t9U 



UNDULATORY FORCES. ELECTIUr 1 TV. 



[SMEK'S BATTKIIY. 



power of liocoming passive that is, of re- 

 action of nitrii- a. i 1 It iii.iv, therefore, sometime* be 

 used in pUoe of platina ; and we believe it WM first 

 propoiod for Uii purpose by I>r. ('allan, of I>ul>lin. 

 There are, however, several inconveniences attending its 

 employment with nitric acid. So long aa the acid re- 

 maun strong, no action takes place on the metal ; but, 

 u.illy, as water is produced in the iron coll, and 

 tli.- .-iil is weakened, it often attacks the iron, ami the 

 .^ quantity of fumes given off render it im- 

 possible ic come near the battery. 



. litications proposed, no arrangement 

 equals Grove's platina battery, in any respect, where 

 great power is required in a small space. 



\Ve untie.-.! S..MIO very singular results, on employing 

 a plate of copper instead of nlatina, in the nitric acid 

 .e's battery. The heating effects were 

 unite equal to those of the platiua arrangement ; but, 

 as might have been expected, a most violent action took 

 place on the copper surface ; still it maintained a nega- 

 stato, in respect to the zinc, when tested with a gal- 

 vanometer, and afforded a strong current for a con- 

 siderable period. When the nitric acid was saturated 

 with the metal, of course a kind of Daniell's battery was 

 produced. The point which we chiefly noticed, was the 

 fact, that the metal most powerfully acted on still retained 

 its negative character, and the action was neither modi- 

 fied or suspended when the zinc and copper were joined 

 by means of a wire. 



In using a Grove's" battery, it is of great importance 

 that the platina surface should be perfectly clean. We 

 have already noticed, that the film of air which always 

 coats polished surfaces, frequently prevents the contact 

 between the acid and the metal Many persons use a 

 charge in the porous parts of equal measures of sulphuric 

 and nitric acid. This, although increasing the jxjwer 

 temporarily, does not permit of so great constancy in tin: 

 ii of tin- 1 tattery, owing to the diminished quality of 

 nitric acid. The mixture must be cooled before charging 

 the cell*. Mixtures of nitrate of soda and common 

 nitre (nitrate of potash), with sulphuric acid, have been 

 recommended in place of nitric acid ; but they have the 

 fatal olijei-tion of forming crystallised salts, which speedily 

 disintegrate the porous cells. 



The next form of battery to which we shall direct 

 attention, is that invented by Mr. Smee ; which lias 

 long been used for a great variety of purposes. It 

 has no greater intensity than the old form of battery ; 

 but it affords great quantity, requires but one fluid, 

 and is the most manageable of any kind. It consists 

 of two plates of zinc, connected together by means 

 of a binding-screw ; between which is placed a plate 

 of silver, previously coated with platina in the form 

 of a fine black powder, by immersing it in a chloride 

 solution of that metal. The extremely fine points 

 thus formed on the silver surface, throw off rapidly 

 fit- 45. the hydrogen, which 



otherwise would adhere 

 to the negative metal. 

 The battery is charged 

 with sulphuric acid and 

 water, in variable pro- 

 portions, according to the 

 power required. This 

 form of battery is perhaps 

 the most suitable for 

 electrotype experiments, 

 especially for beginners; 

 because, if the zincs are 

 well amalgamated, the 

 battery requires no further 

 attention beyond an occa- 

 sional renewal of the acid and water. A single cell U 

 represented in the above i 



A number of Sinee's bftttoffai imy be connected 



together, and they so form an efficient arrangement 



for various experiments. The mode of doing this is 



illiistraU-d in the following cut ; in which a 6 represent 



ii'i wires of the battery; and f c copper bands, 



connecting the zinc of one cell with the silver plate of 



the succeeding one. Aa a rig. 46. 



guide to any of our readers 



who may desire to know 



the relative power of this 



and other arrangements, 



we may observe, that , 



twenty cells of Smee's 



battery, each plate being , 



four inches square, give 



the same heating, chemical, and luminous effects as a 



Grove's battery of four cells, with each platina four 



inches long and two inches wide. In each instance 0111 



measurement refers to the actually immersed surfaces in 



the exciting fluid. 



The following results of experiments we have made 

 with various batteries, may prove generally interesting. 



1st. Discarding all the old forms of battery, we fitted 

 up, amongst many other arrangements, forty-eight cells 

 of Grove's flat-cell battery, each cell containing sixteen 

 square inches of active platina surface. This battery 

 gave an arch of light between charcoal points of the 

 length of nearly two inches, and nearly three-eighths of an 

 inch thick. 



2nd. Seventy- two cells of Daniell's battery in flat cells. 

 Each copper exposed a surface of two square feet, and 

 was distant from the zinc about an inch on each side 

 From this we obtained a splendid light of about an inch 

 and a quarter long, and three-quarters of an inch thick. 



3rd. Twenty colls of Grove's battery, with jilatinas in 

 a central porous pot, surrounded by zinc. The platinas 

 were fourteen inches long, and two inches wide. This 

 battery gave a light of about three-eighths of an inch 

 wide, and half an inch long ; and made a piece of platina 

 foil, of the same thickness as that used in the cells one 

 inch wide, and sixteen inches long red-hot through its 

 entire extent. 



4th. Fifty cells of Bnnsen's carbon battery. The 

 carbons were one inch and a-half wide, and six inches 

 long. This gave a flame half an inch long, and an eighth 

 of an inch wide. 



6th. Fifty cells of Grove's round pots, of the same 

 size as the last, and arranged in a similar manner, but 

 with platina instead of carbon, afforded, for nearly six 

 hours, a light of one inch in length, and rather tlu'cker 

 than the last. 



6th. One hundred cells of Grove's battery, of the same 

 as that we have recommended* aa to size, with tobacco- 

 pipe bowls, &c., gave a light an inch and a-half lone, 

 and about as thick as an ordinary bell-wire. The shock 

 from the battery was very severe. 



Mr. Gasaiot, of Clapham, obtained an arch of light 

 three inches long, by using a battery of 100 cells, of the 

 same size as those mentioned in No. 1, above. 



In all these experiments, the effect on the eyes and 

 face was very severe. The battery No. 2 produced a 

 shadow at nine o'clock in the morning, when a piece of 

 stick was held in the direct rays of the sun, shining 

 clearly ; and the experiment was tried about the early 

 part of May, 1849. 



There have been a vast variety of modifications pro- 

 posed of the different forms of battery we have described ; 

 one of the latest being the use of cast-iron, in place of 

 the copper of the old form of battery. Wo had twenty 

 of these fitted up ; the cast-iron being in the form of a 

 flat cell, six inches high, four inches broad, and half an 

 inch wide. Into each, a slip of amalgamated zinc was 

 placed, which was covered with brown paper to prevent 

 contact with the iron ; and the iron of one cell was con- 

 nected, by copper strips, with the zinc of the next in the 

 usual manner. The charge we used was very strong ; 

 namely, one part of sulphuric acid to two of water. The 

 quantity of electricity produced was sufficient to render 

 a piece of No. 16 gauge copper wire, six inches long, 

 quite red-hot ; but the intolerable stench of sulphuretted 

 hydrogen given off from the battery, compelled each 

 present at the experiment to beat a hasty retreat. The 

 intensity, or chemical effects, wore exceedingly feeble. 



Sec anlr, f. 183. 



