LESSONS IN ENGLISH. 



For exact determinations of onrrent strength, an instrument 

 known RH t. i Compou, or Tangont Galvanom 



usually !::;. ii u represented in Fi^. 54, and oonsista 



of a tri|i ..; cupper about an inoh wide, bent round into a 

 circle about ighteen inohog in diameter. The and* 



of thin atrip are not allowed to t , ro connected with 



the two wires soon underneath ' wooden 



framo in usually placed in the lower half of the circle, and 

 aerves to k< uipe, and, at the aamo time, to lupport 



i Minull . umpaas needle, with an accurately <l 

 scale mm - it 1'iiis noodle ihould not bo more than an inch 

 or an inch and a half lung, and tin- inntrumont should ! 

 placed in the magnetic meridian ; that it, < tiiat tint needle 

 may be in the aamo plane aa the ring. If now tin 



:vth bo connected with the battery, no that the current 

 us round the copper strip, tho noodle will bo at onoe 

 i, and the strength of tho current will be exactly pro- 

 il to tho tangent of tho anglo of deflection. CunvnN 

 of any strength may be measured with this instrnmcn 

 it has thia great advantage, that a broad passage is provided 

 i M rip, and thus little resistance is offered to the 

 passage of tho electricity. In consequence of this, it can be 

 with currents which have quantity but comparatively 

 aity. 



be remembered that tho readings of this only show 

 comparative, and not actual strength. To ascertain tho hitter, 

 ;it of known power must bo passed round tho ring, and 

 tion noted; wo shall then be able to compare other 

 i its with this, and thus learn their intensity. 

 One practical result, then, of the effect of a current on a 

 magnetic noedlo is seen in the construction of the galvano- 

 meter. Tho other is still more important, for Oersted's ex- 

 i! iu-nt contained in it the first germ of tho electric telegraph, 

 the ordinary needlo instrument consisting essentially of a 

 galvanometer so placed that the needle may be vertical. The 

 details of its construction will bo explained further on. 



We shall now proceed to notice the chemical effects of tho 

 electric current, and these we shall find to bo very numerous 

 and important. Faraday applied the term electrolysis to that 

 special branch of the science which treats of the laws of elec- 

 trical decomposition, and it has since been generally adopted. 

 Any substance which is susceptible of being decomposed by the 

 current is called an electrolyte. It is found, however, that 

 only liquids can be thus acted on ; solids, therefore, must be 

 either molted or dissolved before any effect can bo produced 

 on them. Tho poles of the battery, or the ends of the wires 

 by which tho current enters and leaves the liquid, are called 

 electrodes, from tho Greek word luxlos, which means "a way." 

 They are looked upon as the roads along which the electricity 



travels, the positive pole being called the anode, or "road up," 

 and the negative pole the catJwde, or " road down." 

 Now it is found that when substances are thus decomposed 

 there are some of their ingredients that always go to one 

 pole, and some which always go to the other. To distinguish 

 these, those which go to the positive pole (anode) are called 

 onions, and those which go to the other, cations. These com- 

 plete the list of technical terms which will bo employed here. 



For substances to be decomposed by tho agency of electricity, 

 it is essential that they be chemical combinations ; simple sub- 

 stances or mere mechanical mixtures being altogether unaffected. 

 Thus the current may bo passed through a melted alloy without 

 decomposing or altering it. If, however, a solution of any 

 chemical salt be placed between the electrodes, it will at once 

 be separated into two different substances. 



The decomposing power thus possessed by a large battery 

 is very great indeed, some substances being decomposed by it 

 that resist all other attempts to resolve them into their con- 

 stituents. It was in this way that the simple metals sodium 

 and potassium were first obtained, their oxides having been 

 reduced by Sir H. Davy, by means of a powerful battery. The 

 experiment may easily be repeated on a small scale. A piece 

 of caustic potash or soda must be moistened with water, and 

 a little mercury placed with it, so as to form an amalgam with 

 the metal. Tho poles of the battery are now dipped into it, 

 and the potassium will be liberated at the cathode. It can 

 easily be separated from the mercury, as by distilling it out of 

 contact with the air, tho potassium will be left in the retort, 

 while the mercury passes over. 



LESSONS IN K\<;U>H. \i.i 



THE VERB i TKNSE, MOOD. AND fOJf. 



TH English language ha* variations of form to express varia- 

 tion* of paraon, number, tense, and mood. These variations 

 of form exist within narrow limits. 



The term pvrton refers to the distinctions which exiat amof 

 the speaker, the person or thing spoken to, and the paraon or 

 thing spoken of. The speaker ia the first person, the paraon or 

 thing spoken to ia accounted the second paraon, and the person 

 r tiling spoken of is accounted the third per 



are, then, three persons, and these three are represented 

 by the personal pronouns /, or we, the first person ; 

 ye, the second person ; and ht, the, it, or they, the third person. 

 Number has a reference to the fact whether a. subject indicates 

 one person or thing, or more than one. If a noun denotes one 

 >t ia said to be in the " singular number ; " if a noon de 

 notoa more than one, it is said to be in the " plural (from the 

 Latiu plus, plans, more) number." 



Tente (from the Latin temput) has reference to time. An 



action may now bo going on, then it is said to be in " the pre- 



| sent tense." Or an action may be over and gone ; then the 



' verb which describes it is in "the past tense." Or again, aa 



action may be about to commence, in some time to come, then 



the corresponding tense ia called " tho future tense." 



Mood (from the Latin modus, method, or manner) ia a term 

 which refers to the manner in which an action is set forth. Thus 

 you may declare simply he teaches, when you indicate a fact 

 without any qualification; this is called " the indicative (Latin 

 indico, I point out) mood." Or yon may say to a tutor, " Teach 

 tho boy;" then you give a command; in this case the verb ia 

 said to be in " the imperative " (Latin impcro, / command) 

 or commanding " mood." Another mood is called "the infini- 

 tive (from the Latin in, not, and finis, limit) mood," that is, the 

 indefinite mood, the form of the verb which is not bounded or 

 qualified by person, number, or tense. Besides the indicative, 

 tho imperative, and the infinitive commonly set forth in English 

 grammar, the Latins had a subjunctive (or dependent) mood, 

 and tho Greeks had an optative or wishing mood. 



The term voice has reference to the fact whether or not the 

 action of the verb comes back on the subject or actor. If the 

 action of tho verb docs not come back on the subject or actor, 

 tho verb is said to bo in " the active voice." If the action of 

 the verb does come back on the subject or actor, the verb is said 

 to be in " the passive (Latin, patior, I suffer, I am the subject of 

 an action) voice." 



Verbs are modified in person, number, tense, and mood. 

 There are, then, three persons, the first, tho second, and the 

 third. There are two numbers, the singular and the plural. 

 The persons and the numbers are indicated partly by inflections, 

 and partly by the personal pronouns. 



There are two tenses tho present tense and the past tense. 

 There are three moods the infinitive mood, the imperative 

 mood, and the indicative mood. 



All other modifications of verbal meaning are expressed, not 

 by varieties of form, but by varieties of words. 



In these statements and definitions I have said nothing of 

 conjugation; the reason is that tho English verb has nothing 

 which can with propriety be termed conjugation. 



As I have not recognised tho complicated system of moods 

 and tenses, the idea and model of which were borrowed from the 

 classical tongues, so here I do not adept tho distinction of strong 

 and weak preterites or past tenses lately introduced into English 

 grammar from the Teutonic tongues. The native simplicity of 

 the English grammar should be studiously preserved. 



Tho word conjugation is also employed in another cense, viz., 

 to denote the general form of the verb when presented in full. 

 In this sense conjugation is nearly the same as formation or/orm, 

 and for it the term model or example, or to take a term of 

 similar import from the Greek (viz., paradigm) may be employed. 



PARADIOSI OF THE TRANSITIVE VERB "TOUCH." 

 Principal Part*. Tonch, touching, touched. 



INDICATIVE MOOD. 



PBE8HTT TBWSE. 



Sing. Pliir. 



1. I tonch. "We tonch. 



2. Thou tonchest. You tonch. 

 He touches. The/ touch. 



PAST TKHIB. 



1. I touched. "We touched. 



2. Thontonohdrt. Yon touched. 



3. H<* touched. The/ touched. 



