I think we all know what he meant. Scrying is a method of divination to foresee future events. There are many different forms of scrying. It is also called "gazing" sometimes as you gaze into different items to get these visions. You could use a crystal ball, water or oil in a polished metal bowl, eye gazing, cloud scrying, smoke scrying, fire gazing and stones were used in earlier centuries.
Many different people in history have used scrying to foresee events. Celts, Druids used crystals in the forms of scrying plates. In the 1950's a Greek archeologist found a temple where an oracle would do gazing in a bronze cauldron. They also found rooms with mirrors used to communicate with the spiritual realm. Also called mirror gazing. Ancient Babylonians, Egyptians, and Hebrews would use oil scrying. Native Americans would use smoke scrying.
Mirror gazing is a popular method and comes in two forms. The first requires an individual to stand before a mirror and stare into their reflection. By relaxing their vision images appear in the reflection and spiritual messages can be interpreted or questions can be answered. The second method uses a mirror as a scrying plate. A mirror is placed flat on a table or at a 90degree angle. A flame or small light is placed near the mirror to allow the light to reflect onto the mirror. The scryer would then interpret spiritual messages or discern answers to questions from the lights reflection and perceived images.
Cloud gazing is a method that uses the clouds in the sky. The person determines what shapes the clouds are and watches them change to show how current events will take place.
A crystal ball can be used to gaze into and reads the images that appear in the reflection.
Hydromancy is a method of using water. Using color, flows, and ripples produces by pebbles being dropped into a pool. You then interpret the spiral answers in the water.
Lychnomancy is a form of divination by fire or flame. Using the light of an oil lamp, or the flame of fire or candles. Images are seen in the flames, to give messages to the seer.
Oil gazing is a method of scrying using oil in different ways. It can be placed in a dish, rubbed on the hand or forehead, coated within a cup or plate to reflect light directed into the oil.
Scrying plates are often made of stone or crystal polished to a very high gloss for reflection. A scryer would gaze into the reflection or would coat the plate with water or oil and gaze into the reflective service. The scryer would then interpret spiritual messages or discern answers to questions from the images perceived in the reflection.
Smoke gazing is a method of scrying using smoke from a flame or typically a fire. As the smoke rises, images are perceived in the smoke that details spiritual messages for the seer.
I hope this has helped clarify.