- Cross section of the larva of the browntail moth showing the tubercles bearing the poison hairs
- Culex sollicitans. Female
- Culicoides guttipennis - (a) adult, (×15) (b) head of same (c) larva (d) head (e) pupa
- D.F.W. (German-designed) Biplane
A. Hull, which is steel-built, containing pilot and passenger B. Main-planes—the lower at a dihedral angle C. Uptilted stabilising ailerons, which may be locked in position D. Stabilising fin E. Rudder F. Elevating-plane G. 100-h.p. motor (which is enclosed) and propeller. - Dancing Mania
- Demodex folliculorum
- Dermanyssus gallinæ, female
- Diagram of a longitudinal section of a mosquito
It is well known that mosquitoes, when they bite, inject into the wound a minute quantity of poison. The effect of this varies according to the species of mosquito and also depends very much on the susceptibility of the individual. Soon after the bite a sensation of itching is noticed and often a wheal, or eminence, is produced on the skin, which may increase to a considerable swelling. The scratching which is induced may cause a secondary infection and thus lead to serious results. Some people seem to acquire an immunity against the poison. The purpose of this irritating fluid may be, as Reaumur suggested, to prevent the coagulation of the blood and thus not only to cause it to flow freely when the insect bites but to prevent its rapid coagulation in the stomach. Obviously, it is not developed as a protective fluid, and its presence subjects the group to the additional handicap of the vengeance of man. As to the origin of the poison, there has been little question, until recent years, that it was a secretion from the salivary glands. Macloskie (1888) showed that each gland is subdivided into three lobes, the middle of which differs from the others in having evenly granulated contents and staining more deeply than the others. - Dipylidium caninum. Rostrum evaginated and invaginated
- Dipylidium caninum. The double pored tapeworm of the dog
- Dog flea
- Driving-seat of a touring plane
- Dunne inherently stable Biplane
Another machine which is stable in flight, owing to the peculiar formation of its wings, which resist a diving or plunging movement, or a lateral swing, is the Dunne biplane—as designed by Lieutenant J. W. Dunne. This craft is seen in the figure. Using such a machine, pilots have flown for long distances with the control levers locked, the biplane adapting itself automatically to the wind-gusts and preserving its equilibrium without aid of any kind. It has neither fore-plane nor tail; it is made to ascend by elevators which are in the form of hinged flaps, or ailerons, and is steered by two rudders at the extremities of the main-planes. A. Hull containing pilot and passenger B.B. Main-planes C.C.C.C. Flaps used as elevators D.D. Side-planes which act as rudders E. Engine and propeller F. Alighting gear. - Early-type Airship
A typical craft, representing the first of those navigated with any certainty, is shown in Figure. A gas-containing envelope, made of a light, strong, varnished fabric, is kept taut by the pressure of the gas within; the car, constructed of wood or metal tubing, is suspended by ropes from the envelope, and contains engine and crew, with a two-bladed propeller revolving astern. Such a machine, in its control, had an elevating-plane and rudder, upon the same principle as those of the aeroplane. One of the difficulties to be overcome was the expansion and contraction of gas in the envelope owing to differences in altitude and temperature. When the craft ascended, its envelope completely inflated, the gas began to dilate owing to the outer air becoming less dense; and some had to be allowed to escape through automatic valves. Then, should the machine descend to a lower level, there was not sufficient gas in the envelope to keep it tightly stretched, and it tended to sag at the bow as it was driven through the air. A. Gas envelope B. Car suspended below envelope C. Motor, which drives propeller (D) through a shaft E. Small horizontal plane for rising or descending F. Fixed fin, or keel plane, to give stability G. Rudder. - Echidnophaga gallinacea
- Eggs of Anopheles
- Epithelium underlying poison hairs of the larva of the browntail moth
- Epithelium underlying poison hairs of the larva of the browntail moth (larger scale)
- Grahame-White Military Biplane - side view
Once the value of aerial reconnaissance had been proved, France proceeded to the development of a scouting aeroplane; and the need, in such a machine, is that the observer shall have a clear view ahead and below. The construction of machines was, for this reason, modified. The front elevating plane was moved to the rear, where it was fitted in the form of a flap—as in the case of monoplanes—and the pilot and observer placed in a covered-in body, which projected in front of the main-planes, as shown in the figure. By placing the body before the planes, the observer has a clear view ahead and on either side; and even when he leans over the side, and looks directly downward, there is no surface to obstruct him. A. Covered-in body, with seats for pilot and passenger B. Motor (to minimise wind resistance, only the lower cylinders are exposed to the air) C. Propeller D. Main-planes E. Rudder F. Elevator G. Landing gear. - Harvest mites. (Larvæ of Trombidium)
- Head and pronotum of (a) dog flea; (b) of cat flea; (c) of hen flea (d) Nycteridiphilus (Ischnopsyllus) hexactenus
- Head of a spider showing poison gland (c) and its relation to the chelicera (a)
- Hull of a Zeppelin during construction
Hull of a Zeppelin during construction. Craft of the semi-rigid type provide a link between small, non-rigid ships and the very large machine which is built with an entirely rigid framework, and has its example in the Zeppelin. The maker forms a skeleton hull of aluminium or some light metal alloy, a method that is shown in figure. The hull of a Zeppelin, slightly more than 500 feet in length, is sheathed with tightly stretched fabric; and within it are the gas-containers—a row of seventeen separate balloons, each in a compartment by itself, and containing a total of nearly 1,000,000 cubic feet of gas—which give these airships a lifting power of close upon 30 tons. - Ixodes ricinus; male, ventral aspect
- Larva of Anopheles
- Larva of Fannia scalaris
- Larva of Simulium
- Launching a sea-plane from a wire
By another method, shown in figure, the sea-plane is launched from a cable suspended between two masts, and can come to rest upon the cable again after a flight has been made. The machine is hung upon the cable prior to making an ascent; then the pilot starts his engine, and as his machine glides forward along the cable he releases a catch and soars into the air. Upon returning he flies beneath the cable, and makes his craft rise until the “V”-shaped apparatus above his head is caught by the cable and the catch becomes operative; then he stops his motor, and his craft hangs from the cable as it did before. A. Sea-plane B. Cable C. The “V”-shaped apparatus which guides the cable into the clip (D.) and so suspends the machine from the wire. - Launching sea-planes from a ship’s deck
There is a type of aeroplane which will be carried to sea when a fleet sails, stowed in sections within the hull of a transport ship. This machine—a light, high-speed craft—will be assembled upon the deck of its parent ship, and launched into the air by special mechanism, as there is not room for a machine to run upon wheels, and leave the ship’s deck as it might do upon land; the vessel, besides, might be rolling in a high sea. In some cases a platform is built upon the deck, either at the bow or stern, and along this the aircraft moves, so as to gain speed for its planes to lift. In one device, seen in Figure, the machine is mounted upon a light wheeled cradle, and this is placed upon the starting-rail. Then, driven by its propeller, the plane runs forward upon the cradle till it reaches the end of the rail, when it glides into the air, the cradle falling from it and dropping into the sea, from which it is retrieved and drawn back on board the ship. The sea-plane (A.) is seen taking flight, having glided upon its cradle along the platform (B.). The cradle (C.) is just falling away below the aircraft’s hull. - Left hand stigmata of the larvæ of muscoidea
- Left spiracle of nymph of Argas persicus
- Life cycle of the malarial parasite
- Linguatula. (a) larva; (enlarged). (b) adult; (natural size)
- Looping the loop
“Looping the loop,” which has made so great a sensation, has taught airmen one definite lesson; and it is this: no matter how their machines may be beaten and tossed by the wind, they need not fear a fall—provided they are high enough above ground. The movements of a machine, as it makes a series of “loops,” are shown in the figure. The pilot reaches a high speed before he rears up his machine to begin the “loop,” and this downward velocity is attained by diving; then, when he estimates his pace sufficient, he pulls his elevating-lever back and the machine leaps upward, rearing itself vertically towards the sky, turning over on its back, then diving again and coming right-side-up—thus achieving a complete somersault. A skilled trick-flyer, also, will allow his machine to drop sideways or tail first, deliberately working the controls so that it shall do so. Then, just as it seems to spectators that he is falling to destruction, he will dive or twist, regain the mastery of his machine, and descend in a normal glide. - Lucilia cæsar
- Mandible of Scolopendra cingulata showing venom gland
- Maurice Farman Biplane
(Early Type) A. Elevating-plane B. Seats for pilot and passenger C. Main-planes D. Motor with two-bladed propeller E. Vertical panel F. Aileron G. Tail-planes H. Rudders I. Landing chassis. - Mosquito
Anopheles punctipennis. Female - Mosquito
Anopheles crucians. Female - Multiple-engined craft
The fitting of several motors has been shown to be practical; and it has the obvious advantage that, should one fail while in the air, the other or others will maintain a craft in flight. In such a machine as would fly the Atlantic, for example, it is proposed to fit four motors developing 800 h.p., and to carry a couple of mechanics who would constantly be tending them. Thus, should one engine develop trouble, its repair could be effected without descent, and with no worse result than a temporary fall in speed. In the figure is shown a method by which three Gnome motors may be fitted to a biplane. A. First engine (a 50-h.p. Gnome) B. Second engine (which is on the same shaft, but will run independently) C. Third Gnome engine, also an independent unit D. Four-bladed propeller (mounted higher than the crank-shaft bearing the engines, and driven by a chain gearing). - Muscina stabulan
- Notœdres cati, male and female
- Otiobius (Ornithodoros) megnini, head of nymph
- Otiobius (Ornithodoros) megnini, male. (a) dorsal, (b) ventral aspect
- Pediculoides ventricosus, female
- Pediculus showing the blind sac (b) containing the mouth parts (a) beneath the alimentary canal (p)
- Piophila casei
- Poison apparatus of a honey bee
- Rasahus biguttatus
- Reduvius (Opsicœtus) personatus
- Salivary glands of Notonecta maculata
- Santos-Dumont’s Airship
When petrol engines became available, they gave an impetus to the building of airships; for, like the aeroplane, the airship needed a motive agent which gives a high power for a low weight. One of the first to use a petrol motor in an airship with success was M. Santos-Dumont, whose name has been mentioned in connection with aeroplanes. He tested small, light airships, driven by petrol engines and two-bladed propellers—as illustrated in figure; and with one of these, on a calm, still day, he flew over Paris and round the Eiffel Tower. A. Gas envelope B. Wheeled framework which carried motor, propeller, and pilot’s seat C. Elevating-plane D. Horizontal rear-plane E. Rudder. - Sarcoptes scabiei, female
- Sarcoptes scabiei, male
- Sarcoptes scabiei. Diagrammatic representation of the course in the skin of man
- Scouting Monoplane, with occupants below the wings.
To meet the demand for a purely scouting machine, in which pilot and passenger shall have a clear field for observation, both above and below, a monoplane has been designed which is called the “parasol.” This machine, a Morane-Saulnier, is shown. The two sustaining wings, forming a single surface, are raised above the body so that its occupants have nothing to impede their view earthward; and they can also see above them—an advantage of course in time of war, seeing that an enemy might be hovering overhead A. Engine and propeller B. Plane raised above hull C. Seats for pilot and passenger D. Rudder E. Elevating-plane. - Sea-plane to carry a crew of seven
A coastal sea-plane, as now planned, is a craft having, say, two engines, each devolving 120 h.p., with a wing span of some 80 feet, and an accommodation in its hull for three men—the pilot, a combatant with a machine-gun, and an observer with an installation of wireless. But types are changing constantly, and the tendency is to build larger craft. A machine weighing a couple of tons is shown, and a novelty in regard to it is that it has wheels upon either side of its boat-shaped car, upon which it can move on land, and which fold upward when it rests upon the water. A. Hull upon which the machine floats when in the sea B.B.B. Wheels upon which it may move when on land, and which fold upward when it is on the water C. Pilot’s controlling wheel D.D. Main sustaining planes E. Four-bladed propeller driven by chain-gearing from engine within the hull. - Section through a venom gland of Latrodectus 13-guttatus showing the peritoneal, muscular and epithelial layers