104- Mr. ConnelPs Chemical Examination of the 



in which, taking the average quantity of produce from a statute 

 acre of fibre-crops and of food-crops, and comparing, from 

 the data supplied by the analyses of Sprengel, Boussingault, 

 and his own, the weights of materials of which the soil is ex- 

 hausted by each crop, it appeared that the fibre-crops were 

 actually more exhausting than the food-crops; whilst the agri- 

 culturist profits by the materials that the food-crops take out 

 of the ground, and the substances taken up by the fibre-crops 

 from the soil are at present actually rejected as waste and 

 valueless. Hence it is, as Dr. Kane considers, of much in- 

 terest to the agricultural industry of Ireland that the views of 

 ceconomizing the residues of the preparation of flax and hemp, 

 put forward in his memoir, be tested by practical men, as, if 

 they be found correct, and if those residues may be applied 

 with success to prepare and fit the soil for another crop, those 

 fibrous plants will be practically deprived of their exhausting 

 qualities, and the greatest disadvantage under which their ex- 

 tensive cultivation in this country labours, may be removed. 



XIX. Chemical Examination of the Tagua Nut, or Vegetable 

 Ivory, By Arthur Connell, Esq*. 



r T , HIS remarkable nut is now well known as being exten- 

 -*■ sively carved into a variety of ornaments, having a high 

 polish and exactly resembling the finest ivory. 



The nuts which I have seen vary in size from a pigeon's to 

 a hen's egg. They are covered with a brown epidermis and 

 an outer thin shell. The inner substance of the nut is hard, 

 close-grained, and homogeneous in its structure to the naked 

 eye. Its specific gravity at 53° F. is 1*376. 



Dr. Balfour, Professor of Botany in the University of Glas- 

 gow, has been so kind as to inform me that this vegetable 

 ivory "is the albumen (botanically speaking) of a palm called 

 Phytelephas Macrocarpa, which is found on the banks of the 

 river Magdalena, in the republic of Columbia. The natives 

 call it tagua, or cabeza de negre (negro's head)." 



Mr. Cooper has stated that a thin slice of this substance, 

 examined under the microscope, exhibits a homogeneous 

 matter without any cellular or other elementary structure, but 

 traversed by parallel tubes evidently filled with an oily fluid f. 



By a previous analysis of Dr. Douglas Maclagan J, this sub- 

 stance was found to contain 



* Communicated by the Author j being an abstract of a paper read before 

 the Royal Society of Edinburgh. 



•f Microscopic Journal, vol. ii. p. 97- 



I Cormack's Journal of Medical Science, 1841, p. 614. 



