422 MEMORIAL OF JOSEPH HENRY. 



seed was imported from France and distributed through the agri- 

 cultural department of the Patent Office to different parts of the 

 country, with the hope that our farmers w r ould be induced to attempt 

 its cultivation. Although the climate of the country appeared 

 favorable to its growth, and special instructions were prepared and 

 distributed by the Light-House Board for its culture and the means 

 of producing oil from it, yet the enterprise was not undertaken with 

 any approximation to success, except in Wisconsin, where a manu- 

 factory of rape-seed oil was established by Colonel C. S. Hamilton, 

 formerly of the United States Army. To this manufactory the 

 Light-House Board gave special encouragement and purchased at 

 a liberal price all the oil that could be supplied. The quantity 

 however which could be procured was but a small part of the illumi- 

 nating material required for the annual consumption of the Light- 

 House Establishment." 



After referring to some investigations made for the Board by 

 Professor J. H. Alexander, of Baltimore, the Report quoted pro- 

 ceeds : " The chairman of the committee on experiments commenced 

 himself to investigate the qualities of different kinds of oil, and 

 was soon led to direct his attention to the comparative value of 

 sperm and lard oils. The experiments made by Mr. Alexander 

 were with small lamps, and the comparison in this case (as will be. 

 shown) was much against the lard oil. The first experiment of the 

 new series, consisted in charging two small conical lamps of the 

 capacity of about a half pint, one with pure sperm oil and the other 

 with lard oil. These lamps were of single-rope wicks each contain- 

 ing the same number of strands: they were lighted at the same 

 time, and the photometrical power ascertained by the method of 

 shadows. At first the two were nearly equal in brilliancy, but after 

 burning about three hours, the flame of the lard had declined in 

 photometric power to about one-fifth of that of the flame of the 

 sperm. The question then occurred as to the cause of this decline, 

 and it was suggested that it might be due first, to a greater specific 

 gravity in the lard oil, which would retard the ascent of it in the 

 wick after the level of the oil had been reduced by burning in the 

 lamp; or second, to a want of a sufficient attraction between the 

 oil and the wick to furnish the requisite supply as the oil descended 

 in the lamp; or third, it might be due in part to the imperfect 

 liquidity of the oil, which would also militate against its use in 

 mechanical lamps. 



" The lard oil was subjected to experiments in regard to each of 

 these points. It was found by the usual method of weighing equal 

 quantities of the two fluids, that the specific gravity of the lard was 

 greater than that of the sperm ; and also by dipping two portions. 



