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HARD WIC KE'S S CIE NCE - G OS SI P. 



about it or not) will be pleased to learn — if they have 

 not already discovered for themselves— that during 

 the past summer most of the publicans in and around 

 London have found it commercially advantageous to 

 supply ginger-beer on draught at one penny or three- 

 halfpence per glass. I have made inquiries at some 

 large establishments, and find that this innocent 

 beverage has largely replaced the ordinary malt 

 liquoi. It is not absolutely free from alcohol, but is 

 practically a non-intoxicant. 



This is connected with something else a long way 

 off, viz. in China. Mr. Charles Ford, Superinten- 

 dent of the Botanical and Afforestation Department 

 of Hong-Kong, says in his report for 1886, that he is 

 studying, and has taken steps for cultivating, all the 

 kinds of ginger plants used by the Chinese, which 

 possibly include some hitherto unknown elsewhere. 

 He has sent specimens of the underground stems, 

 which constitute the commercial product, to Kew 

 Gardens for investigation. 



Butter Preserving.— At a recent meeting of 

 the French Society for the encouragement of In- 

 dustry, M. Grosfils, of Verviers, described a new 

 method for preserving butter. He takes 98 parts of 

 water, 2 parts of lactic acid, and 3^ of salicylic acid. 

 The lactic acid dissolves the salicylic acid and prevents 

 its crystallisation. This solution is to be beaten up 

 with the butter which, on taking up about 5 per 

 cent., will contain 1 part of salicylic acid in 100,000. 

 M. Grosfils says that good butter may thus be 

 preserved indefinitely even in hot climates. 



However efficient this may be, it is too complex 

 and refined for ordinary domestic use and is not 

 required. In my own small household, we adopt 

 a much simpler method. A supply of butter 

 is purchased in the autumn or later part of the 

 summer, when genuine fresh butter is cheap and 

 good, the cows being then fed on the aftermath ; 

 this butter is made into rolls of one or two 

 pounds each, and placed in strong brine, a piece of 

 wood being employed to keep the rolls completely 

 immersed They remain quite sweet all the winter. 

 The salt penetrates to a depth of about \ of an inch, 

 and thus each roll has a coating of salt butter, but all 

 remains fresh within. 



Alum and Foul Water. — I have received an 

 American newspaper containing an account of an 

 outbreak of typhoid at Mount Holly, N.J., traced, 

 as usual, to the use of polluted drinking-water. 

 The writer adds the following: — "The most re- 

 markable result of the scientific study of the Mount 

 Holly cases by Dr. Leeds, is the demonstration of 

 the fact, that a quantity of alum so small as not to 

 injure the water for drinking purposes is sufficient, 

 not only to clarify it, but also to reduce greatly its 

 bacterial contents. Dr. Leeds' investigation is of 

 great value and interest, and a further trial of alum 



in the capacity indicated will be an important and 

 useful experiment." 



This discovery, although it may be quite original 

 on the part of Dr. Leeds, is by no means new. I 

 heard many years ago that it is a common practice 

 in India to add a small quantity of alum to foul 

 drinking-water and let it stand for a while, the result 

 being that the water becomes clarified and harmless 

 for drinking purposes. I repeated the experiment 

 on an aquarium which had become very foul from 

 the death of two large specimens of Actinia crassi- 

 cornis. Two or three teaspoonfuls of strong solution 

 of alum stirred into the water of the aquarium 

 produced a dense cloud of precipitated alumina 

 which gradually subsided, carrying with it the other 

 constituents of turbidity, and leaving the water above 

 brilliantly clear. 



When the Crystal Palace aquarium was first filled 

 with sea-water, it became very turbid, and the 

 animals with which it was stocked died. I was 

 consulted by the directors at Mr. J. A. Lloyd's 

 request, and made experiments on a large tank set 

 aside for that purpose. I found that the cause of the 

 mischief was alkalinity due to the caustic lime still 

 remaining in the Portland cement, and clarified the 

 water both by alum and the cautious addition ot 

 hydrochloric acid ; but as neither of these appeared 

 to be agreeable to the animals, we determined to 

 apply the milder and slower remedy afforded by the 

 carbonic acid of the atmosphere. The opening of 

 the aquarium was postponed accordingly, and the 

 water kept in vigorous circulation for several weeks. 

 This was quite successful. 



When the old and classical engine works of 

 Boulton & Watt were demolished about thirty years 

 ago to make space for villas, the Upper Soho Pool 

 was abolished by cutting a trench and running out 

 the water ; but it was so fetid when thus disturbed 

 that serious alarm arose, the outflow passing several 

 houses. I was consulted by Mr. Boulton's agent, and 

 prescribed alum mixed with lime. This was effectual, 

 but some hundredweights of alum were required 



Martyrs to Liberty. — In another number of 

 the same paper as that from which the above is 

 taken, is an account of the immolation of birds at the 

 shrine of American Liberty. There was a sudden 

 snap of cold weather in the neighbourhood of New 

 York on Friday morning, 23rd September, and a 

 consequent rush of migratory birds occurred. As 

 they approached Bedloe's Island, they were lured by 

 the flaming torch in the hand of the great Statue 

 of Liberty, and when engineer Eugene Newton and 

 Superintendent Littlefield arrived, they saw a circle 

 of dead birds around the base of the statue. They 

 gathered them in a heap and counted 1375, including 

 more than a hundred different species. The largest 

 bird was a Canadian woodpecker, measuring thirteen 

 inches from wing to wing. The smallest is described 



