680 



REPORT — 1884. 



object of this research is to determine the curves of expansion of solutions which 

 contain, in equal volumes, weights of the salts proportional to the molecular weights. 

 The experiments made show the feasibility of employing simpler apparatus than 

 that hitherto used in determining the coefficients of expansion of saline solutions. 

 The apparatus is a graduated bulb-tube with a bore large enough to admit a small 

 capillary tube with which the solutions are run into the bulb-tube. The solutions 

 are boiled a few seconds, while still hot poured into the bulb-tube, and are then 

 closed off from the air by a mercury thread. The bath is a large vessel of water 

 stirred constantly. Two series of readings are taken, one with the temperature 

 rising and one with the temperature falling. The experiment is rejected unless 

 these two sets give the same results. The experiments recorded in our paper were 

 made with an ordinary thermometer graduated in single degrees and do not give 

 sufficiently accurate results, but we hope with more delicate thermometers to very 

 much increase the accuracy. 



8. On the Production of Permanent Gas from Paraffin Oils. 

 By Dr. Stevenson Macadam, F.B.S.E. 



The paraffin oils employed in the investigation were crude paraffin oil, being 

 the oil obtained direct from the destructive distillation of shale in retorts; (jreen 

 paraffin oil, which is obtained by distilling or re-running the crude paraffin oil and 

 removing the lighter or more inflammable oil by fractional distillation and freezing 

 out the solid paraffin ; aud Hue paraffin oil, which is the product obtained by 

 rectifying the paraffin oil by aulphuric acid and soda, and distilling oft" the paraffin 

 spirit, burning oil and intermediate oil, and freezing out the solid paraffin as 

 paraffin scale. After many trials it was found that the best results were obtained 

 by the simple arrangement of employing iron retorts at a good cherry-red heat, and 

 running the oil as a thin stream direct into the retorts, so that it quickly impinged 

 upon the red-hot metal, and without the intervention of any coke or other material 

 in the retort. The following table gives the condensed results of one series of 

 trials : — 



Specific gravity of oil, "\ 

 (water = 1000) . J 



Flashing point in close \ 

 tester J 



Gas from gallon of oil 



Gas from tun of oil . , 



Candle power of gas 



Light value of one cubic ] 

 foot of gas in sperm J> 

 candles . . J 



Light value of gas fromS 

 gallon of oil in sperm }. 

 candles . . J 



Light value of gas from "| 

 tun of oil in sperm S 

 candles . . J 



Light value of the oils as | 

 oils, determined from ! 

 previous experimental j 

 data ... J 



Percentage of oil light ^ 

 obtained in gas light/ 



Crude Paraffin Oil Green Paraffin Oil 



830 



92° P. 



98-76 cub. ft. 



26,020 cub. ft. 



50'36 candles 



1208-04 grains 



17-052 lbs. 

 449-1 lbs. 



5565 lbs. 

 80-75 



884 



165° V. 



102-52 cub. ft. 



25,977 cub. ft, 



53-24 candles 



1277-76 grains 



18-718 lbs. 



4741 lbs. 



5936 lbs. 



79-87 



Blue Paraffin Oil 



878 



163° F. 



127-42 cub. ft. 



32,492 cub. ft. 



64-28 candles 



1302-72 grains 



23-704 lbs. 

 6047 lbs. 



7420 lbs. 

 81-49 



In these trials, therefore, the gas obtained from the oils is equal in light power 

 to 80 per cent, or four-fifths of the total light of the oils when such are consumed as 



