114 *S: p. Sadtler— Occurrence of Tartronic Acid. 



1. It is easily adjusted to any vertical lantern, from which it 

 can be removed in a moment if desired. 



2. The distance between the deflecting coils being readily 

 varied, it can be adjusted to currents of various intensity. 



3 The resistance of the galvanometer is quickly varied from 

 one-half, to twice the resistance of one of the galvanometer 



■s when desire< 

 I differential galvanom- 

 eter and used in measuring resistance. 



6. It can be constructed in any work-shop at a very small 

 expense. 



St. Louis, Oct. 25, 18T5. 



Art. XI. — On a new occurrence of Tartronic Acid, with some 

 remarks on the Molecular Structure of Glyceric Acid ; by Sam- 

 uel P. Sadtler. 



(Read before the American Philosophical Society, September ]7, 1875.) 



Ln the Propyl series, nine normally formed acids are possi- 

 ble, besides several isomeric unsymmetrically formed ones. 

 They are:— 



bH. 



(5h,' 



6n, 



CO.OH 



60.OH 



6o.( 



II. 







CaHeO, 



C3HeO, 



cVh 











CH..OH 





6H.0H 



c'h.oh 



(JH.( 



i0.0H 



60.0H 



bo.. 



the acids considered as having the molec- 



.rbacetoxylic acid ; VII, malonic acid ; VIII, 

 IX, mesoxalic acid. 



