( 32 ) 
It is very large in proportion to the thickness of the wood in Sambucus , 
Sassafras, Rhus. Only Smilax 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 PIRATE 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, using a solution 
of calcic sulphate : 
P art ca l°i c sulphate in one part of water, yields a very copious 
amorphous precipitate, which readily subsides. 
Winr P art yi^s an abundant bulky precipitate. 
T¥inro p ar l? an abundant precipitate. 
2 g 0 0 part, an immediate cloudiness, and in a few minutes a good 
precipitate. 
TO l roT P ar *5 quite the same result as is given by the solution. 
T^-^Vinr p ar f? a very satisfactory deposit after a little time. 
i nr oV'otr P ar l? a 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. 
Amnionic oxalate fails to precipitate lime in a solution, (Fre- 
senius ). 
It will be seen from the above that the sodic pinate is a much more 
delicate test for calcic salts than the amnionic oxalate. The deportment 
of other calcic salts is quite the same as that of the sulphate. 
