[Vot. v.. Wo. lit
��beat but approximate; but even these are belter than tbe results From cultures scattered over gelatine sur- faces. This method, however, ia good as a prelimi- nary, and Is in briel as loNows: A denuite quantity of the suspected water Is placed in a meaaurs of oulrient gelatine; this la softened by heat, and the two are thoroughly mixed; and the gelatine is then allowed to hardeu in a test-tube, or i[L such a flask as is xbowD in the Hgure (Gg. S). The Qat, thin sur- face thus obtained makes it more easy to count the colonlBB which Witt appear in a few days. For air- germs, the soluble powder spoken of above is the material to be placed in the nutrient gelatine.
The objections to the method ore, that many species of bacteria davelop very slowly at the temperalutc of the air and in a solid medium, and are obscured by other more rapidly growing colonies. The same objections hold in separating the germs in any path- ological process.
The method of fractional sterilization used by the Germans is only useful where egg-albumen, or irther substances coagulable by heat, arc to be employed for culture-media. For this purpose I use a furnace Ifig. 9) designed by myself, and manufactured for me by Mr. Wieanegg. It serves Its purpose well, and is much better than that of Kocb. It Is of double- walled copper, the Intervening space being filled with water. This apace has openings for Ihonnometer Mid regulator. The door is double-walled, filled with water, and has its Bpecial heater, and it ia kept at exactly 16° C. Tubes containing the material to be sterillied are placed in this furnace for one hour daily to kill the full-grown bacteria, and during the rest of the time are kept at SH" C. to favor thegrowth of the spores. In ten or twelve days the greater part of the tabes will be found to be fully sterilized.
Par better tban this is the method of Bltering through a substance suificiently fine to retain all germs, successful results having been long obiaineU by Pasteur by filtering through plaster. Chamber- land's method through porcelain is, however, the best (fig. 10), and Is perfectly satisfactory provided the porcelain tube ia good. This latter is difficult to obtain. Dllut«d egg-albumen and blood-sernm may be easily filtered in this way, although slowly, under a pressure of from two to diree atmospheres. Great care must, of course, be taken, to prevent the con- tamination of the material after It leaves the canula.
This method of sterilization ia peculiarly appro- priate for certain animal fluids whose chemical com- position Is changed by heat, but which it may be necessary to employ as culture-media tor certain forms of bacteria.
��Thk interest In the late project for forcing water for army purposes over the broken and elevated country between Suokin and llerber hy means of
��la tumlihrd by thi touruqi a\
��pipes has called attention to the extent, linportuiee. and utility of the pipe-tines in our own countTj, which convey the crude petroleum of tlte region lying between the Alleghanies and Lake Erie to the shores of that lake and the Atlantic seaboard.
The enploitation of these regiona by means of arte- sian wells began about twenty-six years ago. By June, IS62, 495 wells had been sunk near Titusville, and the dally output was nearly C.OOO barrels, aetliog at the wells at from $4 to $6 a barrel. But as tbe production increased with rapid strides, the mar- ket-price fell with a corresponding rapidity, making the transportation charges to New-Tork City a con- siderable proportion of the total cost.
The question of reducing these eaormoas traas- portation charges was first broached, apparently, in 1864, when a writer in the Sorllt American of Phll- adelphla outlined a scheme for laying a pipe-line down the Allegheny River to Pittsburgh,
Originally the oil waa carried in 40 and 42 gallon barrels, made of oak, and hooped with iron: after- ward tank-cars were introduced. These ir«re St first ordinary flat cars, upon which were placed two wooden tanks, shaped like tubs, eacb boldln^ about 2,000 gallons. On the rivers, bulk-bargea were also, afl«r a time, introduced on the Ohio and All^heoy. At first these were rude affairs, and ofteo of inade- quate strength; but, as now built, they are 130 by iS by 16 feet in their general dimensions, and divided Into eight compartments, with water-tight bulk- heads. They hold about 2,200 barrels. In IS71 iron tank-cars superaedol those of wood, with tanks of varying sizes, ranging from 3,356 to 6,000 gaJlont each. These tanks were cylinders 24 feet inches long and 66 inches in diameter, and weighed about 4,500 pounds.
Among the very first, if not the first, pipe-lines laid, was one put down between the Sherman well and the railway terminus on the Miller farm. It waa about 3 miles long, and designed by a Mr. Hutcliin- Bon: he had an exaggerated idea of the pressure to h« exercised, and at Intervals of SO to 100 feet be SH up air-chambers 10 inches In diameter. The weak point In this line, however, proved to 1>e the joints. The pipes were of cost-irun; and the joint leakage was so great, that little If any oil ever reached the end of the line, and the scheme waa abandoned In despair.
In October, 1S65, the Oil transportation company completed and l«sted a pipe-line 32,000 feet long. Three pumps were used upon it, — two at PIthole, and one at Little Pithole. The first plans to extend such lines to the seaboard seem to have been made in 1S7G, when the pipe-line owners held a meeting to organize a pipe-line company tor this purpoaa; bat the scheme was never carried out. In Jsnuai;, 1878, the Producera' union organized for a aimllar seaboard line, and laid pipes; but they never readied the sea, stopping their line at Tamanend, Penn. About four years ago the National transit company was organised, and succeeded to the properties of the American tranilt company. Its lines, illnatniWd on the accompanying map, were completed In I6S0-
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