For small instruments, such as we are dealing with, the mounting generally adopted is that known as the Altazimuth, from its giving two motions, one in altitude and one in azimuth, or, to use more familiar terms, one vertical and the other horizontal. There are various types of the Altazimuth. If the instrument be of not more than 3 feet focal length, the ordinary stand known as the 'pillar and claw' (Fig. 9) will meet all the requirements of this form of motion. Should the focal length be greater than 3 feet, it is advisable to have the instrument mounted on a tripod stand, such as is shown in Fig. 10. In the simpler forms of both these mountings the two motions requisite to follow an object must be given by hand, and it is practically impossible to do this without conveying a certain amount of tremor to the telescope, which disturbs clearness of vision until it subsides, by which time the object to be viewed is generally getting ready to go out of the field again. To obviate this inconvenience as far as possible, the star or planet when found should be placed just outside the field of view, and allowed to enter it by the diurnal motion of the earth. The tremors will thus have time to subside before the object reaches the centre of the field, and this process must be repeated as long as the observation continues. In making this adjustment attention must be paid to the direction of the object's motion through the field, which, of course, varies according to its position in the sky. If it be remembered that a star's motion through the telescopic field is the exact reverse of its true direction across the sky, little difficulty will be found, and use will soon render the matter so familiar that the adjustment will be made almost automatically. [Illustration: FIG. 10.--TELESCOPE ON TRIPOD, WITH FINDER AND SLOW MOTIONS.] A much more convenient way of imparting the requisite motions is by the employment of tangent screws connected with Hooke's joint-handles, which are brought conveniently near to the hands of the observer as he sits at the eye-end. These screws clamp into circles or portions of circles, which have teeth cut on them to fit the pitch of the screw, and by means of them a slow and steady motion may be imparted to the telescope. When it is required to move the instrument more rapidly, or over a large expanse of sky, the clamps which connect the screws with the circles are slackened, and the motion is given by hand. Fig. 10 shows an instrument provided with these adjuncts, which, though not absolutely necessary, and adding somewhat to the cost of the mounting, are certainly a great addition to the ease and comfort of observation. [Illustration: FIG. 11.--EQUATORIAL MOUNTING FOR SMALL TELESCOPE.]