1S53] 



THE ELECTRIC LIGHT. 



33 



thre;>, four or more, solid cylinders, or rols of charcoal, or other 

 material, place! side by side, close together, but without actual 

 contact, and having as man}' points as there are rods brought in 

 juxta- position (for the light emanating points) to the opposite or 

 positive electrode. And the opposite or positive electrode in such 

 an arrangement may consist of several cylinders or rods, placed 

 and acting side by side, or of only one cylinder or rod, with its 

 extremity brought into close juxta-positiqn with the ends or 

 points of the opposite compound electrode. The group, or bundle 

 of separate cylinders, forming a compound electrode, may have 

 one common connection with the battery ; or each rod or cylinder 

 may itself bo made to constitute an independent conductor of the 

 current 



In all arrangements of light-giving electrodes, wherein the ma- 

 terial forming the electrode is destructible, as charcoal is, one of 

 the electrodes under the action of the electric current, is more ra- 

 pidly worn away than the other ; and the one least acted on is 

 called the " non-consuming," and the other the " wasting" elec- 

 trode. In practically using these proposed compound electrodes, 

 I would sufro'est, out of the numerous modifications of them that 

 can obviously be adopted, the employment of a single rod of 

 charcoal or other material for the "non-consuming" electrode, and 

 the placing of this undermost: whilst the " wasting" electrode 

 is composed of a combination of three separate rods, connected by 

 one common conductor with the battery. But both the electrode 

 may be " compound," and the individual parts of each be collec- 

 tively connected with the battery; or each of its parts or rods 

 may have an independent connection with the battery. And 

 the " nou-consuming" electrode may be a " compound" one, 

 whilst, the " wasting," electrode is made to consist of only a 

 single rod. 



But howsoever varied in its details, the character of the pro- 

 posed plan is the same — -resorting for re-adjustment from time to 

 time of the distance one from the other of the acting electrodes, 

 to any of the ingenious plans already in existence for the accom- 

 plishment of this object when applied to the single-rod electrodes 

 and which contrivances are equally applicable to these compound 

 electrodes — in place of one point of emanation only, as heretofore, 

 formed by the approximation of the ends of single rods, to have 

 several points of emanation for each light obtained by the employ- 

 ment of compound electrodes, from each of whose points the light 

 is evolved. 



In an arrangement, for example, in which three of charcoal 

 form a compound wasting electrode, should one of three points 

 referred to come to be removed from the opposite electrode beyond 

 the maximum light distance, through waste or transfer, or other- 

 wise, then a quantity of the current of electricity that would 

 otherwise pass through this one point is transferred to and passes 

 through the other two points that are still within full acting dis- 

 tance from the opposite electrode ; and this transference of the 

 current or concentration in two, instead of in three of the rods, 

 serves immediately to increase the action of, and consequently 

 the quantity of, light given out by these two more active points. 

 In the same way it results if two instead of one of the points be 

 thrown out of action fully or comparatively, and only one of the 

 three remains close enough to the opposite electrode, and conse- 

 quently in full activity — -a more active current passes through 

 this one remaining active point, and the light it gives out is in- 

 creased in proportion, or in a proportion that neutralises the de- 

 fects in the non or less active points. 



After the same manner it occurs when in place of a compound 

 electrode of three points, one cousistina; of four, five, or of any 

 other greater number is used — the wasting of the material of the 



C 



electrode, or the shifting in distance from the opposite electrode 

 of all the points in such compound electrodes, can seldom, if ever, 

 take place exactly to the same extent, and exactly at the same 

 moment of time ; consequently, a failure in any one point to give 

 out light, or its full amountof light, is comparatively unimportant; 

 and the points that are the least wasted or shifted do, by their 

 consequent increased action, compensate for or reduce the effects 

 of such deficiency to an extent that no contrivance when applied 

 to the old or single rod electrodes has yet been able to secure. 



Second!}', there is a certain point in the space between tho 

 electrodes, or a certain distance of the one electrode from the 

 other, in all arrangements intended to produce light by the 

 electric current, at which the maximum quantity of light is 

 obtained, but which point is not that of actual contact, nor 

 perhaps that the most immediately preceding actual contact in the 

 act of approaching to it. But this maximum light point— or the 

 exact distance corresponding with it, is that which photo- 

 mechanists have hitherto attempted to secure and maintain by a 

 fixture of the electrodes at it, or by contrivances for replacing the 

 points of the electrodes in it when shifted through changes in the 

 structure of the charcoal, by disintegration or transfer, or through 

 alterations in the power of the electric current. But as a solution 

 of the mechanical difficulties that unquestionably exist (whether 

 applied to the single-rod or to the above newly-proposed com- 

 pound electrodes), in the way of keeping the carbon points or 

 electrodes always at the right striking distance, I would suggest 

 that we should not fix, or attempt to fix, the distance of the 

 electrodes at this point, or to replace them in any fixed position 

 when accidentally shifted from it through structural changes in 

 the carbon, or through variations in the acting condition of the 

 battery, requiring corresponding changes in the relative position 

 of the electrodes, but, on the contrary, that we should bring into 

 action a converse method — that is, I would cause the electrodes, 

 one or both, or all of them, if there should be more than two in 

 the arrangement, successively to approach to, but without actual 

 contact, and to recede from each other by such a movement 

 imparted to one or both, or all of the electrodes, that their 

 relative distance, or the space between them, shall, within certain 

 limits, be continually chauging; and this so rapidly that the eye 

 shall be unable to detect the different intensities of the light 

 evolved under the different distances of the electrodes, or when 

 they are the nearest to, and when the farthest apart from each 

 other. 



In other words, I would cause the electrodes to be continually 

 changing their relative position, and in doing so to travel through 

 a certain space within the limits of which is embraced the 

 maximum-light point. In this way is obtained a light, the effect 

 or intensity of which is the mean of all the quantities evolved 

 within the space through which the electrodes travel ; and which 

 light is apparently steady and invariable, by reason of the 

 rapidity of the movement, and the consequent incapacity of the 

 eye to detect the differences that really occur. 



We can obtain these changes in position of the electrodes, or 

 in their relative distance, and the consequent results, by impart- 

 ing, by any convenient mechanical contrivance, a vibratory, an 

 oscillating, or a rotary movement to one of the electrodes, whilst 

 the other remains stationary, or by giving such motion to both 

 electrodes, or to any set or number of electrodes. And we can 

 either employ a single arrangement of electrodes (that is, a single 

 positive, and a single negative electrode, constituting together a 

 set), as the source of the light, or combine together for one light 

 the effects of two or more such sets. 



The particular motion for working the electrodes may be 



