glass-blowers themselves that they are very often as much opposed to the introduction of adult helpers as are their employers, for the reason that they believe adults would not serve them with the same speed as boys. For these reasons, and many others into which it is impossible to enter here, I am convinced that little good will result from a propaganda aiming to show the employers that their economic interests would be best served by the abolition of child labor. In a similar way it has been urged, with ample evidence of its truth, that the employment of children retards the introduction of mechanical devices and their fullest development.[146] This is perfectly true, not only of child labor, but of almost all forms of labor that are unhealthful or degrading. There is absolutely no need of human street sweepers, exposed in all weathers and constantly inhaling foul, disease-laden dust, any more than there is need of little boys working in the glass factories, carrying red-hot bottles to the ovens. In each case machinery has been invented to do the work, and it is used to a small extent. If these occupations, and scores of others, were absolutely prohibited, and the prohibitory law rigidly enforced, streets would still be swept, but by mechanical sweepers, and bottles would still be taken to the annealing ovens, but by mechanical means. The world will probably, let us hope, never become the paradise dreamed of by the German dreamer, Etzler, who believed that all the work of the world would be done by machinery in the future, and human labor become altogether unnecessary.[147] But there is no doubt that much of the work which to-day degrades body, brain, and soul could be done just as well by mechanical agents. Not, however, through sermonizing or appealing to the employers will these mechanical devices be generally adopted to take the place of the life-destroying labor of boys and girls; but by making it increasingly difficult, and finally impossible, for them to employ child labor at all.