You can see what it looks like in _fig. 6_. When alive, it is of a light-green color, but when decayed it becomes brown. It is full of the _spiculae_ above described, which serve to stiffen it, but it easily crumbles and scatters them through the water. Though the microscope shows us many beautiful and interesting objects, yet in the present state of our knowledge we cannot ascertain by its use whether the water we examine is harmless or injurious. VII.--THE BRICKMAKER. The microscope reveals so many strange odd-looking water creatures and plants that we can easily imagine ourselves transported to some new world. Look at this field of view as seen through the microscope. In the centre stands a brickmaker. He is a queer little animal, and so small that he looks like a mere speck to the naked eye, but through the microscope we see how wonderfully curious and strange a creature he is. He is no idle, lazy fellow. He is instead a most busy mechanic. Just now he is building a house out of tiny bricks, and he manufactures the bricks himself, making them one at a time, and when one is finished he lays it down carefully by the side of the last, and fastens it firmly in its place with a kind of cement. The bricks are laid in regular tiers one above the other. We find these brickmakers in still water where various water-plants grow, especially the water-milfoil and bladderwort. They seem to be social beings. They live in large communities, attaching their houses to the stems and leaves of the plants so thickly sometimes that they almost touch one another. They look, to the naked eye, like lines about one eighth of an inch in length. Sometimes they are very thick on the plants in New Jersey ponds. If you take some of the plants and water, and put them in a bottle, you can carry a large number of the brickmakers home, where you can watch them at your leisure. Take a glass slide which has a little cup-shaped hollow to hold a few drops of water, and put a tiny piece of the plant with the house attached into this hollow and fill it with some of the water from the bottle. Now cover it with a very thin piece of glass and lay it over the stage of the microscope, and it is ready to be looked at and studied. You will look with both eyes, for your microscope is a binocular--one that has two tubes to look through. The size of the objects will depend upon the magnifying power you have chosen.