April 13, 1916] 



NATURE 



141 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taketi of anonymous communications.^ 



Smithsonian Physical Tables. 



The Smithsonian Institution has just published a 

 new edition of the Smithsonian Physical Tables, cor- 

 rected and slightly modified from the sixth revised 

 edition. Requests have come from certain educa- 

 tional institutions for separate copies of certain indi- 

 vidual tables for the use of students in laboratories. 

 If there is likely to be a considerable demand for 

 I such separates, the institution will have them printed 

 ' on stiff paf)er and distributed at cost to those who 

 i desire them. With the view of ascertaining the 

 I probable demand for separate tables, it^is requested 

 i that readers of Nature inform the Institution which 

 tables they would desire in separate form, and the 

 ; number of copies of each they would probably require. 

 All tables for which the probable demand of this kind 

 ches 100 copies will be reprinted separately. 

 The tables may be consulted in nearly all the 

 larger libraries. 



C. D. Walcott, 



Secretary. 

 Smithsonian Institution, 



Washington, U.S..\., March 23. 



Effect of Tidal Water in an Estuary on the Level of 

 Subterranean Water. 



A.N artesian well was bored at Portishead last 



' I August lined with 8 in. and 10 in. casing, the annular 



I space between the casings being filled with cement, 



;so that the possible ingress of surface waters is 



i avoided. 



1 The well has been in constant use since that date, the 

 water-level standing in the summer about 10 ft. below 

 Ithe surface of the ground, which is only a foot or 

 I two above high- water mark. A few days ago pump- 

 ing from the well was temporarily discontinued. It 

 was noticed that the level fluctuated with the state 

 jof the tide. When the tide was out the level of the 

 water was about 4 ft. below the surface; as the tide 

 came in the level of the water gradually rose, until 

 at high tide the well was overflowing. 



This behaviour has continued regularly, the rise and 

 fall of level closely corresponding with the rise and 

 fall of the tide. 



This affords an excellent example of the weight of 

 :he incoming tide water in the Severn estuary, sub- 

 jecting the underlying strata to pressure and squeez- 

 ng the water out as if out of a sponge. The water 

 s drawn from strata underlying more than 100 ft. of 

 clayey marl. ' Jas. Kewley. 



Cambrian Lodge, Portishead, March 30. 



Is Soap Necessary for Shaving? 



At the present time when economy is the watch- 

 vord, it may be not altogether a waste of time to ask 

 whether soap is necessary for shaving? 

 The old Romans and Greeks, as evidenced by the 

 ;tues, were evidently gentlemen addicted to shaving, 

 t, save for a small soap factory discovered at Pom- 

 'i, the means of producing soap in those days 

 ust have been verv limited. 



The only conclusion that one can arrive at is that 

 ' y must have shaved without soap, a practice that 

 to the present day indulged in Idv our Oriental 

 lies, the Japanese, as well as by their neighbours, the 

 nnese. 



j NO. 2424, VOL. 97] 



Before deciding definitely to discard such a familiar 

 adjunct of the toilet, it might be of interest to inquire 

 why we have been in the habit of using soap for 

 shaving. 



The answers to the question received from scientific 

 and unscientific persons are very interesting, culminat- 

 ing in the fascinating one of a barber who thought 

 that the soap propped up the hairs and kept them in 

 an upright position. 



Lathering has the effect, when properly done, of 

 reducing the bulk of the soap, and increasing the 

 number of bubbles whereby water is kept in close 

 apposition to the skin by the surface tension. 



This is a roundabout way of using water as a 

 lubricant for the efficient and easy passage of the razor 

 across the skin, but once the lubricating qualities of 

 water are recognised as of value in such circumstances 

 it is but a short step to applying the water direct and 

 shaving while the skin is well soused. 



This is the method for long in use by the Orientals, 

 and is one that can be thoroughh' recommended for 

 trial in this country. 



Apart from its economy, the skin is not so liable t& 

 irritation, the edge of the razor is not so easily dulled, 

 whilst the whole operation is completed in half the 

 time. G. Arbour Stephens. 



March 25. 



MALARIA AND SANITATION.^ 



' I "HE title of this work is somewhat inappro- 

 -*- priate as the book deals scarcely at all with 

 many aspects of rural sanitation, but is devoted 

 in the main to what undoubtedly is a very impor- 

 tant problem, viz., malaria prophylaxis. It is 

 also not quite evident for what class of reader 

 the book is intended. The book has none of the 

 characters of a text-book or treatise on sanitation, 

 but gives the impression of being written rather 

 for the intelligent layman — we have, e.g., two 

 and a half pages of extract from Lafcadio Hearn's 

 works — were it not that here and there discussions 

 on technical points are recorded at some length, 

 e.g., the identity of certain species of .\nophelines. 

 What the book really consists of for the most part 

 is a diary of various sanitary tours made bv the 

 author. The outstanding feature of the book is 

 the author's enthusiasm for his subject, and the 

 best portions,, for they are the fullest, are those 

 devoted to the sanitary problems that arose at 

 every step in the making of the Panama Canal 

 and the descriptions as to how these difficulties 

 were overcome. Out of eighteen chapters, nine, 

 and out of fifty-six illustrations, thirty-six, are 

 devoted to the Canal. 



To malaria in India, on the contrary, the author 

 gives the inadequate amount of only a dozen 

 pages, and these concern the importance of species 

 in determining the prevalence of malaria, a fact 

 fully recognised in India sixteen years ago, 

 which the author confirms from his own experi- 

 ence in the Malay States. The author's work in 

 reducing malaria in Klang and Port Swettenham 

 is well known, t>ut we do not get a clear idea from 

 this book as to how it w'as done. We know these 

 places were drained, but we should have liked 

 sketch-maps of breeding-places showing the 



1 " Rural Sanitation in the Tropics." By Dr. M. Watson. Pp. xvi+32o 

 vLondon : John Murray, 1915.) Price 11s. net. 



