee, Mr. J. Wortley, George Street, Sheffield. 



The reception-room will be at the Cutlers' Hall. 

 Here, in addition to the various rooms and offices 

 usually associated with the reception-room, W'ill be a 

 large luncheon-room, giving, close at hand, sufficient 

 accommodation to prevent the pressure and over- 

 crowding so prevalent in many previous meetings. The 

 Cutlers' Hall is conveniently situated in the centre of 

 the city, close to the tram termini, and the various 

 section rooms are grouped round it, all within a 

 radius of 400 yards, with the exception of that of 

 physiology, which, for evident reasons, is better placed 

 in the University. The president's address, and the 

 popular lectures by Prof. Stirling (types of animal 

 movement), Mr. Hogarth (new discoveries about the 

 NO. 2126, VOL. 84] 



Hittites), and Mr. C. T. Heycock (the Saturday even- 

 ing lecture to operatives), will be given in the Victoria 

 Hall. 



The first evening reception will be at the Town 

 Hall, by the Lord Mayor and Countess Fitzwilliam. 

 The Weston Park is to be the central scene of the 

 second on Tuesday, September 6, at which about 4,000' 

 guests are expected. The University lies along the 

 east side of this park, and the Mappin Art Gallery is 

 in it on the west. Advantage has been taken of this- 

 to have a combined reception by the University and 

 the local committee. The Chancellor and the Duchess 

 of Norfolk will receive one category of guests at the 

 University, and the Earl and Countess Fitzwilliam 

 another in the Art Gallery, but the two' 

 will really form a combined conversazione, 

 with an evening garden-party in the park. 

 One of the features of the latter will be a 

 military tattoo with torches after dark. .•\fternoon 

 garden-parties for the whole association will be given 

 by the Lord Mayor at his seat at Wentworth, and by 

 the local committee in the Botanical Gardens, whilst 

 a number of smaller garden-parties will be given on 

 other days. Arrangements have been made for visits- 

 to more than twenty works, covering the chief staple 

 trades of the city. In the University also the various 

 furnaces in the metallurgical department will be run 

 on different days to illustrate that feature in the 

 L^niversity curriculum. 



Saturday, September 3, will be devoted to excur- 

 sions to the Derwent Waterworks, to Chatsworth,. 

 Welbeck, and Clumber, where members will be enter- 

 tained respectively by the Dukes of Devonshire, Port- 

 land, and Newcastle, also to Haddon, Roche Abbev, 

 and Bolsover Castle. The neighbourhood is so rich 

 in picturesque scenes that there will be ample scope 

 for members to arrange private excursions, such as 

 to the Peak Caverns, the limestone dales, Buxton, 

 Matlock, Wingfield Manor, o<- even further afield, to 

 York, Lincoln, or Newark Castle, and Southwell 

 Minster. 



A local handbook of 500 pages has been compiled 

 under the editorship of Dr. Porter, with the assistance 

 of a large number of local experts, containing a large 

 amount of interesting matter, scientific, historic, and 

 local. During the meeting the University will hold 

 a congregation for the purpose of conferring honorary 

 degrees on the president and other eminent scientific 

 men attending the meeting. 



Provisional Programmes of Sections. 



Section A (Mathematical and Physical Science). — 

 The address of the president {Prof. E. W. Hobson) 

 will be delivered at 10 a.m. on Thursday, September i. 

 Two discussions are under arrangement. On Mon- 

 day, September 5, there will be a joint discussion with 

 Section G on the principles of mechanical flight, to be 

 opened by Prof. G. H. Bryan; and on Tuesday, Sep- 

 tember 6, Dr. C. Ciiree will open one on atmospheric 

 electricity. The section will meet with Sections G and 

 B on Friday, September 2, to participate in the dis- 

 cussion on the report of the gaseous explosions com- 

 mittee, and in papers to follow dealing with combus- 

 tion. Several papers have been already promised to 

 the section, but the programme is still incomplete. 



Section B (Chemistry). — The feature of the pro- 

 gramme is the joint discussions with other sections. 

 These are : — Friday, September 2, with Sections A 

 and G : Subjects of general interest ; in particular, 

 combustion. Monday morning, September 5, with 

 Sections I and K : Respiration ; afternoon, with 

 Section L : The neglect of science by commerce and 

 industry. Reports will be presented by Prof. W. A. 

 Bone, on combustion ; Dr. J. V. Eyre, on solubility. 



