704 SEC. 14. METEOROLOGY. 



which the variation of the temperature, caused by the total expansion or 

 contraction of the tubular system, is automatically recorded from time to time. 

 The motor for the measurement of the atmospheric pressure is composed 

 of 10 aneroid cases, which are joined together in the shape of a column. 

 Their expansion or contraction, produced by the changes in the atmospheric 

 pressure, is transmitted to the writing cylinder by means of a lever. 



The arrangement for registering consists of a cylinder placed vertically, 

 Avhich is turned on its axis every 24 hours by a clock movement in the front part 

 of the box. The two levers, both extending horizontally from the thermometer 

 and the barometer, as far as the same edge of the cylinder, are at a mean tem- 

 perature and a mean atmospheric pi-essure in a position the one in the centre of 

 the lower, and the other in the centre of the upper -half of the writing 

 cylinder. Every 15 minutes, the ends of the levers, which are provided with 

 pencils, are pressed against the cylinder, and by these means the variations of 

 the atmospheric pressure and of the temperature are regularly registered. 

 The instrument is in all its parts so contrived as not to require a fixed 

 position, and being easily transportable, it can be used without difficulty on 

 board ship. 



2873a. Self-registering and Signalling Vessel Baro- 

 meter. Dr. Fricdr. C. G. Muller, Osnabriick. 



This self-registering and signalling barometer is new, both as a whole, and 

 in its details. The points of novelty are : 



J. The bulb barometer, which is entirely independent of the registering and 

 signalling mechanism, and which possesses the following properties: (a.)The 

 reading takes place at the lower level by unchanged position of the upper. 

 (6.) The galvanoscopic adjustments, accomplished by means of the platinum 

 point fused into the Torricellian vacuum, requires no sight, is very simple, 

 quickly performed, and free from errors. (c.) The construction of the 

 cistern with the barometric tube passing through it, whereby the level of 

 mercury in the cistern is kept invariable. (Y/.) No boiling of the tube i? 

 required, (e.) By the introduction of a small quantity of dry hydrogen 

 into the vacuum, the influences of temperature may easily be compensated. 



II. The uninterrupted automatic adjustment, which makes all' changes in 

 the atmospheric pressure,' even the smallest oscillations, audible. Specially 

 deserving of attention are: (a.) The two platinum points in connexion with 

 (6.) the two sliding relays, working in opposite directions, and (c.) the two 

 little electro-motor machines, which by their beats give direct indication of 

 all variations in the atmospheric pressure, and announce it indirectly by 

 setting an electric clock-work into action, (t?.) By connecting the two relays 

 with the same point, the utmost sensitiveness of the automatic adjustment 

 is reached, whilst the machines are in continuous action. 



III. The registering mechanism, which is connected with the self-regulating 

 barometer cistern, and moving in which the mercury in the barometer has no 

 work to perform. Attention is called to the following points: (a.) The 

 force moving the marking pencil is a considerable one, in consequence of the 

 multiplying gear ; the wheels have to revolve 80 times in order that the 

 cistern may move 1 mm. (6.) The registering mechanism allows, without 

 losing anything of its simplicity and reliability, a magnifying of the move- 

 ment of the barometer cistern. (The present apparatus doubles the move- 

 ment.) (c.) The instrument continues working for a month, and even 

 longer, without interruption. (rf.) The introduction of a new slip is easily 

 accomplished in about one minute, and no new correction is then required, 

 (e.) The second fixed pencil marks along the margin of the paper slip a line, 

 which by being broken every three hours marks the time. This line deter- 



