Practitioners in the Victorian Era. A person who practiced medicine in the Victorian era did not always possess a degree from a university. There were doctors with formal educations tending to patients as well as apothecaries freely dispensing medical advice. Furthermore, homemade remedies passed between neighbors.
Martin Luther King Jr. envisaged a time when black and white Americans would no longer be segregated by race. To envisage is to imagine something that does not yet exist. The words envisage and envision share the same Latin root meaning to see. Both words are very similar in meaning but do have slight shades of difference. If you envision something happening, you can see it happening in your mind. I'm sure you can envision yourself graduating from high school!
An example of how an object could appear to be invisible through the use of mirrors. Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, not visible). Comparing light waves to the water, and whatever object that is being cloaked to the stone, the goal is to have light waves pass around that object, leaving no visible aspects of it, possibly not even a shadow. 2  This is the technique depicted in the 2000 television portrayal of The Invisible Man.