D. E. G0DDARD ON MANIPULATION WITH CANADA BALSAM. 131 



When the cabinet for which they are destined consists of trays 

 in which the objects lie flat, the same care need not be taken as 

 when they are placed in boxes fitted with ordinary rack work. 

 The use of the brush is much safer than wiping the slide with a 

 cloth ; many a slide can be cleaned by the former method, when it 

 would be utterly impossible to do so without moving the cover 

 when the cloth is employed. Mythelated spirit, benzole, camphine, 

 or turpentine, and naphtha, are very good solvents for this purpose, 

 the first being the cheapest, and it has this advantage — it has no 

 unpleasant smell. 



Having cleaned, the next process is the finishing. Many first- 

 class preparers do not use any rim of varnish. I prefer doing so, 

 not that I think that asphalte varnish is much protection, but 

 because I think it improves the appearance of the slide. I should 

 not advise the student to trust to asphalte alone ; it is more or 

 less brittle. There is another accident which must be guarded 

 against ; if the balsam be not sufficiently set, the varnish will run 

 over the field and completely spoil the preparation. To prevent 

 such annoyance and give still greater security to the cover, I pre- 

 fer running a rim of gold size round it, and when hard applying an 

 upper surface of varnish. I may mention that I have used asphalte 

 and gold size mixed in the proportion of two of asphalte to one of 

 gold size with great advantage. 



The labels to be used vary with the taste of the preparer. 

 Round disks are less expensive, and look neater than others. I 

 have found the ruled square labels, sold by Messrs. Smith and 

 Beck, the most convenient, as affording room for such particulars 

 as are sometimes necessary. 



The third division of this paper relates to chloroform and balsam. 



I shall not detail the experiments that have occupied me during 

 the past few months ; I will simply state, in the form of a summary, 

 those conditions that I consider necessary to ensure successful 

 manipulation with this medium. 



1. — Old balsam must be used, and should be sufficiently hard to 

 resist the impression of the point of the nail. If none is to be met 

 with, a bottle of ordinary balsam should be heated in a water bath 

 till the requisite degree of hardness be obtained. 



2. — Great care should be observed in selecting the best and 

 purest mythelated chloroform (it is much cheaper than pure chloro- 



