480 



♦ KNOWLEDGE ♦ 



[March 31, 1882. 



iOtlfllfSf. 



^842] — noi.p. — Will liny rciidor kimlly inform mo how I rouUI 

 ■0|innito ({1)1(1 from (wippr? It iH dnubcil from tlio lirniih wliicli hnii 

 Iwcn iihimI for illiimiiintin^r. I rnrlono «|)ocimon. — I'fzzr.r.D. 



[31.1]- LoiisTrii. — WhyilooR thololmtor-aholl tnnifrom blno-ljlnck 

 to rod when it in hoiloil ? — A. 0. (i. 



[3-H] — Ki.K<TRo,sii>PE. — Ih thorp nny cxplnnntion of tho inability 

 of a point to <lm«- tho oloctricity from a charged cloctroncopc ?— 

 Box. 



[3i5] — CnvsTAi.MSATiox. — Will Bomcono in Knowleimk tfU u« 

 •omothinf; about ilondritus moas OKotpK or front on our window- 

 panOR f How it is thoy so much rcscniblo tho crowth of plants ? — 

 B. W. R. 



[310]— SiNKiNO Finds. — Aro there any tables published show- 

 inK what sum per annum must bo paid in order to repay a loan 

 with interest, so as to clear oft both principal and interest in a 

 certain number of years by equal instalments, and what is tho for- 

 mula for arriving at tho result Y — A. N. 



[347] — ("arms. — Wo have had an argument on tho qncstion as to 

 whether it is proper grammar to say " Club" is trump or " Clubs 

 are trump." or "Clubs are trumps. Would tho Editor, (r any 

 reader, kindly decide tho question ? — R. U. S. 



[3J8] — NoN-CoNnrcTOR. — Would some kind friend assist mo in 

 this matter ? I want to know some ingredients to make a kind of 

 paint that will be a non-conductor of heat. — J. H. 



IxfpIifS to ©iirn'fsf. 



[218] — SEA-nLCE Bird of March, "underneath the hdrren hush," 

 is explained by an ornithological friend to he probably tho blue-tit 

 (as shown in a Christmas card). The lines quoted by "Ondeis" 

 refer to the kingfisher, but why should the other lines ? — W. W. F. 



[273]— Strength of M.aterial.— In reply to " F. M.," the dis- 

 tance, 8 feet, is measured horizontally between the rail and tho 

 pivot ; 917 feet is tho length of the slanting line shown between 

 rail and top of pivot. To make Anderson's figures correct, the 

 surface of rail on which roller runs must be sloped so as to touch this 

 line, the roller being, of course, set at a corresponding angle. When 

 this is done, " F. M." will see at once that the force acting on pivot 

 is no longer vertical, but in the direction indicated by tho arrow to 

 the left of diagram, marked 82 tons. The resolution of this into 

 vertical and horizontal components is shown correctly. " F. M.'s" 

 figures are correct for tho diagram as it stands. — C. II. Wingfield. 



[270]— PicoTOGBApnY.— 1. In reply to W. E. F., he will find it 

 much better to purchase collodion. Price according to quality, say 

 from si-vpcncc jjcr ounce. 2. The thin metal plates can be pur- 

 chased at any shop where photographic materials are sold ; but 

 neither collodion nor plates are of any use without a lens, camera, 

 and other requisites ; also some experience in their use. 3. The 

 crystals referred to aro probably prosulphite of soda. — A. 

 Brothers. 



[307]—" Descriptive Geometry," by Edgar and Pritchard, 3s. Gd. 

 or 4s. Cd. (Slacmillan & Co.) ; also Angel's " Practical Plane and 

 Solid Geometry" will bo helpful (Collins' " Elementary Series," at 

 Is.). Don't attempt the subject without models, which can be 

 made of pasteboard, strings, and wire. You would not study plane 

 geometry ivithout diagrams. — A. II. H. 



[310]— Quartz in Coal.— Veins of quartz are frequently found 

 in shales and coal. Such veins appear to have once been chinks, or 

 small cavities, caused, like cracks in clay, by the shrinking of the 

 mass, which has consolidated from a more or less fluid state, or has 

 simply contracted its dimensions in passing from a higher to a 

 lower temperature. Siliceous, calcareous, and occasionally metallic 

 matters frequently have found their way into such empty spaces by 

 infiltration from the surrounding rocks. And see Lyell's " Ele- 

 mentary Geology," 1855, p. 027.— Lewis E. Emmet. 



[311] — He.vting Room.— "J. W. B." asks me whether there is 

 any sanitary objection to heating a room with Bunsen burner, 

 without stove-pipe or vent. lie evidently supposes that " with a 

 perfectly blue name " the atmospheric burner has some sanitary 

 adrantage over ordinary burners. This appears to be a commonly 

 prevalent idea, but it is without foundation, provided alwavs that 

 tho ordinary flame with which the Bunsen is compared is burning 

 properly, with ample supply of air. Both supplv tho products of 

 combustion of bisulphide of carl)jn and the other impurities of 

 coal gas, while a parallin lamp or candle, burning a pure hydro- 



carbon, only produces carbonic acid and water. A bad burner may 

 supply a smoky luminous flnme, and even a Bnnscn may go wrong 

 if it lights inside the tube- W. Mattieu Wim.iams. 



[312^ •Pviioi.ooirAl,. — Colonel Ross hos given his address in 

 Knowledge, No. 17, p, 354, for tho convenience of pyrological 

 inquiries ; to save tho editor and printers the trouble of inserting 

 inrpiiries on this head, and to avoid replying to anonymous com- 

 munications, which ho declines to do. 



[313] — Botanical. — Jemima will find just tho things required in 

 " .Manual of Botanic Terms," by M. C. Cooke, publishers, London ; 

 Ilardwicko A Bogue, price 2s. Gd. This little work is eminently 

 useful for reference. — Amatei'R Botanist. 



[317]— Seal Fisherif-s. — Seals aro skinned (in a few minutes), 

 their carca.oes aro left (alive) on the ice until the cold or death puts 

 an end to their sulTerings. If allowed space, I will give you the details 

 of a dav in Greenland. Some call it sport, but I have another name 

 for it.— T. D. Kennie. 



[320] — Botany. — If " F " requires an inexpensive work, I should 

 recommend him to procure " Lindley's School Botany." It is a 

 capital book, giving an insight into " Structural Botany." If ho 

 intends making a collection of wild flowers, he will find "John's 

 Flowers of the Field" (profusely illustrated) an extremely usefnl 

 book.— J. C. L. 



[326] — DoBSET.sniRE " Valley Tereaces." — These are tho ram- 

 parts of the ancient " camps," or fortified towns, for which Dorset 

 is remarkable. Several are very prominent objects from the rail- 

 way. — R. N. Worth, F.G.S. 



[32'J] — PnospiioREscEXCE of Fish. — It seems most probable that 

 this phenomenon is due to the jirocess of putrefaction, the decom- 

 position by oxidation of the bones, of which phosphorus is an im- 

 portant constituent. It is observed in the decay of all animal sub- 

 stances, but more especially in the case of fish ; so that in the 

 instance of the cured haddock, chemical action would take place in 

 a sulHcient degree to liberate the phosphorus in small quantities, 

 forming PjOj with the O of the air. From recent investigations, it 

 has been set forth (I believe by M. Chappuis) that phosphorescence 

 is due to the generation of ozone. — R. C. F. 



[332] — Mosses. — Let " Eupteris " try Wilson's " Bryologia Bri- 

 tanniea ; " it is an excellent work on British mosses. — Alexaxoeb 

 Blake. 



[333]— Sakkaea Tablet.— This list of the Kings of Egjrpt wag 

 discovered by tho late M. Mariette about 1863, and is now in tho 

 Boolak Museum. It was found in the tomb of a priest named 

 Tounari, who is represented rendering homage in the name of 

 Rameses II., in whose reign he lived, to fifty-eight of the monarch's 

 ancestors. Among these are a large number of names, especially 

 of tho first six, and extending to the nineteenth dynasties. This 

 invaluable list was supplemented in 1864 by the so-called second 

 Tablet of Abydos, also found by Mariette, which, with the sixty- 

 four names of kings engraved on the " Hall of Ancestors," from 

 Karnak, at Paris, and the first Abydos tablet in the British Museum, 

 made up the monumental lists of the kings. M. Maspero's arrange- 

 ment of these is to be found in his " Hist. Ancienne des Peoples de 

 L'Orient," published by Hachette, of King William-street. Any 

 recent history of Egypt will give an account of the tablet, as also 

 does Lenormant in his " Ancient History of the East," published 

 by Aslier ; for a complete commentary see De Rouge " Monuments 

 des six Premieres Dynasties. — A Member of the Society o» 

 Biblical Archeology. 



angtoers to CorrrsfponlinitEi. 



*^*All eommitmcatiotu for fhe Editor requiring f<irly afffnf ion should rea^h tkt 

 Office on or b^ore the Saturday preceding the current itfite of £nowlkdob, tkt 

 increasing circulation of ichich compel* u» to go to press early in the week. 



Htxts to CoRRKSPOSTmyrs. — 1. iVb qnestions ashing for sdentijie informaiiom 

 can be ansvn-ed through the post. 2. Letters sent to the Editor for corrf^spondenSa 

 cannot bg forvarded ; nor can the names or addresses oj" correspondents be given im 

 answer to private ingtiiries. 3. No queries or replies sarottring qf the nature qf 

 advertisements can bs inserted. 4. Letters, qttericf, and replies are inserted, unJsm 

 contrary to Utile 3, free of charge. 5. Correspondents shouU tcriie on oM sid* 

 only of the paper, and put dratcings on a separate UaJ. 6. Each letter, query , cr 

 reply shonlJ have a title, and in replying to letters or queries, reference should h* 

 Xi-ide to the number of letter or query, the page oh which it appears, and Us tHU, 



Studens. Our edition of Ganot later than yours, and cannot iden- 

 tify tho passage. However, if «(y + 5) = n + j^ + y + ^, it follows that 



(n-1) (7 + (T)=.a + /3 

 How you "eliminate (y + l) from both sides" passes my com- 

 prehension. If you have -10 marbles and 40 tops, and are told they 

 aro equal in value to 3 shillings and 6 ponce + one marble and one 



