292 



SCIENCE. 



[Vol. II., No. 30. 



accurate determination of caseine might be effected 

 by some rapid-fermentation pi'ocess by wliicli caseine 

 could be brolcen up into other organic products tliat 

 could be separated by albumen. He held to this 

 point as to caseine, because it cannot conveniently be 

 added in the manufacture of oleomargarine; while 

 the acids upon which the saturation oo-etficient 

 depends could readily be added as sodium com- 

 pounds. 



On account of the difiBculty of getting accurate 

 results in determining nitrogen, it was thought best 

 to use the wet-combustion method with permanga- 

 nate, because a small quantity of material might be 

 used, and there would be fewer chances for loss that 

 otherwise occurs in nitrogen determinations that are 

 effected by the combustion of butters. 



Dr. Wheeler called the attention of the section to 

 the use of what is known as 'cotton-seed-oil stock,' 



. in the manufacture of oleomargarine. This, doubt- 

 less, contains considerable nitrogen, and, of cour.se, 

 would reduce the value of the caseine-test for adul- 

 teration. A sample was shown, supposed to contain 

 cotton-seed-oil. 



The sense of the discussion was, that it was very 

 desirable that Professor Wiley should continue his 

 experiments, as they are of great value ; hut there is 

 yet a great deal of work to be done in the investiga- 

 tion. 



List of other papers. 



The following additional pai>ers were read in this 

 section: — The formation and constitution of cblordi- 

 bromacrylic acid, by C. F. Mabery and Rachel Lloyd. 

 Orthiodtoluolsulfonic acid, by C. F. Mabery and G. 

 M. Palmer. Estimation of carbon and nitrogen in 

 organic compounds, by C. Leo Mees. New forms of 

 burettes, by W. H. Seaman. 



PROCEEDINGS OF SECTION D. — MECHANICAL SCIENCE. 



PAPERS HEAD BEFORE SECTION D. 



A comparison of terra-cotta lumber with other 

 materials. 



BY T. E. BAKER OF MILLEKSVILLB, PENN. 



The material called ' terra-cotta lumber ' is made 

 out of clay and sawdust. The investigation which 

 formed the subject of this paper was to ascertain 

 certain qualities of this artificial product. The paper 

 also described the apparatus used for the tests. The 

 results indicated that the material was 875 times as 

 permeable to air as pine, and 135 times as brick. Air 

 was forced by pressure of a column of water. Other 

 tests showed that the material was four times as hard 

 as pine, but not so hard as bi'ick. Its grip on nails 

 driven into it was about half that of pine. Tlie 

 author was careful to disclaim any intention of adver- 

 tising the merits of the material, but he evidently 

 regarded it as serviceable for the purposes for which 

 it is intended. Specimens were exhibited. 



Improvements in shaping-machines. 



BY J. BUEKITT WEBB OF ITHACA, N.Y. 



In the ordinary shaping-machine there are two de- 

 fects, one of which is found also in the planer. The 

 ram of a shaping-machine is a bar sliding in bearings, 

 and carrying at one end the cutting-tool. If we rep- 

 resent by a the variable horizontal distance from the 

 tool to the first bearing (or nearest end of the long 

 bearing), and by b the variable horizontal distance 

 from the tool to the second or farthest bearing (back 

 end of long bearing), and by c the length of stroke, 

 we shall have, — 



Maximum value of a = (minimum value of a) + c. 

 Maximum value of 6 == (minimum value of 6) -f- c. 



In other words, the length of the ram is variable, 

 and the spring of the ram from the work is variable, 

 the tool springing away from its work more at the end 

 of its stroke. This springing takes place mostly in 

 the joint between the ram and its bearings, and cannot 



be wholly avoided without a change of construction. 

 To remedy the defect, the author proposes a reversed 

 construction of the sliding parts; the two bearings 

 (preferable to a long bearing) to be formed on the 

 ram, so as to make the distances a and 6 constant, 

 and the long slide being part of the bed of the ma- 

 chine. 



The second defect, which is also common to the 

 planei', is in having a ' drop-block ' which fits but in- 

 differently between the jaws and against the bottom 

 of its seat. From the necessity of the usual construc- 

 tion, the tool attached to this block will have more or 

 less spring. The remedy is to dispense with the drop- 

 block, and introduce an automatic motion to lift the 

 tool on the return stroke, as has been done, the author 

 has understood, on some large machines. 



Regularity of flovsr in double-cylinder rotary 

 pumps. 



BY J. BUEKITT WEBB OF ITHACA, IT.Y. 



The speaker introduced his subject by exhibiting a 

 number of models of these pum^js from the cabinets 

 of Cornell university, which has recently purchased 

 copies (243 in number) of the celebrated models of 

 the Eeuleaux collection in Berlin. Class I. of this 

 collection is devoted to these pumps. Tlie speaker 

 then produced and demonstrated a formula for the 

 flow of these pumps, and showed that the regularity 

 of flow depended upon otlier principles opposite to 

 those which have been given for determining this 

 point. The formula given for the flow was : — 



7r[B'^ +R"-^ — ()•'- 4- )•"-)] = Flow for 

 one revolution, when R' and R" (generally equal to 

 each other) are the extreme radii of the two revolv- 

 ing wheels; and )■■ and )•" are the radii (often, per- 

 haps generally, variable) from the point of contact 

 between tlie wheels to their centres. It was shown 

 that the regidarity of flow depends upon )•'- + r"'- = 

 constant. R' and R" may he called the ' piston radii,' 

 and r' and r" the ' valve radii.' These pumps are 



