Jan. 2, 1890] 



NATURE 



197 



by the state. Once more however we admit that the 

 scope and limits of his work have imposed upon him 

 almost insuperable difficulties. 



Introductory Lessons in Quantitative Analysis. By John 

 Mills and Barker North. (London : Chapman and 

 Hall, 1889.) 



This book of eighty-five pages is the first part of a larger 

 work by the same authors, which will shortly be published. 

 It is designed mainly for the use of "students in evening 

 classes who have but little time to spare in acquiring 

 such knowledge," and also to be of service for the Science 

 and Art Department examination, as well as those of 

 London University. The descriptions contained in the 

 three chapters constituting the book, and which treat of 

 preliminary operations, gravimetric analysis, and volu- 

 metric analysis, respectively, are meagre in the extreme, 

 and lack many details essential to a primer. Slips and 

 loose statements are numerous. For example, the student 

 is led to infer that the ash of any of Schleicher and Schiill's 

 filter-papers is negligible. Lead is estimated by means 

 of " bichromate of potash," which is formulated as K^CrOi. 

 On p. 62 the authors assert that " Normal solutions of 

 univalent substances like iodine, silver nitrate, sodium 

 chloride, &c., contain their molecular weight in grams in 

 one litre." Whatever be the meaning attached to this, 

 it is in no way confirmed by what follows on p. 63 — 

 namely, that " The atomic weight of iodine being I26'5, a 

 normal solution would contain this number of grams in 

 one litre." 



The general scheme of work set out in the lessons is 

 satisfactory, and if carefully elaborated might be useful. 

 In its present condition, however, the effect of the book 

 on the beginner cannot be other than confusing. 



LETTERS TO THE EDITOR. 



( TTie Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents . Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature, 

 No notice is taken of anonymous communications. '\ 



Note on a Probable Nervous Affection Observed in an 

 Insect. 



Whilst walking in the garden one bright September morning, 

 my attention was called to a moth fluttering in a peculiar manner 

 on the ground ; it kept going round and round in a circle, 

 running with its feet on the stones, its wings meanwhile being in 

 rapid motion. 



I captured the insect, which proved to be a quite fresh speci- 

 men of a male Orgyia antiqua (vapourer moth), of which there 

 were many in the garden. 



I replaced the insect without injury on the path, and watched 

 it more closely. 



The movements of the wings were irregular, convulsive, and 

 very rapid in character; the feet and body were also in rapid 

 movement, resulting in a circular motion of the whole insect 

 from right to left — that is, in the same direction as the move- 

 ments of the hands of a watch. 



1 again captured the insect, thinking that perhaps one of its 

 antennx- might have been injured ; but on careful examination 

 with a hand lens, I could detect no lesion nor the presence of any 

 parasite which might account for the condition. 



I again placed the insect on the path, when it immediately 

 began to rotate as before. It seemed unable to keep still, 

 though evidently trying to do so. 



Occasionally it would wedge itself in between two or more 

 small stones, with its head downwards, and the under surface of 

 its body upwards, its wings resting on the stones below ; in this 

 position it appeared to obtain some relief, as the movements 

 were less continuous, though every breath of wind caused a 



convulsive twitching of the wings and body. On one occasion 

 a leaf fell upon the insect whilst wedged in, causing a very 

 violent convulsion of the whole insect, by which it was jerked 

 quite out of its retreat, when the gyrating movements at once 

 began again. 



I tried stroking the antennae with the point of a pencil, but 

 this had no effect, nor could I obtain cessation of movement 

 by stroking the body or the wings ; on the contrary, when the 

 insect was wedged in each touch caused a convulsion, varying 

 with the intensity of the stimulus applied. 



These movements continued without interruption for fully 

 forty minutes, the insect gyrating in a space about a foot square. 

 At the end of that time I placed it upon a piece of smooth 

 paper, when the movements became more rapid and the 

 gyrations less ample, it completing a turn in much less time than 

 on the stones, owing, no doubt, to there being no projections on 

 the paper to cause the insect to deviate. 



I then placed it in a shallow cardboard box in the full sun- 

 light, but protected from the wind. In this way the convulsive 

 movements were less intense and less frequent ; the insect, how- 

 ever, was often jerked over on to its back, then, after a struggle 

 or two, would right itself, and begin to go round. When, how- 

 ever, it managed to press the top of its head against the side of the 

 box, so that its antenna; were pressed between the head and the 

 side of the box, all movement ceased till some external stimulus 

 again set it in motion. 



At the end of one hour the insect seemed quite exhausted, a 

 strong stimulation being required to develop one convulsion. 



On examination I found that it had worn away, in its move- 

 ments, all its legs with the exception of the left hind leg, which 

 was apparently pretty intact, and had broken both its wings on 

 the right side, so that the greater part of them hung useless over 

 its body. 



After a few more violent convulsions, the upper wing of the 

 right side was broken off, and the insect now began to revolve 

 from left to right, owing, I suppose, to the movements of the 

 left leg ; the others being reduced to mere stumps would have 

 little power of propelling the insect. 



About twenty minutes later, during a convulsion, the right 

 hind wing was broken off. 



Shortly afterwards I noticed that the convulsive movements 

 of the antennas, which had been slight up to that time, were 

 much increased ; indeed, they were moving so rapidly as to have 

 the appearance of two small black wings. 



One hour and fifty-five minutes after I first noticed the insect 

 all convulsions had ceased ; no stimulus could excite any ; the 

 moth was dead. 



Conclusion. — The insect, suffering from no apparent injury, 

 and being attacked by no internal or external parasite, was, I 

 believe, suffering from some nervous lesion. I was unfortunately 

 unable to examine the insect microscopically to ascertain if the 

 nervous centres exhibited any pathological characters. 



E. W. Carlier. 



Does the Bulk of Ocean Water increase "i 



The idea was, I think, suggested by myself, and has been 

 referred to with approval by Mr. Jukes-Browne, that much of the 

 water on the surface of the globe was originally occluded in the 

 molten interior, and has been emitted by volcanic action in the 

 course of ages. Mr. Mellard Reade argues against this, that the 

 moon is covered with volcanic craters, and yet has no water on 

 its surface, and that if the accumulation of surface water has 

 followed volcanic action on the earth, it ought likewise to have 

 done so on the moon. He concludes : — " At all events, it seems 

 a reasonable question to ask why oceans should be supplied with 

 water from the perspiring pores of mother earth, while her off- 

 spring, the moon, is so dry as to have absorbed into herself all 

 evidence of any aqueous envelope that may have formerly 

 existed." 



It is a singular coincidence that one possible answer to this 

 objection is suggested by a notice in the " Astronomical Column " 

 of the same number of Nature which contains Mr. Reade's 

 letter. Therein Prof Thury attributes apparent changes in the 

 aspect of a lunar crater to the melting of snow or ice around it. 

 Neither is he the only selenologist who thinks that those crater- 

 rings consist more or less of frozen water. If they do so, then 

 there is water on the moon, although in a solid state. On the 

 other hand, Proctor, in his work on the moon, says that her 



