Draftsman's fifth method for drawing an ellipse

Ellipse Fifth Method

Draftsman's fifth method for drawing an ellipse

Draftsman's fourth method for drawing an ellipse, case 3

Ellipse Fourth Method Case 3

Draftsman's fourth method for drawing an ellipse, case 3

Diagrams showing the origins of eskers. A) A tunnel under the ice, nearly filled with sand and gravel by the subglacial stream which built up its bed to the level of the outlet. B) The same deposit after the ice melting of the supporting ice walls. Slumping has produced the characteristic steep side slopes.

Origin of Eskers

Diagrams showing the origins of eskers. A) A tunnel under the ice, nearly filled with sand and gravel…

Draftsman's second method for drawing a parabola

Parabola Second Method

Draftsman's second method for drawing a parabola