SCIENTIFIC SUMMARY, 
97 
formed from tlie above given total. The flowers are gathered in the middle 
of May, and the harvest continues for three weeks. The blossoms collected 
each day are at once worked, in order that none of the odour may be lost. 
The process consists in distilling them in water, and then causing the water 
alone to undergo distillation, when the oil is skimmed from the surface. 
The labour is principally done by women and children, at wages of about 
ten cents per day. The otto is always adulterated, before transmission to 
market, with one-third or one-fifth its quantity of geranium oil. 
Zinc precipitated by Water. — It seems from a letter by Mr. J. L. Davies, 
in the u Chemical News ” [October 2, 1874], that zinc may be added to the 
list of metals which can be precipitated by means of water. The conditions 
seem to be these. If to a solution of zinc chloride, just sufficient only of 
ammonia be added to re-dissolve the precipitate at first formed, the addition 
of water throws down zinc in the form of a gelatinous and bulky precipitate. 
In the cold the whole of the zinc is not thus precipitated, but possibly with 
continued boiling it might be. 
An Improvement of the Bunsen Burner for Spectrum Analysis . — Mr. F. 
Kingdon, Assistant in the Physical Laboratory of Owens College, read a 
paper before the Manchester Literary and Philosophical Society [Nov. 2, 
1874], in which he said that the students in the Physical Laboratory of 
Owens College having occasionally experienced some difficulty in obtaining 
the spectra of some salts with the ordinary Bunsen, through apparently a 
deficiency of pressure in the gas, it occurred to him that the amount of light 
even at this deficient temperature might be increased by multiplying the 
number of luminous points. This is accomplished by broadening out the 
flame of the Bunsen, that is, causing the gas to issue through a narrow slit, 
instead of a round hole. He has, so far, only made a rough experiment, the 
slit being about f in. long and ^ in. wide. The result is, as expected, a more 
brilliant spectrum. 
Formation of Bed Vapour during Sugar-boiling . — In the a Chemical News ,f 
of Oct. 30th, 1874, M. E. J. Maumene states that he has observed an extra- 
ordinary evolution of red vapours at the moment when the air-pumps of the 
vacuum pans began to work, and at nearly all stages of the operation. There 
is generally a notable amount of nitrates in the juice of the beetroot. M. 
Maumene finds that sugar may be the cause, or one of the causes, of the' 
formation of these red vapours. Whenever the juices contain nitrate of 
ammonia, their decomposition is imminent. This is certainly one of the 
most active causes of discolouring the boiled mass, and of molassification in 
the last stage of the boiling process. The ammonia may be expelled by 
lime. The juice mixed with lime and water is considerably ameliorated if 
allowed to stand for twenty-four hours. 
Bismuth Bromide. — This rather novel substance has been recently written 
on by Mr. B. W. E. Macivor, who states that the combination of metallic 
bismuth with bromine to form "Br'^Erg is not, as is the case with antimony 
and arsenic, attended with the emission of light. The compound is pre- 
pared by heating finely-powdered bismuth with dry bromine in a hand-glass 
tube closed at the end. Bismuth bromide, as obtained by this process, is a 
solid substance of a dark grey colour, fusing at a temperature of 198° to 202° 
C. to a dark red liquid which boils below a dull red heat. It is insoluble in 
YOL. XIV. — NO. LIY. H 
