May 19, 1887] 



NATURE 



53 



Scorpion Virus. 



I AM much obliged to Sir J. Fayrer for pointing out a mistake 

 in my paper on this subject in the Proceedings of the Royal 

 Society of January 6, 1887. In referring to his experiments I 

 remarked, "They show conclusively that the cobra poison will 

 not affect a cobra, and will not even affect the viperine ptyas. " 

 " Ptyas" was written by mistake for '* Daboia." 



I take the opportunity of recording an observation with regard 

 to the slight power scorpions possess of withstanding the heat of 

 the sun's rays. If a scorpion is placed in an open pie-dish in 

 the sun (the experiments were tried in Madras on an averagely 

 hot day), it will run violently round and round, lash its sting 

 about, and then gradually become torpid ; this happens in from 

 seven to ten minutes. If then removed into the shade, it will 

 gradually recover ; but if left for longer in the sun, it dies. As 

 the scorpion is an inhabitant of hot countries, this sensitiveness 

 to the sun's rays is very remarkable. A. G. Bourne. 



Madras, April 13. 



Weight and Mass. 



I FIND it convenient to distinguish in writing between mass 

 and weight by using the symbols gr. or kgr. or lb. to denote 

 masses, and reserving capital letters Gr., Kp-., &c., where 

 weights, or forces in gravitation measure, are understood ; say, 

 50 kgr. of stone, or wood, or iron — looo Kgr. denoting a stress 

 in some structure or the like. Some agreement in these nota- 

 tions would be desirable. W. 



Lemberg, May 14. 



Dynamical Units. 



In reference to this subject may I remark that the proposed 

 term "cei" is etymologically incorrect for the meaning in- 

 tended to be conveyed? It might stand as a contraction for 

 "celerity," i.e. velocity, but not for the rate of increase of 

 velocity. The essential distinction between velocity and 

 acceleration is wholly expressed in the prefix "ac." If we 

 must cut all our words down to one syllable, the "ac" would 

 really have in it more correct meaning than the " eel." 



Early in 1886, Prof. D. H. Marshall, of King's University, 

 Kingston, published a book on dynamics, in which he uses the 

 word "tach" to mean unit velocity of one centimetre per 

 second. He has no special name for the unit of acceleration, 

 but the unit of momentum he calls a "gramtach," and the unit 

 rate of doing work a "dyntach." The unit pressure-intensity 

 of one degree per square centimetre he calls a " prem." 



I would like to suggest that names for the units might be 

 formed syste natically by the addition to the ordinary name for the 

 quantity of the invariable affix "on," which is the root part of 

 the word "one." Thus as unit names we would employ 

 "velociton" or "velon"; " acceleron " or "accelon"; 

 " momenton " ; " presson " ; " tenson," &c., &c. For the 

 sake of uniformity we might change "radian " into "radion." 



Birmingham, May 4. Robert H. Smith. 



Monkeys opening Oysters. 



So many people have expressed their surprise at hearing that 

 I constantly saw monkeys breaking open oysters with a stone 

 on the islands off South Burmah, that it may be of interest to 

 give a short description of their method of using such a tool. 



The low-water rocks of the islands of the Mergui Archipelago 

 are covered with oysters, large and small. A monkey, probably 

 Macacus cynomo/gus, which infests these islands, prowls about 

 the shore when the tide is low, opening the rock-oysters with a 

 stone by striking the base of the upper valve until it dislocates 

 and breaks up. He then extracts the oyster with his finger and 

 thumb, occasionally putting his mouth straight to the broken 

 shell. 



On disturbing them, I generally found that they had selected 

 a stone more apparently for convenience in handling than for 

 its value as a hammer, and it was smaller in proportion to what 

 a human being would have selected for a proportionate amount 

 of work. In short, it was usually a stone they could get their 

 fingers round. As the rocks crop up through the low-water 

 mud, the stone had to be brought from high-water mark, this 

 distance varying from 10 to 80 yards. This monkey has chosen 

 the easiest way to open the rock-oyster, viz. to dislocate the 

 valves by a blow on the base of the upper one, and to break the 



shell over the attaching muscle. The gibbon also frequents 

 these islands, but I never saw one of them on the beach. 



Alfred Carpenter. 

 Marine Survey Office, Bombay, April 14. 



Zirconia. 



Our attention has been drawn to a letter in Nature, vol. 

 xxxv. p. 583, written by Mr. Lewis Wright. He makes the 

 statement that we supplied him with a sample of zirconia as 

 "pure," which, upon examination, he found to contain silica, as 

 well as some soda, rendering the sample quite useless for the 

 purpose for which it was required. 



We trust you will allow us to correct this statement. We 

 sold the zirconia as " impure," and when Mr. Wright asked us 

 to purify it further for him, declined to do so. We told him 

 that it was an article obtained as a residue produced during the 

 preparation of another body, and was sold, in consequence, at a 

 price far lower than the usual price at which the article can be 

 produced in a pu'-e state. HoPKiN and Williams. 



16 Cross Street, Hatton Garden, London, E.G. 



Sunspots. 



Dr. Veeder is perfectly correct in his letter appearing in 

 Nature, vol. xxxv. p. 584, in his description of the tiny group 

 of spotlets which were seen on November 15, 16, and 17. The 

 complete record of spots for the month of November 1886 

 appears to have been as follows, the areas of the spots being 

 expressed, as in the Greenwich results, in millionths of the sun's 

 visible hemisphere. 



The mean daily area of these seven days, the only days in the 

 month showing spots, was only 7 millionths, and for the month as 

 a whole, i '6 millionths. The exceptional character of the month 

 will be better seen when it is remembered that the Greenwich 

 results give 24 millionths as the mean daily area for 1878, the 

 year of minimum ; whilst at maximum, as in 1883, the mean 

 daily area was 11 55. 



With reference to the "six days" which Dr. Veeder quotes 

 from the note on "Solar Activity in 1886," appearing in the 

 Astronomical Column of Nature, vol. xxxv. p. 445, the asser- 

 tion was based on a record which was defective for three or four 

 days. The group he describes as making its first appearance on 

 December 8 was not seen here until December 10, and had 

 only become important by December 12. Since the appearance 

 of Dr. Veeder's letter, I have been privileged to inspect the 

 series of photographs taken in India and in the Mauritius, under 

 the aitspices of the Solar Physics Committee. These show that 

 the group had not come into view at the east limb until after 

 the photographs on December 8 had been taken, so that, for 

 Europe and Asia, December 9, which was cloudy here, was 

 practically the first day of the spot. 



The Writer of the Note. 



"The Game of Logic." 



In the course of a review of Lewis Carroll's "Game of 

 Logic" (p. 3), Mr. A. Sidgwick says incidentally that "In 

 Mr. Venn's scheme propositions either tell us that a com- 

 partment is empty or tell us nothing about it." This is not 

 quite correct ; he should have confined his statement to univer- 

 sal propositions. It is quite true that on the schemes of Boole 

 and Jevons nothing is recognized but o and i ; nothing but the 

 excision of a combination and the letting it stand ; and they 

 both make the attempt to express particular propositions with 

 such resources. But I have taken particular pains to show that 

 such a scheme of dichotomy will not suffice to represent affirma- 

 tives and negatives, universals and particulars ; and that for this 

 purpose, when we are dealing with logic on the compartmental 



