be induced by scheming men in an old one. Not the least attractive feature in this museum is the collection of portraits of great inventors. The marked individuality in every countenance is very observable. But these are the lineaments of the famous and fortunate discoverers. The philosopher must in his own mind draw a picture of the amount of care and struggle represented by the great mass of patents in this room. Of the many years spent in efforts which have only terminated in the total impoverishment of the thoughtful toilers, of the many hopes blasted, of the castles in the air that have been transformed to dismal prisons, we do not see here the expression on the canvas, but be sure they have existed, and will exist as long as there remains in man an irresistible impulse in the path of progress, and a God-like energy to pursue it at all cost and sacrifice.
GREEN SEAWEEDS.
Most people who have visited the sea-side know some little about seaweeds. They are familiar with the characteristics of the three great orders into which this class of plants has been divided, have learned to distinguish some of the commoner and more elegant species, and have perhaps made a small collection of specimens more or less skilfully dried upon paper. They know, too, something of the purposes to which some of the seaweeds are applied, have probably tasted laver and Irish moss, and have heard that the Scotch eat dulse, and that the ashes of the fuci are made into kelp. And with this amount of knowledge very many rest content. Yet there are few objects which offer more points of interest than the seaweeds to any one who is willing to look a little way below the surface, and to spend a few hours in learning something of their modes of growth and propagation.
The name seaweed can in its strict sense be applied only to plants growing in the sea. If, however, we use it as a translation of the botanical term algæ, it becomes applicable not only to these, but to a considerable number also which are never found in salt water. Every river and brook, every pond, ditch, and roadside puddle has its algæ—even on damp earth and walls they are seldom wanting. On the other hand, at least one plant growing in the sea, the Zostera marina, sometimes called seagrass, is a true flowering plant, and cannot therefore properly be called a seaweed. It has been found convenient to divide the algæ into three great divisions: the confervoideæ, otherwise called chlorospores, or green-spored algæ; the florideæ rhodospores, or red-spored algæ; and the fucoideæ melanospores, or dark-spored algæ. Colour, which is generally a mark of very small value in classification, is here a tolerably safe guide, so that we shall not go far wrong in calling all the brown seaweeds melanospores, all the red seaweeds rhodospores, and all the green seaweeds chlorospores. It would be impossible in the space of a single article to give even the slightest sketch of the history of these three orders, and we shall therefore for the present confine our attention to the last only, the chlorosperms or green-spored algæ, and to those only of this order which are found in salt water.
The green seaweeds which we find growing on our seaside rocks belong most commonly to one of the four genera: conferva, cladophora, enteromorpha, and ulva. The broad bright-green fronds of the Ulva lactuca, the lettuce ulva, or laver, are too well known to need any description, but there are some curious episodes in its history which are far less generally known.
Among the strange facts which modern improvements in the microscope have brought to light, there are few more unexpected and more startling to our preconceived ideas than the possession by certain plants of a faculty of motion so like in every respect to that of some of the lower animals, that the first observers had no suspicion of their vegetable nature. You may perhaps feel inclined to doubt the possibility of the existence of these moving plants; you may think that the story is a mere scientific figment contrived for the purpose of puzzling the unlearned, and you ask why we cannot be contented with the good old definition of our younger days, “Plants live and grow; animals live, grow, and move.” If you happen to be by the sea-side, you may soon satisfy your doubts, and in no way more easily than by bestowing a little attention upon the common green laver. Go down to the beach at almost any state of the tide, and in the first rock pool you see you will probably find some of the conspicuous bright green fronds of this seaweed. Probably, too, if you look closely you will see that some of the fronds seem to have lost their brilliant hue and are limp, transparent, and colourless, not unlike wet tissue paper. They are faded, you say, and dying. By no means. Never were they more full of life than they are now. Gather one of these colourless fronds, or rather one which is half green, half colourless, and take it home with you for examination. Cut off carefully a small piece from that part of the frond through which the line passes, dividing the green from the uncoloured half, and having placed it in a little sea water on the stage of the microscope, examine it with an object-glass of a quarter of an inch focus. You will, in the first place, see that the frond of laver is composed of a network of small, many-sided, irregularly-shaped cells densely packed together with their sides in contact, and by slightly altering the focus you will find that another and precisely similar layer constitutes the under surface of the frond. Next, if you turn your eye from the seaweed to the water in which it is floating you will see, nimbly swimming about, a considerable number of small green bodies in shape something like a pear. These, if you now see them for the first time, you will, beyond all doubt, pronounce to be animals, probably belonging to the class of the infusorial animalcules. But you will be very far from the truth in your guess, for these pear-shaped bodies are the zoospores, or moving spores of the green laver, and have probably just emerged from one of the cells of the fragment at which you are looking. Now look again at the seaweed, and observe particularly the cells of which the coloured portion is made up. These you will find to be filled with a