November i, 1900] 



NA TURE 



But really there must be some agreement between us and the 

 said eminent men as to what practical science is when the 

 examination paper is composed. 



IMay I give my illustration ? The Cambridge Local Syndicate 

 have introduced Elementary Experimental Science, three papers, 

 into their junior syllabus. The other day I set two of these 

 three papers for 1899 to a number of boys who had had 

 a most careful experimental training in the matter of the 

 syllabus. They made wry faces over it, and were heard to 

 remark afterwards that they did not see what it had to do with 

 the experiments they had been doing. On marking the papers 

 I found that the best boys, really very good and careful experi- 

 menters and observers and good draughtsmen, for boys, barely 

 reached forty per cent, of the marks. The same papers were set to 

 a sharp boy of the same age who had done no experiments, but 

 had been through the same subjects, mechanics, hydrostatics, 

 and heat, in the old way, viz., text- book and problems. He 

 scored nearly full marks on all the physics questions. 



The fact is, that except for the heading, "Experimental' 

 Science," there is nothing in two of these papers to indicate 

 that they are set to candidates whose knowledge is based on 

 and drawn from experimental work of their own. 



I should like to ask you to print these papers in full, that the 

 eminent men who set them might have a chance of saying some- 

 thing, but on the whole I think your space is too valuable. I 

 will simply quote two questions from the mechanics paper. 



" (3) Explain how work is measured, and in what units. 



"A 50 lb. shot is fired from a cannon with a velocity of 

 1500 feet per second. Compare the work done on the shot with 

 that done by a man weighing 12 stone who walks up a hill 

 1 500 feet high. 



" (4) What is the mechanical advantage of a machine? 



*' How would you arrange three separate pulleys, each of which 

 weighs I lb., so that the power required to raise a weight of 

 40 lbs. may be a minimum ? 



" What arrangement of pulleys is most commonly used in 

 practice ? And why ? " 



Now these are exactly the old Cambridge — " Describe the 

 common pump, &c., questions?" and the way to answer them 

 is to waste no time on experiments, but read your text-book, 

 get up your formute and work examples. The second question 

 is of exactly the same type. The other two require a graphical 

 construction, but such as would be readily done by a boy who 

 had used a text-book in which graphic methods were explained. 



The first paper is almost equally bad ; it is all (chemistry 

 included) text-book science of a very common order. Against 

 the practical paper I have nothing to say. 



Now Cambridge men can write excellent elementary text- 

 books on these subjects, witness those of Prof. Glazebrook. 

 Can they not produce among them a paper on Elementary 

 Experimental Science, which shall be what it professes to be, 

 or is the tradition of the common pump still too strong, and 

 the impress of the Mathematical Tripos too indelible ? 



A. H. F. 



Literature of Coffee and Tobacco Planting. 



In the issue of Nature of August 9 it is stated, in reviewing 

 a book by a French author, that several books on the same 

 subject, i.^. coffee — its growth, cultivation and preparation for 

 the market — have already been published in English. 



Could you kindly inform me of the names of the publishers 

 or authors of any good works in English on coflfee and tobacco 

 growing ? I have been, so far, quite unable, out here, to find 

 the names of any publishers of works on tobacco or coffee, 

 and as it is a matter of considerable moment to me to gain the 

 best of information on these subjects, I trust you will see your 

 way to help me. 



Salisbury, Rhodesia, South Africa. G. H. James. 



[Mr. J. R. Jackson, Keeper of Museums at the Royal 

 Gardens, Kew, to whom we referred our correspondent's 

 inquiry, has kindly sent the following list of books, which may 

 meet the requirements and also be of service to other planters. 

 — Ed. Nature.] 



Works on Coffee and Tobacco Planting. 



"The Coffee Planter of Ceylon," by William Sabonadiere. 

 Published by E. and F. N.- Spon, 125, Strand. (1870.) 



" CofTee Planting in Southern India and Ce)lon," by E. C. P. 

 Hull. E. and F. N. Spon. (1877.) 



NO. 1618, VOL. 63 J 



Article on cofTee in "Spon's Encyclopaedia of the Industrial 

 Arts, Manufactures and Commercial Products." E. and F. N. 

 Spon. 



" Liberian Coffee in Ceylon." From the Ceylon Observer. 

 Published at Colombo by A. M. and F. Ferguson. (1878.) 



"All About Tobacco." Compiled by A. M. and F. 

 Ferguson, Colombo, Ceylon. Agents, John Haddon and Co., 

 Bouverie Street, London. 



Article on tobacco in ' ' Spon's Encyclopaedia of the Industrial 

 Arts, Manufactures and Commercial Products." E. and F. N. 

 Spon. 



Autotomic Curves. 



In Nature, October 11, Mr. A. B. Basset justly inveighs 

 against the use of the term "non-singular curve " to denote a 

 curve which has no double points. Doubtless, also, the ex- 

 pression " an anautotomic curve " is objectionable. 



May I suggest that, in this instance, we may obtain from 

 Latin the help unknown to Greek, and designate curves which 

 have, and curves which have not, double points, by the terms 

 sesecting and non-sesecting respectively ? 



H. Langhorne Orchard. 



44 Denning Road, Hampstead, N.W., October 20. 



In answer to your correspondent, Mr. A. B. Basset, would 

 not the Anglo-Saxon negative prefix " un " combine more 

 euphoniously with " autotomic " than the Greek " an " ? We 

 find analogy for such a combination in the familiar words "un- 

 authorised" and " unauthenticated," where it is used in con- 

 junction with words of Latin origin ; so there seems no valid 

 philolo gical objection to its association with a Greek derivative, 

 while the phrase "an unautotomic curve" would certainly sound 

 more pleasantly to the ear than " an anautotomic " one. 



Arthur S. Thorn. 



4, Malcolm Road, Penge, S. E., October 25. 



THE PRESENT CONDITION OF THE INDIGO 

 .,., INDUSTRY. 



OF late years attention has often been drawn to 

 German Technical Chemistry, more especially in 

 connection with the advance and growth of the coal-tar 

 colour industry, an industry which received its birth in 

 this country, but which has now taken up its abode on 

 the continent, the loss of the industry to this country 

 being largely due to the conservatism of our manufac- 

 turers, and also partly to the want of proper scientific 

 training on the part of the few chemists whom the 

 manufacturers have deigned to employ.^ 



Before 1870 the madder plant was very largely culti- 

 vated, in order to obtain from it the important dye-stuflf 

 alizarin. But in 1869 a process for obtaining alizarin, by 

 fusing anthraquinone sulphonic acid with caustic soda, 

 was patented simultaneously in this country and in 

 Germany. As a consequence the madder plant is now 

 hardly cultivated at all."-^ Now, thirty years later, another 

 and perhaps even more important natural dye-stufT is in 

 jeopardy owing to the advances of German science. The 

 dye-stuff referred to is indigo, which is cultivated in such 

 large quantities in our Indian Empire. If, then, the 

 natural indigo is to be driven out of the market by the 

 artificial substance, prepared from coal-tar products, it 

 cannot fail to exert a great temporary, if not permanent, 

 influence upon the wealth of India. Perhaps, then, a 



1 In the hand-book for the International Exhibition of 1862 (vol. i. p. 120), 

 the following sentences occur : " It is impossible to overrate the importance 

 of the coal-tar dyes to this country. From having the sources of the raw 

 material in unlimited quantities under our very feet, we are enabled to 

 compete most favourably with continental nations in this respect, and we 

 shall soon become the great colour -exporting country, instead of having, as 

 hitherto, to depend on Holland and other countries for our supply of dye- 

 stuffs." 



^ Madder root contains about i per cent, of alizarin, and in 1859-1868 

 the best qualities of Turkey roots fetched 50J. per cwt. ; this would make 

 the price of alizarin about 45J. per lb. When artificial alizarin was first 

 produied, the dry product fetched about 45^. to 50^. per lb. A 20 per cent, 

 paste of alizarin is now sold for yd. per !b. 



