Renseignements généraux

Nº de série

S/O

Nº de partie

1

Nombre total de parties

1

Ou

S/O

Brevets

S/O

Description générale

Brass/ wood/ glass/ silver plate

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

52,1 cm

Largeur

25,4 cm

Hauteur

57,2 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Physique

Catégorie

Géophysique

Sous-catégorie

S/O

Fabricant

Ou

Inconnu

Pays

Inconnu

État/province

Inconnu

Ville

Inconnu

Contexte

Pays

Canada

État/province

Alberta

Période

1906-1954

Canada

This instrument was standardized at KEW Magnetic Observatory in 1906, in England and was the standardized instrument for the measurement of the horizontal intensity H of the earth's magnetic field at Agincourt Magnetic Observatory (near Toronto) from 1906 to 1932. From 1932 to 1954 it served as the standard for the measurement of H at Meanook Magnetic Observatory, north of Edmonton, Alberta.

Fonction

Measures horizontal intensity of earths magnetic field, and the angle between true and magnetic north.

Technique

This instrument was provided with two magnets - one long and one short. The long magnet is hollow, and contains a collimating lens and a glass scale. To measure the magnetic declination, it was suspended by a strand of silk and its direction was observed with the lower telescope. The direction of geographic north was determined from the sun or stars by the upper telescope and mirror. The intensity of the horizontal component of the geomagnetic field was determined by the method attributed to Gauss and Weber. First, the period of oscillation of the long magnet was measured. It depends on the moment of inertia of the magnet, and on its magnetic moment times the horizontal intensity. Then, the short magnet, which is provided with a mirror, is suspended on the fibre. The long magnet is placed on the deflection bar an accurately known distance from the short magnet. The angle by which the long magnet deflects the short magnet depends on the ratio of the long magnet's magnetic moment to the horizontal intensity. From the product and the ratio, both the magnetic moment of the long magnet, and the horizontal intensity can be calculated.

Notes sur la région

Inconnu

Détails

Marques

S/O

Manque

A thermometer which fitted into the taped hole in the top of the oscillation box, and the inertia bar

Fini

Dark (black)/ (oxydized?)

Décoration

S/O