918 ' APPENDIX. 



259b. Iridio-platintun Standard Metre, in course of 

 manufacture. Johnson, Matthey, and Co. 



259c. Section ofc Metre when finished, showing the form 

 determined upon by the International Commission. 



Johnson, Matthey, and Co. 



278a. Magneto-Electric Water Level Indicator. 



Siemens and Halske, Berlin. 



A float which rises or falls with the level of the water in the reservoir or 

 tank communicates motion by a metallic chain to a magneto inductor, which 

 generating electric currents, works at any distance an indicator connected by 

 a cable or insulated wire. 



319a. Casts of a Collection of Roman Measures to hold 

 liquids. Archceological Museum, Madrid. 



The originals, of alabaster, are preserved at the Archaeological Museum of 

 Madrid. They were discovered at the end of the last century in the Torre del 

 Mar, Province of Malaga, Spain. 



322a. Series of Standard Measures of Capacity, in 



copper, with glass discs, measuring from the centilitre to the 

 double decalitre. (11 measures.) 



Messrs. Collot Brothers, Boulevard de Montrouge, Paris. 



331a. Pamphlet. " Procedimientos mecanicos de cubicacion." 

 4 to . Madrid, 1876. Don Eduardo Saavedra, Madrid. 



Sr. Saavedra explains in this pamphlet the method adopted by him in taking 

 out quantities for the projected railroads of the central Spanish Pyrenees. 



344a. New description of Balance of Precision, designed 

 by M. Mendeleef, Professor of the University of St. Petersburgh, 

 and constructed by Oertling. It is more particularly described 

 in Appendix 10 to the Ninth Annual Eeport of the Warden of the 

 Standards. H. W. Chisholm. 



The peculiarity of this balance is that it has very short arms, and thus 

 occupies very little room, and by its more rapid motion time is saved in weigh- 

 ings, whilst it gives results of weighings quite as accurate as those given by 

 balances of precision with arms of greater length as ordinarily used. 



Though constructed to carry a kilogram in each pan, the total length of 

 the beam of this balance is less than 4f inches, whilst it is intended to give 

 results within one tenth of a milligram. The balance beam to carry a kilogram 

 is ordinarily 20 inches in length. 



It can be used as a vacuum balance, as well as for weighings in air. 



344b. Balance of Precision for minute weighings of 10 

 grains and under in each pan, constructed by Oertling. 



H. W. Chisholm. 



The beam is made as light as possible, and unusually so. The pans and 

 suspending wire are of aluminium. The balance works upon fine points. 

 A single action lowers the support of the beam and the supports of the 

 pans. 



