frame, they revolve over another cloud, which is introduced in the place of the middle house: all the houses being taken away through this cloud, the water in the infulated veffel is made to pafs and to descend in a stream. When a ball is interpofed between this cloud and the revolving ones, there will be frequent flashes upon it; but when, instead of a ball, a point is put there, the electric matter passes off gradually and filently without any flash. Thus, SIR, I humbly apprehend, the whole current of these experiments tends to fhew the preference of points to balls, in order to diminish and draw off the electric matter when excited, or to prevent it from accu-mulating; and confequently the propriety or even neceffity 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 neceffary 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 corroborating proof of the refult of the experiment themselves. XXX. Sitodium incifum et macrocarpon, ufufque fructuum qui exinde nafcuntur, defcripta a Carolo Petro Thunberg, M. D.; communicated by Jofeph Banks, Efq. P. R. S A Read May 13, 1779. UCTORES, qui defcriptionem dederunt hujus arboris vel fructus ejus, quantum fcio, pauci funt. RHEEDE, HENR. in Horto Malabarico, Amft. annis 1678 et feq. fol. macrocarpon defcribit. RUMPHIUS, GEORG. EVERH. M. D. et medicus Amboinenfis annos ab hinc octoginta, utriufque fpeciei hiftoriam dedit, quæ invenitur in Herbario Amboinensi, a Prof. LAUR. BURMANNO, annis 1741 feq. publici juris facto. ZANONIUS, JACOB. in Hiftoria ftirpium rariorum, Bonon. 1742, fol. macrocarpon memorat. HAWKESWORTH, JOHN, Voyages round the World, Lond. 1773, vol. III. 4°, incifi mentionem facit. ELLIS, JOHN, fructum hujus defcripfit anno 1775, in a Description of the Mangoftan and the Bread-fruit, Lond. 4°. FORSTER, FORSTER, JOH. REINH. et GEORG. in Characteribus generum Plantarum, p. 101 et 102. tab. 51. Lond. 4°: 1776, descriptionem genericam et figuram dederunt. Ego, anno 1775, Bataviæ Indorum commoratus, arbores hafce characteribus botanicis defcripfi et ad genus fecundum fexuale fyftema reduxi, quæ defcriptio fub nomine Radermachiæ incifæ et integræ in actis Stockholmienfibus, anno 1776, p. 250. invenienda eft. Eodem anno, 1775 fcilicet, femina S. macrocarpi mifi ad hortum medicum Amftelodamenfem. Poftea redux e Japonia, anno 1777, plantas minutas vivas utriufque fpeciei plantatas ad eundem hortum e Batavia transmisi. Deinde in Europam anno 1778 ipfe revertens infignem numerum mecum duxi e Ceilona, tam plantarum utriufque speciei vivarum, quam alterius fpeciei feminum, quæ pluribus modis confervare ftudui, fcilicet: 1°, In chartulis, quæ theca includebantur, et aliquando aeri in umbra exponebantur. 2o, In lagenis vitreis bene obturatis. 3°, In cera. 4°, In arena ficca. Ultimæ hæ duæ methodi optimæ fuerunt. Præterea 5°, Sub ipfo itinere fingulis menfibus femina terræ mandavi, ut fenfim excrefcere poffent fub vario cœlo et vario anni tempore. |