142 



. KNOWLEDGE 



[AcG. 31, 1883. 



The term " Kepler's second law " conveys no particular meaning 

 —in fact, Clifford, in his " Dynamic," 187S, calls it Kepler's first 

 law, and it is sometimes misunderstood to apply only to forces yaryin-j 

 inversely as the square of the distance. "Angular momentum" 

 seems a preferable term to " moment of momentum." " Conserva- 

 tion of areas " is a very misleading designation. 



The ivriter suggests that in the same way as the term lialf the 

 vis viva has been superseded by energij, so now might Kepler's 

 second law be replaced >vith advantage by the expression Consena- 

 timi of awjular jiiomentum. A. Babclat. 



WART-CHARMING (SO-CALLED). 



[909]. — I am both amazed and amused at the wonderful theories 

 started upon the very simple subject of destroying warts. Will 

 you allow me to give a simple explanation of a natural process, 

 which has as little connection with the *' imagination " or the 

 " influence of mind on body " as the moon has with green cheese ? 



Pasteur has killed small animals by inoculating them vrith the 

 saliva of an ordinarj- living person. To this poisonous quality of 

 the saliva (especially so in the mornings and evenings) most of the 

 feats of so-called wart-charmiug may no doubt be traced. 



I myself had a wart on my left cheek for a very considerable 

 time, caused, no doubt, by an unclean razor. I wetted the wart 

 with my own saliva every morning and evening, and in about a 

 fortnight the wart had entirely disappeared. 



It is evident thai; persons less fond of soap and water, or those 

 with disordered stomachs, possessing, therefore, a more poisonous 

 saliva, may effect quicker cures. 



I have always found it more reliable and satisfactory to seek for 

 the natural cause of everything than to ascribe it to the super- 

 natural and marvellous. Mephisto. 



[Our friend from warmer regions ought to know what is super- 

 natural and what not ; but he appears not to do so. The influence 

 of mind on body is among observed natural phenomena, and cases 

 of so-called wart-charming are among the most interesting iUnstra- 

 tions, but certainly not by any means the most surprising. The 

 saliva is not used in one case out of twenty. — E. P.] 



SOME AMERICAN WARTS. 



[910] — When a boy in Concord, Massachusetts, only thirteen 

 years ago, I had about a dozen warts on my hands. Another boy 



told me that Mr. C , the jeweller, could charm them away. I 



had two years before removed a lot of warts under direction of my 

 mother by applying three times a day a saturated solution of sodic 

 carbonate, and had much less faith in charms than in chemicals 

 My playmate, however, maintained that his warts had been re- 

 moved by the cliaraiing process, and so I went to the jeweller and 

 asked the same favour. He rubbed his fingers over each one, and 

 told me to put on them every day the juice of the milkweed 

 (Asclepias cormiti). I did this as often as I thought of it, and the 

 warts gradually became smaller, and after a few weeks I was sur- 

 prised to notice that they were gone. The success did not convince 

 me of the efficacy of charming, for "they say" in Massachusetts 

 that milkweed juice will cure warts, and I have thought that the 

 metals which the jeweller handled may have given some virtue to 

 his touch. Feitz F. 



New York, Aurj. 7. 



GIXGER-BEER PLANT. 



[911]— The ginger-beer plant described by T. H. Perry (878) is 

 probably an aggregation of one of the yeast-plants. The aeration 

 of the water is no doabt effected by the vegetative process induced 

 by the sugar. Snbstitute essence of lemon for the ginger, and you 

 will have a " lemonade " plant. 



W. H. Shecbsole. 



IRON SHIPS AND FLOATING DOCKS. 

 [912] — Will you kindly allow me to inquire through your 

 columns whether the builders of iron sliips ever make allowance 

 for the effects of wide differences of temperature in producing 

 irregular expansion and contraction of the metal, and consequent 

 cracks and fissures ? Fownessaysin his "Manual of Chemistry" that 

 " the force exerted in the act of expansion (by heat) is very great. 

 In laying down railways, building iroTi bridges, erecting long ranges 

 of steam-pipes, and in executing all works of the kind in which 

 metal is largely used, it is indispensable to make provision for these 

 changes of dimensions." Yet I am told that this rule does not 

 apply to iron ships, as in them the expansion or contraction is 

 uniform. May I venttu'e to ask if the immersion in water has no 

 neutralising effect, and whether also the building of iron ships has 



been tried to any extent in countries subject to great variations of 

 temperature, such as Norway and Northern Russia ? To put the 

 question as plainly as I can in my utter ignorance of the appropriate 

 technical language, would a builder be willing to leave the shell of 

 an iron ship the whole year through without any covering in such 

 a country as those just named, and expect no harm to result from 

 the vicissitudes of the weather, leaving out of view the liability to 

 rust? 



I am induced thus to trouble you on account of a question which 

 has lately arisen as to the immunity of iron floating docks from the 

 risk of having their efficiency impaired by exposure to the wide 

 variations of temperature that occur in certain climates. It has 

 been stated positively by a presumed authority that " the expansion 

 and contraction of the iron in a dock would have the same effect as 

 in a ship," and yet it seems to me that the resemblance between 

 the two structtires is not so exact as to make that proposition self- 

 evident. 



Again, it has been publicly stated that " as the advanced science 

 of the present day demands the use of iron and steel for the con- 

 struction of ships, so it does for docks, and in the whole of Europe 

 at the present time no engineer would think of using any other 

 material in their construction." Is this true or is it not j" 



X + Y. 



HEIGHT OF ANCIENT EGYPTIANS. 

 [913] — Being much interested in Egyptology in all its phases, I 

 recently made a tour up the Nile, and having previously noted some 

 statements respecting the sizes of certain mummies, when in Cairo 

 I measured several, especially those of the recent great find in 

 Thebes. I give my measurements below, and would be glad if it 

 leads to an " official " publication, as it would settle a good many 

 points in reference to this interesting and remarkable ancient race. 

 Measitbemexts. 



King Unas VI. Dynasty 4ft. 9in. 



King Ea Skemen'XVII. Dynasty 5„ 8„ 



King Amenoph Ist XVIII. Dynasty 5,, 2„ 



King Amosis XVIII. Dynasty 5„ 0„ 



King Thothmes 2nd XVIII. Dynasty o„ 6„ 



King Sethi 1st XIX. Dynasty 5,, 2„ 



King Rameses 2nd XIX. Dynasty 5„ 1„ 



King Pinotem 1st XXI. Dynasty 5 ,, „ 



Queen Nofritasi XVIII. Dynasty 5„ 4,, 



Queen Notimaut XIX. Dynasty 4„ 8„ 



Queen Makara XXI. Dynasty 4„ 6„ 



Baby of ditto 1 ., „ 



Princess Trinkheb XXI. Dynasty 4„ 9„ 



High Priest Nebsemui XXI. Dynasty 5 „ 6 „ 



The coffin of Rameses measures only 6 ft. 3 in. over all, and the 

 mummy does not reach to the wood (the thickness of which is 2 in.) 

 by several inches. Wm. Oxley. 



SINGULAR XUMEEICAL PROPEETY. 



[914] — I send the following as curious example of figure-magic, 



with the hope that it may be of interest to readers of Knowledge :— 



If the number 142,857 be multiplied by 1, 2, 3, 4, 5, or 6, each 



result gives the same figures in the same order, only beginning at a 



different point. Thus : — 



142,857x1 = 142,857 

 142,857x2 = 285,714 

 142,857x3 = 428,571 

 142,857x4 = 571,428 

 142,857 x5 = 714,2S5 

 142,857x6 = 857,142 

 If it be multiplied by 7, we get aU nines. Thus : — 



142,857x7 = 999,999 

 If it be multiplied by 8, we get 1,142,856. Now add the first 

 figure to the last, and we have the original number — 142,857. If 

 it be multiplied by 9, we get 1,285,713, and then we find that the sum 

 of the digits of the product is equal to the sum of the digits of the 

 original number, each being 27. 



Moreover, the sum of the digits of each product is the same in 

 every case but one, namely, when we multiply by 7. and then the 

 sum of the digits is 54, or just double the sum of the digits in 

 each of the other products. H. Askew. 



[The number 142,857 is 999,999-;- 7, and is also -what we get on 

 dividing 1,000,000 by 7, less f. Now noting that 10, 20, 30, 40, 50, 

 or 60, when divided by 7 leave remainders 3, 0, 2, 5, 1, and 4, &c., 

 ail the digits less than 7, that 80 divided by 7 gives 11, with re- 

 mainder 3, and that 90 divided by 7 gives 12 and remainder 6, we 

 fiod all the above facts accounted for, seeing that the digits in 

 dividing 1000000, 2000000, 3000000, &c., to 6U00O0O must recur in 



