Deckmuer I, 1898] 



NA TURE 



99 



iinnual and semi-annual periodicities ; nor has an effect 

 pf the ocean tides yet shown itself. It does not seem to 

 36 established that there is any connection between earth- 

 fluakfes and electric or magnetic or auroral phenomena. 

 Slow changes of slope of the earth's surface at any place 

 •ire continually going on ; these are more pronounced in 

 he direction of the dip of certain strata. Those that are 

 mostly of importance in astronomical observatories are 

 ,iue to differences in soils and crops in retaining power 

 or moisture ; and Prof. Milne seems to have made a 

 i:areful study of soils, not merely in regard to their ab- 

 ■lOrption and retention of moisture from the air, but also 

 n regard to their condensation of vapour coming up 

 "rem beneath, and the results of his observations and 

 experiments seem as if they might be of value to 

 agriculturists. 



j The author dwells at some length upon curious earth 

 ipulsations and earth tremors which seem to be uncon- 

 iHected with earthquakes. They occur everywhere, and 

 , their study ought to be of importance to all who have an 

 interest in astronomical or magnetic observatories or in 

 licxact measurement of any kind ; for e.xample, in careful 

 ^weighing. 



i| Earth pulsations have periodic times of two to three 

 (minutes, or even ten or more minutes, beginning and 

 pending for no known reason, lasting for one to three 

 -hours. Are they connected with the curious sea-swells of 

 lithe Pacific which recur annually at very high tide and 

 j.llast for twenty-four hours ? Then there are the curious 

 'earth ireinors, not to be confounded with the effects of 

 traffic on roads — they are storms lasting eight to twelve 

 ilhours, sometimes two to three days, never less than 

 athree hours. 



ij No doubt in some cases mere air currents inside the 

 licovers of the instruments produce some of the effects 

 lobserved, but in most cases they are real earth tremors, 

 ;due possibly to expansions and contractions of the soil by 

 iheat and other causes, but this will not explain everything ; 

 jnor will meteorological changes ; nor will winds acting 

 lupon the ground in the neighbourhood. The level and 

 slope of ground change perpetually, and the changes seem 

 Jnever to be quite continuous. Prof Milne cites many 

 observations which show the great importance of the 

 study of these earth tremors in connection with changes 

 !of barometric pressure and the escape of fire-damp in 

 'mines. 



I I know that what I have here jotted down after read- 

 ing this most interesting and valuable scientific work will 

 give only a very poor idea of its contents, and the author 

 will consider that his views are described very crudely. 

 But what can be done in a short notice of such a book 1 

 Every sentence in the book contains the result of much 

 thought and observation, and yet it is a book which is 

 just as easy to read as the report of a popular lecture. 

 One has also the feeling that the writer is appealing for 

 sympathy and co-operation of all kinds, without which 

 his great work in the establishment of observatories 

 cannot go on : it is the kind of appeal that one reads 

 between the lines of a traveller's book sometimes, an 

 appeal that the author does not know that he is making. 

 It certainly adds to the interest of an already interesting 

 subject. John Perry. 



NO. 1518, VOL. 59] 



COFFEE AND INDIA-RUBBER IN MEXICO. 

 Coffee and India-rzibber Cullure in Mexico. Preceded by 

 Geographical and Statistical Notes on Mexico. By 

 Matias Romero. Pp. xxvi -f 417. (New York and 

 London : G. P. Putnam's Sons, The Knickerbocker 

 Press, 1898.) 



AT a time when both the products mentioned at the 

 head of the title-page of this book are attracting a 

 great amount of attention as important cultural industries 

 suitable for many of the British Colonies, as well as for 

 other parts of the world, and when india-rubber or 

 caoutchouc especially continues to increase in value and 

 demand, anything bearing on the cultivation of these 

 plants is sure to be eagerly sought after. 



It would almost seem that in selecting the title for his 

 book Mr. Romero had in view the probability of catching' 

 readers by reversing the order of its correct title, which 

 should more properly stand as " Geographical and 

 Statistical Notes on Mexico : followed by Chapters on 

 Coffee and India-rubber Culture," for in a volume of 417 

 pages it is not till we arrive at p. 281 that the consider- 

 ation of the cultivation of coffee is commenced, and it is 

 finished at p. 359. Again, with india-rubber this subject 

 is disposed of in the thirty-three concluding pages of the 

 book. The statistical portion of the book, therefore, 

 occupies its greatest bulk, and is placed first in order. 

 Besides which Mr. Romero candidly says in his intro- 

 duction that the papers on coffee and rubber were written 

 about a quarter of a century ago, and simply appear now 

 as a translation without any attempt at bringing them up 

 to date ; while the geographical and statistical notes were 

 only just published when the introduction was written in 

 January last. 



It may be of some interest, as showing how the book 

 has been put together, to quote a few paragraphs from 

 the author's introduction. At p. v. he says, speaking of 

 the article on coffee : 



" I published in Mexico three editions of my manual, 

 correcting and adding to each new one, the last one 

 being published in July 1874. There was at the time no 

 interest in coffee culture, and very little attention was 

 therefore paid to my manual. By the advice of a friend, 

 I placed in a book-store about fifty copies on sale, 

 and four or six years later only two or three had been 

 sold." 



Again, on p. vi. Mr. Romero gives his reasons for not 

 bringing his -natter up to modern times as follows : 



" I am very sorry that my present engagements have 

 prevented me from revising this paper up to date ; that is, 

 changing such views expressed in the same as my e.x- 

 perience has taught me not to be entirely correct, at least, 

 in so far as other regions outside of the southern coast of 

 Chiapas are concerned, as that would require more time 

 than I ran afford ; and, in my inability to do that work, 

 I prefer to use the paper I wrote long ago exactly in the 

 shape in which it then came out. Since that time all 

 circumstances and conditions of coffee raising have 

 materially changed." 



In the introduction to the paper on rubber culture Mr. 

 Romero puts forward the same reasons for not revising 

 his paper, which he says : 



" I publish now exactly as it came out over a quarter 

 of a century ago." 



