466 Transactions. 



the New Zealand area throughout this lapse of geological time. It is 

 noticeable that where the basement beds are of greatest age, as at the 

 Clarence Valley, and also at Batley, in the north of Auckland, the over- 

 lying limestone member of the series is a deep-sea ooze — globigerina, 

 diatomaceous, or radiolarian. 



While the palaeontological evidence at present available strongly sup- 

 ports th.e conclusions stated, it is certain that much still remains to be done. 

 The collections that have already been made are capable of much ex- 

 tension even from the same localities, while doubtless other localities will 

 yet be found that will add greatly to our knowledge of the fauna of the 

 lowest members of this system of younger rocks. 



Art. XL. — On the Absorption of Lime by Soils : An Investigation of the 

 Hutchinson- MacLennan Method of determining the Lime Requirements 

 of Soils. 



By Leonard J. Wild, M.A., B.Sc, F.G-.S., and James G. Anderson, M.Sc. 



[Read before the Canterbury Philosophical Institute, 6th December, 1916 ; received by 

 Editors, 30th December, 1916 ; issued separately, 7th December, 1917.] 



Contents. 

 Part I.— Practical Test of the Method. 



Lime Requirements of some Adjacent Limed and Unlimed Southland Soils. 

 Lime Requirements of some Adjacent Limed and Unlimed Canterbury Soils. 

 Comparison of Requirements of Southland Lime-requiring Soils with those of South- 

 land Soils not requiring Lime. 

 Comparison of Southland Lime -requiring Soils with Acid Canterbury Soils 



Unresponsive to Liming. 

 Discussion of Results. 

 Part II. — Theoretical Investigation. 



Parallelism between Absorption by Soils and Adsorption by Colloids. 



Absorption Experiments and Graphical Representation of Results. 



Expression of Experimental Results in Terms of the General Formula for Adsorption 



by Colloids. 

 Time Curves. 

 General Conclusions. 



In a paper* read by one of us before this Society last year the Hutchinson- 

 MacLennan method of determining the lime requirement of soils was de- 

 scribed, and some preliminary trials of its reliability were recorded. It was 

 stated that " a more practical test of the method would be to determine 

 by it the lime requirements of two similar and adjacent soils, one of which 

 had received a known dressing of lime at a sufficient time previously to 

 allow of its being incorporated with th.e soil." It was also shown that " the 

 result for any given soil varies with the strength of the solution." 



The present paper consists of two parts : (1) A practical test of th.e 

 method on lines indicated in the first quotation ; (2) an investigation of the 

 reason for the variable absorption. 



* L. J. Wild, Studies on the Lime Requirements of certain Soils, Trans. N.Z. 

 Inst., vol. 48, 1916, pp. 513-17. 



