198 



It scarcely needs to ho pointed ont that, under the influence of 

 the volatile components of a later intruded igneous rock, a peridotite 

 mass may also be altered into serpentine. 



Let it be recalled here that a resume of the olivine-serpentine 

 problem has i)een brought forward by W. N. Benson (Origin of 

 .Serpentine, American Journal of Science 46 p. 693, 1918). It is to 

 be regretted, however, that the problem has not been dealt with 

 from a physico-chemical point of view. 



Finally I beg to use this opportunity to thank Mr. A. C. de 

 JoNGH, Director of the Research Committee of the Mining Department, 

 for his willingness to have the analysis and the slides made in his 

 laboratory. 



From the above it may be inferred that many difllicuUies liave 

 stood in my way by the insufficiency of my laboratory-equipment. 

 It is to 1)6 hoped that the Government of the Netherlands East 

 Indies, wiiicli are so extremely rich in occurrences of beautiful 

 rocks, may, at no distant date, take measures for the building of a 

 well-equipped petrographic laboratory. 



Weltevreden, Aug./Dec. 1922. 



