44 M. Van Svvinden on the Invention of Pendulum-ChcJcs 
as he does not mention one, I must consider the assertion as un- 
supported by any proof. Notwithstanding this, Mr Bode had 
lately asserted, as an indubitable fact {Jahrhuch for 1816), that 
Byrgius had been intent on the application of the pendulum as 
early as 1660. So easily are errors copied when once hastily 
admitted by a writer of eminence ! 
But with regard to this clock, it is farther added, that Tycho 
Brahe had made use of it in his astronomical observations. Now 
Tycho Brahe died in 1600, two years after his Instaurat(Z 
Astronomidd Mechanica had appeared, in which he describes all 
his instruments, especially his clocks, complains of the irregula- 
rities of the best of them, without ever making mention of single 
pendulums to measure the time. But I can produce an appo- 
site instance to show, that a clock of Tycho Brahe had actually 
undergone the alteration before mentioned. The Ambas- 
sador of the Court of Denmark at the Hague was in posses- 
sion of such a clock at the time of Huygens : it bore the date 
1576, and had belonged to Tycho Brahe. Huygens^ oh first 
seeing it, wrote in his Adversaridy which are preserved ( Leyden 
MSS.) : No mention of pendulums (in Tycho’s Mechanics). 
On the clock of Mr Crag, the Danish Ambassador, is the year 
1576, if I remember right. But if Tycho had already at that 
time discovered the application of the pendulum, how comes it that 
he never, during the twenty-four years that he lived after that 
period, once mentioned in his writings such a valuable and wish- 
ed for discovery ? 1 suppose, therefore, that a pendulum was 
afterwards affixed to Mr Crag’s Tychonian clock, designedly to 
make it seem as if it had been thus formerly constructed.” A 
little below we find, and, as the colour of the ink indicates, writ- 
ten on a subsequent occasion : That this is really so, the ce- 
lebrated Roemer, when he came from Denmark to the Hague, 
has testified to me, and that he knew with certainty when it had 
been done.” He adds, and by whom,” in his manuscript 
AnecdotOy where he relates the same again; 
In confirmation of his reasoning on the improbability that 
Tycho being in possession of this capital invention, it should 
never have become known, I shall farther observe, that the nu- 
merous disciples of this astronomer, and the many learned men 
of every country who visited him, and examined his apparatus. 
