138 THE NATIONAL SCIENTIFIC INSTITUTIONS AT BERLIN. 



for the business affairs of the commission, and of attached members 

 to be called in for conference ; their number is to correspond to the 

 demand. They are recommended for appointment of five years by the 

 director and confirmed by the chancellor of the Empire. Their office is 

 an honorary one, but members, non-residents of Berlin, are refunded 

 expenses incurred on occasion of ofiicialbusiness conferences at Berlin. 

 All projects relating to the entire system of measures are to be consid- 

 ered in full session. 



The business instructions provide that the director be assisted by two 

 experienced technicians, well versed with gaugiug; further, some per- 

 son or persons skilled in making mathematical computations or physical 

 examinations, a secretary, a messenger, and the required number ot 

 clerks and copyists. 



The scientific publications of the commission relate to measurements, 

 weighings, barometric, thermometric, and areometric examinations, 

 to which are added experiments on alloys, inflammability of petro- 

 leum, etc. 



The commission employs the following apparatus : universal com- 

 parator, by A. Repsold Sons, at Hamburg ; longitudinal comparator, by 

 A. Repsold Sons, at Hamburg; universal cathetometer (vertical, trans- 

 versal, and longitudinal comparator), by C. Bamberg, at Berlin; kilo- 

 gram scale, within hermetical glass bell, by P. Stiickrath, at Berlin; 

 scale of 100 grams by P. Stiickrath ; scales of 500 milligrams, by P. 

 Stiickrath ; standard barometer and manometer, with vertical compar- 

 ator ; thermometers, and apparatus for the testing of air thermometers, 

 by Fuess. 



In addition to the above the commission possesses a number of ap- 

 paratus and instruments, consisting of comparators, scales, barometers, 

 barographs, thermometers, alcoholom«!ters, areometers, hollow meas- 

 ures, gas-meters, cubic apparatus, petroleum tester, crucibles and fur- 

 nace for alloy, measuring-scales of platinum, brass, crystal, iron, and 

 aluminium. 



The more delicate apparatus are mounted in rooms having double 

 walls of zinc, the intervening space of which is tested by gas for the 

 preservation of a constant temperature. They are lighted by Siemens's 

 regenerative shallow burners, the radiation of which is prevented by 

 cloaks of water, while the light is carried through a hollow lens filled 

 with a solution of alum and is reflected by mirrors upon the scales to be 

 read. The instruments have been isolated by placing them upon pillars 

 extending in wells to a depth of 8 meters. 



The Hydrograpkic Office of the Imperial Admiralty. — On December 18, 

 1853, Professor Berghaus suggested to Prince Adalbert, of Prussia, the 

 establishment of a hydrographic office. The plan was accepted, but 

 its execution delayed on account of insufiicient funds. The desirability 

 and necessity of such an establishment becoming more urgent, a Direc- 



