May 9, 1907] 



NATURE 



l^ 



yRE\CH EXPERIMENTS ON RIVETING.' 



AS'IUDV of the most elementary form of con- 

 nection used by the engineer may not appear 

 to offer anything- in the way of novelty or scientific 

 value, as a contrivance at once so old and so simple 

 as a rivet seems at first sight not likely to afford 

 much scope for an investigation considered as a unit 

 apart. Indeed, the chief interest has rather been in 

 the groupinji;' and arrangement of rivets, and the 

 analv-iis of their behaviour under stress when 



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assembled in the v.irious joints and connections used 

 by engineers in boilers, bridges, and the like. In 

 the present instance the author, keeping strictly to 

 the simpler problem, has produced a memoir of great 

 interest. 



In the early pages tlie ordinary processes of hand 

 riveting are described, and a series of measurements 

 :uid photographs, after the manner of Marey, shows 

 in an interesting way that the well-known preference 



Fig. 2. — Punching from a thick pal-. 



of the striker for the full swing of the hammer for 

 long-continued effort as compared with the short 

 swing and greater number of blows is an instinctive 

 solution of the problem of obtaining the maximum 

 effect for the effort exerted. 



The section following traces the growth of riveting 

 machinery, and describes the characteristic effects pro- 

 duced when steam, air, or water is employed as the 



working lluid. Specimens of riveting obtained from 

 various types of machines are noteworthy as show- 

 ing that the shank of the rivet does not, as a rule, 

 bear against the plates, and that eccentricity in the 

 rivet head is common even in the most favourable 

 circumstances. The essential difference between rivet- 

 ing by hand and that produced by a riveting machine 

 is made clear by photographs of sections of rivets 

 at different stages of their formation, the surfaces 

 being prepared by polishing and etching in the usual 

 way. The superficial effect of a 

 blow, as compared with the 

 squeeze of the pressure machine, 

 is apparent in all the illustrations 

 shown in the memoir. 



The interesting question of the 

 pressure required to produce the 

 head of a rivet is taken up, and 

 the various circumstances which 

 influence this are the subject of 

 much experimental study. These 

 include the influence of tem- 

 perature, the chilling of the metal 

 by the die, the influence of the 

 time in w^hich the head is formed, 

 and the effect of an excess of 

 material in the shank, whereby 

 waste material is squeezed up and 

 forms a ring round the rivet head 

 proper. 



In addition, the diagrams 

 drawn by the recording gear give 

 precise infoimation as to the 

 work done on the rivet when the 

 time of formation of the rivet- 

 head is varied ; they also show 

 the effect of the cooling in draw- 

 ing the plates together. 

 .; ui ihe hamn er. '^ detailed examination of the 



strength of the rivet gives special 

 attention to the behaviour of the head and the way 

 it ruptures under stress, and as a result a form of 

 head is recommended having a radius of 0.86 

 the diameter of the rivet and a height of two-thirds 

 the diameter. 



The author, all through, has made great_ use of 

 photographs of sections of pieces of material, but 

 without magnification, and it seems possible that this 

 side of the investigation would have yielded still 

 more interesting results if it had included a detailed 

 examination of the sections under the microscope. 



As an instance of this, the accompanying figure 

 shows the well-known form of punching produced 

 from a thick plate, in which the characteristic sharp 

 edge appears near the middle of the depth. Sections 

 of such punchings would be well worth examitiing 

 under the microscope, and, in fact, the possibilities 

 of further research, with the microscope pressed mto 

 service, seem well worth consideration. 



E. G. C. 



BIG GAME PRESERVATION. 



A BLUE-BOOK containing correspondence re- 

 lating to the preservation of wild animals in 

 .\frica was issued at the close of 1906, and sets forth 

 ten vears' official work in the British Empire, and 

 in the dominions of other European nations in Africa, 

 for the preservation of wild animals. 



The Blue-book is not a satisfactory example of 

 careful printing. It is extraordinary that before 

 being issued, apparently from the Colonial Office, 

 the '^proofs should not ' have been submitted to a 

 zoologist for revision and correction. The names, in 



