Leaving now the problem of getting over the mechanical difficulties of our speech, let us see what the little explorer has to do when trying to use verbal sounds with their right meanings. Here, too, we shall find that huge difficulties beset his path, and that his arrival at the goal proves him to have been in his way as valiant and hard-working as an African explorer. One feature of the early tussle with our language is curious and often quaintly pretty. Having at first but few names, the little experimenter makes the most of these by extending them in new and surprising directions. The extension of names to new objects on the ground of some perceived likeness has been touched on above (p. 3); and many other examples might be given. Thus when one child first saw a star and wanted to name it he called it, as if by a poetic metaphor, an "eye". In like manner the name "pin" was extended by another child to a crumb just picked up, a fly, and a caterpillar, and seemed to mean something little to be taken between the fingers. The same child used the sound "'at" (hat) for anything put on the head, including a hair-brush. Similarly children often extend the names "Mamma, baby" to express any contrast of size, as when a small coin was called by an American child a "baby dollar". In this extension of language by the child we find not merely a tendency to move along lines of analogy, as in the above instances, but to go from a thing to its accompaniments by way of what the psychologist calls association. This is illustrated by the case of Darwin's grandchild, who after learning to use the common children's name for duck, "quack," proceeded to call a sheet of water "quack". In like manner a little girl called the gas lamp "pop" from the sound produced when lighting it, and then carried over the name "pop" to the stool on which the maid stood when proceeding to light it. There is another curious way in which children are driven by the slenderness of their verbal resources to "extend" the names they learn. They will often employ a word which indicates some relation to express what may be called the inverted relation. For example, like the unschooled yokel they will sometimes make the word "learn" do duty for "teach" also. In one case "spend" was made to express "cost". It was a somewhat similar inversion when a little girl called her parasol blown about by the wind "a windy parasol," and a stone that made her hand sore "a very sore stone".