( 3 3 2 ) 
colleclione Camphorae non nifi ex audit u commemo- 
rari, &C viros coeteroquin eruditos Ten Rheine , 
Breynium , Hennannum coeterofque, alium ex alio 
tranfcripfilfe, nullum vero, quantum credere par eft, 
rem oculis in arbore ipfa confpexiife, qus quidem 
fallacia in Hiftoria naturali prima non foret. Bine 
denique concludo, efle omnino hanc fpeciem Cam- 
phors; tarn raram, ut earn oculis cernere nemini li- 
ceat, nec foiTan unquam contingere queat. 
C. Neuman. 
111. ObferVations of the Dipping Needle , made at 
London, in the (Beginning of the Tear \ 723 . By 
Mr. George Graham, Watchmaker, F. R. S. 
A BOUT the Time I was obferving the Varia- 
tion of the Horizontal Needle, I made like- 
wife fome Experiments with the Dipping Needle, to 
try, if the Dip and Vibrations were conftant and 
regular. The Needle I made for this Purpofe was 
12 Inches and one Tenth long, hair an Inch broad in 
the Middle, but not above one Tenth near the Ends j 
the Ends themfelves being filed to fine Edges ; and in 
Thicknefs it was about one Third of a Tenth. The 
Ends of the Axis, upon which the Needle turn’d, 
were very fmooth, and not bigger than was necefiary 
for the Support of the Needle, which weighed nine 
Pennyweights twenty one Grains, or about half an 
Ounce Troy. The Ends of the Axis were placed 
upon the Edges of two thin Plates of Steel, that were 
hard and well polilh’d, and parallel to the Horizon 
that the Needle, when vibrating, might roll, and 
not Hide upon the Edges of the Plates, to avoid the 
Friction 
