### Children Holding Rulers

Illustration of children holding rulers that can be used to write mathematics story problems involving…

### Shaper Clamp Micrometer Scale

A shaper micrometer scale by clamping onto the material to measure the thickness reading the rotation…

### Shaper Spindle Micrometer Scale

A shaper micrometer scale measuring crossâ€”feed spindle to measure the diameter by reading the raised…

### Scales

Top and side views of mechanical drawing scales.

### Triangle Scales

The triangle scale has six surfaces for different graduations, and the scales are arranged so that the…

### Sector

The sector is a hinged rule with scales used for various mathematical calculations.

### King Looking Over Ships

An illustration of a king looking over ships.

### Cracks in the soil

A patch of soil and grass which has cracked after having been worked too fine in the fall.

### Adjustable Head T-square with Ruler

An adjustable T-square to create straight lines at different angles with a ruler attached to the head.

### Adjustable Head T-square

An adjustable T-square to create straight lines at different angles.

### English T-square

An English T-square for drawing straight lines. The narrowing of the bottom blade makes the T-square…

### Long Fixed Head T-square

A long fixed head T-square for drawing straight lines. The head shape of the T-square allows for drawing…

### Regular Fixed Head T-square

A regular fixed head T-square for drawing straight lines. The blade must be perfectly straight in order…

### Taou-Kwang

"The emperor of China, Taou-Kwang, was born in 1782, and is a grandson of Kien-long. He succeeded his…

### Pair of timothies

A pair of timothy plants growing side by side, illustrating the difference in yield. Each one grew from…

### Elliipsograph Tool

An instrument for describing ellipses, often called a trammel.