Perpetual Moon 38 Mintnight

In the Mintnight Hour

The Perpetual Moon 38 Mintnight rises in a colourful yet just as poetic version featuring hints of mint green. After placing the moon and space at the heart of its imagery, Arnold & Son is shifting its perspective. This new women’s complication timepiece presents a view from Earth. Diamonds, mother-of-pearl and ruthenium crystals comprise this latest instalment in a graceful line.

‘Mintnight’ showcases the night in shades of mint green, turquoise, teal and sky blue. A gentle graduation of coloured mother-of-pearl adorns this limited edition of 18 timepieces. The mother-of-pearl’s opalescent sheen is complemented by the shimmer of the ruthenium moon and dial foreground, together with the diamonds that sparkle on the bezel, horns and hour-markers of this poetic creation. 

From its very first appearance, the Perpetual Moon 38 was destined to rise. This range is distinct from the larger, more deliberately masculine Perpetual Moon 41.5 collection. Behind both lies the unwaveringly high quality with which Arnold & Son designs its movements and the elements that adorn them.

White and green

Measuring 38 mm in diameter and 10.44 mm thick, the case of the Perpetual Moon 38 Mintnight is fashioned from a block of white gold. Its bezel, four horns and crown host a total of 80 brilliant-cut diamonds. When added to the 22 diamonds adorning its buckle, they amount to a total weight of 2.57 carats. These gemstones pave the way for the ornamental riches that have been lavished on this delicate complication by Arnold & Son. 

Behind a wave of ruthenium crystals, a maze of blue, mint-green and turquoise hills emerge one after the other before receding towards the horizon. The sky above this scene, scattered with hand-painted stars, is filled with an immense moon. Its surface, also made from ruthenium crystals, illuminates the sky. The use of this rare material has become a special signature of Arnold & Son, adding preciousness, light and texture. Five marquise-cut diamonds indicating the hours provide the finishing touch on this work of art.

A feminine mechanism

The Perpetual Moon 38 Mintnight transposes the high watchmaking standards that have always guided Arnold & Son into the world of ladies’ timepieces. The Swiss manufacture thus created a specific calibre, the smallest in its collection, especially for the Perpetual Moon 38. 

The proportions of the A&S1612 calibre, which measures 29.4 mm, were designed with the case in mind. This manually wound movement with an autonomy of 90 hours perpetuates the range of Arnold & Son calibres with impressive power reserves.

Axes of the moon

The emblematic complication of the A&S1612 calibre is its moon phase. The Perpetual Moon 38 Mintnight houses a large moon disc with its various crescents occupying the wide window situated between 10 and 2 o’clock, cut out to faithfully depict the appearance of the Earth’s natural satellite.

Staying true to its tradition as a precision watchmaker and its legacy of high-sea navigation, Arnold & Son has ensured that this moon-phase timepiece will remain accurate for 122 years. This means that, if kept constantly wound, it would take more than a century for the moon on the timepiece to experience a one-day time lag with its real-life counterpart in the sky. 

Technical specifications 

Functions                 

• Hours, minutes, astronomical moon phases

Movement

• Calibre: A&S1612, mechanical with manual winding
  
• Jewels: 24
  
• Diameter: 29.4 mm
  
• Thickness: 4.95 mm
  
• Power reserve: 90 hours
  
• Frequency: 3 Hz/21,600 vph
  
• Finishes:
  mainplate: rhodium-plated, Côtes de Genève stripes radiating from the centre
  bridges: polished and chamfered
  wheels: circular satin-finished
  screws: blued and chamfered, polished heads                                          

Dial                          

• Ruthenium crystals and mother-of-pearl marquetry tinted in graduated shades of green and blue hour-markers set with 5 marquise-cut diamonds 

Moon phases           

• sky: mother-of-pearl tinted with graduated shades of blue
  
• moons: ruthenium crystals
  
• Big Dipper and Cassiopeia constellations: hand-painted                                

Case

• Material: 18-carat white gold, set with 80 brilliant-cut diamonds
  
• Diameter: 38 mm
  
• Thickness: 10.44 mm
  
• Crystal: Domed sapphire with an anti-reflective coating on both sides
  
• Case back: Sapphire with an anti-reflective coating
  

Water resistance        

• 3 bar (30 metres/100 feet) 

Strap

• Material: teal-blue satin-feel alligator leather, raspberry-pink alligator-leather lining, hand-stitched
  
• Buckle: pin buckle, 18-carat white gold, set with 22 brilliant-cut diamonds 

Diamonds                

• total weight: ~2.62 carats
  
• colour: D-E-F
  
• clarity: IF-VVS                                 

Limited edition         

• 18 timepieces            

Reference                

• 1GLM.WZ03A.C247A
  

Astronomy, Chronometry and World Time

Arnold & Son's three founding principles

Throughout human history, measuring time has always referred to the stars. It was by observing certain stars and understanding their cycle that the first calendars were established with impressive accuracy. It took several millennia before this precision was enclosed in a timepiece like the ones designed by John Arnold. 

The golden age of maritime explorations and discoveries ushered this precision into a new technical ideal – determining longitude at sea. Its immediate corollary was the identification of local time, which changed constantly as the observer moved along an east-west axis. Astronomy, chronometry and what we now call world time are thus inextricably linked within one and the same question, to which John Arnold and his son devoted their lives, their art and their genius. 

This is how these three dimensions – astronomy, chronometry and world time – have come to be embodied in the House's contemporary timepieces.  Echoes of John Arnold's inventions and preoccupations, these pillars represent the foundations on which the Arnold & Son collections are based.

Chronometry: Be accurate

Rate accuracy, which is known as chronometry, is the key requirement of Arnold & Son's contemporary watchmaking. It is the standard of excellence for its collections, the first condition to be met and constantly checked, whether it is at the forefront or in the background of a watch designed by Arnold & Son. It is the most discreet of a movement's characteristics. 

When building an Arnold & Son collection, all the thinking is focused on this chronometry. The manufacture calibres are based on advanced technical fundamentals that are not necessarily the best known. One of them is the choice of small, lightweight balances capable of rapidly returning to their isochronous rate after the latter has been disturbed by inevitable everyday shocks. Another is the routine use of large barrels or even two series-coupled barrels to store the energy required for the movement to function.  They consequently provide Arnold & Son's manual winding calibres with above-average power reserves of 90 hours and more. A third is the particular attention paid to manufacturing the gear trains, roller-burnishing the pinions and polishing the gear teeth, as well as the precision of the machining and therefore the relative positions of the moving parts, a key concept in rate accuracy.

The tourbillon (or the fact of putting the regulating organ in rotation on its axis to best adjust the effects of gravity on the balance and its hairspring) was patented after John Arnold's death, but it was undoubtedly at the heart of his chronometric research and discussions with his friend Abraham-Louis Breguet, who incidentally assembled his first tourbillon on a John Arnold pocket watch in homage to this great watchmaker. Nowadays, the tourbillon has become a must in Arnold & Son collections.

While the tourbillon was not a complication in John Arnold's time, constant force underpinned the design of his marine chronometers. The regularity of the rate of the sprung balance relies on the consistency of the energy that it receives. However, this naturally fluctuates due to the circular and spiral nature of the mainspring contained in the barrel. To achieve a perfectly smooth torque, in other words a constant force, Arnold & Son uses a one-second constant-force mechanism. Housed just before the escapement, it stores up a small but always equal amount of energy in a secondary spring, the remontoire. Thus, every second, the sprung balance receives very precisely the same force to power its oscillations. These become more even, thereby creating the conditions for a high-precision rate.

Arnold & Son also works with another of John Arnold's historical chronometry indicators: deadbeat seconds, a mechanism that was indispensable to navigators at the time for calculating longitude. This mechanism advances one step each second, rather than six or eight smaller jumps in sync with the frequency of the balance. Instead of the term deadbeat seconds, Arnold & Son prefers a name whose very sound means accuracy: “true beat second”. Its jump is a signature of John Arnold's marine chronometers and a complication that is still alive and well in the House's collections.

Astronomy: Under the sky

The Pole Star, Southern Cross, astrolabes and sextant: measuring time has relied on the recurrence of astronomical phenomena in order to find long, reliable points of reference there that can be used under any conditions. The fruit of the human ingenuity, patience and dedication of countless observers and astronomers from every culture, these markers of cyclical time are foundational for Arnold & Son watchmaking.

Astronomical complications are a signature of Arnold & Son collections, with the moon as the heavenly body of choice, main subject and major inspiration. The distinctive feature of the Brand's moon phase timepieces is that they feature “astronomical” display precision as a matter of course. This term corresponds to an accumulated one-day deviation in the moon phase display every 122 years. Since setting this complication requires great finesse, the Arnold & Son moons generally have a double display with a secondary indicator on the case back next to the movement. This extremely rare display bears witness to Arnold & Son's involvement in all types of development and reflects its favoured themes, which are as much chronometric as astronomical.

Over and above their precision, Arnold & Son's moon phases attract all the light, either with a large moon opening up over half the dial, or with a 12-mm three-dimensional rotating moon, making it the largest of all moons. Whether in two or three dimensions, the moon is always treated as a small work of artistic craftsmanship, composed of materials that are rare in watchmaking such as marble or Paraíba tourmaline, or delicate such as mother-of-pearl, meteorite or aventurine glass. The Arnold & Son moon also shines at night, often with a subtle addition of luminescent material. 

World Time: Here, elsewhere, everywhere

With ocean navigation, humankind divided up the world and invented longitudes, which were calculated by comparing the local time, observed using the sun, and the time at a starting point, kept by an extremely reliable timepiece. John Arnold was one of the leading suppliers of chronometers to the British Navy. He was the one who successfully improved the reliability and simplified the production of these indispensable marine chronometers, so much so that he became a benchmark among great explorers such as James Cook and later Dr David Livingstone. The indication of several time zones is therefore integral to Arnold & Son's watchmaking identity.

As this navigation was itself inseparable from cartography, for this world time complication Arnold & Son has chosen to depict a three-dimensional terrestrial hemisphere, making it possible to tell what time it is at any point.

In parallel to this graphic vision, Arnold & Son has developed a second approach to the time elsewhere in the world: with a double tourbillon featuring two distinct rotating regulating organs, making it possible to follow time zones offset by 15, 30 or 45 minutes compared to a full hour – a freedom in terms of setting that remains extremely rare. 

Once again, and because this double display is based on a profoundly chronometric complication, Arnold & Son’s fundamental principles are interwoven. One never advances alone; there are always two – if not three – together. This is how a pillar's strength is measured: it relies on the next one, creating the conditions for a solidity that stands the test of time.