294 Bi-Malate of Lime in the Berries of the Sumach, 



be suggested, which might obviate this difficulty, by establishing such 

 uniformity would doubtless materially enhance the value of these 

 records in promoting the advancement of Natural Science. 

 Baltimore, Oct. 10th, 1834. 



Art. XII. — On the Existence of the Bi-malate of Lime in the 

 Berries of the Sumach; and the mode of procuring it from them 

 in the Crystalline form, ; by William B. Rogers, Prof, of 

 Chemistry, and Natural Philosophy in William and Mary College. 



The berries of the Rhus glabrum and Rhus Copalhnum, the two 

 species of Sumach common in Virginia, have long been remarked for 

 their acidity and are still used in some places as a substitute for lem- 

 ons in different forms of beverage as well as for various other purpo- 

 ses in domestic economy and medicine. In some experiments made 

 more than two years ago upon the acid liquor obtained by macerating 

 the berries in warm water, I found it to contain a large quantity of 

 an acid salt of lime which I have since determined to be the bi-ma- 

 late. At the same time too a microscopic examination of the ber- 

 ries of the R. glabrum enabled me to discover the pure crystals of this 

 salt on the outside of the berries mingled with the down. To ob- 

 serve the form of the crystal distinctly the berries should be slightly 

 moistened and then allowed to dry. The crystals may then be 

 readily seen by the naked eye, and when viewed through the micro- 

 scope they appear as beautiful hexagonal prisms of the most perfect 

 symmetry. 



The existence of this salt in the berries of the Rhus is a fact 

 which appears hitherto to have escaped attention. The only ex- 

 periments relating to the acid of these plants which I have met with, 

 are those of Mr. I. Cozzensof New York, published in the 1st vol- 

 ume of the Annals of the Lyceum of that city ; and that chemist 

 seems to have regarded the infusion of the berries of the Rhus gla- 

 brum as containing malic acid uncombined with any base but "merely 

 contaminated with a small portion of gallic acid which probably pro- 

 ceeds from the pulp of the berries." In his paper on the subject he 

 does mention having tested the acid Uquor for lime, which he would 

 have discovered at once either by evaporating a few drops in a plati- 

 num capsule and then igniting, or by adding to the liquor a little oxa- 

 late of ammonia. 



