Science, experimentation and measurement

  • Pendulum

    Record number: 1708
    Form of acquisition: donation
    Dimensions: 30 x 0 cm
    Maximum diameter: 6.5 cm
    Maximum diameter: 2.2 cm

    Physics apparatus comprising a circular metal base made from gilt brass with a cylindrical cowl connected to the transparent, cylindrical glass body or stem. At the top there is another cylindrical part enclosing the glass and supporting a piece of gilded metal in the form of an arc, with the pendulum or lead ball hanging from the end. This device was used to experiment with the phenomenon of the attraction and repulsion of objects.

  • RBM tachometer

    Record number:12874
    Date: first quarter of the 20th century
    ​Form of acquisition: purchase
    ​Weight: 2.12 kg

    Carriage tachometer made by RBM. This was one of the first tachometers to be made, and is particularly unusual for its characteristics. The clockwork mechanism of the tachometer is housed within a particularly solid metal capsule. This capsule opens in two halves, with the winding mechanism operated by a wheel on the top half, which also serves to hold the sheet of paper marking the time intervals. The rest of the mechanism, including the paper punch, is located in the lower half.

  • Barlow's wheel

    Record number: 1686
    Form of acquisition: donation
    Dimensions: 20 x 25 x 15 cm

    Invented by P. Barlow in 1828 to demonstrate the action of the magnetic field on an electric current.

    The object is mounted on a rectangular wooden base with four feet. It comprises a toothed copper wheel rotating around a moulded horizontal axle of gilded metal, which is submerged as it passes through the base of an iron container for mercury. The two poles of the direct current circuit, in gilded metal, are connected respectively to the mercury and to the axle. A magnet creates a normal magnetic field in the plane of the wheel, and it rotates, the direction of rotation depending on the respective directions of the magnetic field and the current.

  • Replica Carolingian astrolabe

    Record number: 9164

    Date: last quarter of the 10th century

    Geographical specifications: Catalonia

    Form of acquisition: purchase

    Dimensions: 17 x 16 x 1 cm

    Weight: 600 g

    An astrolabe is a flat representation of the celestial sphere. The engraved lines can be used to establish and predict the progression of the celestial bodies. This one in particular is built according to the Barcelona meridian and is important because of its numbering system, using Latin letters that nonetheless correspond to Arabic numerals.

    It has two sides, one of them set deeper, with two engraved discs known as timpani, on which the different latitudes are marked. Each of them has a stereographic projection at the top of the circles of the celestial sphere: theoretical horizon, visual horizon, meridian, tropics, equator and, on the lower semicircle, the lines for the odd-numbered hours. The spider is superimposed onto the timpani, a kind of engraved chart of the heavens, with a projection of the ecliptic and eighteen stars (ten boreal and eight austral), without any name engraved. One of the timpani bears the names ROME and FRANCE, in capital letters. According to the historian Julio Samsó, these provide fairly clear proof of its provenance, as Ifranja was the name used by the Arabs before the 12th century to refer to the Christian states of the north-east of the Iberian peninsula. The letters are also similar to those used in the late 10th century in Latin manuscripts produced in the region of Catalonia.

  • Ramsden static electricity machine

    Record number: 3137

    Date: -

    Form of acquisition: purchase

    Dimensions: 143 x 127 x 58 cm

    Static electricity machine with a glass disc, known as a Ramsden machine, on a wooden table. It comprises a fixed glass disc with a metal axle in the centre, rotated by means of a handle. As the glass passes through two wooden struts or parts supporting the axle, the surface rubs against the two bearings on the struts. The rotating movement serves to electrify the glass disc, which receives a positive electrical charge on both sides. A long transversal brass cylinder is the isolating conductor, on two glass feet. The far ends of the cylinder have two gilded arms, which end in points which almost touch the disc, discharging the electricity without rubbing.