472 



KNOWLEDGE ♦ 



[Dec. 15, 1882, 



c r.o- :■:. !. v To taTo to wriic ono note on a subject is sniiiptiiiics 



;i i It daplicution of the nuisanco is simply tortiir»\ 



'■ iid on inqairy, gwcs in for a d instead of a t. 



. ,j to ferret tlio cause of this. For my own part 



. >. ...,^kUt to think about it. The brain can seai-ccly 



hj\.- i». Ju wiiii tliis calligraphic confusion. Perhaps it is general. 

 I almost hope it is. T. A. R. 



'Wl.on tiro»l. 1 find myself vcr)- apt to omit the last letter of a 

 wi.-: I !■ .»: '.■ -.-.IT ixvurs as a etroiip letter in the next; thus, if 

 1 .> ^^r. «orils "he had made," to write " ho ha made," 



ii.i..: . ::.• the mistake, however, before I have finished 



tl..- " .- ; : . n.v.^ that whose last letter has been omitted. When 

 I was a lad at scUlhiI, I often wrote, in hurried work, "g" for " d," 

 as " aog " for " and." I find myself occasionally making this mis- 

 take now. and, which rather suqirises me, ofteucr with the type- 

 writer than with the pen .' R. A. P.] 



l658] — Uay I add my little exjierience of "Brain Trouble" to 



;:. St- ;i;.vji\ n , orJed r When tired or worried, I find the most 



les, or rather strings of words without the 



'!!, chasing each other through my brain with 



V and persistence. The combination of words 



;> : . iicukins I often wish to remember some of them, 



l.j: :l._v .irv L-iiie as rapidly as they come. At first it nsed to 



distrvts me, but now it rather amuses me to (as it were) listen to 



the nonsense in my own head, which I am powerless to stop. It 



gecemlly ends in a bud nervous headache, unless I can sleep it off. 



The words which most frequently recur, and which I begin to 



watch for, are " rimililus horuin" ('.), "caterpillars," and "the 



old man with the wooden spoon." I cannot at all account for their 



frequency. M. G. 



ELECTRICITY IN DENTISTRY. 



[059] — I obser^-o in a recent number of KxowtEDGE, what 

 appears to be a reply to the inquiry of a correspondent under the 

 hiad of " Denti.Ht," whether the shock of a galvanic coil might not 

 be made use of to deaden the pain of tooth extraction. Your reply 

 is unfavourable to the idea, but as I happen to have had practical 

 experience of its utility, I will proceed, with your permission, to 

 relate what I know on the subject. 



When I was livingat Cork, about twenty years ago, I had occasion 

 to (TO to a dentist to get a back tooth extracted which was aching, 

 and not knowing any one in particular, I called on the first 1 came 

 to, whose name I have quite forgotten, and can now only recollect 

 llujt l,e lived on the south side of the South Mall. When I was 

 s<at<-<l ii] the o|)emting chair ho told mo that ho made use of a 

 galvanic tnrrent to deaden the pain of extraction. To the best of 

 my n-c<jllcttion 1 held in my hand ono pole of a coil machine, while 

 the other wn.<i in connection with the extracting forceps, and I well 

 recollect that the passage of the current, which was very slight, 

 caiiw-d a numbness in the tooth, wluch almost entirely overcame 

 the pain. Being at the time a dabbler myself in electricity, 1 got 

 ir,:. . .^i.-.i r-a:i..ii with him, and examined his battery, which, I 

 - lo cell " Smee," and ho told mo that he always 

 I never had any difficulty with patients since ho 



■ .idvertisod his method of extraction, and as I 

 f.'THards I lost sight of him. I never met with 

 "l this method of extraction before or since; 

 publication of my experience may elicit some 

 ' -M on the subject. Taos. C. Uaines. 



l'.'i;a.-, Suv.O. 1882. 



[This in news to us. The "shocks" were evidently very feeble 

 We sboald be glad to hear more on tho subject. — Ed.] 



II , .In 



SUGAR AND THE TEETH. 

 [^^'j—^a answer to your corresfiondont, letter G07, page 3C4, 

 proi.^K of refining, sugar is treated with 

 ■ ;iik, is hurtful to the teeth. Tho 

 .r would have the most effect on 

 •liO least. II. Zlcciikko. 



ilmjt j.,..:^^ <,iL« U«^i,», 111* Pkatton ud JTinJoo." 

 BtOfU Boi, with sU th« kindi, li. Id. hj Pott. 



>■«»* • <nl. th« n.nr«."-Ol<ill 3 



/ Prnkol<l,T: 



Sn^trs( to CorieficpoiUitntfi!* 



This section is limited to one coluiiiii as tho viazimum. Only a 

 jmu/J propurtion of liw Icltcrs recciicil can, therefore, be answered 

 here, ilanij not ansiccrcJ may nevertheless be noted and aeted 

 upon. Letteri raising religious, political, or persMial questions, 

 asking for tent-book information, yroposiny class-room problems for 

 solution, and so forth, pass at onco to a recoptaclc specially proi-ided 

 for them. A stem atid inlieiibte censor has been specially appointed 

 to stand between a too-yieldiny Editor and those u-ho thus unreason- 

 ably claim his attention and syaco which should be otherwise occupied . 



No LETTEBS ANSWERED THROIIGII THE POST. 



Anna Byhon Dennys. Wheels arc very ancient. No one knows 

 when they were first used. Wo see pictures of them on nil the most 

 ancient carvings of all nations. — E. A. Maktin, Dr. R. Leigh, An 

 Anxious Mothek. Anti-corset articles in typo before yours arrived, 

 or would have inserted. You will find your arguments considered, 

 uud many others. — J. B. Y^oung notes that llowney & Co. supply 

 special water-colour paints very suitable for painting on gloss. — 

 A. Z. Such spots wore visible. — E. Uai-ikax. Best exercise for 

 reasoning powers is, I think, tho study of books in which matters 

 scientific, legal, historical, and so forth are nbly reasoned. The 

 study of logic seems to impair them. — A Constant Reader and 

 Well-wishek. Expected rather to be sat upon for talking of 

 those howling swells, as if (which is tho case) they were just two 

 possibly well-behaved possibly not woll-bohaved German persons. 

 Certainly cannot bo blamed for thinking unduly of Tel-cl-Kcbir : 

 shades of Marlborough and Wellington defend ns ! — Hitherto 

 CON.sTANT Reader. Your kindly letter noted. Cannot find fault 

 with views once my own. Emotion by no means dead through 

 science ; yet reason must bo satisfied. I'ersou in question 

 so much hotter than kinsfolk, that probably even future judg- 

 ment will bo ns you say ; liut one cannot but remember how 

 kinsfolk were applauded in life and utterly scorned (by same 

 persons) when no longer " Founts of Honour." — J. Ballot. Thanks 

 for pleasant letter. All success with your telescope. — Fellside. 

 (1) All in motion. (2) C. G. of universe would not bo centre of 

 motion for any star, any more than for earth or moon. — T. Radmore, 

 W. O. Prosser, F. EnsTALL, J. N. Morris. Thanks; but sufficient 

 attention given to spot for present. — F. D. Bhown. Many thanks. — 

 C. H. W. Uammick. Brave, but not affording special evidcnco of 

 reasoning. Thanks. — S. E. C. Howling papers sent us (marked at 

 howling places) glanced at, W.-P.-basketed, names not noted. 

 Science has nothing to howl at. Consider the tone of Darwin's 

 letter in No. 57 ; how gentle, considerate, and modest. Tho last 

 five words present his pure philosophy, "Wo can do our duty" 

 (not " Thou shalt do what I consider thy duty "). Darwin imagined 

 his correspondent would follow the lino usual among gentlemen. 

 Dear me ! what could not some of us toll about tho views of such 

 men, if wo felt free to jjublish private letters or utterances. — 

 Atiikoi'A Gvmreio. Seismometer is an instrument for measuring 

 earth tremors. Many kinds exist. No space for description, which 

 would require illustrating; and other subjects intervene. — A. Black. 

 On return to town will ascertain tho dif. cal. numbers. — H. B. (1) 

 Not solar system gaseous as a whole, but its several pnrLs. Why 

 does not our air fly off, then ? (2) Trosca's experiments 

 require long and careful description. (3) Porous bodies would 

 be soaked as a consequence of pressure. Consider case of block 

 of wood, taken deep under water: pressure forces water in, so that 

 wood never rises to surface unless drugged up. (4.) Apart from 

 absorption by object-glass, yon may have tho same brilliancy, or 

 loss (with magnifying power 200), but never more : same brilliancy 

 if object-glass largo enough, viz., 200 times size of oyo-pupil, say 

 diameter about 3 inches. (5.) Pancratic eye-piece is ono which can 

 bo BO changed ns to vary the power ; not useful for sea-side tele- 

 scopic purposes. — H. Ii. Shaw. So many such books. See notice 

 atheadof this column. — A. E.D. Battue sport (?) absurd, as you say ; 

 but hardly in our line. — A. Smith. Can only say the comet affords no 

 just cause for anxiety. It does not seem now likely to return for 

 years; but if it were even nbHorbe<l shortly by tho sun, it would do 

 no harm, I feel assured. — M. J. Haiidino. Maps now obtainable, 2d. 

 each.— J. B. R. The theory " bosh."— E. Skinner. Letter inserted, 

 Tho numbers you mention aro out of print. Cannot get them 

 myself.— Jas. Graham. Away from my books.— Senkx. Theory 

 of tides given in most of the books quite wrong. Try Beckett's 

 " Astronomy without Mathematics." — T. G. Elliott. Hut tho earth 

 is not elongated from pole to pole.— W. W. W. Know of no good 

 books to meet your case. I only remember two English Grammar 

 rules learned at school, and ono of those is ^vrong. Read freely 

 books by good authors.- J. A. L. R. notes that " J.'s" problem is 

 dealt with in Burchett's " Practical Plane Geometry" (W. Collins 

 & Bon : London and Glasgow). 



