Page:Collier's New Encyclopedia v. 09.djvu/368

TESTING CLAUSE 316 TESTUDINIDiE which the deed consists, the names and designations of the witnesses, the name and designation of the person who penned the deed, and the date and place of signing. TESTING MACHINES, machines used for the accurate testing of iron, steel and other materials used in con- structive work. The problem which these machines are intended to solve is the adjustment with certainty of a safe mar- gin of strength with a minimum of weight, which can be determined only by experimental tests on full sized sections of the materials used in the construction. One method is to use machines designed to test small sample pieces under such conditions that the breaking strength of the test-piece is measured by the ma- chine, and from the figures thus obtained is calculated the strength per square inch of the full-sized constructive material. A common feature of such machines is the common steelyard balance, supported by knife edges. There are several ma- chines of this class, some of them built up to 100,000 pounds capacity and over. The hydraulic testing machine, invented by A. H. Emery, was originally used at the United States arsenal at Watertown, Mass. The greatest peculiarity of the Emery testing machine is the method by which the stress produced on the piece tested is conveyed to the scale and ac- curately weighed by mechanism that is entirely without friction, and hence re- sponds to the same increment of load re- gardless of the amount of strain on the specimen. This result is accomplished by receiving the load against a flat closed cylinder called the hydraulic weighing head. One of the government experi- ments with this machine was the break- ing by tension of a forged iron link 5 inches in diameter between the eyes, at a strain of 722,800 pounnds, and imme- 7 diately after a horse-hair of an inch 1000 in diameter was slowly strained, and, after stretching 30 per cent., snapped under the recorded strain of 16 ounces. TEST OATH, an oath prescribed by the United States Congress July 2, 1862, to be taken by persons in the former Con- federate States appointed to office under the National government. The text was as follows: "I, A. B., do solemnly swear (or affima) that I have never voluntarily borne arms against the United States since I have been a citizen thereof ; that I have voluntarily given no aid, counte- nence, counsel, or encouragement to persons en- gaged in armed hostility thereto ; that I have neither sought, nor accepted, nonr attempted to exercise the functions of any office whatever, nnder any authority or pretended authority in hostility to the United States : that I have not yielded a voluntary support to any pretended government, authority, power, or constitution within the United States, hostile or inimical thereto. And I do further swear (or affirm) that, to the best of my knowledge and ability, I will support and defend the Constitution ol the United States against all enemies, foreign and domestic ; that I will bear true faith and allegiance to the same ; that I take this obligation freely, without any mental reservation or pur- pose of evasion, and that I will well and faith- fully discharge the duties of the office on which I am about to enter, so help me God." TEST PAPEBS, in chemistry, are made by dipping unsized paper into an alcoholic solution of a vegetable coloring matter which changes color when ex- posed to the action of an acid or alkaline solution. The paper, after being gently dried, is cut into slips of a suitable size. Hence, by dipping the appropriate test papers into any solution, one can ascer- tain whether it is acid, alkaline, or neu- tral. Litmus and turmeric are most commonly used as the coloring matters; litmus for the detection of acids, and tur- meric for that of alkalies. Test papers are also employed for detecting sulphu- retted hydrogen, etc., and for such a purpose the paper must be dipped in the solution of an appropriate substance. Thus acetate of lead paper becomes black in presence of sulphuretted hydrogen, while starch paper becomes blue when touched with iodine. TESTUDINARIA (so named from the resemblance which the great, rugged, cracked root of the plant bears to the shell of a tortoise), in botany, the ele- phant's foot or Hottentot's bread; a ge- nus of Dioscoreacese, akin to Dioscorea, but with the seeds winged only at the tip, instead of all round. Rootstock above ground sometimes four feet in diameter. Stems occasionally 40 feet long; flowers small, greenish-yellow. T. elephantipes is the common elephant's foot or Hot- tentot's bread. The rootstock is a large, fleshy mass, covered with a thick bark, cracked deeply in every direction. The Hottentots in time of scarcity made use of the fleshy inside of the root as a kind of yam. TESTUDINID^, the land tortoises; a family of Chelonia, very widely dis- tributed in both hemispheres, but ab- sent from Australia. "The carapace is very convex; claws blunt; feet club- shaped, adapted for progression on land only; neck retractile. They are vegetable feeders, and the greater part of the spe- cies belong to the type genus Teshido. In some classifications the family in- cludes the freshwater tortoises, now gen- erally made a separate family of EmjcH- doe. The family appears in the Miocene of Europe and the Eocene of North America.