SCIENTIFIC NEAVS. 



Oan. 6, 1888. 



CORRESPONDENCE. 



The Editor does not hold himself responsible for opinions expressed 

 by his correspondents, nor can he take notice of anonymous com- 

 mutiications. All letters must be accompanied by the name and 

 address of the writer^ not necessarily for publication, hut as a 

 guarantee of good faith. 



MOLEHILLS UNDER SNOW. 

 Have any of your readers observed the peculiar forms 

 of molehills which are sometimes thrown up by moles 

 under the snow ? Instead of the usual tumulus-like heaps, 

 I have seen the molehills lying arranged in more or less 

 symmetrical ridges of uniform height and breadth. Of course, 

 it is known that in their laborious work of excavation, moles 

 require to get to the surface of the earth here and there, to 

 dispose of the loose material which they have scraped out. 

 If, in their work, they come upon a hard road, they get 

 out and run across it, and start afresh again. When frost 

 cakes the ground for some time, they will run for some dis- 

 tance on the surface to endeavour to get a softer field of 

 operations. Now it would appear, that underneath a heavy 

 wreath of snow the moles make galleries about the size of 

 their own bodies, on the surface of the turf in the bottom of 

 the snow, into which they push the earth to be disposed of. 

 Though the temperature of the air is much below freezing, 

 the surface of the sod, under a heavy wreath of snow, is never 

 frozen, and the moles can continue t!"eir work. They cannot 

 make the heaps on account of the weight of snow, and they 

 make these tunnels. Have any others observed this ? 



Mole. 



A CURIOUS PHENOMENON. 

 I was told lately of a very curious iphenomenon by an 

 intelligent observer. In sailing with (|ne of the pleasure 

 steamers on the West Coast of Scotland, ion a very calm day, 

 he observed the reflection of coast objects clearly pictured in 

 the smooth surface of the water, but with everything, of 

 course, inverted from its real position. But strange to say, 

 further out from the shore, he observed a reflected image of 

 this last picture, with everything standing up as in the 

 original position on the coast. Have any of your readers 

 observed this mirage-like phenomenon in similar circum- 

 stances on the West Coast, or elsewhere ? What is the cause 

 of the appearance ? I should be glad to get an explanation. 



Observer. 



SERPENT POISONS. 

 It is commonly reported in South America that any person 

 who has been bitten by a venomous serpent and recovered 

 is henceforth proof against all tropical fevers. Do you know 

 any facts which ever support or controvert this popular 

 belief? Surinamensis. 



ELECTRIC SEWAGE TREATMENT. 

 May I ask whether as far as you are aware electric 

 currents have been used, on anything like a practical scale, 

 for the purification of sewage and waste waters ? I am aware 

 that electric action has been proposed for this purpose in 

 several patents. S. P. E. 



MICRO-ORGANISMS AND THEIR CAPABILITIES. 



Your recent article, " A word for Germs," is suggestive 

 and may be accepted as an instalment of the truth. But it 

 might, I submit, have been carried further. These tiny beings 

 will very probably play in the future no unimportant part 

 in the manufacture of organic products. Indigo is doubtless 

 not the only valuable article which is or may be generated 

 by germ-action. But the activity of these minute organisms 

 may, perhaps, do mankind more service in the destruction of 

 vermin. Attempts have already been made to occasion by 

 their means epidemics among locusts, house-flies, rats and 

 field-mice. With reference to the rabbit-plague in Australia, 



tor the extirpation of which the colonial government of New 

 South Wales has offered a reward of ,£25,000, we find that 

 M. Pasteur proposes to launch against them fowl-cholera, a 

 disease which does not seem to extend to the larger domestic 

 animals nor to mankind. 



But whenever any novel power is put into the hands of 

 mankind, there are always certain persons who apply it 

 especially to evil purposes, and sometimes indeed, as in the 

 case of the so-called "high explosives," the evil may out- 

 weigh the good. A lamentable instance of disease-germs being 

 used for a criminal purpose has occurred in Chili. A man 

 who entertained an intense hatred for a neighbouring family, 

 contrived, during an epidemic of malignant small-pox, to pro- 

 cure some of the " crusts." This matter he mixed up with 

 tobacco and dropped it near his neighbour's house. The 

 tobacco was found and smoked, the germs being probably 

 volatilized and absorbed before they could be destroyed by 

 the heat. The consequence was the death of the entire 

 family. Nemesis, however, did not sleep. This inventive 

 murderer himself took the infection and confessed his crime 

 just before death. Sigismond. 



EFFECTS OF ELECTRIC LIGHT UPON BOOKS. 

 An attempt has been made to prove that the electric 

 light is, after all, more injurious to books than gas. It is 

 certainly true that if paper, made from \vood-fibre, is exposed 

 to the electric light, or indeed to the sun or to strong dayliglit, 

 it will turn yellowish, whilst gas-flames do not produce any 

 similar effect. But gas burning in a library acts upon the 

 bindings of books, not merely when they are opened out for 

 reading, but all the time as they stand closed up on the 

 shelves. So that, even if we leave the risk of fire out of the 

 question, the electric light is far preferable for libraries. 

 What might be the case if we could produce gas absolutely 

 free from sulphur, I cannot say. A Book-Worm. 



AUTOM.A.TIC ADDITION. 

 While adding up some long columns of figures a little 

 time ago, I noticed that I arrived at 100 at about the same 

 part of the page each time. The sum came to 100 at about 

 the twenty-second line of from the bottom. If we take one 

 column at a time, the possible numbers vary from o to 9 ; 

 the average value of a figure is therefore 4j, and since 100 

 divided by 4i is 22-22, if we had a book ruled with an average 

 of 22'22 lines to a page, the totals would be in each case con- 

 veniently near 100. How far this would be a convenience I 

 do not know, but it might be of use in getting out rough statis- 

 tics. In the same way, the average value of any figure in the 

 pence column is five pence halfpenny, and columns containing 

 an average of 43'63 figures will have a sum of about ^i. In 

 adding shillings and pence, the average on each line will be 

 9s. iijd., so that 20 lines will give very nearly ^10 for the 

 sum of the shillings and pence, provided that there were no 

 tendency for the figures to run in whole numbers or small 

 amounts. A. P. T. 



JUBILEE COINAGE. 

 Enough outcry has been made about the wretched design 

 and execution of the Jubilee coinage, but your note on 

 page 222, describing the production of the dies from which it 

 was struck by the electro-deposition of iron and a plaster 

 model, shows how the means were worthy of the ends. I do 

 not think that Mr. Ruskin goes so far as to say that a work of 

 art on which a great time has been expended, on account of 

 the difficulty of working the material, v.'ill necessarily be more 

 noble than one which, owing to mechanical facilities, has been 

 completed more rapidty ; but he has certainly pointed out^ 

 that the greater skill called forth in the former case, together 

 with the close application and consequently deeper study 

 and love for the work, is in favour of a better result ; and it 

 is evident that the harder material offers much greater scope 

 for the artist's skill. What wonder, then, when the softest, 

 most friable, and least polishable material was used, that the 

 results were cheap and nasty ? W. S. 



