Correspondence—J. B. Scrivenor. 383 
Mr. Crook appear to think—I hope that I am not doing them an 
injustice—that because the two definitions apply to the same thing, 
therefore they are the same. ‘This is hardly logical. They emphasize 
distinct characteristics, scientific and commercial, and are therefore 
different. 
An example illustrating the difficulty, however, will be more to 
the point than a long argument. In the Federated Malay States 
the chief crystalline rock is granite, and the mode of weathering is 
excellently shown by many miles of road sections in hilly country, 
where the transition from fresh rock to soil can frequently be followed. 
The rock weathers in situ to a soft mass, red or yellow, sometimes 
white, in colour, in which one sees round boulders of fresh granite 
that has resisted decomposition and so formed ‘ core-boulders’. 
I have taken a specimen from about midway between the soil and 
the fresh rock, and after drying have treated it with sulphuric 
acid for about one hour over a water-bath. The iron and aluminium 
that went into solution were precipitated as hydroxides, and the 
aluminium hydroxide separated by K HO and re - precipitated by 
ammonium chloride. After ignition I obtained over 13 per cent. 
of alumina, and as I must assume that this alumina exists in the rock 
as a hydrate or hydrates, the rock falls under the proposed new 
definition of laterite. It is a weathering product of a crystalline 
rock containing aluminium hydroxides in a tropical country. But 
no one here calls it laterite or wishes to do so; it does not harden on 
exposure, and is therefore of no use as a substitute for brick. It is 
decomposed granite, and it would be an unnecessary complication to 
eall it anything else, in spite of the interesting fact that a considerable 
percentage of aluminium hydroxide has been formed during the process 
of decomposition. Indeed, it may prove that this feature of tropical 
weathering is so general that it cannot be regarded as characteristic of 
any one decomposition product, and that, if the presence of aluminium 
hydroxides is to be the test of laterite, then there will be a difficulty 
in excluding rocks that have no resemblance to Buchanan’s laterite, as, 
for instance, the china-clay and clay-slate mentioned in my last letter. 
We know that the composition of laterites varies with the character 
of the rock from which it is derived; and I have ventured to propose 
that, for the sake of simplicity, we should call bauxite certain laterites 
in India that have been stated to be bauxite. ‘‘ Laterite is bauxite 
in various degrees of purity.” ‘‘ These are bauxites in blocks and in 
powder.”’ Iam now told that I am guilty of endeavouring to degrade the 
term ‘bauxite’ completely, and that my suggestion is positively harmful; 
while I am furthermore invited to assert that a mineral of a definite 
chemical composition, which has not yet been proved to exist, does not 
exist, and to state what name I propose to give it if it should be 
proved to exist. The word ‘bauxite’, Mr. Crook says, must be reserved 
for a hypothetical mineral of the composition Al, 0, .2H,O, and it 
may not be used as a rock-name until that hypothetical mineral is 
proved to be amyth; but there is some plausibility in my suggestion 
because the term has been used carelessly. 
Bauxite was discovered in France, and France possesses a 
mineralogist who cannot be accused of using mineralogical terms 
