Barometers Realm

At the top of the barometer, slightly angled toward each other, are two register plates engraved with barometric scale in London inches of mercury. The scale is calibrated to account for variations in the mercury level in the cistern. These brilliant white plates are made from luxurious ivory, cut from the tusks of Indian elephants. Upon the polished and brightened surface of the dentin, one can observe faint Schreger lines — the telltale “herringbone” pattern unique to genuine elephant ivory. The surface bears the natural marks of time: fine scratches, cracks, and irregularities typical of aged ivory. During the Victorian period, ivory was among the primary exports of the British Empire’s colonial trade, alongside gold, rubber, and cotton.

The engraving on these register plates — both for the barometric scale and the textual weather indications — is a marvel of craftsmanship. Each mark was incised manually with fine needles or burins, then filled with ink or pigment in a technique known as intaglio. In the upper corners, the maker’s signature L. Casella & Co. and the address 23 Hatton Garden, London are finely inscribed. In close-up photographs, one can even make out the faint alignment lines used to guide the hand of the engraver — a testament to the meticulous care involved.

An extraordinary level of detail is also visible in the engraved weather terms, which deserve both a magnifying glass and a place in a museum. These are miniature works of decorative art, where each stroke is deliberate and executed with jeweler-like precision. The letters are cut in a classic Victorian style, where every line serves not just as a character, but as an ornamental motif. Inside the bold contours of each letter lies a complex botanical pattern: delicate flowers, palmettes, crossed petals, and radiant lines reminiscent of sunbeams or falling rain. A fine background shading lends each letter depth and optical relief, transforming simple text into architectural ornament.

The register plates are equipped with ivory vernier sliders, which are adjusted by two elegant ivory knobs on the front of the case, just below the plates. The left plate and its vernier track the reading from the previous day; the right displays the current reading — allowing for an immediate grasp of the weather trend. Each of the verniers allows readings to 1/100th of an inch. The plates are protected by flat mineral glass, which appears to be a replacement. The original glass likely featured beveled, thicker edges, which are absent here — suggesting the earlier glass was damaged and substituted.

Regrettably, any restorative work performed on this barometer was executed with unforgivable roughness. The ivory near the screw fixings is badly scratched and scarred, as though someone had attempted to align a screwdriver with the screw head in a state of inebriation. I also suspect that the original barometric tube was replaced, as the current one is noticeably narrower than what the original maker would have intended. This has necessitated the insertion of cotton padding along the channel where the tube runs. However, such a replacement is not unusual or unwarranted: within less than a century, the adhesive securing the tube to the boxwood cistern would likely have cracked and failed. And this is but one of many possible effects of time’s slow erosion.

Finally, the crowning touch of this impressive instrument is a mercury thermometer mounted on the case, marked with both Fahrenheit and Réaumur scales. The rectangular thermometer plate, with its temperature scales and textual indicators referencing standard fixed points, is once again made of ivory — reinforcing the artistic status of the instrument. The mercury capillary, featuring an elongated reservoir, is secured by small brass clips and mounted within a recessed wooden housing, protected at the front by a clear glass pane, itself slightly set into the barometer’s body.

This rosewood cistern barometer by L. Casella & Co. stands as a quintessential example of mid-19th century English craftsmanship, created for the most discerning of clients.

The Hidden Signature of the Master

During a restoration inspection, a barely discernible inscription was discovered on the inner surface of the lower section's back panel of the barometer—specifically, in the area where screws secure the niche containing the reservoir. This inscription, applied directly onto the wood, is entirely concealed from view and only becomes visible when the rear panel is fully removed and the barometric tube is taken out—making it all the more intriguing. The inscription consists of the number 22 and the elegantly rendered initials LC, almost certainly referring to Louis Casella, the founder and proprietor of the renowned London workshop L. Casella & Co.

At first glance, the number 22 might appear to be a date, yet the hypothesis of it signifying the year 1922 is immediately ruled out—by that time, Louis Casella had long passed away, and the company was already in the hands of his successors. The year 1822 is equally implausible, as the master would have been only a ten-year-old boy and far from establishing his own practice. Nor is it likely to be a routine internal marking, as such annotations were typically made hastily and for utilitarian purposes—whereas this inscription was written with noticeable care and even a degree of formality, suggesting a special significance.

The most plausible interpretation is that “22” denotes the 22nd year since the founding of Casella’s firm—that is, the year 1859 (given that the workshop was established in 1837). This method of dating was not uncommon in artisan workshops, particularly when the inscription was not intended for the client but for internal record-keeping or as a discreet personal trace left by the maker. The presence of the initials LC alongside the number makes this theory especially compelling: the inscription may well represent a hidden signature, left either by Casella himself or under his direct supervision.

That said, more mundane—though still possible—explanations cannot be entirely dismissed. For example, “22” might have been the production number for a specific order within the workshop, or the serial number of an instrument made as part of a private commission.

In any case, the discovery of this inscription adds a layer of historical depth and personal character to the object. The barometer seems to speak in the voice of its creator, leaving behind a message—encrypted by time, yet still legible today.