Show how to boro a hole in a pm N r brij place a pin in the end of a cork in each aide of which a penknife lias been inserted obliquely the knives be aa nearly as possible of equal by opening one or alio other of them more or leas they can be made to balance in order to bring atheni to alie exact petition required that ia to bring the pin the cork and the knives to a horizontal position place iho head of the pin on the end of your finger and ascertain if the two kniat kni vt ara on alie same level if nut adjust them butil they are so then lake the cork in your hand and lay the stem of the pin on the point of a needle the head of which ia fastened in the cork of a bottle you carefully change the point of support of the pin until you have fouad that tion in which it remains horizontal when left to itself mow blow upon ono of the penknives at first and then more strongly you 1 l cause the ahola to rapi illy after a time the needle beina the harder i have worn n giuy bole in the pin and if you continue the will finally pierce it entirely the experiment can alio be made by placing the pin in a cirk m the direction dirE clion of its axis while the needle penetrates it perpendicularly the ia then obtained by means of two burks as ia the experiment of the ege |