34 A Mechanical Finger for the Microscope. By G. Hanks. 
When the end of the hair is exactly over the object, which is 
dimly seen out of focus, a turn of the milled head of the sub-stage 
lifts the slide until the object touches the hair and remains attached 
to it. When the sub-stage is lowered, the object remains suspended 
to the end of the hair. The slide may then be removed and another 
substituted, to which the object may be transferred by simply 
elevating the sub-stage, the slide rising to meet the suspended 
object. If the slide has been gently breathed upon, the object 
leaves the hair and attaches itself to the glass. This applies only 
to minute objects. When the object is larger and too heavy to be 
lifted by a hair, it will be necessary to substitute a bristle, and to 
wet the end of it ; when the second slide is placed under it, a few 
minutes will suffice to evaporate the moisture, and the object will 
fall into the desired position. 
The hair may be used to push away worthless matter which 
may surround the object desired. It is perfectly easy to push any 
portion quite out of the field, simply by using the stage movements 
while the slide rests on the parabola. 
If a piece of fine aluminium wire, the end of which has been 
flattened by a pah - of steel rollers, be substituted for the hair, and a 
low power used, a crystal may be lifted with as much ease as a 
lump of coal on a shovel. To prevent the object from being pushed 
before the chisel edge of the wire, a small piece of glass may be 
placed in the direction of the movement, against which the object 
is held, while the edge of the flattened wire passes under it. 
It will he found difficult to place a hair firmly in the jaws of 
the stage forceps. This difficulty may he overcome by cementing 
the hair or bristle between two small pieces of thick paper, which 
the forceps will hold rigidly. 
Nothing can be more simple than this device, and I question if 
any mechanical finger can he more effective. A few minutes will 
suffice to make it perfectly understood . — A paper read before the 
San Francisco Microscopical Society, May. 
