7 lily Z, 1880] 



NATURE. 



when away from home (as was frequently the case) to write and 

 indicate not simply in what part of the library the book would 

 be found, but in what portion of the volume, and almost always 

 •whether on the left or right hand page, any given passage 

 required would be found . 



Of late years I have found it desirable to rebind my tracts in 

 something of a uniform manner. Their external individuality is 

 thus destroyed, but the aspect of their title-pages and the 

 location of particular passages of the contents remain as fresh 

 as ever. Cornelius W.-vlford 



London, June 24 



Stags' Horns 



With further reference to the above question I have pleasure 

 in inclosing a letter received to-day from the head keeper at 

 Eradgate Park, near Leicester, where both red and fallow deer 

 are kept. 



I may add that I saw at the end of July last, near the head of 

 Loch Eribol, in Sunderland, a quantity of stags' horns in a gipsy 

 encampment, which I supposed had been collected for sale by 

 that curious fraternity. Herdert Ellis 



62, New Walk, Leicester 



" To Herbert Ellis, Esq. 



"Bradgate Park, 22nd Jiiiie, 1S80 

 " Dear Sir, — In answer to yours of the 19th inst. respecting 

 what becomes of the stags' horns after being shed, I beg to say 

 they are regularly collected and sold. Bat there is not the 

 slightest doubt of their eating each other's horns. I have myself 

 seen several cases where both brow antlers and the top points 

 have been gnaived off. I have also seen Scotch heads that have 

 been quite spoiled by the tines having been gnawed, which must 

 have been done after the horn had become hard, and whilst the 

 animal was living. I am, sir, yours respectfully, 



"C. Overton" 



Cup and Ring Stones 



Many of the markings mentioned by Mr. Middleton are 

 hollows made by rain, or rather deepened by rain-water holding 

 many low organisms in hollows, on the upper surfaces of exposed 

 grit stones ; overflow from these accounts for the groove or spout 

 noticed at the margin of some of them. They are to be seen on 

 the stones erected near Boroughbridge, and speak to the length 

 of time these stones must have been raised into their present 

 position. W''. S. 



June 21 



Diatoms in the London Clay 



To enable mz-\o determine tlie e-iict extent of the diato- 

 maceous band in the London clay, I am anxious to obtain 

 information of any wells in progress, or in contemplation, any- 

 where in the London Basins, west and noith of London. With 

 the help of some of your readers I have no doubt that I shall 

 shortly be able to show that the one referred to is co-extensive 

 with the London clay. The details I wish for are : — 



1 . Locality of well. 



2. If begun, the depth attained. 



I shall also be glad to hear of any railway cuttings now being 

 made in the same area. W. H. Shrubsole 



WATER SUPPLY 



A MONGthe improvements in sanitary matters that 

 "'"*• this generation has witnessed not one ranks higher 

 than the settled and still growing conviction of the im- 

 portance of a pure water supply", and nowhere are the 

 various aspects of the question more keenly debated and 

 ■considered than in the Metropolis at the present time. 



At a discussion at a recent meeting of the Chemical 

 Society there seems to have been some doubt thrown on 

 the conclusions arrived at by chemists in determining the 

 wholesomeness of a water by no less an authority than 

 Prof. Huxley, and it may be well to inquire how far his 

 allegations are borne out by facts. 



In the earlier days of the history of chemistry, as was 

 to be expected, the processes adopted in the analysis of 

 water were crude in the extreme, and the quaint ideas 

 promulgated in the treatises then published are not a little 

 amusing. Gradually, however, and especially during the 

 last few years, the methods of analysis have improved, and 

 although, judging by the wide diversities of opinion that 

 exist as to what may or may not be pronounced a water 

 sufficiently pure for drinking purposes, the subject cannot 

 yet be said to have arrived at a stage completely satis- 

 factory ; still, so far as the purely chemical evidence is 

 concerned, it would seem to be able to furnish results 

 which are sufficiently e.xact for all practical purposes. 

 The operations involved are among the simplest and 

 easiest the chemist has to perform, and consequently it is 

 not the data furnished by analysis that are called in 

 question, but the conclusions drawn from them. 



Persons interested in sanitary'questions, but who have no 

 special knowledge of the difficulties that beset the forming 

 a correct judgment as to the wholesomeness of water, are 

 apt to express themselves as scandalised, and it must be 

 confessed with some show of reason, that it should be 

 possible there should be so little' agreement amongst 

 those who are looked up to as authorities on such 

 matters. 



This disagreement, however, is more or less inevitable 

 in the present state of our knowledge, and is largely due 

 to the intricacy of some of the problems involved in the 

 question, which is by no means a simple chemical one. 



The debatable ground is the nature and estimation ot 

 organic matter and the amount of significance that should 

 be attached to the presence of oxidised nitrogen com- 

 pounds. 



Organic matter may be of animal or vegetable origin, 

 the former being dangerous and the latter much less so, 

 if indeed it be not altogether innocuous. To distinguish 

 bettt-een the two kinds is therefore all important; but 

 unfortunately it is impossible directly to do this, as 

 both animals and vegetables yield albuminoid matters, 

 which are, cheinically speaking, practically identical in 

 composition. 



Of the various processes for the estimation of organic 

 matter there are three that are in general use. One, the 

 oldest, known as the permanganate process, finds its 

 advocate in the present day in Dr. Tidy, and consists in 

 measuring the organic matter by the quantity of oxygen 

 required to oxidise it. .'Xnother, originated by Prof. 

 Wanklyn, and which he calls the albuminoid-ammonia 

 process, consists in decomposing the organic matter by 

 an alkaline solution of potassium permanganate, and 

 taking the resulting ammonia as the measure of the 

 organic matter. The third process, the one employed in 

 the laboratory of the Rivers Pollution Commissioners 

 and advocated by Dr. Frankland, its originator, estimates 

 the organic carbon and nitrogen separately. 



A good deal may be said in favour of all these pro- 

 cesses, as affording a rough estimation of the quantity of 

 organic matter, but none of them can be relied upon as 

 giving any indication of its nature, i.e., as to whether it is 

 dangerous or not; and yet it is the almost invariable 

 custom to judge of a water by the quantity of organic 

 matter it contains, no matter what its origin, and a 

 variation of two or three times a given amount is 

 held to make the difference between a good and bad 

 water. 



It was to this point that Prof. Huxley especially ad- 

 dressed himself in his remarks already referred to. He 

 gave it as his opinion, speaking as a biologist, "that a 

 water may be as pure as can be as regards chemical 

 analysis, and yet, as regards the human body, be as 

 deadly as prussic acid, and on the other hand may be 

 chemically gross and yet do no harm to any one." " I 

 am aware," said he, "that chemists may consider this as 

 a terrible conclusion, but it is true, and if the public are 



