Late Victorian Collapsible Artificial Horizon by Cary of London in Original Case

For sale, a late Victorian mercury type collapsible artificial horizon by Cary of London.

This top quality instrument is comprised of a mahogany hinged case with original lock and additional hook and eye fixings to the front. Contained within the box is a black painted metal trough and triangular lid with a two paned glass top to enable viewing and to protect the mercury from the elements when in use. The case engraved to, “Cary, London” is hinged in such a way that it can be collapsed flat for convenient storage. The box also contains its original painted metal mercury flask with ingenious reversible lid to allow for the decanting of the mercury back from the trough into safe keeping after use. Please note, there is no mercury present with this piece.

In addition to the engraving on the instrument, there is a second label on the box for the reseller, Henry Hughes & Son Ltd, Opticians, 59 Fenchurch St, London.

Most extant examples of this collapsible type seem to be made by the Cary firm although I can find no form evidence to confirm that it was invented by this company. However, the Porter family who were the last owners of the Cary name advertised an improved example of a similar type which was used by Shackleton during his polar expedition.

The history of the artificial horizon can be traced back to the sixteenth century but developments were largely popularised in the eighteenth century by John Hadley, John Elton and by the famous instrument maker, George Adams, the latter of whom is merited in 1738 with inventing the mercury trough of which this is an example. It was devised as a means of navigation when the horizon was obscured by darkness or through the effect of inclement weather.

Its principle was based upon the first law of optics, that the angle of reflection from a mirror is equal to the angle of incidence, therefore a sextant would be employed to measure the angle between the sun or the stars and their reflection on the mercury contained in the metal trough. Although the instrument was dogged by criticism relating to the tremoring of the mercury when excessive movement was involved, it must have proved popular enough owing to its continuing manufacture.

The Cary dynasty were highly regarded instrument makers of the late eighteenth and nineteenth centuries, the two brothers William and John forming a partnership manufacturing both scientific apparatus and globes from the London address of 181 & 182 The Strand. William had previously served his apprenticeship with the hugely renowned London instrument maker Jesse Ramsden whilst John was a trained mapmaker. A devastating fire in 1820 led to the brothers combining the two businesses into a single premises at 86 St James Street although throughout the 1820’s they seem to have individually occupied various premises on The Strand in addition to the former.

William Cary died in 1825 leaving generous sums of money to his brothers and his immediate family and his nephews George and John Jr Cary continued their Uncle’s business initially at their father John’s original address at 182 The Strand and then later moving to 181 The Strand in 1828 suggesting that they had re-occupied both original premises after the fire. As before it separated the map making and scientific instrument businesses apart but maintained close proximity.

Having both been brought up and trained as map-makers and lacking the training and skill of their Uncle, the brothers maintained the services of Charles Gould, William Cary’s foreman and it seems likely that Gould was largely responsible for running the scientific instrument making arm of the family businesses from this point. Gould was responsible for the invention of the historic Cary-Gould microscope and given the freedom that he was given to advertise his name in association with the instrument, it is sensible to assume that