94 



NATURE 



[March 29, 191 7 



tion and depression. From time to time caves have 

 been found in the Carboniferous limestone. Tv^'o of 

 these were examined by a local clergyman about the 

 middle of the last century, but the exploration was 

 carried out in an unscientific way, and the remains 

 discovered, without precise identification or record of 

 stratification, are now deposited in the Tenby Museum. 

 A more careful examination of the rock shelter, known 

 as Nanna's Cave, has recently been made by local 

 archaeologists, and the results are described in a paper 

 by Mr. A. L. Leach, reprinted from Archaeologia Cam- 

 brcnsis ior ]u\y, 1916. Remains of two skeletons, one 

 female, the other male, were found. The female skull 

 presents no characters which enable us to separate it 

 from modern British skulls, or from remains which 

 have been found in Neolithic or later Palaeolithic de- 

 posits. It may be as old as the Aurignacean ; but it 

 -howed no character which would disprove it. being- of 

 Neolithic or historic age. In association with it .was 

 found a skilfully struck flint flake, similar to that 

 obtained from the Hoyle Cave near Tenby, which is 

 probably of the late Palaeolithic age. This fact, how- 

 ever, is not conclusive of the age of the human re- 

 mains. In the Romano-British age the cave was 

 again occupied, and some fragments of pottery of that 

 period formed parts of an olla, or cooking-pot, and 

 a mortarium, probably used for rubbing down fruits 

 and other soft food. 



POTASH FERTILISERS FROM FELSPARS. 



THE dearth of potassium salts In this country 

 owing to the war has caused renewed attention 

 to be devoted to the possibilities of preparing soluble 

 potassium salts from the large deposits of felspar 

 which are found in certain parts of the country. The 

 problem has occupied the attention of chemists inter- 

 mittently for many years, but the processes devised 

 in the past have proved commercially unsuccessful, 

 owing largely to the failure to obtain, along with the 

 potash salts, other saleable products which might 

 share the cost of manufacture. This difficulty would 

 appear to have been largely overcome in the process 

 patented by Mr. J. Rhodin, a Swedish inventor, in 

 which, along with the soluble potassium salts, a mar- 

 ketable white cement is obtained. The successful 

 results obtained by this process with Swedish felspars 

 have been brought to the notice of the Board of Agri- 

 culture and Fisheries, and under the auspices of a sub- 

 committee of the Fertilisers Committee of the Board 

 further tests with British felspars from Roche, in 

 Cornwall, and Loch Eriboll, in Sutherlandshire, have 

 been carried out, the results of which are summarised 

 in the February issue of the Journal of the Board of 

 Agriculture. 



The Roche felspar, containing 108 per cent. K.O, 

 yielded 75 per cent, in a soluble form, whilst the Loch 

 Eriboll spar, with 8-6 per cent. KoO, gave 60 per cent, 

 soluble. A Swedish spar, with 129 per cent. K;0, 

 yielded 54 per cent, in a soluble form. Expert opinion 

 described the cement as a true hydraulic cement, of 

 satisfactory colour, but of much lower tensile strength 

 than Portland cement. 



As the result of its examination, the sub-committee 

 expresses the opinion that encouragement should be 

 given to any movement for the manufacture of potash 

 and white cement by the Rhodin process on a com- 

 mercial scale, and that in the event of a public com- 

 pany applying to the Treasury for permission to raise 

 capital to work this process, the application should 

 -receive the strong support of the Fertilisers Com- 

 mittee. 



NO. 2474, VOL. 99] 



THE NATURAL SCIEXCES IX PUBLIC 

 I SCHOOLS.' 



Age Limits for Sciwol Science. 



THE teaching of natural science in public schools is 

 of recent growth. Until quite recently most of 

 the boys who took up this subject did so with the in- 

 tention of making use of the training in their future 

 careers. Even now, in some public schools, the num- 

 ber of boys learning science is small. It is, however, 

 becoming recognised that science should form part of 

 every boy's general education. For this reason it is 

 necessary to put some, at least, of a boy's general 

 training in science before the age at which specialising 

 should be allowed. Too early specialising is bad 

 policy : the age at which this may be begun by the 

 average boy is about sixteen and a half years. 



Before this age (or its equivalent for forward or 

 backward boys) the pupil should have spent, on an 

 average, four hours a week at science for a period of 

 at least two years, and six hours a week for a 

 further two years. Thus the work should be begun 

 in the preparatory schools. The only work recom- 

 mended to be done there is in nature-study and prac- 

 tical measurements. See " Nature-Study in Prepara- 

 tory Schools " and " The Correlation of Mathematical 

 and Science Teaching " (Bell and Sons, each 6d.). 



.'Vfter a boy has reached such a standard of general 

 education that he may be allowed to specialise to a 

 certain extent, he should have the opportunity of de- 

 voting about eight hours a week to science if he 

 chooses to do so. At a still later stage the specialisa- 

 tion should be more marked in the case of those who 

 choose a scientific career. 



Science /n Examinations. 



If these ideals can be reached by any means other 

 than making science compulsory in examinations, 

 those means should be employed. If they cannot, 

 compulsion by examination regulations must be ap- 

 plied. But this should then be recognised as a neces- 

 sary evil. It is possible that some system of inspection 

 of schools by examining bodies, combined with the 

 granting of certificates on the recommendation of a 

 properly qualified master, might prove to be the solu- 

 tion of the difiicult problem of insisting on science 

 being learnt by every boy, without the restrictions 

 necessarily imposed when there are examination 

 syllabuses. But the details of such a scheme would 

 require careful thinking out. 



But there is, at present, a yet stronger argument 

 against the attempt to foster the teaching of science 

 by making the subject compulsory in examinations. 

 So long as instruction in science was given, only to 

 those who were destined for a scientific career, it was 

 natural (if, perhaps, unwise) to aim chiefly at incul- 

 cating scientific method, with a certain disregard of 

 general knowledge of natural phenomena. This was 

 done, for the most part, by logical courses in hydro- 

 statics, heat, light, electricity, and chemistry. But in 

 some of the schools where science has already become 

 a compulsory subject it has been recognised that such 

 courses may be unsuitable for the non-scientific mind. 

 The attempt is made to arouse a boy's appreciation of 

 the value and scope of science rather than to teach 

 him the elements of a subject which he will drop even 

 before leaving school. In such schools a considerable 

 proportion of his science hours is devoted to 

 studying subjects ranging from the universe to 

 the electron : astronomy, geology, biology, physio- 



1 Abridged from a memorandum drawn up by the committee of the 

 Association of Public School Science Masters to serve as the text of the 

 evidence offered on behalf of the association to the Goverr ment Committee 

 on the Teaching of Science. 



