Hammer drills may be classed under several heads, as follows: (1) Those mounted on a cradle like a piston drill and fed forward by a screw; (2) those used and held in the hand; and (3) those used and mounted on an air-fed arrangement. The last two classes are often interchangeable.
Mr. Leyner, though now making drills of the latter classes, was the pioneer of the large 3-inch diameter piston machine to be worked in competition with large piston drills. The smaller Leyner Rock Terrier drill was brought out for stopping and driving; it could not, apparently, compete with machines of other classes.
When the drills are thus divided we have:
1. Cradle drills—Leyner, Leyner Rock Terrier, Stephens Imperial hammer drills and the Kimber.
2. Drills used only with air feed—Gordon drill and the large sizes of the Murphy, Little Wonder, and others.
3. Drills used held in the hand or with air feed—Murphy, Flottman, Cleveland, Little Wonder, Shaw, Hardy Nipper, Sinclair, Sullivan, Little Jap, Little Imp, Traylor, and others. Again, they may be divided into those that are valveless, with the differential piston or hammer itself acting as a valve. The Murphy, Sinclair, Little Wonder, Shaw, Little Imp, Leyner Rock Terrier, and Kimber drills belong to this class. The large Leyner drill is worked by a spool valve resembling that of the Slugger drill; the Flottman by a ball valve; the Little Jap by an axial valve; the Gordon drill, by a spool valve set at one end of the cylinder at right angles to it; the Waugh and Sullivan drills by spool valves set in the same axial line as the cylinder; the Hardy Nipper, and the Stephens Imperial hammer drills by an air-moved slide-valve set midway on the side of the cylinder; the Cleveland by a spool set towards the rear of the cylinder.
They may again be divided into those drills in which the piston hammer delivers its blow on the end of the steel itself. A collar is placed on the drill to prevent its entering the cylinder. The other class has an anvil block or striking pin. This anvil block fits into the end of the cylinder between the piston and the steel. It receives and transmits the blow, and also prevents the drill end from entering the cylinder.[36]
Powerful among the enemies of Shakespeare are the commentator and the elocutionist; the commentator because, not knowing Shakespeare's language, he sharpens his faculties to examine propositions advanced by an eminent lecturer from the Midlands, instead of sensitizing his artistic faculty to receive the impression of moods and inflexions of being conveyed by word-music; the elocutionist because he is a born fool, in which capacity, observing with pain that poets have a weakness for imparting to their dramatic dialog a quality which he describes and deplores as "sing-song," he devotes his life to the art of breaking up verse in such a way as to make it sound like insanely pompous prose. The effect of this on Shakespeare's earlier verse, which is full of the naïve delight of pure oscillation, to be enjoyed as an Italian enjoys a barcarolle, or a child a swing, or a baby a rocking-cradle, is destructively stupid. In the later plays, where the barcarolle measure has evolved into much more varied and complex rhythms, it does not matter so much, since the work is no longer simple enough for a fool to pick to pieces. But in every play from Love's Labour's Lost to Henry V, the elocutionist meddles simply as a murderer, and ought to be dealt with as such without benefit of clergy. To our young people studying for the stage I say, with all solemnity, learn how to pronounce the English alphabet clearly and beautifully from some person who is at once an artist and a phonetic expert. And then leave blank verse patiently alone until you have experienced emotion deep enough to crave for poetic expression, at which point verse will seem an absolutely natural and real form of speech to you. Meanwhile, if any pedant, with an uncultivated heart and a theoretic ear, proposes to teach you to recite, send instantly for the police.[37]
Analyses are to be divided also upon the basis of whether the subject is an individual or a group of individuals, that is, whether the subject is, for example, the quality of patriotism, which is to be analyzed into its components, or, in the second place, shade trees, which are to be grouped into the classes which together constitute such trees. Of these two kinds of analysis we call the first Partition and the second Classification. The logical process is the same in the two cases, in that it divides the subject; the difference lies in the fact that in the first case the subject is always single, though it may of course be complicated, and in the second it is always plural, and may contain a very large number of individuals, as for example the human race—all the billions of all the ages gone and yet to come.
In this treatment of analysis you will find the main divisions made on the basis of formality and the matter of single or plural subject treated under each of the other headings.