2 14 



SCIENCE. 



[Vol. XIII. No. 320 



great deal of drilling has been going forward, and the productive 

 districts remain as at the end of 18S7, four in number; viz., the 

 Berea grit, the Ohio shale, the Clinton limestone, and the Trenton 

 limestone. The last-named stratum, which is both a gas and oil 

 bearing rock in northern Ohio and central Indiana, is, excepting pos- 

 sibly the Bradford sand, the most important single source of petro- 

 leum and gas on this continent. The oil is still ranked as inferior, 

 on account of the present difficulty of refining it ; but there is no 

 drawback to the gas, as is apparent from the following analyses, 

 made for the United States Geological Survey : — 



The small fraction, one-fifth of one per cent, of sulphuretted hy- 

 drogen is held to be decidedly advantageous, as it affords a certain 

 means of detecting leaks. 



No place within the natural-gas belt has derived greater advan- 

 tages from this fuel-supply than Findlay, where in November, 1884, 

 it was first found that the Trenton limestone, at some places at 

 'east, contained stores of high-pressure gas. Since January, 1886, 

 ;he population of the town has increased from 5,ooo to 30,000. 

 Although there are rolling-mills, chain-works, machine and edge- 

 tool shops, etc., the principal industry is glass, 155 pots being used 

 'by the ten firms engaged in making window-glass, fine flint ware, 

 and bottles. 



This growth has been built up in Findlay, as in other towns, by 

 giving free, or nearly free, gas to manufacturers, — a gift which in 

 some instances has been supplemented by land and contributions 

 to capital, either from the town or parties interested in real estate. 

 Under these circumstances, the question of the continuance of the 

 supply is a vital one. Professor Orton has contended that the sup- 

 ply is a stored one, and notwithstanding the reasonableness of the 

 theory, in view of the exhaustion of all deposits of liquid hydro- 

 carbons, the gas has been used most profusely for the rough work 

 of founderies, rolling-mills, brick and tile works, lime-burning, and 

 the like, until, a short time since, Findlay found itself short of gas. A 

 new well was drilled in, and, on being shot, responded with a press- 

 ure in the open casing of from 38 to 40 pounds, equivalent to a 

 yield of about 30,000,000 cubic feet per day. The famous Karg 

 well, which has been the main reliance of the town for the past two 

 years, was estimated to discharge 12,000,000 cubic feet. 



This shortage of gas has led to an investigation, from which the 

 ■professor concludes that none of the large wells in the field have 

 flowed three years, practically unrestrained, without giving unmis- 

 takable signs of nearing their limit. In some cases oil invades 

 them ; in others, salt water. The smaller wells appear in some 

 instances to have a longer lease of life than the great wells. In 

 some of the town wells the original rock pressure has been reduced 

 by about three-eighths, but in others it is claimed it is fully main- 

 tained, only more time is required for gathering. The area ex- 

 hausted by a vigorous well is not yet determined, but it is thought 

 that the central portion of Findlay is partially drained of its original 

 supply. As the city has pledged itself to furnish many million feet 

 of gas each day, great energy and sagacity will be required to 

 maintain in full vigor the splendid industries now established, and 

 insure the continued prosperity of the town. 



What is predicted of the Ohio Trenton limestone gas-field may 

 probably be asserted as to the 2,000 square miles of the field in 

 Indiana, though, if wells yielding 30,000,000 cubic feet of gas per 



day, equivalent to nearly 1,000 tons of coal, are to be found when- 

 ever a shortage occurs, there may be a longer lease of the indus- 

 trial life of that region than a cursory reading of Professor Orton's 

 article might lead one to infer. 



THE DENISON MOTOR AND DYNAMO. 



The accompanying illustration shows the form of dynamo and 

 motor now manufactured by Mr. J. F. Denison of New Haven, 

 Conn. These machines do not differ in their construction much 

 from that which experience has shown to be desirable, but the 

 motors have some points worthy of special consideration. 



An arrangement known as the Denison interlocking starting at- 

 tachment is contained in the base of the machine, and is said to 

 prevent any mistake in operating the motors. This attachment is 



TSON MOTOR 



SO arranged that the current cannot be thrown on unless the re- 

 sistance in the rheostat in the base is in the proper position. This 

 is manipulated by a hand-wheel. In case of accidental breaking 

 of the circuit, an automatic lock makes it impossible to turn the 

 current on until the resistance is again in normal condition. The 

 absence of attachments external to the machine, which are usually 

 placed on the wall, the machine being entirely self-contained, does 

 away with the expense of sending out special attendants to set it 

 up. Further, as there are but two binding-posts, it is impossible 

 to make a mistake in wiring. 



HEALTH^ MATTERS. 

 Analysis of Foods. 



The commissioner of internal revenue of the United States has 

 published the regulations concerning the analysis of foods and 

 drugs in the District of Columbia. These regulations are based 

 on the Act of Congress passed in 1888, entitled " An Act to prevent 

 the Manufacture or Sale of Adulterated Food or Drugs in the Dis- 

 trict of Columbia." Section 1 2 of this Act provides that any health- 

 officer, inspector of nuisances, or any food-inspector, may procure 

 any sample of food or drug, and, if he suspects the same to have 

 been sold to him contrary to any provision of the Act, he shall sub- 

 mit it to the commissioner of internal revenue to be analyzed. An 

 offence shall be deemed to be committed in the case of drugs, if it 

 differs from the standard of strength, quality, or purity laid down 

 in the pharmacopoeia, or falls below the professed standard under 

 which it is sold. In the case of foods, the regulation gives a stand- 

 ard for butter, cheese, cocoa, chocolate, coffee, honey, lard, malt 

 liquors, milk, mustard, olive-oil, oysters, pepper, tea, vinegar, wheaten 

 flour, bread, and wine. 



A large number of coloring-matters are prohibited for use in 

 foods. Among these are aniline, gamboge, fuchsine, naphthol yel- 



