132 Speedy and easy Method of copying Drawings. 
lity and identity ; and looking round and perceiving a sup~ 
pressed smile in the countenances of some of his auditors, the 
first speaker resumed, by saying , that he considered the evidence 
of various historical facts, ‘such for instances, that there was 
such a man-as Julius Cesar, and that there is such a place as 
Rome, &e. as not less complete and perfect, with any mathema- 
tical truth whatever!. * Nay (continued he), [ have even been as- 
sured by single persons of some things, I as firmly believe as I 
do any truths whatsoever !.” 
Perceiving now a more general and stronger tendency to: 
smiling, in the attentive circle around -him, the speaker (who is 
a North Briton) rather hastily concluded, by saying, “1 know 
that in this country such opinions are only laughed at, and that 
every English mathematician holds a different opinion ; but that 
shall not induce me to change mine :’—and I think I heard him 
add, while the group which had stood around him was in the 
act of separating, that he intended shortly to enlarge on these 
topies in his Journal. : 
Relying confidently, as I do, on the issue of any investigation 
into the paramount pretensions of mathematical, over almost 
all, if not every other kind of certainty (which latter are in- 
deed but probalilities, sometimes of a very high amount it is 
admitted*), I sincerely hope that the learned Editor will not 
fail of either supporting or retracting his rather singular opinions, 
as above mentioned. Whether this may or may not happen 
to be the case, I judge it proper to request the favour of your 
insertion of this notice of these epinions ; and to request of 
some more able hand, who heard them advanced, or others, to 
enter without delay on thgir refutation in your Magazine, which 
will oblige, 
Yours, &c. 
MatTHEMATICUs. 
— —— ad 
XXX. Speedy and easy Method of copying Drawings. 
By M,. Dz Lasruyvrief. 2 
M. DE LastEyRiE first followed the method of rendering the 
paper transparent by rubbing it with oil of petroleum or asphal- 
* The speaker insisted much, on the absolute certainty that the sun will 
tise tomorrow; and was very free 3 in his censures, of what the celebrated 
Laplace has advanced on this as a probable event. Speaking of the laws 
of nature, he said, none ought to be admitted as such which every man, 
does not know and fully admit without demonstration; that is, intuitively f 
was added, either by the speaker or some one of his hearers, without any 
xine therefrom on his part. 
¢ From the archives des Decouvertes, 
tum, 
ae 
