( 32 ) 



It is very large in proportion to the thickness of the wood in Sambucus, 

 Sassafras, Rhus. Only Smikix has no pith : it belongs to the endogenous 

 plants. 



To treat of the wood here, would lead us too far, for the matter is too 

 ample to be condensed into a small space. 



The plates will aid somewhat in the identification of specimens. 



SODIC PINATE AS A TEST FOR LIME. 



By J, A. SEWALL. 



Pinic acid or sodic pinate precipitate salts of calcium, magnesium 

 and iron. 



1 have recently made some experiments with the sodic pinate, with re- 

 ference to its delicacy as a test for detecting the presence of the salts of the 

 first mentioned metal (calcium ), with the following results, vising a solution 

 of calcic sulphate : 



"25ir¥ P^^*" ^^ calcic sulphate in one part of water, yields a very copious 

 amorphous precipitate, which readily subsides. 



"SItVt P^''* yields an abundant bulky precipitate. 



TTffiT'D" V^^^i ^^ abundant precipitate. 



g go Q part, an immediate cloudiness, and in a few minutes a good 

 precipitate. 



g Q Q part, quite the same result as is given by the ^y^-g-y solution. 



ns\oo part, a very satisfactory deposit after a little time. 



2 5 6^0 inr V^^^i ^ distinct turbidity, and after a few hours a satisfactory 

 deposit. 



I observe that on adding a few drops of the reagent to distilled water, 

 the solution becomes, after several days, slightly opalescent. 



The reagent was prepared by dissolving one part of the sodic pinate in 

 fifteen parts of distilled water and filtering the solution. 



The quantity of the solution of the calcic sulphate operated on in each 

 trial was one fluid ounce. The quantity of the sodic pinate solution used in 

 each trial varied from two to ten drops, the larger quantity being used in the 

 stronger solution of the calcic salt. 



Ammonic oxalate fails to precipitate lime in a -=.1-^^- solution, (^Fre- 

 semus) . 



It will be seen from the above that the sodic pinate is a much more 

 delicate test for calcic salts than the ammonic oxalate. The deportment 

 of other calcic salts is quite the same as that of the sulphate. 



