and Description of the Eidograph. 423 



replied, that the nature of the thing was such, that accuracy en- 

 sued infallibly, and as it were spontaneously : so that it was im- 

 possible to err without design. I inquired whether the effect 

 was wrought by the drawing of lines, or by the help of a mate- 

 rial instrument ? Here he began to hesitate, and to speak eva- 

 sively, avoiding a clear answer, and hiding a thing, dark and unin- 

 telligible in itself, in obscure language. This alone he admitted, 

 that the thing was done by the help of compasses depending 

 upon a firm centre. I asked him to shew me these compasses : 

 he refused, upon the plea that whoever saw them would at once 

 comprehend the whole mystery. At length I earnestly entreat- 

 ed that he would make a disclosure to me under the seal of se- 

 crecy, and a pledge of keeping silence, promising to reveal it to 

 none without his knowledge or against his will ; to all which he 

 gave a round denial. Seeing that I talked to one deaf to im- 

 portunity, I changed my style ; telling him that I trusted to dis- 

 cover the thing by the blessing of God, who would, according to 

 my desire, communicate the invention to me in his own good 

 time, while he might chafe and fret in vain. He laughed at my 

 threats, saying, that the invention surpassed the power even of 

 the Devil himself ! These things happened in the beginning of 

 the year 1603, at which period, turning my attention to the in- 

 vestigation, I laboured with all my might. I tried the thing at 

 first with a cord, which I imagined fixed at one end (for I form- 

 ed the whole in my mind only, and in thought, until I had at- 

 tained a true knowledge, along with a clear demonstration) ; then 

 taking the other end in my fingers, I moved it round on imagi- 

 nary paper, there being upon it two small spheres acting as cur- 

 sors, to mark out points and proportional lines. These, indeed, 

 I saw, might be formed about a fixed centre ; but then, neither 

 was there any motion to or from the centre by means of the 

 flexible thread, nor did the cursors change their positions upon 

 it, which yet was necessary to increase or diminish the motion 

 proportionally. Dismissing, therefore, lines formed by threads, 



