As the Duchess of Cornwall enjoyed an ice cream with Dame Judi Dench on the Isle of Wight, the Prince of Wales was in a Staffordshire forest learning about CO2 levels.
Camilla's day with Dame Judi consisted of a trip to Queen Victoria's former home, Osborne House, while Charles spent most of his time with horses and trees.
The prince was taken through the finer points of horse dentistry at Pool House Vet’s Equine Clinic, Staffordshire before heading over to woodland in the county to learn about University of Birmingham’s Institute of Forest Research (BIFoR) Free-Air Carbon Dioxide Enrichment (FACE) experiment.
Meanwhile, Dame Judi, who is patron of the Friends of Osborne House, welcomed the duchess to the island after she arrived at the Queen's private beach.
The actress showed Camilla the house's restored Durbar Room, which was one of the locations for Victoria And Abdul, a film starring Dame Judi in the title role.
Osborne House was purchased by Victoria and Prince Albert in 1845 and was one of the Queen's favourite family homes - she once said: "It is impossible to imagine a prettier spot."
In the forest Charles learned about work to model how forests could help tackle climate change.
University of Birmingham’s site was established with a £15 million donation in 2014, to provide fundamental science, social science and cultural research on woodlands and forests.
The outdoor facility is made up of 80ft-90ft gantry towers in the oak forest.
Unveiling a plaque made of planed oak, he quipped: “You’re not going to put it at the top of the tree are you?”
Carbon dioxide is pumped through large pipe workings, up into the canopy and measured at ground and leaf level.
It is aimed at modelling the effect of CO2 levels based on assumptions of levels in 2050, and using that data to help understand climate changes and what forests might be able to do to help.
He was presented with a gift from the university – an engraved bottle found in the forest during construction, which was filled with air from the forest at its predicted CO2 level in 2050.
Accepting the present, he joked with the scientists, researchers and dignitaries: “I’ll be 102 by then.”
Later in the day Charles visited Pool House Vet’s Equine Clinic and got hands on with the animals when he donned a rubber glove and carried out an ultrasound on a horse which once rode in the same hunts as the royal visitor.
There were grimaces all around the room when he was told that pulling a horse’s tooth can take up to two hours.
The prince met an old acquaintance, Lenny, a 20-year-old horse who was ridden alongside Charles in his hunting days, as he went hands-on with the ultrasound inspection.
Lenny stood quietly while the royal visitor looked at the ultrasound image of his foreleg on the monitor, and Charles said: “He’s been very patient for a horse – you haven’t tranquillised him have you?”
After touring surgical theatres and stables, he unveiled a plaque and was presented with an ornamental gift by Annie and Martha Withers, aged five and three, the daughters of the clinic’s medical director.
Charles also sat down with Action Oak campaigners who are working to protect the nation’s oak trees from pests and diseases.
Professor Michael Tausz, director of the University of Birmingham's CO2 experiment, said the facility was “massively important” to understanding and accurately modelling climate change and added that Charles’s visit was “very important”.
“He has such a high profile and can tell people about what we are doing here,” he said.