It's time for cherries at the Croft:
Juice of one lemon
Remove pips from cherries. Crack open at least 12 and preferably more pips and extract the kernels. Cover cherries and kernels with the sugar and warm slightly so that the sugar dissolves in juice. Leave to stand 24 hours.
Remove cherries and boil down the syrup to 107ºC on the sugar thermometer
Add the cherries. Boil and count 2 minutes. Take off the heat for 2 minutes. Put back on heat and boil 2 mins. Take off for 2 mins. Put back and boil for 2 mins - in other words you do the hokey-kokey on-and-off-the-boil thing three times.
Put the cherries into sterile jars. Reduce the syrup again to 107ºC, then fill up the jars. I normally finish off the whole thing by sterilising the jars in a bain marie.
These cherries are really good for using in cakes and pastry afterwards. They are a little like prunes (pruneaux séchées if you are reading this in France...)