I 



128 ANNUAL OF SCIENTIFIC DISCOVERY. 



overlook most effectively the manoeuvres of the steersman and pilot. 

 This self-register consists of three principal parts: 1st, a clock 

 movement placed at the center of the apparatus for causing the point 

 or pivot carrying the needles to move up and down at regular inter- 

 vals ; 2d, an endless screw furnished with a nut carrying the point for 

 piercing the paper ; 3d, the compass-card, made of three needles fixed 

 to a sheet of mica, a material as little hygrometric as possible. The 

 mica is covered with a desk of velvet firmly glued to it by means of 

 strong glue, and whose tissue has been saturated with a kind of glue 



<T> ^j * ^j 



that is soft when cold. On cooling, the glue has an even surface 

 pierced with an infinity of pores, into which the point will readily 

 penetrate after having pierced the paper compass-card. Owing to 

 this addition, the process of puncturing does not stop the movement 

 of the needle, a principle essential to the success of any method of 

 self-registering. When the needle is fixed towards the north, the axis 

 or diametral line of the compass-card is placed in the line of the axis 

 of the ship, and the punctures made every three minutes, will indi- 

 cate the deviation of this axis with reference to the magnetic needle. 

 The succession of points, or the nearly continuous line which they 

 trace, shows to the eye the course of the route. 



IMPROVEMENTS IN GALVANIC BATTERIES. 



Some new and improved galvanic batteries have been described by 

 M. Kukla, of Vienna. The combination used in one of these, is anti- 

 mony or some of its alloys, for a negative plate, with nitric acid of 

 specific gravity 1.4, in contact with it, and unamalgamated zinc, for a 

 positive plate, with a saturated solution of common salt in contact 

 with it. A small quantity of finely powdered per-oxide of manganese 

 is put into the nitric acid, which is said to increase the constancy of 

 the battery. The alloys of antimony which Mr. Kukla has experimented 

 with successfully are the following : Phosphorus and antimony, chro- 

 mium and antimony, arsenic and antimony, boron and antimony. These 

 are in the order of their negative character, phosphorus and antimony 

 being the most negative. Antimony itself is less negative than any of 

 these alloys. The alloys are made in the proportions of the atomic 

 weights of the substances. All these arrangements are said by Mr. 

 Kukla to be more powerful than when platinum or carbon is substituted 

 for antimony or its alloys. In this battery a gutta percha bell-cover is 

 used over the antimony, and resting on a Hat ring floating on the top of 

 the zinc solution, this effectually prevents any smell, and keeps the 

 per-oxide of nitrogen in contact with the nitric acid solution. When 

 a battery of twenty-four cells was used, Mr. Kukla found that in the 

 third and twenty-first cells pure ammonia in solution was the ultimate 

 result of the action of the battery ; but only water in all the others. 

 This experiment was tried repeatedly, and always with the same 

 result. A battery was put into action for twenty-four hours, at the 

 end of that time the nitric acid had lost thirteen-twentieths of an 

 ounce of oxygen, and one-quarter of an ounce of zinc was consumed. 



