NA TURE 



5^1 



THURSDAY, OCTOBER i, 1896. 



CHEMISTRY IN DAILY LIFE. 

 Chemistry in Daily Life : Popular Lectures. By Dr. 

 Lassar-Cohn. Translated by M. M. Pattison Muir. 

 Pp. X + 324. (London : Grevel and Co., 1896.) 

 A BOOK which professes to instruct the public, un- 

 t\ initiated into technical language or methods, con- 

 cerning the results of the application of scientific 

 principles to the purposes of daily life, must possess a 

 combination of qualities not easily associated together. 

 It ought to be true — that is, the positive statements it 

 contains ought to be facts, and yet, though its pages 

 should present the truth and nothing but the truth, it is 

 impossible that it should give the whole truth in regard 

 to many subjects it must pretend to discuss. Here is 

 the grand opportunity for the e.xercise of judgment on 

 the part of the writer, without which and a large pro- 

 portion of sympathy with his readers the book will be 

 both unintelligible and uninteresting. There must be — 

 and there are— many subjects which, from their nature, 

 are incommunicable to the mind not already prepared 

 with a knowledge of fundamental ideas and some 

 familiarity with the technical language or symbols by 

 which these ideas are expressed. Such subjects as many 

 divisions of pure mathematics and, we will venture to 

 add, of modern chemistry belong to this category. 



However, acting upon the view that the best test of 

 the suitability of such a book for the general reader is 

 not merely the opinion of the chemical expert on the 

 subject-matter and the degree of accuracy of the notions 

 introduced, the writer of this notice has placed this little 

 volume in the hands of an educated but not technically 

 instructed friend, with a request to read it carefully, 

 appealing for help or explanation if necessary. This 

 is the kind of thing that follows : — 



" Please tell nie the meaning of this : ' The green parts 

 of the leaves are called chlorophyll-grains,' also ' silica 

 is the chemical name for pure sand ' ; and, pray, what is 

 humus ?" (pp. 38-40). 



.•\ little later the reader says : 



" Listen : ' .-^ cannon exhibited by Krupp at the Chicago 

 Kxhibition, when charged with 115 kilos of this powder, 

 propelled a shot weighing 215 kilos to a distance of 

 20,226 metres ; the flight of the shot occupied 70 seconds, 

 and the highest point attained was 6540 metres above 

 the earth, while the height of Chimborazo is only 6421 

 metres.' What does all that mean, and what has the 

 highest point got to do with it ?'' 



These are sufficient examples of the, perhaps, not very 

 serious difficulties encountered by the general reader, 

 who at the end remarked, " Oh, yes ; I found it 

 interesting." 



Now let the chemist take a look at the volume. As 

 already hinted, the impossibility of stating some things 

 without resort to technical language leads to a great 

 deal of extremely loose and objectionable phraseology. 

 Take the following passage (p. 46) for example : — 



" Most of the phosphoric acid in the materials we have 

 mentioned is combined with lime in the proportion of 

 three molecules of lime to one molecule of the acid. 

 Sulphuric acid is a stronger acid than phosphoric; but 

 one molecule of sulphuric acid combines with only one 



NO 1405, VOL. 54] 



molecule of lime. If then two molecules of sulphuric 

 acid are caused to react with burnt bones or mineral 

 phosphorite, a new compound is obtained, in which one 

 molecule of phosphoric acid is combined with one mole- 

 cule of lime, and, at the same time, two molecules of 

 sulphate of lime or gypsum., as it is commonly called, are 

 formed. The following scheme makes the process more 

 evident. 



: Lime 



Phosphoric Acid \ Lime 



Sulphuric Acid 

 Sulphuric Acid 



Lime 



Here we have a series of statements all more or less 

 open to criticism, the culminating misrepresentation being 

 embodied in the scheme, which asserts that sulphuric 

 acid withdraws lime from the phosphate without leaving 

 anything in the place of it. This, however, is just the 

 kind of thing which it is well-nigh impossible to express 

 correctly in popular language. The worst of it is that 

 the same erroneous idea crops up in so many other places. 

 The worst case we have encountered occurs on p. 51, 

 where ammonia is said to be " an alkali or a base, for 

 these names have to-day the same meaning." And a 

 few lines further on it is announced that " bases and acids 

 may be gases, liquids, or solids. Ammonia, for instance, 

 is a basic gas, carbonic acid is an acid gas, sulphuric 

 acid is a liquid, and silicic acid is a solid." After such a 

 descent towards the popular level, it is difficult to believe 

 that anything can be gained by the introduction of 

 chemical formula?, especially such as occupy the last 

 ten pages, where an attempt is made to explain the 

 constitution of alkaloids and other complex carbon 

 compounds. 



All this kind of thing was managed much more suc- 

 cessfully in "The New Chemistry" of the late Prof. 

 Josiah P. Cooke, which, though published twenty years 

 ago, is still trustworthy and, in point of literary quality, 

 incomparably superior to such a jumble of information 

 not always to be depended upon for accuracy, and some- 

 times descending to the almost ludicrous. One cannot 

 but wonder whether the author was serious or cynical 

 when he wrote that phosphoric pig-iron " is only fitted 

 for making the coarsest sorts of cast-iron ware, such 

 as railings for graves and the like, in which no great 

 durability is looked for." The italics are ours. 



The author does not often exhibit emotion, but 

 bimetallism is too much for him, and he lets his pen run. 

 The whole story is too long to quote, but one passage 

 affords such a remarkable example of style, unspoiled by 

 a conscientious translator, that it is worth reproducing. 



"There is one thing which the bimetallists would 

 certainly achieve, as long as they do not get rid of the 

 fluctuations in the price of silver, were they to induce the 

 civilised States to inaugurate an international bimetallism 

 in that Utopia which they depict to any one who will 

 hearken to them as the approaching economical 

 rejuvenescence of the nations — for none of them has 

 brought forward a decisive argument in favour of their 

 assertions because no such argument exists, for if there 

 were such an argument it would certainly be easy to 

 induce the most influential nations to adopt bimetallism 

 again— and this one thing which they would undoubtedly 

 do would be to enable the proprietors of American and 

 .Australian silver mines, one of whom is already the 

 richest man in the world, to make yet much greater 



Z 



