I have been occupied for about two years past, assisted by the practical pupils in the laboratory belonging to the College of Glasgow, in analysing the most important specimens in my mineral cabinet, which seemed to me to require further elucidation. As my practical pupils are seldom fewer than six, and as they are employed the whole day, from nine in the morning till dinnertime, during the whole year, about six weeks in the summer excepted, which I have been in the habit of spending in the country, the number of analyses which has accumulated within that time, has become so great, and some of the results are so curious, that I have selected a few out of the number, for the gratification of the mineralogical public. It may be requisite to mention, in the first place, that when a pupil comes into my laboratory, the first thing which he does is to transcribe a set of practical rules, which I have drawn up for the benefit of my pupils. He is then set to analyse an easy mineral, with the composition of which I am already acquainted. I either shew him myself the different steps of the analysis, or request some of the farther advanced pupils to superintend the progress of the analysis, and ensure its accuracy.