THE DUBLIN INTERNATIONAL EXHIBITION; 225 
slightest solidification was observed. Lubricating oils for fine machinery, 
procured from the glycerides will always be open to the objection that 
they become rancid upon exposure to air and light, and the reporter is 
of opinion that the best oil for these purposes is to be procured from 
some of the less volatile hydrocarbons, which are the products of distil- 
lation of mineral oils. 
In the Canadian department, we get a speeimen of the oil from the 
mineral springs exhibited by D. Bogart, Gaspe (Canada, 5) ; also a 
specimen marked cedar oil, which was examined by Professor Jellett,- 
who gives the following account of it : — The specific gravity is '9235. 
Rotates the plane of polarisation of a transmitted ray to the left. 
Taking the rotary power of American oil of turpentine (which is in an 
opposite direction) as unity, the rotary power of oil of cedar is 1*2479. 
In this department chrome yellows are exhibited, procured from the 
native chrome iron, considerable quantities of which are found among 
the mineral riches of Canada. 
In the collection of colours, Hare and Co., Bristol (United Kingdom, 
19), carry off the palm by their fine display, in all the gradations of the 
chromatic scale— viz., shades known under the names of Brunswick 
green, chrome yellow, Prussian blue, Chinese blue, Pure blue, Bruns- 
wick and celestial blue, purple, browns, Indian red, and lakes. The 
specimens of white lead are numerous, and both those of Messrs. Walker, 
Parker, and Co., Chester (United Kingdom, 837) and Messrs. S. and W. 
Tudor, London, (United Kingdom, 35) are excellent. Good specimens 
will also be found in the Belgian department. There are several second 
qualities of this article scattered through the building ; but according 
to the analyses made by Professor Galloway in every case the deteriora- 
tions are produced by the admixture of sulphate of barium. In pigments 
for metal work there is one in the Belgian department which requires a 
short notice from the fact that the ferruginous pigments are becoming 
very general. The objection to the old " priming " colour, red lead, is, 
that for iron work it seems to produce some oxidising influence upon 
the surface of the metal. This objection also holds good in connetion 
with precipitated oxides of irons unless they are very carefully washed. 
There is a class of ferruginous oxides which consist of burnt ochres,: 
containing a considerable amount of clay, which would interfere very, 
much with the body and protective power of the pigment. The specimen 
exhibited by De Cartier, Auderghem (Belgium 15), under the name of 
"Minium de fer d'Auderghem," seem to posses advantages over the: 
ordinary preparations, as they consist of roasted hematite finely levigated 
with water. 
The candle and soap-making trades are well represented in this 
Exhibition. The British and Irish exhibitors are on the whole very 
superior to Foreign and Colonial both in candles and soaps, and it is 
perhap the only branch in this section where any marked superiority 
is observed. It is evinced doth in the appearance anp quality, most of 
