Plaster model of Fresnel Wave Surface in three parts, by Delagrave, 1876.

Conoid in contact with a hyperbolic paraboloid, string surface model, 1872.

Hyperbolic paraboloid, string surface model, 1872.

Skew surface with its tangent paraboloid. String surface model, 1872.

Model of a groin, string surface model, 1872.

Model of a groin, string surface model, 1872.

Model of helix or screw thread, string surface model, 1872.

Cylinder, cone and two conoids, string surface model, 1872.

Wheatstone's wave machine, c 1842.

Conoids, string surface model, 1872.

Hyperboloid and Asymptotic Cone, string surface model, 1872.

Hyperbolic Paraboloid, surface string model, 1872.