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some organs of plants, tlie gases being taken from the same 
plants at different times of the day and year to demonstrate 
the action of the sun’s rays. This paper is entitled “Memoir 
sur la Vegetation/’ and may be found in Volume V. of “The 
Comptes Eendus.” In the following year the diseases of 
beer engaged his attention, and some interesting facts were 
embodied by him in a paper read to the Societe de 
Pharmacie, “Sur la fermentation visqueuse de la biere.” 
From 1843 till tTie time of his leaving France he was 
engaged in a research on some compounds of lead which 
first brought him into note. One of the papers consequent 
on this may be found in the “ Comptes Eendus ” of 1848, 
entitled “Precede au moyen duquel on obtient un protoxyde 
de plomb cristallise et ayant la couleur du minium.” 
In 1844, he wrote “ On the presence of indigo in the 
Orchidaceous plants in 1846, “On the preparation of 
Calomel on the large scale and, in the same year, a 
compilation of facts relating to the properties of animal 
black. 
On returning to England at the latter end of 1846 he was 
first appointed to the chair of the honorary professorship 
of chemistry at the Eoyal Institution, and afterwards to 
that of lecturer on Chemistry at the School of Medicine in 
Pine Street, Manchester. 
In 1847 he published a paper “On Bleaching Powders,” 
and in 1848 one “ On the Bleaching of Cotton and Flax.” 
About this time Dr. Calvert gave a long series of lectures 
on his favourite subject at the Atheiipeum, Manchester, 
“The Application of Chemistry to Manufactures.” These 
were recorded iii Ihe daily papers. 
During the following years many other subjects engaged 
his attention, but we may notice the following publications 
as some of the results of his labours. 
In 1849, “Process for the Preparation of Chlorates, parti- 
cularly the Chlorate of Potash.” 
