48 G. Lufft, Stuttgart. 



Scientific Barometers, 



These barometers ,are made in three sizes, viz. with dials of 45 mm 

 (l a / 4 inch), 80 mm (3 inch) and 130 mm (5 inch) diameter. The latter 

 are fitted with fine leather sling cases. 



These instruments are made with the greatest care and accurately 

 compensated , so as to render their indications independent of changes 

 of temperature. 



In order, however, that they may in this respect be tested at any 

 time, each barometer is provided with a thermometer, which is fitted 

 inside the casing upon the dial; the leather case also is fitted with a 

 thermometer for determining the temperature of the external atmosphere 

 surrounding the instrument. 



The dials of these barometers are silvered and are, according to 

 the purpose which the instrument is to serve, graduated in l / 2 , Vi anc ^ 

 2 /i millimeter or Y 60 , 1 / 24 and Yi2 inch: if desired they are also pro- 

 vided with so-called ,,orometric'' divisions, i. e. divisions for directly 

 reading altitudes of 1800 m (5300 feet), 2600 m (9000 feet), 5000 m 

 (16500 feet) and 8500 m (28200 feet). 



These instruments may in the simplest manner be used for sur- 

 veying purposes, by engineers, explorers and aeronauts. 



Self -registering Barometers, 



which save meteorologists the time wasting trouble of having to read 

 the barometric indications, so that he has to insert the prepared strip 

 of paper into the instruments and to wind up the clock work once a week. 

 These instruments are compensated, extremely solid and made 

 with great precision. They accurately mark the position of the baro- 

 meter every 15 or 20 minutes within Yio millimeter. 



25 different kinds of 



