504 



SCIENCE. 



[Vol. V., No. 124. 



best but approximate; but even these are better than 

 the results from cultures scattered over gelatine sur- 

 faces. This method, however, is good as a prelimi- 

 nary, and is in brief as follows: A definite quantity 

 of the suspected water is placed in a measure of 

 nutrient gelatine ; this is softened by heat, and the 

 two are thoroughly mixed ; and the gelatine is then 

 allowed to harden in a test-tube, or in such a flask 

 as is shown in the figure (fig. 8). The flat, thin sur- 

 face thus obtained makes it more easy to count the 

 colonies which will 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 are, that many species 

 of bacteria develop very slowly at the temperature 

 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 other 

 substances coagulable by heat, are to be employed 

 for culture-media. For this purpose I use a furnace 

 (fig. 9) designed by myself, and manufactured for me 

 by Mr. Wiesnegg. It serves its purpose well, and is 

 much better than that of Koch. It is of double- 

 walled copper, the intervening space being filled with 

 water. This space has openings for thermometer 

 and regulator. The door is double-walled, filled with 

 water, and has its special heater, and it is kept at 

 exactly 75° C. Tubes containing the material to be 

 sterilized 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 35° C. to favor the growth of the 

 spores. In ten or twelve days the greater part of the 

 tubes will be found to be fully sterilized. 



Far better than this is the method of filtering 

 through a substance sufficiently fine to retain all 

 germs, successful results having been long obtained 

 by Pasteur by filtering through plaster. Chamber- 

 laud's method through porcelain is, however, the best 

 (fig. 10), and is perfectly satisfactory provided the 

 porcelain tube is good. This latter is difficult to 

 obtain. Diluted egg-albumen and blood-serum may 

 be easily filtered in this way, although slowly, under 

 a pressure of from two to three 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 is 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 for certain 

 forms of bacteria. 



TRANSPORTATION OF PETROLEUM 

 TO THE SEABOARD.* 



The interest in the late project for forcing water 

 for army purposes over the broken and elevated 

 country between Suakin and Berber by means of 



1 Abstract of an article in the Engineering news of last week, 

 from advance sheets furnished by the courtesy of the editor. 



pipes has called attention to the extent, importance, 

 and utility of the pipe-lines in our own country, 

 which convey the crude petroleum of the region 

 lying between the Alleghanies and Lake Erie to the 

 shores of that lake and the Atlantic seaboard. 



The exploitation of these regions by means of arte- 

 sian wells began about twenty-six years ago. By 

 June, 1862, 495 wells had been sunk near Titusville, 

 and the daily output was nearly 6,000 barrels, selling 

 at the wells at from $4 to $6 a barrel. But as 

 the production increased with rapid, strides, the mar- 

 ket-price fell with a corresponding rapidity, making 

 the transportation charges to New-York City a con- 

 siderable proportion of the total cost. 



The question of reducing these enormous trans- 

 portation charges was first broached, apparently, in 

 1864, when a writer in the North American of Phil- 

 adelphia outlined a scheme for laying a pipe-line 

 down the Allegheny River to Pittsburgh. 



Originally the oil was carried in 40 and 42 gallon 

 barrels, made of oak, and hooped with iron: after- 

 ward tank-cars were introduced. These were at 

 first ordinary flat cars, upon which were placed two 

 wooden tanks, shaped like tubs, each holding about 

 2,000 gallons. On the rivers, bulk-barges were also, 

 after a time, introduced on the Ohio and Allegheny. 

 At first these were rude affairs, and often of inade- 

 quate strength ; but, as now built, they are 130 by 22 

 by 16 feet in their general dimensions, and divided 

 into eight compartments, with water-tight bulk- 

 heads. They hold about 2,200 barrels. In 1871 iron 

 tank-cars superseded those of wood, with tanks of 

 varying sizes, ranging from 3,856 to 5,000 gallons 

 each. These tanks were cylinders 24 feet 6 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 was 

 about 3 miles long, and designed by a Mr. Hutchin- 

 son : he had an exaggerated idea of the pressure to 

 be exercised, and at intervals of 50 to 100 feet he set 

 up air-chambers 10 inches in diameter. The weak 

 point in this line, however, proved to be the joints. 

 The pipes were of cast-iron; and the joint leakage 

 was so great, that little if any oil ever reached the 

 end of the line, and the scheme was abandoned in 

 despair. 



In October, 1865, the Oil transportation company 

 completed and tested 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 1876, when the pipe-line owners held a meeting to 

 organize a pipe-line company for this purpose; but 

 the scheme was never carried out. In January, 

 1878, the Producers' union organized for a similar 

 seaboard line, and laid pipes ; but they never reached 

 the sea, stopping their line at Tamanend, Penn. 

 About four years ago the National transit company 

 was organized, and succeeded to the properties of 

 the American transit company. Its lines, illustrated 

 on the accompanying map, were completed in 1880- 



