If the horse has been accustomed to work the lesson, with a lady he will obey these aids. But in some cases it is necessary for the master (to supply the absence of the right leg of a man to the horse), to push firmly with his left hand against the horse's ribs to move him off. The rider, while leading the horse off with the left rein, should keep up a continual, light easy play of the right rein, so as to preserve the bend inwards. The instructor should count "one, two," in very slow time, as the horse moves first his fore and then his hind leg. After a few steps onward the horse should be halted, by the rider feeling both reins, and closing the whip firmly on the off side. He should then be made much of and moved on again. A quarter of an hour is ample for the first lesson. After the pupil understands and can apply the aids for the "shoulder in" (riding on the snaffle), she maybe taught to do it on snaffle and curb together, and then on the curb alone, when she will find the nicest balance in her seat and the most careful and delicate manipulations of the reins necessary--joined, however, to distinct and perceptible feeling upon the horse's mouth. And on moving her horse forward she will find that her hand is true and steady. The "shoulder in" having been neatly done, the lady should rein her horse lightly back and ride him forward, _making the corner_ of the school quite square, and then halt at the centre marker. On the word "right half passage," she should turn the horse's head square down the centre of the school, and exactly reverse the aids by which she worked the "shoulder in"; that is, she should lead the horse off with the right or inward rein, well balancing and assisting its power by the outward one; with her leg she should press the horse until he places one foot before the other, gaining ground to his front, and obliquely to his right at the same time, until he arrives at the boards, when he will completely have changed the hand he was working to, and at a canter would, if necessary, be called upon to strike off with the left leg instead of the right. After executing the "half passage" correctly, the pupil may practice the "full passage," the difference between which and the "shoulder in" is again concisely explained in the "Aid Book." "Q. What is the difference between the 'passage' and 'shoulder in'?--A. In the passage the horse bends and looks the way he is going. The outward are crossing over the inward legs, and the inward rein leads. In the 'shoulder in' the horse does not look the way he is going. The inward are crossing over the outward legs, and the outward rein leads." "Q. What is the difference between the full and half passage?--A. In the 'full passage' the horse crosses his legs. In the 'half passage' he only half crosses them, placing one foot before the other."