Images(10)

Iseli Y level

Datecirca 1880

Inventory Number5229

ClassificationSurveyor's Level

Subject

Maker R. Iseli circa 1880

Cultural Region

Place of Origin

Dimensionslevel: 20.6 × 13.4 × 37.6 cm (8 1/8 × 5 1/4 × 14 13/16 in.)
case: 19.3 × 40.7 × 25.5 cm (7 5/8 × 16 × 10 1/16 in.)

Material

Accessorieswalnut case with two adjustment tools, objective lens cap, and lens shade; Iseli trade card (inside box lid)

DescriptionBrass Y level consisting of the following major components (from top to bottom): a telescope tube in two Y supports; a spirit level; a compass; and a tripod mount with three leveling screws.

The telescope has a knurled eyepiece. Around the telescope near the eyepiece is a brass ring from which four brass pins project. Just outside this is a second ring, of bronze, to which is attached a brass knob. A large brass pin sticks out from the tube between the eyepiece and the center. Two fitted bronze rings around the telescope tube protect its points of contact with the Y supports.

Each of the telescope's Y supports has a hinged top piece. It latches closed around a knurled knob. Projecting out from the bottom of each of the Y supports' arms is a brass post into which a brass pin has been threaded, perpindicularly.

A brass spirit level sits on top of the leveling bar, held in place by the long pin projecting down from one of its two square black end caps. The level has a rectangular glass window marked with two scales. The leftmost scale has values (labeled on the brass tube) descending from 3 to 0; the rightmost scale has values ascending from 0 to 3.

Below the level bar is a brass disc from which projects a black box. Extending out from the box are two knurled knobs (one horizontal and one vertical). Below the disc, one each through three bars projecting out from the vertical spindle, are three leveling screws with knurled knobs.

The instrument is stored in a walnut case with felt protectors and brass clasps, which also contains two adjustment tools, an objective lens cap, and a lens shade. Iseli's trade card is pasted to the inside of the box lid.

Signedengraved on side of spirit level: Iseli, 149, Boulevard St. Germain Paris; printed on trade card pasted to inside of box: 149, Bould. St. Germain, 149. / Place St. Germain des Prés / ISELI / Neveu & Elève d ERNST / Fournisseur à l'ecole des Ponts et Chaussées / et au Dépôt des Cartes et Plans de la Marine. / PARIS; on circular tag pasted to inside of box lid: DIRECTION DES TRAVAUX DE PARIS / SERVICE DE L'ASSAINISSEMENT / SECTION de la SALUBRITÉ / HABITATIONS & VIDANGES / INVENTAIRE / 801

Curatorial RemarksDid this belong, at some point, to Paris's department of sanitation? See circular sticker inside box lid.; This object was previously numbered DW0168.

FunctionFor use in surveying, to measure contours.

After mounting the Y level on a tripod at his starting location, the user levels the instrument by means of the spirit level and the four leveling screws. Then he sights a stadia rod through the telescope, moving the rod as needed until the target is centered behind the telescope's cross hairs. The difference in height between the telescope and the rod target indicates the gain in elevation over the horizontal distance between the two.

ProvenanceDavid Wheatland purchased from Roux-Devillas Paris, March 29, 1966 (lot 4/41).