HARDWICKE'S S C I E N C E-GO SSI P. 



87 



ments so that they can be so used. Of course 

 there are exceptions, and it has been to meet these 

 tiiat I have contrived the piece of apparatus I am 

 about to describe. In fact it was to assist just 

 such hungry inquirers after knowledge, and lift 

 (hem over their difficulty, that I contrived my 

 supplemental stage. It consists of a sheet of brass 

 a trifle thinner than an ordinary slide. This is cut 

 and bent in such a manner that there is a plate of 

 the same size as an ordinary slide, only having a 

 hole in the middle which rests upon the stage of 

 the microscope and is held in position by the 

 spring clamps attached thereto. The hole in the 

 middle is not necessary, but sometimes convenient. 

 From one of the longer sides, the one next the 

 observer, rises an upright, which is part of the 

 original sheet of brass bent, or it can be soldered 

 on afterwards. This projects upwards about three 

 quarters of an inch, and is then bent at right angles 

 so as to run parallel with and over the bed-plate, 

 where it has its middle portion cut away, so that it, 

 in fact, becomes two strips, each about a quarter of 

 an inch wide. At an inch and a quarter from their 

 upright portions these strips are again bent, but 

 this time over something round, like a cedar pencd, 

 so as to come down again on top of the horizontal 

 supporting portions, and form spring clips, by 

 means of which the slide is held in place when laid 

 upon the slips themselves. Using this contrivance, 

 the slide is held above the stage of the microscope, 

 having absolutely nothing under it to obstruct light 

 of the greatest obliquity. 



And, lastly, a cheap form of amplifier by means 

 of which the magnifying power of any objective 

 and ocular may be doubled or even enlarged to a 

 greater extent. The idea of this dodge we owe to 

 Mr. E. C. Bogert, the worthy Treasurer of our 

 Society, another dodge-contriver. This is simply a 

 double-concave lens, such as is used to form the 

 eye-lens of common opera-glasses. These are 

 very cheap, and when placed between the ocular 

 and objective, increase their magnifying power -very 

 greatly, without interfering to any great extent 

 with the definition. 



At some future time I will send you a few more 

 chips struck off from our active Society. 



THE WRYNECK. 



riPHE adaptation of the structure of the Wry- 

 ■*- neck to its habits is not inferior to that 

 of the Woodpecker, or indeed of any other bird. 

 Those warm, lowland, and (compared with the North 

 and West of the country) dry regions to which it 

 comes, abound with the minuter insects, especially 

 with aphides and the smaller tribes of ants. These 

 last arc continually careering about on the boles 

 and branches of the trees ; and it is to them es- 

 pecially that the attention of the Wryneck is 



directed, so much so as to have merited and ob- 

 tained the provincial name of the "Emmet-hunter." 

 These auts the Wryneck catches with the tongue, 

 an organ which it can protrude at least an inch, and 

 retract again with the rapidity of lightning, so that 

 when the ants are coursing about they are picked 

 up, oue by one, without the capture producing any 

 alarm, or even being noticed by the rest. They are 

 captured not only on the stems of trees, but on the 

 ground, and they are even picked from their dens 

 and hills, especially at those times when they are 

 busy in bringing out the larvae to the sun and air. 

 Disturbing their dwelling readily brings out the 

 auts at any time, if the weather is dry, and the 

 Wryneck uses both its bill and the horny point of 

 its tongue for that purpose; aud when the little 

 warriors mount the breach to reconnoitre and try if 

 they can repel the enemy, the Wryneck picks them 

 up, soldier after soldier, till none are left. When 

 it is engaged over an abundant supply of its favour- 

 ite food, whether on the trunk of a tree or on the 

 ground, the body is motionless, but the head is con- 

 tinually moving from side to side, and the dark 

 mesial line on the back twining like a serpent. At 

 those times the motions of the tongue are so quick 

 that they can hardly be observed. Indeed, the bird 

 is altogether so shy and retiring in its habits, that 

 it is difficult to be got sight of, unless one come 

 softly upon it at those times when it is basking on 

 or near the ant-hills, while the ants are taking their 

 siesta, which most of them do, though at different 

 times, according to the variety. — Jludie, " The 

 Feathered Tribes of the British Islands." 



THE MINA AND THE CHOLERA. 



A CURIOUS phenomenon has recently occurred 

 -£*- at Mauritius, where that terrific scourge the 

 cholera has been raging with desolating effect. 

 There is a bird in that island called the Martin, but 

 it is more properly the Mina. This bird is about the 

 size of the starling, whose habits it possesses in a 

 great degree. It exists in immense numbers, and is 

 a grand destroyer of all insects. On this account it 

 is seldom or ever shot at, especially as it is a great 

 comforter to all cattle, whose hides it entirely clears 

 from ticks and other vermin. During the prevalence 

 of cholera at Mauritius, these birds disappeared. 

 Such a circumstance had never before occurred, and 

 the real cause of their departure is still a mystery. 

 May it not have been that some species of insect on 

 which they fed had likewise migrated, and that 

 certain noxious animalcules which had been kept 

 down by this class had thus multiplied in the at- 

 mosphere until their numbers caused disease ? All 

 suppositions on such a subject must, however, remain 

 in obscurity, as no proof can be adduced of their 

 correctness.— S. W. Baker, " Wanderings in Ceylon" 



