nearly three hundred thousand dollars; and the patriotic American asks only for that boat which, within its field of usefulness, is best adapted to safeguard our national interests.

The Holland boats, while partaking somewhat of the nature of the French "submersibles," are strictly to be classed with the Gallic "submarine" when judged by their sea-going or sea-keeping performances up to the present time; while the Lake boat Protector is the French "submersible" much improved. The reasons for these differences are those peculiar to the model and the principle upon which each has been built. The Holland boats belong to what is now termed the "diving" type of submarine; the Protector is of the "submerging" type-an order of craft permitting a wide range of adaptability and promising still greater things in the future. This is not said in derogation of the Holland boats, for, within their necessarily restricted field of evolution, their present development is the result of skill of a high order. The palm, in the future, however, must go to that type which is proved to be constructed on the broadest principles.

The "diving" type differs from the "submerging" type only in the method employed in getting beneath the surface. To the layman this may seem immaterial, so long as each is able to get rapidly under cover; but practical experiment has proved to the contrary. The two boats, when running under the surface, do so by overcoming a constant tendency to rise, due to a certain amount of reserve buoyancy. This reserve buoyancy ranges generally in the neighborhood of 150 to 200 pounds. In the "diving" boat-the craft being under way-this buoyancy is overcome by the aid of two horizontal rudders at the extreme stern. To make the boat dive, these rudders are given a downward dip of sufficient degree to effect a destruction of the longitudinal stability of the craft and to cause her to plunge head foremost beneath the water. To make the vessel sufficiently sensitive to these horizontal rudders, the boat must be as nicely balanced as a pair of scales in equilibrium. Weights must not be shifted in a fore-and-aft direction during the periods of submergence, and the men

must remain nearly immobile at their stations.

Upon one man, however, rests the brunt of successful submergence and the burden of insuring safety, and he is the man controlling the wheel that governs the horizontal or diving rudders. His task is nearly akin to that of the tightrope equilibrist, the wheel of his controlling gear being the counterpart of the other man's balance pole. Directly facing him is a large depth-gauge upon which his eyes are riveted; and his is the task of watching the fluctuations of that tell-tale pointer, and, as far as human skill can do so, of anticipating the movements of the craft up or down. At best he can maintain only an approximately uniform depth, and the course of the vessel in any case is of necessity sinuous. Because of the boat's delicate balance, the Holland type, when submerged, is very sensitive to the influences of currents, eddies, and the sub-surface effects of waves, all of which add to the task of the diving-rudderman. When running "awash"-that is, ready for instant diving-these vessels are very sensitive to a seaway, their spindle-formed hulls tending to "bury" by the head as the waves tumble onto their bows, thereby making them sluggish and keeping them so low in the water as to render it nearly impossible to observe an objective through the ports of the conning-tower. Besides, this action of the waves gives the boats a constant impulse to dive. The Holland boats cannot be made to dive when going at less than six knots an hour, and, on coming to the surface for observation through the dead-lights in the conningtower their optical sighting tubes having proved generally unsatisfactory— these vessels "broach," or break water, and show almost their entire length in "porpoising" for a new dive. Apart from the tell-tale disturbance thus made and the possible target thereby offered to an enemy's rapid-fire guns, sufficient warning of the course of the submarine is given to enable the much swifter surface craft to avoid attack.

Ground for the assertion that the Holland boats properly belong to that class. restrictively designated as "submarines" by the French, is found in their sea performances. Under very favorable con

the boats are not fitted for habitation for a longer period than a few hours, it is the practice to transfer the crews to the towing ship, attach a tow-line to the bitts of the submarine, and drag her to her destination. The term "drag" is used advisedly, for even at the moderate speed of six knots, the vessels are hard to tow. How disastrous this tow-line method is, was proved by a recent mishap to the submarines Adder and Moccasin on their way into the Chesapeake.

The ability of the Holland submarines to get within striking distance before detection, has never been established in spite of all the experiments made last sum

certain inherent peculiarities, they do not now meet the maximum requirements of a successful submarine torpedo-boat.

The Protector, of the Lake type, is purposely almost identical in general dimensions of length and maximum beam. with the boats of Holland design belonging to the Navy; but beyond that, she is a distinct departure. To the main spindleshaped body-designed to withstand water pressure at a depth of 150 feetis added a light, ship-shaped superstructure. The purpose of this superstructure is two-fold, and is the result of some years of practical experience gained by Captain Lake in his Argonaut I., built in

1897, and his Argonaut II., a remodeled form of the earlier vessel, built in 1900. The superstructure gives to the craft great buoyancy and a seaworthiness that is denied to the spindle-shaped hull. Such was its primary purpose. The second purpose in its design was to form a convenient and safe storage for the explosive gasoline and the high-pressure air-flasks. By keeping these out of the main spindle hull, the danger of gasoline leaks was minimized, and space was secured for

THE "PROTECTOR" RUNNING AT FULL SPEED, WITH ONLY THE OMNISCOPE ABOVE WATER.

other much-desired uses. Some notion of the seaworthiness of the Protector may be had from the knowledge that she recently made the run of 110 miles from Bridgeport, Conn., to Newport, R. I., having in tow a large sloop; and that she pulled this vessel around Point Judith in the teeth of half a gale from the southeast blowing in directly from the full sweep of the Atlantic.

To bring the Protector to war-time cruising trim, the superstructure is filled with water, at which time her broad deck is awash. To bring the boat to submerging trim, it is necessary to fill her ballast tanks with water enough to bring the top of her conning-tower awash. At this point her armored sighting-hood is above water, and the vital hull of the craft is six feet below. In this condition, the boat has two hundred or three hundred pounds of reserve buoyancy; and further refinements of submergence, involving finally nothing but about a foot of the omniscope or sighting instrument above water, are within the immediate control of the commanding officer. In the condi

tion with the sighting-hood above water, the boat is forcibly submerged by the operation of four horizontal rudders, or, as Captain Lake terms them, "hydroplanes," which are large, flat, rectangular paddles pivoted in the center and located in the guards on line with the superstructure deck. These hydroplanes are moved in unison, and, being symmetrically disposed, bring pressure to bear at four equidistant points. When the boat is under way, a dip of the forward ends of these hydroplanes brings pressure to bear upon their upper surfaces, thereby causing a downward thrust, the pressure depending upon the speed of the boat and the angle of the dip. When this pressure overbalances the reserve buoyancy of the boat-that constant tendency to rise to the surface-the Protector sinks on an even keel below the waves. As deliberately as she sinks, just so deliberately does she come to the surface, exposing gradually to view nothing but the modest target of the head of her omniscope. As it is possible to submerge the Protector at any speed, there is, of course, no risk of the boat "broaching" when coming to the surface. With even a gently disturbed surface for a cover, it would be possible for the Protector safely to drift down upon a foe, or to creep upon her at a slow speed, to within torpedo range, without the slightest fear of detection, even in broad daylight.

Because of the hydroplane method of submergence, it is not necessary that the Protector should be delicately balanced. Her longitudinal stability is so great that large masses may be shifted and the crew permitted to move with the utmost freedom, when the boat is running below the surface. Apart from the freedom from restraint and the absence of nervous tension upon the crew, this preservation of an even keel bears directly upon the working efficiency of the craft when under water. When only the sighting instrument is above the surface, even in a considerable sea, the boat lies steadily. This permits increased range of vision. When the craft is totally submerged and is steering a compass course, the compass, because it is not disturbed by any rolling or pitching motion on the part of the boat, as is the case with the diving

type, is a true guide of direction; and it is thus possible to run with precision. It is also possible to preserve substantially a uniform depth, because with the hydroplanes set and the electric motors constant, only that depth will be attained at which the upward thrust of the water balances the downward push of the pressure on the hydroplanes. The maintenance of this depth, once chosen, becomes nearly automatic.

Now, to get within striking distance of the enemy depends greatly upon the efficiency of the omniscope. This instrument-unlike the altiscope of the boats now in the Navy, which has only a linited, fixed field of vision forward-commands the whole horizon by the aid of four finder-lenses; while a fifth lens, which can be brought to bear upon any point, gives normal vision and a means of reading distances correctly, which is impossible with the present type of altiscope. The omniscope of the Protector has been tried under all conditions, and has been found entirely satisfactory. So much for the means of getting within striking distance.

The offensive power of the Protector is centered in three torpedo tubes-two

THE "PROTECTOR" TOTALLY SUBMERGED. The mast is no part of her military equipment.

forward and one aft. The two forward tubes can be fired simultaneously, while the after one is intended to be discharged after the boat has turned for flight. The Holland boats carry three torpedoes, but have only one torpedo tube; and, moreover, in order to recharge the tube, a boat of this type would have to come to the surface, and would lie there a target

for a foe's guns for the considerable period of time required for reloading.

For the purpose of seeking shelter upon the bottom within a depth of 150 feet, or for under-running and countermining an enemy's mine fields, or for entering an enemy's harbor by following the bed of the channel, the Protector has two great wheels upon which she can travel along the bottom, the driving power being supplied by the screws. To enter an enemy's harbor, all that would be required would be to steer the charted courses, the depths being given by the depth-gauge, while the distance traveled would be recorded by the odometer attached to the wheels. To enable the boat to cut mine connections and submarine cables, the diving compartmentin principle a diving bell-permits a diver to pass out from the boat and onto the water bed. This compartment is the foremost division of the craft. Next after this comes the air-lock, by which intercourse may be had with the rest of the boat-not under pressure-while the diving compartment is in operation. Abaft the air-lock are living quarters designed for eight men, where comfortable folding berths and transoms afford ample sleeping accommodations. Next abaft the living space is the pantry, where cooking is done by electricity, while the aftermost compartment is given up to the gasoline. engines and the electric motors. The engine-room is a wonderful example of skillful installation. There is a wide, free passage between the engines, and space enough overhead for a six-foot man to stand upright.

In the conning-tower, quite naturally, centers most of the interest in the boat, for from this point the commanding officer has complete personal control of the entire craft. This conning-tower is large enough to accommodate four men. In it are all sorts of gauges, registers, indicators, means of communication, and facilities for control. The commanding officer, the steersman, and the man at the hydroplane wheel are in constant touch with one another, while automatic indicators advise the steersman and the gunner at the bow torpedo tubes of the proper bearing of the boat.

When running under gasoline propulsion alone, it is possible to submerge all

dashes covering periods of from four to eight hours; and it is possible to couple in the motors with the engines at lower speeds so that the motors become dynamos and recharge the batteries while the boat is still going along at a considerable speed.

The habitability of the Protector has been proved by months of service, in which her crew have lived aboard. For protection against the chill of winter weather, the boat is equipped with electrical heaters.

It is not possible, in an article necessarily limited as this must be, to go into the full technical detail of this vessel, but enough has already been given to furnish a fairly adequate idea of the practical working plan of this craft and of the submarines now in the Navy. In a circular issued in 1893 by the Navy Department, in which the broad requirements of

ton emergency keel and let go two anchors weighing together a ton; and, in addition, the escape of the crew, if all other efforts fail to release the boat, is assured by means of the diving compartment, the practicability of which has been demonstrated.

Wonderful as the Protector really isand she has established her claims to recognition only after months of servicestill she is but the beginning of what her inventor has planned along these lines. The inventor of the Holland type did the nation a great service in giving to the submarine in the United States a standing it had never enjoyed before, but it is to the possibilities of the more recently developed Lake type of submarine torpedo-boat that the present position of this country at the head of the world in this important branch of naval architecture is apparently due.