178 



THE POPULAR EDUCATOR. 



any inequality of manufacture or momentary interruption of 

 the current becomes extinguished, all the lights on the same 

 circuit will go out, until once more the carbons are bridged 

 over with a connecting link. Mr. Wilde, of Manchester, has 

 remedied this in his form of candle. He dispenses altogether 

 with the plaster partition, the carbons being merely separated 

 by a film of air. Normally, they fall towards one another, 

 so that their points touch, but the same current which causes 

 them to glow passes through an electro-magnet, which draws 

 them apart. Should they fail for an instant, they once more 

 fall together, and the light is renewed. 



In the incandescent system of electric lighting we have 

 quite a different thing to deal with. Supposing that we have at 

 hand a few cells of Grove or Bunsen, and fasten wires to their 

 terminals in the usual way. If we bridge over the ends of 

 these electrodes with a few inches of fine iron wire, the resist- 

 ance which that wire exerts towards the current is shown by 

 its getting white hot and melting into globules. A fine platinum 

 wire will hold out longer, and will continue to give a brilliant 

 light for some time. If such a wire be arranged in a glass 

 globe exhausted of air, its lasting power will be much increased, 

 but the danger remains of its fusing if the current be stronger 

 than it can bear. 



Edison, Swan, Maxim, whose lamps are shown at Fig. 85, 

 and many others, have remedied this by employing very fine 



Edison. 



Maxim. 

 Fig. 8-3. 



Swan. 



filaments of carbon. The first named uses bamboo fibre for 

 the purpose, but Swan employs carbonised thread. In the 

 form of a horse- shoe loop this carbon filament is placed in a 

 glass bulb, which is then carefully exhausted of air, and a 

 lamp so prepared will last for many months. Supposing 

 that we passed the current through such a conductor 

 without exhausting the globe, the carbon would unite with 

 the oxygen of the air, and ordinary combustion would ensue. 

 Several years ago this method of electric illumination was 

 tried, but it failed, not because of anything intrinsically wrong 

 in the method of procedure, but because at that time no 

 thoroughly efficient air-pump existed. The Sprengel and 

 other forms of modern air-pumps have enabled Edison and 

 others to succeed where the pioneers of the system failed. 

 There are in the patent office numerous old specifications 

 giving details of lamps which do not differ materially from 

 the modern incandescent arrangements, except that the carbon 

 or platinum employed is very much more substantial than a 

 mere thread, such as is used now. 



Although, as must be apparent, the incandescent method of 

 electric lighting is more especially suitable for domestic pur- 

 poses, it has also been employed for the illumination of large 

 buildings. At the Fisheries Exhibition immense halls have been 

 lighted by this means, many hundred lamps being employed for 

 each. In New York, where Mr. Edison has adopted this system, 

 a whole colony of houses are fed with the electric current from 

 a central source. Again, in London we have the same system 

 shown in certain thoroughfares, not only in the adjacent shops, 

 but also in the street lamps. In one of the London theatres, 

 too, the plan has been tried of lighting both auditorium and 

 stage with these electric globes, and with marked success. 



In order to show the adaptability of the light for domestic 

 use, we will give an account of the means employed at Mr. 

 Swan's house at Bromley, which is wholly illuminated from 

 cellars to attics by incandescent lamps. From a recently 

 published description we condense the following remarks : 

 The lamps in each room are controlled by little switches 

 placed outside the door, so that a person entering or leaving 

 has merely to touch the switch in order to lighten or darken 

 the apartment, as may be required. A light at a reading-desk, 

 a toilet table, or even above the pillow of a bed can instantly 

 be had by the touch of a button. The lamps are placed in 

 ornamental chandeliers and brackets, except in the lower part 

 of the house, where they are naked. On the dining table 

 stand lamps which are connected when required by wires 

 passing through the table-cloth into the table. By a simple 

 form of electro-motor, the current can be directed to a sewing- 

 machine, a coffee mill, or anything requiring motion. Alto- 

 gether there are about 70 lights employed in and about the 

 house. They are fed by two small Siemens' dynamo machines, 

 each driven by an Otto gas engine of half-horse power nominal, 

 but capable of developing two-horse power. These engines 

 consume 75 cubic feet of gas per hour, which amount, if ex- 

 pended in gas lighting, would feed 30 gas jets, each of 15 

 candle power. The incandescent lamps give more light than 

 this, besides which the light given is of far purer quality 

 there are no unhealthy fumes given off, and no consequent 

 injury to goods and chattels. 



LESSONS IN ENGLISH. LIII. 



SYNTAX: DEPENDENCE. 



Dependence or Government. There is another relation which 

 it is necessary to understand. I mean the relation of indepen- 

 dence. When I say, The man drinks WATEE, I state a proposi- 

 tion in which a noun, or object, appears in a state of dependence ; 

 the noun water is dependent on the verb drinks. 



This dependence is a logical dependence, a dependence in 

 thought and not in form. This you may see if, changing the 

 form of the sentence, you make water the subject of the propo- 

 sition ; thus, THE WATER is drunk. 



Water, then, remains the same, whether it is a subject or an 

 object. Consequently the agreement is not in form, as there is 

 no change of form to meet a change in sense. 



In sense, however, water in the former sentence is dependent 

 on drinks. It is, in fact, that on which the action of the verb 

 falls. 



Hence it is the thought you must consult to know whether a 

 noun is or is not an object. This remark is necessary, because, 

 for want of inflections, ambiguity may arise, as in cases when the 

 subject may become the object, and the object the subject ; for 

 instance, 



Subject. 

 The man strikes 



Object. 

 the boy. 



Subject. 

 The boy strikes 



Object, 

 the man. 



These two statements are the reverse of each other, and ob- 

 serve that the reversal is made by a mere change of position ; 

 man, which in the first sentence is the subject, becomes in the 

 second sentence the object, by being put after the verb. You 

 thus learn how important a part position plays in English 

 grammar. 



In the instances here considered, the dependence is that of a 

 noun on a verb. There is another kind of dependence ; that of 

 a noun on a preposition, as seen in the following sentence, The 

 water is drunk BY THE MAN. Here tlie man is in sense depen- 

 dent on the preposition by. 



Not only nouns but verbs also are dependent on prepositions ; 

 thus, The physician ORDERS the man TO drink water; where in 

 sense, or logically, drink depends on to. 



The sentence presents a third case of dependence, for you see 

 that the verb drink is in sense dependent on the verb orders. 



Position here, too, is of consequence, for the dependent verb 

 drink comes after orders, and after to ; in no way could drink 

 precede to, and scarcely could orders follow drink. Instances of 

 dependence may also be considered as instances of government. 



One word is said to be governed ly another when the former 

 is dependent on the latter; as, Tlie man DRINKS the water, 

 where ivater is governed by drinks, because water is dependent 

 on drinks. 



