T. J. ENGLISH ON A PNEUMATIC INJECTING APPARATUS. 101 



bilities of holding condensed air, so that should it be faulty and 

 break, it will do so then in all probability ; but I do not think that 

 such a result would occur with ordinary care, as the vessels of the 

 animal which is being injected burst if much force be used. 



It is not my intention to enter into the respective merits of the 

 bottle and the syringe, but there are two advantages which the 

 former possesses over the latter. The first is that it leaves both 

 hands entirely free during its action, and the second is its cheap- 

 ness, the whole instrument costing when finished about 4s. 



An Omission Corrected. 



We regret an omission in our last issue, which occurred inad- 

 vertently, no report having been furnished to us. It was to notice 

 the new pattern ^Lth immersion lens, by Schieck, of Berlin, which 

 attracted so much attention at our meeting held on the 28th of 

 June last. We may here mention that it was greatly admired for 

 its remarkable abundance of light, perfect flatness of field, and 

 brilliancy of definition. 



The objects used with it were (1) Surirella Gemma^ the longi- 

 tudinal and transverse lines of which it shewed with the utmost 

 distinctness ; (2) Navicula Cuspidata, the lines on which were 

 beautifully resolved into " dots." Some, on the other hand, objected 

 to the presence of colour — a faint ruby tint — which seemed to be 

 associated with its best performances. This, however, is character- 

 istic of almost all German lenses, and is owing to the preponder- 

 ance generally given by the German opticians in their immersion 

 combinations to the crown glass over the flint glass. Mr. Schieck, 

 we believe, was, till within the last two years, a pupil of the cele- 

 brated Dr. E. Hartnack. 



