Gideon the Cutpurse by Linda Buckley-Archer
Peter was supposed to have a special birthday treat from his father, but was once again disappointed when his father chose business indtead. Peter was not happy when the Maid woke him up and proposed that he was to go with heron her trip to the farm for a few days.
When they arrived at the farm Peter was not in the mood to enjoy any of it. But as it turned out, he goes along with Kate and her father, a known scientist to see a top secret machine, called the Van de Graf generator. It was on this short trip that everything starts to go out of wack.
When Molly the dog runs off, the children chase her through the complex when suddenly they disappear along with the antigravity machine. Everything is all down hill from here. Peter and Kate get thrown back in time to the 1700's. When they arrive on the hillside they do not arrive with out notice. More than one person is watching, questioning their arrival out of thin air.
On arrival they are knocked out and just when they are coming round they look up to see the villianous "Tar Man" who is the most evil man of the 17th century. Waiting, watching is another, gideon the Catpurse, but is he friend or foe? With a noisy diversion Gideon is able to distratct the Tar Man away from Peter and Kate to alow them to escape. In time Gideon is able to take them under his wing and together they begin a journey to recover the time machine from the infamous Tar Man and hopefully return home to their own century. There is only a slight problem as the Tar Man wants the machine for himself and will do anything to get it.
This is just the beginning of the journey, with two other books to come after...for which I can hardly wait to read.