1890.] on Welding hy Electricity. 187 



other, with the result that the surfaces were welded and that there 

 was made a projection all round the weld (owing to the plastic con- 

 dition of the metal), which projection was afterwards beaten down 

 on the anvil. That is the kind of weld that you will see practised 

 to-night electrically. I bring the matter forward now to show you 

 that a butt weld is old in itself. 



Now the heating of these pieces of metal was done in a " smith's 

 fire," and the smith's fire, as made in London with Newcastle coal, 

 was really a work of art. The smith succeeded in building up a 

 perfect " grotto " of small coal, and coal dust, beaten together and 

 moistened. In this grotto the thing to be welded could be put. The 

 object of that w^as as far as possible to obtain the heat, while prevent- 

 ing the introduction of dirt between the surfaces to be united ; for 

 one of the greatest difficulties in welding is that there is a danger 

 of foreign matter being introduced between the surfaces, thus pre- 

 venting a good union being effected. In this way the heating and 

 welding were done in former times, and when proper care and skill 

 were exercised the welds were extremely good. To my mind, there 

 is no more interesting work than that of the smith. It is one 

 of the few things left, in which skill of eye and hand, and the 

 intuitive knowledge born of experience, are all that the man has 

 to trust to, and in which the result of the work is in no wise due to 

 dies and moulds, which have in some other departments of handicraft 

 pretty well superseded the skill of the man. It has always been to 

 me, and is still, a source of pleasure, to see a smith at work. I 

 must qualify this remark about the use of dies a little, because 

 there are those present who know that we do in these days, even in 

 smiths' work, use dies which get rid to some extent of the necessity 

 for his skilled labour. 



It is obvious that in all welds where the heat is obtained from 

 the ordinary fire the metal must be heated from the outside. Under 

 that condition you are sometimes subjected to the difficulty which 

 at times occurs in the unskilful cooking of a joint of meat, the out- 

 side being burnt, while the inside is raw. But this difficulty is, you 

 will find, entirely obviated in the case of electric welding. 



Now, the desiderata in heating for welding are — uniformity of 

 heating throughout the sectional area of the metal, regulation of the 

 heat, freedom from the possibility of introduction of dirt, arising 

 either from particles of fuel or from the presence of sulphur in the 

 coal, or any matter of that sort ; and also, facility of inspection 

 during heating. This last point is of great importance, because in 

 the ordinary method of welding by heating in a forge, the work has 

 to be frequently taken out to see how the heat is progressing, and in 

 this taking it out, and in putting it back, the risk is run of doing that 

 which you wish to avoid, i. e. introducing dirt between the surfaces. 



Probably the majority of the present audience are aware, that the 

 heating eff3ct of an electric current depends upon the quantity of 

 that current and not upon its pressure, or voltage, or, to use the 



