RFXENT WORK IX A(;RICULTURAL SCIliNCE. 



CHEMISTRY. 



The heat of combustion as a factor in the analytical examination of oils 

 and the heats of combustion of some commercial oils, H. C. Shekman and J. F. 

 Snell (Jour. Amcr. Chem. Soc, 23 {1901), No. 3, pp. 164-172).— The accuracy and 

 the rapidity of the determination of the heat of coinlnistion or calorific power Itvthe 

 u>«e of tlie l)onil) calorimeter, has led the authors to attempt to apply this method in 

 the ideutitication of oils. In the work reported the heats of combustion were deter- 

 mined with a bomb calorimeter of the Atwater-Blakeslee type. The results are sIk )wn 

 in a table and are the mean of two or more determinations, the figures being reduced 

 to c-ombustion at constant volume. In making the determinations, the oil was 

 absorbed by a small amount of fibrous asbestos and was ignited directly by elec- 

 trically fused iron wire. The sources of the oil are given and the probable age of the 

 sample. In each ca.se the specific gravity, the iodin absorption, the free acid aa 

 oleic, and the heat of combustion per gram under constant volume and constant pres- 

 sure are sliown. Of the 40 samples reporteil, it was found that the sperm, rosin, and 

 mineral oils were considerably higher in calorific value than the fatty oils. Among 

 the fatty oils the nondrying were of slightly higher value than the drying oils. 

 Castor oil and l)oiled linseed oil showed a low heat combustion. The old samples 

 whose specific gravities were high and iodin figures low gave in all cases rather low 

 heats of combustion. Oxidation caused by light and air seemed to lower the heat of 

 combustion to almost the same extent that it raised the specific gravity. By divid- 

 ing the heat of combustion by the specific gravity a value was obtained ranging from 

 10 to 10.3 in the fresh fatty oils examined. The value obtained from sperm oil was 

 11.2 and for mineral oils from 11.8 to 12.8. The authors conclude that from the 

 determination of the heat of combustion, accomplished in less than one hour, it 

 wouM appear that the result would be of value, considered in relation to the specific 

 gravity, in detecting ininei'al or rosin oils in fatty oils or fatty oils in sperm oil. 



An apparatus for the determination of the melting point of fats, F. T. Shutt 

 and H. W. Charlton {Trans. Roy. Soc. Canada, 2. ser., 6 (1900-1901), Sec. Ill, pp. 

 21-25, fig. 1). — An electrical method, using mercury as the medium for conveying 

 the heat to the fat and having a bell in the circuit to note the moment of fusion. It 

 is to some extent a motlification of the method of Christomanos, but is much more 

 rapid. The apparatus employed is figured and descril)ed. The advantages claimed 

 for the method are that (1) there is no necessity to remelt the fat, as when drawn- 

 out glass tubes are used, thus avoiding one source of error, (2) the factor of jiressure 

 is practically cliininatcil, {'.-)) the iiiftliod is rapid. 



A rapid method of determining the amount of salt in butter, C. L. Pitch 

 ( Xnt. f\eam. Butfermakers' A.'^.tor. Rpt. 1901, pp. 176-181, fig. 1) . — This method, which 

 the writer has used in 6 creameries during 1 year, is carried out as follows: The but- 

 ter is sampled with a trier, and from the sample small portions are taken here and 

 there and carefully packed in a little I)rass mea,sure. The measure is suspended in 

 a large cylinder partially filled with a known amount of hot water, and the cylinder 

 stoppered and shaken until the butler melts; 17.6 cc. of the aijueous solution ia 



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