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170 LARD LARDNER presence of flour is sometimes indicated by the substances fried adhering to the pan. In phar- macy lard is the material which forms the bulk of most of the ointments and cerates, and may be used alone as an ointment. A good article for this use, that contains no noxious ingre- dients, and is not liable to melt in warm climates, is difficult to be procured. The ten- dency to rancidity may be partly counteracted by adding to the melted lard a tincture of ben- zoin, of guaiacum, or of poplar buds. The oil of pimento and balsam of Peru are said to have the same preservative influence. The substance is also employed for lubricating ma- chinery, for which use it is particularly impor- tant that it should be free from glutinous adul- terants. By the separation of the stearine and margarine from lard the oily product called lard oil is obtained. The manufucture of this is carried on to an immense extent in Cincin- nati and Chicago. Of the stearine are made candles, and other portions of lard enter into the production of soap. A large portion of this oil is sent to France, where by the skill of the chemist it is incorporated witb olive oil to the amount of 60 or 70 per cent., the mix- ture then coming back to be sold as pure olive oil. Some interesting properties of lard when combined with rosin, in the proportion of 3 parts by weight of lard to 1 of rosin, were communicated by Prof. Olmsted to the Ameri- can association at their meeting in New Haven in 1850. When melted together, the mixture is semi-fluid in cold weather. When applied to leather, it renders it very soft and imper- meable to air and moisture, and it is particularly well adapted for lubricating the pistons of air pumps, as it is found to protect the brass from corrosion, which the ordinary lubricants in- duce. The rosin appears to prevent the for- mation of an acid in the lard, and thus the compound is well adapted to protect the sur- face of any metal from rust. When used for iron, a little powdered graphite may be added. When the mixture is used instead of other oily substances for making soap, the tendency of this to become rancid when wet and remaining damp is checked. Other uses readily suggest themselves. As an illuminating agent in solar lamps, Prof. Olmsted found lard oil combined with rosin superior for a time to lard oil alone, but the wick after a time became clogged, less- ening the brilliancy of the light. In the year 1878-'4, 191,139,000 Ibs. of lard were produced in ^the United States, chiefly in Illinois and Ohio ; the product in the preceding year was 218,655,238 Ibs. The chief centres of this in- dustry are Chicago and Cincinnati. In 1873 230,534,207 Ibs. of lard, valued at $21,245,815, were exported from the United States, chief- ly to Germany, England, and Belgium. The amount of lard oil exported was 388,836 gal- lons, valued at $298,731. According to the census of 1870, the total value of the lard oil produced in the United States in that year was $2,552,510. LARDNER, Dionysins, a British writer on phys- ical science, born in Dublin, April 3, 1793, died in Paris, April 29, 1859. After four years' ex- perience in the office of his father, a solicitor, he entered Trinity college, Dublin, in 1812, and graduated in 1817. He continued a resi- dent member of the university till 1827. Du- ring his college career he evinced an extraor- dinary aptitude for mathematical studies, and gained between 15 and 20 prizes in metaphys- ics, pure mathematics, natural philosophy, as- tronomy, and moral philosophy. He took or- ders, and was for some time chaplain at his college ; but he subsequently desisted from all clerical functions. During his residence at the university he published various mathematical works, including an edition of the first six books of Euclid, with a commentary, and con- tributed a number of articles on mathematical subjects to the "Edinburgh Encyclopaedia" and the " Encyclopedia Metropolitan," and a series on various branches of natural philoso- phy to the "Library of Useful Knowledge." In 1828 appeared his "Popular Lectures on the Steam Engine," for which he received a gold medal from the royal Dublin society. Upon the establishment of the London univer- sity he accepted the professorship of natural philosophy and astronomy ; and fixing his resi- dence in London in 1828, he published in the same year a "Discourse on the Advantages of Natural Philosophy," and an " Analytical Trea- tise on Plane and Spherical Trigonometry." This was followed by his " Cabinet Cyclopae- dia," commenced in 1830 and continued till 1844, embracing 132 vols. 12ino. In this work he secured the cooperation of the most eminent authors of the day. His own contributions comprised treatises on arithmetic, geometry, heat, hydrostatics and pneumatics, and me- chanics. While engaged on this work he wrote occasional articles on physical science and its application to the useful arts for the periodi- cals, and was frequently before parliamentary committees as a witness in behalf of railway companies. In 1840 he eloped with the wife of Captain Heavyside, and came to the United States. He was sued for damages, and a ver- dict for 8,000 was entered against him. He married this lady after her husband's death. During five years' residence in America he de- livered in the chief cities a series of lectures, which were published and have passed through many editions. On his return to Europe in 1845 he settled in Paris, where he resided until his death. Dr. Lardner's remaining works are : "Railway Economy " (1850) ; "Handbook of Natural Philosophy and Astronomy " (2 vols., 1851-'2); "The Great Exhibition Reviewed" (1852); "The Museum of Science and Art," a series of popular treatises on the physical sci- ences and their application to the industrial arts, commenced in 1854, and completed in 12 vols. 12mo; and handbooks of "Natural Phi- losophy and Hydrostatics," of "Pneumatics and Heat," of " Natural Philosophy and Me-