Pond and Maclaurin. — On the Soil of the Taupo Plains. 231 



The conclusions arrived at by Dr. Dyer were that air- 

 dried soils ingested in a 1-per-cent. solution of citric acid for 

 seven days would yield to solubility all the material available 

 for plant-food, and no more, thus leaving still undissolved 

 a considerable amount not immediately available to the roots 

 of plants, and which might be termed " latent." This we re- 

 moved by treatment with hydrochloric acid, still leaving, after 

 this acid treatment, elements of nutrition so locked up as to 

 be of no avail for plant-life. The analysis of this material 

 was then arrived at by fusion, thus giving a knowledge of the 

 total constituents of the soil in three forms, as follows : (1) 

 Non-available mineral material of plant-nutrition ; (2) latent 

 mineral material of plant - nutrition ; (3) available mineral 

 material of plant-nutrition. 



The method of the chemical analysis has already been 

 detailed, but we felt that this would be incomplete without 

 a mechanical analysis, which has been arrived at by sifting 

 through various grades as shown in Table IX., using meshes of 

 twenty, thirty, sixty, and ninety holes to the linear inch, thus 

 making five gradations by mesh, whilst a further division was 

 made of the portion passing the 90-mesh by elutriation, this 

 being performed in a conical glass vessel Sin. in depth, with a 

 constant stream of water 17 in. in height issuing through a 

 hole j^in. in diameter, 1 in. from the bottom of the elutriator. 

 As all the samples were treated under similar conditions the 

 results are comparable. From all the samples stones were 

 rejected which would not pass through a ^in. mesh, but there 

 were very few in any of them. The results of this mechani- 

 cal analysis will be found in Table IX. In this table we find 

 that the combustible material is much lower in the Taupo 

 soils than the Mount Eden, while the Waikato soil is between 

 the two in this constituent. 



The capillarity of all the soils was tested in tubes of 

 1-5 cm. diameter, standing in water. In some of these tubes 

 the soil was shaken in loosely, and in others hard pressed. 

 In all the capillarity was excellent, but the rise was greater 

 in a given time in the hard-pressed samples than those loosely 

 shaken. 



The results of our analyses are shown in the following 

 tables, and are arranged as follows : Nos. 1 to 6 (inclusive), 

 from Taupo; Nos. 7 to 10 (inclusive), from Mount Eden; 

 No. 11, from Waikato ; and Nos. 12 and 13, from Rothamsted 

 barley soils. The last two are taken from Dr. Bernard Dyer's 

 paper, to which we have already referred, and they represent 

 constituents found in contiguous plots of ground which had 

 been under barley-crops for thirty-eight years. During that 

 period No. 12 plot had received no manure of any kind, 

 whilst No, 13a had received annually 3^ cwt. of super- 



