1 9 1 3 



NATURE 



5°3 



Congleton and Matlock to the south, embracing 

 portions of five counties, and sources of several 

 head-streams of the Mersey, Dee, Trent, and 

 Yorkshire Ouse. 



There are several elevations of a little more 

 than 2000 feet, and a large proportion of the 

 district consists of unenclosed moorland and 

 grassland. The maps are coloured to show the 

 plant formations of acidic peat, siliceous soil, 

 calcareous soil, sandy soil, and of cultivated land. 

 The plant formations are subdivided into associa- 

 tions. For example, the formation of acidic peat 

 exhibits associations in which Vaccinium Myrtillus, 

 Eriophorum vaginatum, Calluna vulgaris respec- 

 tively dominate, and others in which two of these 

 units are more or less equally dominant. 



Following an introduction, dealing, among other 

 things, with rainfall, temperature, and winds, are 

 chapters on woodland, scrub, grassland, moor- 

 land, rocks and screes, marsh, and aquatic and 

 cultivated land associations. Summaries of the 

 plant communities (these include formations and 

 associations) of the Peak district and of Britain 

 conclude a most interesting book, the illustrations 

 and maps of which are excellent. W. B. H. 

 Outlines of Stationery Testing. A Practical 



Manual. By H. A. Bromley. Pp. 74. 



(London: C. Griffin and Co., Ltd., 1913.) 



Price 2S. brf. net. 

 This little manual deals chiefly with the technical 

 examination of paper, though other articles of 

 stationery are included in its scope. It avoids 

 theoretical considerations, and gives in simple 

 language concise instructions for the practical 

 testing of paper, physically, microscopically, and 

 chemically. Under the first heading come questions 

 of colour, nature of the paper, surface or "finish," 

 texture, opacity, ink-bearing properties, and 

 strength. Short notes are supplied explaining 

 these terms as applied to paper, and the methods 

 of testing the properties indicated by them. 



Few words are wasted in the chapter devoted 

 to explaining the microscopic examination of 

 paper. The author has managed to condense the 

 description of the examination into five small pages, 

 whilst another five are allotted to plates showing 

 tlie microscopic characters of the principal fibres. 



Under the head of chemical examination, direc- 

 tions are given for determining the nature and 

 amount of the mineral matter used as "loading," 

 and of the organic substances, such as gelatine, 

 rosin, casein, and starch, employed in the "sizing " 

 of paper. Methods are also propounded for dis- 

 criminating the colouring ingredients and detect- 

 ing chemically certain fibres and impurities. In 

 all cases, the author claims, the chemical pro- 

 cesses described are those which require the sim- 

 plest possible apparatus. The characteristics of 

 special kinds of paper are indicated briefly, and 

 the book concludes with short sections on the 

 testing of ink, gum, sealing-wax, and other 

 miscellaneous articles included in the term 

 "stationery." Within its limits — those of a col- 

 lection of notes for use in practically examining 

 stationery — the book will be found useful. 

 NO. 228l, VOL. 91] 



LETTERS TO THE EDITOR. 



The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. .Wither 

 can he undertake to ret urn. or to correspond with 

 the -.crilcr.-. of, rejected manuscripts intended for 

 this or any other purl of NATURE. No notice is 

 taken of anonymous communications.] 



Pianoforte Touch. 



I can fully endorse Dr. Heaviside's opinions as to 

 the possibilities of the piano-player, and could only 

 wish that there were some reasonable prospect of this 

 instrument being used to save a great portion of the 

 uninteresting drudgery of the usual school music- 

 lesson. At the present time a considerable amount 

 of school time is wasted in attempting to learn an 

 instrument which is so difficult to play that few 

 succeed in obtaining any satisfactory results. This 

 system does not succeed in producing musicians any 

 better than the ordinary school algebra lesson suc- 

 ceeds in producing mathematicians. 



On the other hand, my recent experiments in con- 

 nection with this "patent" control have led me care- 

 fully to test the existing commercial piano-players, 

 and I can fully endorse Mr. Wheatley's complaints 

 as to their lack of responsiveness and their persistent 

 assertion of their mechanical individuality in opposi- 

 tion to the most strenuous efforts of the performer 

 controlling them. The methods of varying expres- 

 sion by means of punch-holes, or by damping down 

 all the notes on one side or other of a hard and fast 

 dividing line, produce a very pleasing impression at 

 first, but one soon tires of their very limited capa- 

 bilities. 



In these circumstances I would strongly recommend 

 Mr. Wheatley and any other readers of Nature who 

 are interested in the subject to experiment with the 

 methods of control claimed in my patent specifications. 

 Even a rough and ready device rigged up with sticks, 

 strings, and kitchen weights produces such a great 

 improvement in the range of effects and flexibility of 

 the instrument that after experimenting with such 

 an arrangement I found it impossible to obtain any 

 satisfaction without it. I think it may be safely said 

 that the mechanical self-assertiveness of the instru- 

 ment can be reduced to a small quantity of the second 

 order, and can be further reduced by a method of 

 successive approximation. So soon as dynamical con- 

 siderations are introduced the possibility of accenting 

 notes in chords (i.e. proper chords, not the miserable 

 arpeggios which are so often substituted for them in 

 recently cut music rolls) becomes evident, and the 

 production of variations of tone quality by differences 

 of touch is probably much easier when effected this 

 way than when the keys are played by hand. All 

 this appears less difficult to learn than the control 

 of the speed regulator, which must always remain a 

 difficulty. 



The absence of these capabilities constitutes the 

 great defect of the commercial player. But the 

 ordinary "practical man" cannot understand anything 

 based on the principles of dynamics and physics, 

 consequently he treats the pressure as if it were con- 

 stant instead of a very variable function ol the time, 

 and the result is an instrument which is mechanical 

 and little else, and can only be played with an 

 unnecessary expenditure of energy. 



I have heard a professional pianist perform a very 

 delicate pianissimo passage in which the accented 

 notes rang out clearly and brilliantly above the back- 

 ground without being played any louder. It was 

 simply a difference of tone quality produced by a 

 corresponding difference of touch. My dynamically- 

 controlled piano-player is quite capable of giving a 



