the side wall into the cement waste way between the two rows of tanks. The water enters the aquaria in most cases through a shaft formed by a fold (a, figs. 34 and 35) in the fire clay at the end of the tank and spreads out over the bottom, and the waste water is drawn off at the top. The spillways from one tank to the next are formed

FIG. 32.-Aquaria, Millport biological station. Longitudinal section of interconnecting single series of fire-clay sink-aquaria (A, fig. 29). A, B, C, tanks in series; tank A arranged for independent circulation, with connecting outlets at a closed with solid stoppers (C, fig. 36) and drained by vertical standpipe (glass) at b, into lead waste pipe below. Tanks B and C with connected circulation through perforated plugs (B, fig. 36) at c and é, washout closed (F, fig. 36).

either by a tunnel (C, fig. 34) closed by a perforated fire-clay plug (B, fig. 36) or by a channel closed by a perforated shield (A, fig. 36) held in place in a slot (tanks B and C, h, figs. 34 and 35). The flow of water can also be checked by perforated plates (D, fig. 36) set in the base of the vertical shafts (a, figs. 34 and 35).

FIG. 33.-Aquaria, Millport biological station. Fire-clay aquaria with glass sides (E, fig. 29, and upper aquaria, Pl. XXXVII, B). Dotted lines show position of plate glass.

The advantages of aquaria or culture basins of this material are a smooth, noncorrosive surface, easily cleaned, entire absence of all metals, and for purposes of sorting and exhibition, a clear white background, though a considerable range in colors may be had if desired. To these advantages are to be added great durability,

as to size, support of sides, etc., any form required can be made." "Fire clay is a delightfully plastic material, and within certain limits tion, and great adaptability in form. As Doctor Gemmill writes, small risk of breakage, ease of combination with cement in construc

b

FIG. 34.-Double-bank fire-clay aquaria at Millport station (B and D, fig. 29; Pl. XXXVII, B, and lower aquaria in A). Longitudinal section of tanks
A, B, C. Tank A arranged for independent circulation with orifice at d into middle cement channel (see fig. 35) closed with solid plug (C, fig. 36),
as is also the outlet at c into tank B. The connection between A and B is shown as a circular orifice, between B and C as an open channel with
perforated stopper (A, fig. 36) at h. Outlet from tank A goes through vertical fire-clay stand-pipe g (G, fig. 36) into lead waste pipe below. Outflow
from tank B passes either through perforated stopper (B, fig. 36) at e into middle cement channel or through perforated strainer (A, fig. 36) at h into
tank C, passing down vertical fire-clay shaft a to bottom of tank. The bottom of the shaft is protected by a fire-clay strainer (D, fig. 36) at b.

feet) and library (15 by 20 feet) above. The elementary laboratory 10 feet) and the stair leading to the laboratory (fig. 30) (24 by 27 In the rear, adjacent to the tank rooms, is the pump room (10 by

has desk room for 35 students, and is abundantly lighted by 18 windows and opaque glass on the northern slope of the roof. The adjacent museum is also lighted in part by skylights. A small research room (10 by 14 feet) and an L-shaped storeroom occupy the space between the class room and

the library.

The water supply is drawn through 3-inch lead sea pipe, 200 feet in length, extending to a depth of 8 feet below low tide and terminating in a lead rose held in place in an iron pyramid. A gas engine originally employed in pumping has been replaced by a "Samson" paraffin engine of 4 horsepower. The pump is a specially constructed double-suction pump, with gun-metal plungers and lining. The water is stored in a tank of cast-iron plates protected inside by a coat of tar and outside by red lead, 19 feet 3 inches long, 11 feet 6 inches wide, and 6 feet 3 inches deep. The distributing system is entirely of soft lead piping, with gunmetal valves and brass cocks at the terminals. Some difficulty has been experienced in corrosion of the solder used in setting the cocks in the lead pipe. The water is delivered to the aquaria in overhead sprays and is passed but once through the tank or tanks.

The laboratory has a fair

FIG. 35.-Double-bank fire-clay aquaria at Millport station (B and D, fig. 29; Pl. XXXVII, B, and lower aquaria in A). View of tanks of fig. 34 from above.

amount of glassware and chemicals, used in biological work, and an exceptionally complete equipment of scientific instruments, including 4 highest grade microscopes of the best makes, with a wide range of accessories; 25 student microscopes and an equal number of dissecting