Mr. G. Gulliver's Observations on the Blood Corpuscles. 23 



seen by transmission, the light twice reflected causes rings 

 which are easily visible, although one portion of the inter- 

 fering light is less than g^yth part of the other by the undu- 

 latory formulae, and about y^^thby my experiments; also, in 

 the former experiment, the polarizing angle for glass {B6h° 

 nearly) is approaching towards the polarizing angle for dia- 

 mond (about 68"), therefore, the whole light reflected by the dia- 

 mond would be only a small fraction of the incident light, and 

 that by the glass, according to Mr. Green's formula, would bear 

 a considerable ratio to it, and therefore the rings should be very 

 distinct, in place of which none are to be seen at all ; so that 

 Mr. Green's formula neither represents the facts nor agrees 

 with Fresnel's. 



Professor Forbes also says, in the second sentence of his 

 memorandum, "but the chief evidence for the truth of this 

 remarkable law rests on the indirect observation of the change 

 of the plane of polarization of an incident ray after reflexion." 

 He here alludes to a series of valuable experiments made by 

 Sir David Brewster, and published in the Phil. Trans, for 

 1830. If we look over Sir David's table at page 75, we see 

 the results of the experiments on the change of the plane of 

 polarization after reflexion by diamond, affording errors of 

 observation, although, from the nature of the experiment ne- 

 cessarily large, (averaging 46^') yet all lying on one side of 

 the calculated I'esults. When the theory is true we naturally 

 expect the errors of observation to fall sometimes on one side 

 and sometimes on the other side of the calculated place. 

 Hence, it is clear, that the undulatory theory, even in this 

 vaunted case, does not give the accurate results. 

 Queen's College. 



IV. Observations on the Blood Corpuscles or Red Disks of the 

 Mammiferous Animals. By George Gulliver, F.R.S., 

 Assistant-Surgeon to the Royal Regiment of Horse Guards'^\ 



\ COMPLETE history of the blood corpuscles of the 

 -^^ mammalia would be a very acceptable addition to ana- 

 tomical science, and probably no less advantageous to zoo- 

 logy. To accomplish this work, however, the co-operation of 

 so many circumstances is necessary, that the contributions of 

 different observers are especially desirable. I have long been 

 engaged in the inquiry ; and, as I have been favoured with 

 the liberal permission of the Council of the Zoological So- 

 ciety f to avail myself of the advantages of their collection, I 



^Communicated by the Author, Nov. 23, 1839. 

 tMn 



fMn returning my best thanks on this occasion to the Council, I cannot 



