NA TURE 



[May 30, 1 90 1 



these certificates as President of the Royal Society ; he knew 

 the licensees to be fit persons to have the respective licenses, but 

 there was no question of individual intimate friendship. 



(3) The occurrence of pain after inoculation experiments is 

 relatively very rare, and to refer to these experiments to a 

 popular audience as vivisections is certainly misleading it, and 

 Mr. Coleridge must have known this. The statement that the 

 majority of these so-called vivisections were mere pin-pricks is 

 true. 



(4) We do not complain of Mr. Coleridge's statement of 

 what he terms the " diversion " of hospital funds to the corre- 

 sponding medical schools, but we simply say that the allotment 

 of the Prince of Wales's Hospital Fund was not influenced in 

 any way by whether a hospital had laboratories or so-called 

 vivisectors attached to it or not. We regard the statement that 

 Lord Lister wilfully diverted public funds to endow vivisection 

 as scurrilous. We entirely deny that hospital funds are, by 

 being used for the support of medical schools, "diverted," in Mr. 

 Coleridge's sense, from the patients. Medical schools are essen- 

 tial to large hospitals, and any grant made to them out of 

 hospital funds is only in return for services rendered, although 

 it indirectly helps the progress of medical science. 



(5) The statement that -Mr. Coleridge tried to make a bargain 

 with a London hospital concerning the appointment of its staff 

 and that the hospital declined is true ; the mere wording of the 

 reply is a matter of no importance. If Mr. Coleridge will 

 publish the correspondence to which he refers we shall be pre- 

 pared to consider it exhaustively. 



(6) We entirely object to the relation between hospitals and 

 medical schools being put before the public subscribers to the 

 Hospital Sunday Fund in the way Mr. Coleridge suggests. If 

 Mr. Coleridge has any scheme by which the large hospitals can 

 receive the services of the medical profession more cheaply than 

 they do at present he is quite justified in putting this before the 

 public. He is, however, not justified in stigmatising grants 

 made to medical schools as being " diverted " from the use of 

 the sick. — Editor.] 



■Vitrified Quartz. 



A STurn' of the viscous properties of vitrified quartz in which 

 I was engaged last year, and which I communicated to the 

 Geological Congress of 1900, revealed a degree of plasticity 

 and m olecular instability which I think justify Mr. Shenstone's 

 reserve in pronouncing on the applicability of this substance to 

 thermometry at high temperatures (Nature, May 16). A few of 

 the measurements I obtained may be of interest. I may 

 observe that the method of observation w.as to stretch a quartz 

 fibre (as supplied by the Cambridge Instrument Co.) in a 

 horizontal platinum tube, which is heated by a current and 

 clamped in the meldometer, its temperature being determined 

 in terms of its thermal expansion. The fibre, which passes 

 axially through the tube, is fixed at one extremity, and at the 

 other is attached to a light pendulum, the mass of which can 

 be increased, and which it deflects from the vertical. It is 

 observed by two micrometers placed at some few centimetres to 

 either extremity of the tube, so that any slip in its fixed 

 attachment will be detected. The tube is 10 cm. in length 

 and '2 cm. in diameter. Tensions are calculated in kilos, per 

 square centimetre, and rate of elongation in centimetres per 

 minute per unit of tension per centimetre of fibre. The 

 dift'erent fibres used are designated a, i, c, &c. 



This table is abridged from one giving fuller details. The 

 fibres varied greatly in diameter and possibly somewhat in 

 NO. 1648, VOL. 64] 



their viscous properties, but the results are all one way — an 

 increasing yield with increasing temperature and a rate of 

 stretch approximately proportional to the applied force. But 

 this last assertion cannot go without some reservation. At the 

 higher temperatures, the rate of elongation was observed to 

 diminish steadily when the observations were much prolonged. 

 Ultimately the fibre generally breaks. When observed now 

 between crossed nicols the fibre is found to be partially 

 crystallised, the crystallisation extending inwards from the 

 surface. This crystallised layer is sometimes cracked and 

 peeled from the core beneath, the result, probably, of the very 

 great volume-change attendant on crystallisation. The gradual 

 diminution in rate of stretch, and a certain degree of irregularity 

 in the results at higher temperatures, may well be due to this 

 molecular alteration. 



So far as can be inferred from the observations, the results are 

 due to plasticity, complicated at higher temperatures by gradual 

 crystallisation. Nor is there anything, so far as I can gather, in 

 the least opposed to this view contained in Prof. Callendar's in- 

 teresting experiments on the thermal expansion of vitreous 

 quartz. 



It will be seen from the experiments I have quoted that the 

 viscous stretch at the lower temperatures is small in amount. 

 With prolonged use, however, and if any considerable difference 

 between internal and external pressure existed, thermometers 

 would be affected by it sufticiently to necessitate frequent re- 

 adjustment of fixed points. I find, for exainple, as the result of 

 a rough estimation, that with an excess of pressure of one atmo- 

 sphere within, a spherical bulb i cm. in diameter and \ mm. 

 thick in the walls would, at 785° C, increase in volume by 

 0"i per cent, in about 83 hours. At 870° C. this increase will 

 occur in about 40 hours. At 920° C. the same increase in 

 volume would occur in about 8 hours if the contraction due to 

 crystallisation, which the experiments lead us to expect, did not 

 act the other w.ay. The final result, after 8 hours' heating at 

 920" C, would be impossible to predict. 



I have more recently found that vitrified quartz, reduced to 

 powder and exposed over a Bunsen for 35 days in a closed un- 

 glazed porcelain crucible at a temperature just under the meliing- 

 point of gold (1066°) loses its sharp edges, rounding every point 

 and angle, and simultaneously develops incipient crystallisation, 

 which appears in the form of radial spherulitic structures, often 

 with anisotropic centres. J. JOLY. 



Geological labor.atory. Trinity College, Dublin. 



Statistical Investigations on Variability and Heredity. 



Earlier appeals in your columns have met with such 

 friendly response from scattered workers that I venture again 

 to trouble you with an appeal for aid. I have three investiga- 

 tions in progress w'herein help would be very welcome : — 



(i) The measurement of physical and intellectual characters 

 in pairs of brothers or sisters. Upwards of 1400 have now been 

 observed and measured, but I have still not sufficient data. 

 Village schools usually present a great deal of measurable 

 material, but it is difficult to reach their teachers except through 

 individual approach, .-^ny of your readers who can interest 

 their local teachers in observing and measuring pairs of children 

 will do me a great service, and I shall be glad to send papers of 

 instruction and a head-spanner for their use. 



In examining carefully the data from nearly thirty primary 

 schools recently returned to me, I only found two cases in 

 which the teacher had not been fully able to use the spanner to 

 advantage. Of course I shall be equally pleased to send papers 

 and head-spanners to masters or mistresses in secondary schools. 



(2) I shall be glad of any number of orange-tip male butter- 

 flies. They must have been caught wild and not bred, and I 

 should like contributions from as many districts as possible. 

 The specimens need not be very carefully set, and if the upper 

 wings are not badly damaged they will be sure to be of use. 



(3) Clutches of blackbirds' or thrushes' eggs. Each clutch 

 must be kept perfectly separate, and certainly be from one bird. 

 They are better unblown. If blown the hole or holes must not 

 be at the ends. As some of your readers may have clutches 

 they wish to preserve, but would not mind the risk of lending, 

 I will return those so desired. 



Contributions desired under (2) and (3) are for determining 

 the intensity of homotyposis, a factor, I believe, to be at the 

 basis of all hereditary resemblance. Karl Pe.\rson. 



University College, London, W.C., May 25. 



