September 3, 1886] 



SCIENCE. 



207 



copper, and then contains a higher percentage of 

 akiminium, and always contains nitrogen. It has 

 a resinous kistre, and decomposes water at 100°. 



A paper by Clifford Richardson, on some con- 

 stituents of the embryo of wheat, showed the un- 

 expected presence of a soft wax, cane-sugar to 

 the amoimt of more than ten per cent, a new 

 saccharoid, and allantoin, a nitrogenous substance 

 of the uric acid series, together with other similar 

 substances not yet isolated. The relations of these 

 substances to the transfer of nitrogen in the plant 

 were discussed. 



William McNurtrie described the chemical ex- 

 amination of specimens of ropy milk and cream, 

 which description, together with the discussion 

 which ensued, showed that this unfortunate con- 

 dition is brought about probably by some organ- 

 ism, and that cleanUness and disinfection are the 

 best means of prevention. 



The poisonous matter sometimes occuiTing in 

 old cheese and ice-cream, which he has named 

 ' tyrotoxicon,' was described by V. C. Vaughan. 

 He showed it to be of ptomaine nature, and had 

 been able to induce its formation in a mixture of 

 milk, sugar, and eggs, by inoculation with a 

 small portion of ice-cream which contains the 

 poison. This would seem to point to its origin in 

 the growth of some microbe. Its toxic effect is 

 shown in the extremely rapid production of 

 symptoms similar to those observed in cholera 

 infantum. 



Thomas Taylor presented an exi)osition of his 

 views on the characteristic differences in fat 

 crystals, which have already attracted considerable 

 notice in print, and are well known to most of 

 our readers. 



Other papers read were as follows : ' Action of 

 heat on ethylene,' by L. M. Norton ; 'A new vis- 

 cometer,' by S. M. Babcock ; 'Method for the 

 determination of the melting-point of fats,' and 

 ' The areometric method of estimating fat in 

 milk,' by H. W. Wiley ; ' Manufacture of sodium 

 carbonate,' by Adolf Kayser, presented by Alfred 

 B. Young ; ' Substituted acrylic and propiaric 

 acids,' by C. F. Mabery ; ' Determination of 

 caffeine,' by Dr. Hodgson EUis ; ' Composition of 

 soiling rye,' by William Frear ; ' Preliminary 

 analysis of leaves of Juglans nigra,' by Lillie J. 

 Martin ; ' Some laws of chemical union,' by C. F. 

 de Laudero and Paul Prieto, read by the secretary; 

 and ' The torsion analytical balance,' by A. S. 

 Springer. 



An exhibition of apparatus for the destruc- 

 tion of parasites of cultivated plants will be held 

 at the Horticultural school in Florence during Oc- 

 tober. 



PROCEEDINGS OF THE SECTION OF 

 PHYSICS. 



The first matter presented to the section was 

 a recently devised instrument, by Mr. John A. 

 Brashear, which he terms a ' gravity parallel- 

 ometer. It is used in making the surfaces of a 

 plate of plane glass truly parallel. The art of 

 executing a single plane surface has been carried 

 to a very high degree of perfection, but peculiar 

 difficulties are encountered in making two sur- 

 faces pai-allel. By Mr. Brashear's method a varia- 



tion in thickness of -wt. 



of an inch can be de- 



tected. In one case, two surfaces about a quarter 

 of an inch apart were made 'so nearly parallel, that, 

 were they extended, they would not meet in five 

 miles. 



Prof. W. A. Rogers described the combined yard 

 and metre, which will be used by the department 

 of standards of the British board of trade in a 

 definite determination of their relative lengths. 

 The latest value of the metre in English measure 

 is 39.37012 inches. 



Prof. J. W. Sanborn has been for several years ex- 

 perimenting on the relation of dew to soil-moisture. 

 One means of investigation has been to weigh pre- 

 pared portions of soil night and morning. His 

 conclusion is, that, except in rare cases, the idea 

 that the soil receives moisture at night is false, and 

 the contrary is really true. This appHes where 

 there is no vegetation. 



Major H. E. Alvord presented the results of 

 extensive temperature observations at Houghton 

 farm relative to dew formation. Thermometers 

 were placed so as to determine the temperature 

 from several inches below the surface of the 

 ground to about four feet above the surface. The 

 results, from observations during several months 

 in the summer of 1884, show that the minimum 

 temperature during dew formation is about four 

 inches above the ground, which was not imfre- 

 quently six or eight degrees lower than the tem- 

 perature at the surface. The temperature at the 

 surface was less than the temperature several 

 inches lower. Some surprise was expressed at 

 these results, and the dew problem was regarded 

 as still more perplexing. The temperature of the 

 surface on which the dew is formed is an essential 

 factor in the solution. Discussion showed the 

 difficulty in determining the exact temperatm-e 

 of the surface particles, which differs from that of 

 the earth above or of the soil below, and the total 

 inadequacy of the mercury thermometer as a 

 means of determining it. 



Prof. T. C. Mendenhall prefaced his paper on 

 electric thermometry bj^ saying that the strictures 

 upon the mercurial thermometer should not be 



