i.ECTEICITT. 



271 



East Indies ; !U)c|iwMen, (the) Wont Indies; and before the names 

 r.liiml points; as, Clint, (the) east; aOefteit, (the) went; 



rtotltli ; illi'ili-n, (tli'-\ imrlh. 



(3.) .\'../.-, again, tliut th. < . using certain collective 



.ceded by adjectives, employ the indefinite article where 



the English would UHO tlio dofinito, as cm bwfm'rii'cr !Kuib,, the (lit. 



Burned Senate; cine liMict;e lliiwtfuit, tho (a) honourable 



University. 



(4.) In Qerman, also, the indefinite article stands be/ore (not 

 after, as in English) the words such, half: thus, cin folder 9)Jann 

 (not folder cut i'lonn), such a man ; cin tyalbe* 3af>r (not b.albe cin 

 r), half a year. In questions, direct or indirect, like tho fol- 

 lowing : tfitien tine Kingen ra$icrritt fat cr gemactyt how long a ride 

 has he taken ? it must be noticed that tho article stands before 

 IMC: thus, cineit nric langen (a how long), and not, as in English, 

 how long a. 



(5.) The German differs again from the English in not using 

 an article at all in tho phrases answering to tho English : a few; 

 a, thousand ; a hundred. 



KEY TO EXERCISES IN LESSONS IN GERMAN. 



EXERCISE 184 (Vol. IV., page 13). 



]. In human life there are sometimes cloudy moments. 2. Now 

 and theu one must (five the miud relaxation. 3. He has frequently 

 been here. 4. I have frequently said this. 5. Sometimes, too, it goes 

 wrong. 6. There is not time now to take a walk. 7. He has still 

 sufficient time to finish this work to-day. 8. He will have more time 

 another day to visit you. 9. This house is worth a thousand dollars. 

 My coat is worth ten dollars. 11. That man is worth five hundred 

 dollars. 12. He is worth ten thousand dollars. 13. This family h:is 

 a good competency. 14. That poor day-labourer has ouly a scanty 

 subsistence. 15. There came so many political fugitives that all of them 

 could not find shelter. 1C. All the soldiers found shelter in tho barns 

 am] stables of tho peasants. 17. Yesterday I paid the merchant his 

 bill. 18. He has not yet paid the tailor for the coat. 19. He forgot 

 to pay the shoemaker for the boots. 20. The sick person asks for a 

 glass of water. 21. I long to know the truth of this matter. 22. I 

 wish to spend a cheerful hour in the circle of my dear family. 23. I 

 wish for the book that lies there. 24. One thiug I beg of you, be 

 careful in the choice of your friends. 25. The man asked for patience 

 and forbearance. 26. As he begged his pardon, he could not be angry 

 any longer. 27. I ask you for a glass of wine. 



EXERCISE 185 (Vol. IV., page 13), 



1. SWcin au tft taufcnt Sranfcn uxrtf;, abcr taS mcincS SBruterS fiinf. 

 jeljnljunmt. 2. 3encS Sanquiert iBcrmogen ifl taufent ?Pfunb gtcper al 

 jone Smnmc. 3. 3ufrtetenf)ctt ifl on gropcrcm SBertlie a(3 aflcr JRcicb 

 tfutm tcr Grte 4. SBtr fonntcn bet unfcrcr 2lnfunft in s .'lmcrifa nirgcntS 

 cin llntcrfommcn ftntcn, tcnn a(tc (VajMiflufct hwrcu sett. 5. 3cter, tec 

 lucb. ?luftraltcn gcfir, faun cin Untcrfcmmcn ftnten. 6. SMcjcnijctt, niefcfye 

 cin nctf'titrftigeg SluSfommcn fiatcn, finb jurocUcn tic SBtrfjeuge tcr gruHtcn 

 v -l>erbrcd;cn. 7. Qftein SSrutcr bittct mid;, gctultig unt nat$fk$ttg jii fcin. 

 8. (It fucbt meine S3ergcbumj, unb tejjb,alb fann tcf> tftm nid;t (Anger 

 jiirncn. 9. ie Jlotfyroentujfcit crfottcrt, tap ivir unferm Jtorper jumciten 

 Grftolung gi'tincn. 10. a er fcincn SRocf ju b^afylcn ccrgajj, fo crfurt;te 

 i|)n tcr djneitcr, tenfclbcn ju bcjafylcn. 



EXERCISE 186 (VoL IV., page 13). 



1. At the outbreak of the revolution in Berlin there was fighting 

 till late at night. 2. He gave him the book, with the request to keep 

 it clean. 3. A letter was sent to him yesterday. 4. I showed him 

 the new paintings which I had bought at the auction. 5. Music is 

 bis most favourite pastime. 6. He sings, jokes, and laughs for 

 pastime, instead of occupying himself with serious matters. 7. I 

 often take a walk in the morning, at noon, and in the evening. 8. 

 They pursued the enemy as far as the frontiers of the country. 9. She 

 had perused the book up to this passage. 10. They ventured out as 

 far as this place, but not farther. 11. He tried in vain to solve the 

 question. 12. They took pains to gain the good-will of their master. 

 13. He strives to get wealth. 14. I have been here (in this town) 

 about five years. 15. I have been here this half-hour (in this room). 

 16. Has anybody been here during my absence ? 17. Mr. N. has been 

 here and wished to speak to you. 18. A Berlin paper gives us the 

 following interesting communication. 19. The Nuremberg ginger- 

 broad is celebrated through all Germany. 20. The Heidelberg cask is 

 known on account of its size. 21. Good-bye, sir. 22. Remember mo 

 to your family. 23. He took leave of tho company. 24. As the old 

 huntsman could not otherwise give vent to his fury, he beat his dogs. 



EXERCISE 187 (Vol. IV., page 13). 



1. SWetn Sreuab fcbicfte mir ciit '-Bud; mit tcr iBttte, eS turdijufefen. 

 2. 3d; b.abe 3b.t JBud; bid jum jacitcn tfatitel curcbgelefen. 3. Gin 



{Pacfet wunc mir flcfttrn }ugefeb.uft 4. etulierm ift mcin fwbftft 3dt 



verticil' :>. Itt 'Du'c.j<n jtuttcrc id;, unt rel ftta4 umemdjie u$ 

 mine ^dpultr. (>. \\n\t\tt grcunte mcgcn brau^cn trtt unl nu$t yt 

 I'ciniii-fii , ct betatf unfcrtt ^ulfe nid;t. 7. SBd^rritt t<r bnfcn^l 

 unfcica tcb,rer< fptcltcn wir, anf)att )u lernrn 8. Sit lanyt fin 9k i 

 tcnron gemcfcn '*. 9. 3d; bin bcina^c trci 3jbre hicr. 10. fBar rnrin 

 Waiter iuAfa,rcnt mcincr Vlbn>cfcnb,cit ^in? 11. Wan, ft at RU^t \j\rt. 

 12. Tarf id; te bemub,en, mir ticfcn Brief ju frbmbtn? 13. tn 

 fleipigcr Jlnabc bcmul;t fid;, Jtcntniffe ju cflangcn. 



VOLTAIC ELECTRICITY. XVII. 



THE TELEPHONE PAGE'S GALVANIC MUSIC BEISS'g TOW* 



TELEPHONE THE THREAD TELEPHONE GRAHAM BELL'S 



MAGNETIC RECEIVER. 



WK have seen in a previona lesson that the electric telegraph, 

 in its various forms, makes certain signs which can afterwards 

 be readily translated into letters and words. Some systems, 

 indeed, print the words automatically. In the telephone we have 

 quite another instrument to consider for it actually reproduces 

 speech although tho talker and listener may be separated by 

 Home hundreds of miles. Before we can readily understand 

 how this marvellous result is achieved, we must call to mind 

 tho manner in which sound generally is produced and conveyed 

 to our sense of hearing. 



Sound has been defined as vibration appreciable by the ear. 

 More broadly, we might say that all sound is caused by vibra- 

 tion. Let us take the case of a glass tumbler strnck with, 

 the finger-nail. It will give a bell-like note which gradually 

 dies away. To prove that this sound is caused by the vibration 

 of the elastic glass, we may suspend a pith ball or a hollow 

 bead by a piece of silk, and hold it against the sounding glass ; 

 wo shall then find that the vibrations are made evident to our 

 si'^ht ; for the little ball or bead will dance away from the side 

 of the vessel, and will refuse to come to rest until the sound 

 ceases. If we pluck a violin-string and then let it go, its 

 vibrations as it sounds are plainly evident. A sounding tam- 

 bourine or drum will likewise show its vibration if we scatter 

 sand on the parchment surface. Tho buzz of the fly and the 

 hum of the bee are familiar instances of sound produced by the 

 rapid vibration of membranous wings. 



There is another important point belonging to the acous- 

 tical part of the subject, which we must consider before pro- 

 :eeding to the electrical phenomena, and that is the physical 

 lifference between mere noise and music. Many readers will 

 be inclined to think that the distinction is obvious, but they 

 will perhaps find some difficulty in stating why vibration in one 

 case should produce mere noise and in another case should 

 result in music. A large bird by flapping its winga will simply 

 make a noise, a bee by exactly the same movement gives us a 

 musical note. Why is this P Simply because the bird's wings 

 lo not move with sufficient rapidity to produce vibrations 

 which we can recognise as a musical note. Vibrations which 

 follow one another with less rapidity than sixteen a second 

 reach our ears as distinct beats, but if they are more frequent 

 than this, and if they follow one another periodically, we 

 recognise them as a musical note. The pitch of the note 

 lependa entirely upon the number of vibrations per second. 

 Thus the lowest note upon a musical instrument may have 

 perhaps 32 vibrations per second, and the highest 4,000 or more. 



Remembering those facts, we shall be able to understand how 

 Professor Page, many years ago, produced what he called 

 ,' ilvanio music. He found that when an electro-magnet was 

 >i i-Tuelised, or demagnetised, it gave forth a kind of metallic 

 lick. (This is most likely due to the particles of metal being 

 udividually magnetised, and setting themselves parallel to the 

 i3ar of iron. Indeed, Joule proved that such a bar when 

 magnetised increased in length to a certain degree.) Now it 

 was only necessary to make these clicks follow one another 

 quickly, and to make them strictly periodic, to combine them 

 into a musical note. The greater or lesser number of clicks per 

 sooond, the higher or the lower the note produced. Thus by 

 varying the number of electrical contacts with the battery 

 employed to magnetise his iron bar, Professor Page was able to 

 produce any note he wished. 



Acting upon these experiments, Reisa, in Germany, made, 

 in the year 1852, the first instrument called a telephone ; which, 



