57& PHILOSOPHICAL TRANSACTIONS. [aNNO 177Q. 



3. It may also be seen by another experiment. Take 2 jars, coated as in the 

 Leyden experiment, and charge one by the prime conductor, the other by the 

 anti-conductor; the 1st will be positively, and the 2d negatively electrified; 

 which is proved by applying a discharging rod to the balls connected with the in- 

 side of the jars, when both immediately discharge themselves, which they 

 would not do, if both jars were charged from the same conductor. 



Some few more experiments are added, to the same effect : after which Mr. S. 

 adds the following conclusion. 



Thus, I humbly apprehend, the whole current of these experiments tends to 

 show the preference of points to balls, in order to diminish and draw off the 

 electric matter when excited, or to prevent it from accumulating; and conse- 

 quently the propriety, or even necessity, of terminating all conductors with 

 points, to make them useful to prevent damage to buildings from lightning. 

 Nay the very construction of all electrical machines, in which it is necessary to 

 round all the parts, and to avoid making edges and points which would hinder 

 the matter from being excited, will, I imagine, on reflection, be another cor- 

 roborating proof of the result of the experiment themselves. 



XXX. Description of the Sitodium Incisum and Macrocarpon, luith their Fruits. 

 By Charles Peter Thunherg, M. D. From the Latin, p. 462. 



The authors who have described the bread tree or its fruit, are but few in 

 number, viz. Rheede in the Hortus Malabaricus. Rumphius in his Herbarium 

 Amboinense. Zanoni in his Historia Stirpium rariorum. Hawksworth in his 

 Voyages round the PVorld. Mr. John Ellis in his Description of the Mangostan 

 and Bread-Fruit Tree. Lond. 1775, 4io. The two Forsters, father and son, 

 viz. John Reinhold, the father, and George the son, have given the generic cha- 

 racters, with a figure, in their work entitled Characteres generiim plantarum, 

 &c. Lond. 1776. 4^0. 



I myself (says Dr. T.) while at Batavia, described, according to the sexual 

 system, the species of this genus, under the names of Radermachia incisa, and 

 R. integra, in the Stockholm Transactions for 177^, and in the same-year sent 

 the seeds of the Sitodium macrocarpum to the Amsterdam physic-garden. 

 Afterwards, on my return from Japan, in 1777? I sent some very young living 

 plants of both species to the same garden from Batavia ; and lastly, on my re- 

 turn to Europe, in 1778, I brought with me a great number of both species, 

 from Ceylon, with the seeds of one species ; some in papers included in a box, 

 and sometimes exposed to the air in the shade; some in glass jars well secured ; 

 some in wax, and some in dry sand : these last 2 methods are the best. Every 

 month, during the voyage, I planted some of the seeds in mold, in order that 

 they might have a chance of vegetating in a different air, climate, and season. ' 



