Ori Magnetic Observations transmitted from York Fort. 143 



3. The consequences of this paralysis of the heart are the cessa- 

 tion of the voluntary and reflex movements in the first and second 

 hour after the introduction of the poison. 



4. The Antiar paralyses in the second place the voluntary 

 muscles. 



5 . In the third place it causes the loss of excitability of the great 

 nervous trunks. 



6. The heart and muscles of frogs poisoned with Urari may be 

 paralysed by Antiar. 



7. From all this it may be deduced, that the Antiar principally 

 acts upon the muscular fibre and causes paralysis of it. 



So much for this time. My experiments with the Antiar upon 

 warm-blooded animals have only begun, and I am not yet able to 

 draw any conclusion from them. As soon as this will be possible, I 

 shall take the liberty to submit them to the Royal Society, together 

 with the results of my experiments with the Upas tieute, which 

 poison I had also the good fortune to obtain through the kindness of 

 Sir Benjamin Brodie and Dr. Horsfield. With regard to the Antiar 

 I may further add, that experiments made independently, and at 

 the same time, by my friend Dr. Sharpey with this poison, have con- 

 ducted to the same results as my own. 



January 7, 1858. — J. P. Gassiot, Esq., Vice-President, in the Chair. 



The following communication was read : — 



" Remarks upon the Magnetic Observations transmitted from York 

 Fort in Hudson's Bay, in August 1857," by Lieut. Blakiston, of the 

 Royal Artillery. By Major-General Sabine, R. A., Treas. and V.P.P-.S. 



In the spring of 1857, Her Majesty's Government, designing to 

 send an expedition to exariiine and survey the yet unsettled country 

 north of the boundary-line between the British territory and that of 

 the United States, and comprised between Canada on the east and 

 the Rocky Mountains on the west, notified their intention to the 

 Royal Society, and invited suggestions regarding any objects of 

 physical research, for which the Royal Society might deem this to be 

 a fitting occasion. 



Amongst the subjects to which attention was called in the reply, 

 the expediency of confirming and extending the Magnetic Survey of 

 British North America, which, at the instigation of the Royal Society, 

 was made in the years 1843 and 1844, and of which the results are 

 contained in the ' Philosophical Transactions ' for 1846, Art. XVII., 

 was not forgotten ; and Lieut. Blakiston, of the Royal Artillery, per- 

 sonally known to Mr. Palliser, the conductor of the proposed Expedi- 

 tion, "having been appointed to the special charge of the Magnetic 

 Observations, and to assist generally in Geographical Determinations, 

 the Royal Society undertook to provide the instruments suitable for 

 the purpose, and with the sanction of the Committee of the Kew 

 Observatory of the British Association, placed their preparation 

 under the superintendence of Mr. Welsh, Director of that Observa- 

 tory, where also Lieut. Blakiston received instructions for their use, 

 and acquired practical experience in their manipulation. About the 

 middle of June, Lieut. Blakiston sailed in the Hudson's Bay Com- 



