Jive S, 1883.J 



♦ KNOWLEDGE ♦ 



347 



uhancement of onr race that I think it ought never to be deemed 

 ti>o late while one stays-wearer remain to be benefited by informa- 

 tion upon it. 



When about fifteen years old, the dominant powers encased me 

 in stays. At first I cried much ; then common-sense urged some- 

 thing more executive. Now and again I removed a bone or two, 

 then cut a piece off, gradually lessening the size of the hated 

 encumbrance until it was reduced to a mere belt, and finally I gave 

 that up. 



I need not tell you the inflictions those wretched instruments of 

 torture entailed upon my young supple body, because you had the 

 courage to try them — for which honest confession I feci so pleased 

 with you that, in return, 1 confess, in my case, vanity aided good 

 sense; for always after visiting the statnary in the British Museum, 

 I was exceedingly discontented with the appearance of my own 

 wooden-looking bust. That was thirty-eight years ago, and I have 

 never once since been induced, or derided, into anything even 

 resembling stays. Back-ache, chest-ache, headache, anil indiges- 

 tion in any form, are unkno^^■n to me. When you receive this I 

 shall have entered my fifty-seventh year. Running is an enjoyment 

 I often take, and I can jump, when necessary. 



For twelve years, with the exception of a few months, I rode 

 and drove daily, often five, six, or seven hours in the saddle. If 

 your readers — especially the lady portion — will reflect upon the 

 fact that it was during those years my children were born, and 

 that they are now powerful men, healthy in mind and body, they 

 will understand the thoroughness of the test. Wei-o K.nowledge a 

 medical journal, I could give other proofs, almost too astounding 

 for belief by those who have gone through very different 

 experiences. 



I have watched healthy girls gradually become weak and sickly 

 after commencing stays-wearing. Both publicly and privately I 

 have advocated the adoption of a more healthful mode of dress, 

 and have satisfactory proofs of success mth some, but the infatua- 

 tion for displaced ribs is so strong that yet awhile the generality of 

 women would rather listen to the sophistries of such people as 

 your correspondent "Observer" than to the soundest reason, born 

 of experience. Any one sincerely wishing the progress of humanity 

 cannot look at our beautiful (in face) young girls without a feeling 

 of pain, hobbling along in their compressing boots, squeezed 

 waist, unpleasantly-swelled hips, and crooked shoulders. As years 

 increase, the baleful effect of outraging nature can be sadly seen 

 in their countenances. Long internal suffering of that sort injures 

 the brain; hence the thousands of nothings of both sexes. For 

 those, like myself, earnestly wishing and hoping the rise of woman 

 — which means the rise of all human-kind — it is a most distressing 

 cause for serious thought. 



I cannot doubt your excellent articles upon it will be beneficial 

 to all who really observe, think honestly, and act truthfully. You 

 wield a great and responsible power. May you long continue to do 

 so faithfully and fearlesslv, H. A. Dfciui-K. 



Camberwell {Victoria),'.4|)ri7 11, 1883. 



RATIONAL DEESS. 



[841] — Haring read your various articles on dress reform, I am 

 constrained, in gratitude, to acknowledge the benefits I have received 

 from its adoption ; and I should like, in a few words, to show how 

 easily such reform may be effected. I need only mention that I 

 now wear a flannel combination, aud, in place of the objectionable 

 stays, I have a loose, twilled, calico bodice, which reaches down to 

 my hips, and is set in a band, on which is buttoned tlie divided 

 skirt ; over this is my ordinary dress, having the skirt and jacket- 

 bodice attached. I was led finally to this arrangement from reflect- 

 ing on the more rational character of my husband's attire ; and I 

 may add that the comfort and freedom I now enjoy from my new 

 costume have exceeded my most sanguine expectations. L. M. 



[842] — It may interest you to know that, being inspired by j'our 

 article in Knowlebge, I have left off wearing stays. Since I have 

 done so I have been in better health, I have been able to walk 

 greater distances without fatigne, and my voice for singing has 

 greatly improved, and altogether I have derived immense comfort 

 from the free use of all parts of my body. 



I cannot resist writing to express my gratitude to you for having 

 pointed out one of the greatest errors women are guilty of. I oidy 

 hope that many of my fellow countrywomen may benefit by your 

 advice. 



I may mention that I am eighteen, and have worn corsets 

 (owing to my height) since I was twelve. Since I have left them 

 off I have never missed the support, and would not, on any account, 

 wear them again. ' L. M. G. B. 



A FEW OBSERVATIONS ON HEAT. 

 [843]— In a large number of heat problems we have to multiply 

 specific heat by temperature ; but, so far as I am aware, no attempt 

 has ever been made to explain the nature of the resulting product. 

 Nor is such explanation possible by means of physics alone ; 

 though by the aid of dynamics, it seems to bo remarkably simple. 

 Mass X specific heat x temperature = quantity of heat 



= quantity of motion 

 = momentum 

 = mass X velocity 

 .*. Specific heat x temperature = velocity 

 Which, for simplicity, we may write — 



ht" = V 

 This rcsnit enables us to deduce the formula for specific heat 

 from a purely dynamical theorem ; for in the method by mixture, 

 we have merely to regard the two substances as composed of im- 

 perfectly elastic particles moving with certain velocities, and 

 impinging directly upon one another. Let us consider a single 

 molecule, with mass A, in the one substance, and a single molecule, 

 with mass B, in the other ; and let u ii, be the velocity of A before 

 and after impact, and i^ i', the same with respect to B. 



Then, since action and reaction are equal and opi)osite, 

 total momentum before impact = total momentum after impact 

 i.e., AuiT Bi-i = Au + Bv 

 :. Au-Au, = B,-t-Bv 

 Representing the required specific heat of A by h and its tem- 

 perature by (°. and supposing /ij and t^ to stand in the same capacity 

 for B, and 6 to be the temperature of the mixture, and substituting 

 these values in the above equation, we get 

 Ahir-e) = Bhtid-f) 



■ h = — — ;' which is the formula 



'^^'"-"^ ,. . 



for specific heat. If B bo ice-cold water, then A impinges upon B 



at rest, and r = 0; also 'ii = l, so that 



; iJ9 



A(r-ii) 



It will also be seen that by the same theorem we can easily arrive 

 at the general value for 9 



Aht + Bh,t,.t-. . . S(Aht) 

 Ah -hlJ/i, -i-T". ."s(Xh) 



Many other important results may be deduced without much 

 difficulty ; but, for the present, let us confine ourselves to one in 

 particular. Since .4?i(° = 3/ (momentum), if 3/ and C be constant, 

 hxl/A. Does not this give us the reason why specific heat is in- 

 versely proportional to atomic weight ? Such certainly seems to be 

 the case ; and moreover, this question embodies the results ex- 

 jjerimentally obtained by Regnault and others. But here at once 

 we come to an apparent discrepancy ; for only elementary solids 

 are supposed to follow Dulongand Petit's law, whereas our equation 

 would lead us to expect it to be universal. In the case of gases, 

 however, I think this discrepancy will disappear when we compare 

 them under similar conditions ; and, in order to do so, we must 

 bring to 'our aid another formula, mass = volume x density. The 

 numbers obtained for solids varj", owing to experimental differences, 

 from 57 to 69 ; the following table will show that those for many 

 gases do not show a greater variation. 



w„ Product of 

 Name of Gas. 



r Hydrogen 

 1 Nitrogen 

 Simple gases •; Oxygen 

 I Chlorine 

 [ Bromine 

 Gases formed ( Hydrochloric acid 

 without < Carbon monoside 

 condensation (. Nitrogen dioxide 



f Carbon dioxide 

 Gases formed I Sulphur dioxide 



with < Nitrogen monoxide 

 condensation ( Steam 

 1_ { Water 

 To this list may, I think, be added alcohol, ethyl sulphide, ethyl 

 cyanide, and many other vapours of a more complex constitution ; 

 but I have omitted them, as I am not quite certain of the exact 

 change in volume which takes place in their formation. 



It would be irrational to suppose that the closeness of these 

 figures, not only amongst themselves, but also to those of the 

 elementary solids, is a scries of coincidences ; it follows directly 

 from the equation -4/i('' = J/, and may fairly be claimed as a cor- 

 roboration of that equation. The case of the carbon compounds is 

 especially noteworthy. AlthouL'h their behaviour is perfectly 

 regular, carbon itself is at ordinary temperatures a decided excep- 



