630 SCIENCE PROGRESS 



same method has now been adopted for the jointing of aluminium, 

 the only difference being that fluxes are required in the case of 

 aluminium to remove the oxide film with which the surface of the 

 metal is normally coated. Although apparently so small a point, 

 it has been thought well to lay stress on this matter because of 

 the consequences with which it is fraught. Until the method 

 of jointing by autogenous soldering was perfected the use of 

 aluminium in the chemical industries could not be made general. 

 By its introduction a weapon has been forged which has enabled 

 those who have devoted themselves to the solution of the problem 

 to place at the service of the chemist and chemical engineer a 

 metal with which, on account of its special properties, many 

 grave difficulties affecting the use of other metals may be over- 

 come ; above all to render the manufacture of all materials 

 destined for human consumption safe and hygienic. The diffi- 

 culties which have so long stood in the way of the manufacture 

 of aluminium apparatus on any but the most restricted scale, in 

 fact, may now be said to have disappeared and the photographs 

 which illustrate this portion of the article are sufficient evidence 

 that any apparatus which the chemist may require to have made 

 in aluminium is now readily obtainable. 



The author wishes to express his thanks to the British 

 Aluminium Co. and the Northern Aluminium Co. for permission 

 to use the photographs shown herein. 



