FIFTY-FIRST CONGRESS, 1889-1891. 1515 
it, which, patented for the Government, introduced the use of lard instead of sperm 
into the light-houses. 
These experiments upon lamps and oil were made in the light-house established 
at Staten Island by Professor Henry. They involved a great deal of time, were very 
arduous, and very detrimental to health on account of the necessary high tempera- 
ture of the room in which they were conducted. The value of the change to the 
Government may be measured to a certain extent by the difference between the 
price of the oils. This was at first over a dollar on every gallon, and very nearly 
$100,000 a year, but the price of sperm fell and of lard was raised, so a mean of 
prices must be taken. 
For the actual saving to the Government from 1867 to 1889, light-house records 
give the highest price of sperm oil $2.43}; lowest, $1.09; but the oil went down lower 
still, to 62 cents; mean, $1.523; highest price of lard in these years, $1.29; lowest, 50 
cents; mean, 89 cents; the difference, and therefore the savings in each gallon of oil, 
63 cents. 
The number of gallons used was 1,777,000, and the saying to the Government, 
therefore, by these experiments of Professor Henry, $1,118,510. 
But this is not all. 
The use of lard oil by the light-houses raised the price, a cheaper luminant was 
required, and a new series of experiments were undertaken by Professor Henry with 
mineral oils, which had been considered too dangerous to be employed in the Light- 
House Service. These experiments were also made at Staten Island. They were 
attended with great danger to his person and life on account of the explosive 
character of the oils. The first difficulty was with the lamp, but there were many 
other questions to be settled, such as the flashing test, the fire test, the freezing test, 
at which it should remain limpid at zero, etc. The experiments were successful, but 
they were the last made by Professor Henry; through a cold taken in the course of 
them, and the fatigue of them, he contracted the disease of which he died. He left 
his home in the full vigor of health for Staten Island, to return in a few days broken 
down by the illness which soon ended his days. 
For the saving effected we have highest price of mineral oil, 30 cents; lowest 
price of mineral oil, 6} cents; mean, 18 cents; mean price of sperm oil, $1.523; 
difference, $1.34; number of gallons used, 2,044,554; saving, $2,739,702.36; add to 
this the saving on the lard oil, $1,119,510; total, $3,859,212.36. 
The present price of sperm oil, as given by one of our largest groceries, is $1.50 per 
gallon; of mineral oil, 10 cents; the difference is $1.40. Last year 333,000 gallons 
were used. Not less will be employed this year. Professor Henry’s experiments 
are therefore saving to the Government this very year over $420,000, and before the 
year has closed the saving from 1867 will amount to over $4,000,000. Nor do these 
figures truly represent the amount of the saving, for the fall in the price of the sperm 
was caused by the withdrawal of the Government patronage, and the comparison 
should be made with the higher price to which it had been raised by the use of the 
light-house. 
Great as these figures are they sink into insignificance beside the immeasurably 
greater value of mineral oil as a reliable light-house illuminant over lard oil. This 
it is difficult to explain, but it may be indicated. 
Lard oil became more or less solid in cold weather and had to be liquefied by heat 
before it could be put inthe burners. Betty’s or small hanging alcohol lamps had 
to be hung lighted under the goose neck, or connection between the reservoir and the 
burner, to insure liquefaction of the lard and the combustion of the oil. Mineral oil 
is liquid at zero and is always ready for instant use. Hence all the machinery for 
keeping lard oil liquid was done away with and all danger from the solidification of 
the oil avoided. 
