Arrange the sentences P, Q, R and S to form a logical sequence between sentences 1 and 6.

1. Henry was able to study the Loch Ness monster for four minutes, the length of time for which it remained in view.

P. Soon, it zigzagged up the loch at about five miles an hour.

Q. It was dark in color and had a three-foot long neck and a slim head about the size of a dog's.

R. It remained in view for four minutes by Henry's watch.

S. The monster was half a mile from shore but clearly visible in the sunlight.

6. And finally, submerged opposite to him, leaving a frothy streak on the surface.