Pocket Sextant Salmoiraghi - Milano, Regia Marina, circa 1915

Pocket Sextant, or rather "box sextant", produced from 1915 until 1918 by Salmoiraghi and supplied to very few senior officers of the Royal Navy embarked on ships and submarines. In addition to the writing Regia Marina, it also bears the number 3, which most likely refers to the assignment number. Also imprinted on the case is the number 176, which should correspond to the serial number of the instrument: this number is in fact also found imprinted on the "lid" or "base" followed by the date of production or assignment of the sextant, i.e. 1915.

It consists of a cylindrical box with a diameter of 75 mm. approximately and 45 mm high. Unscrewing the lid reveals two distinct parts; one is the box itself, properly speaking, one with the lid, the other is the whole body of the sextant. This consists of a drum of which one of the bottoms forms, with its external part, the other face of the box opposite the lid, with double breading on the edge. On the external face of the other background you can see the arc graduated in degrees and half degrees on which a vernier alidade can slide, equipped with a lens, which gives the first, pivoted at the center of the arc.

A circular button protrudes onto the drum which operates the mobile mirror and therefore the alidade for observing the angle; on the face itself are the heads of two small dials for correcting the verticality of the fixed mirror. Laterally, on the cylindrical part, opposite the fixed mirror, a small extractable telescope for observation; on the opposite side there is another quadrant screw for correcting the parallelism of the fixed mirror to the mobile one. When you want to use the sextant, it is unscrewed from the lid and screwed back on with the other breading; then the body of the lid is used to hold the instrument with the hand.

It is preserved in excellent condition.

Salmoiraghi was a company resulting from the experience that Angelo Salmoiraghi acquired, after graduating from the Milan Polytechnic, in the Filotecnica, founded in 1865, under the guidance of the founder Ignazio Porro. In Filotecnica, Eng. Salmoiraghi held positions of manager until acquiring the property in 1873, transforming the name into „Salmoiraghi, Rizzi e C.“ for the production of optical and topographical instruments.

In 1877 the company dissolved and Angelo Salmoiraghi continued the business alone with a new company called Filotecnica Salmoiraghi. At the end of the century he had excellent collaborations: above all that of Francesco Koristka, improving the offer of optical and precision instruments. Under his guidance, the company developed considerably, until it acquired a leading role among the manufacturers of optical and precision instruments, the Regia Aeronautica and the Regia Marina.